WorldWideScience

Sample records for dworshak dam impacts

  1. Dworshak Dam Impacts Assessment and Fisheries Investigation Project: Kokanee Entrainment Losses at Dworshak Reservoir, 1996 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo A.; Elam, Steve

    1998-10-01

    We used split-beam hydroacoustics to monitor kokanee Oncorhynchus nerka kennerlyi abundance in Dworshak Reservoir from 1995 to 1996 in order to quantify the impacts of water releases from Dworshak Dam. The kokanee population was at a record high level of 1.9 million age-1 and age-2 fish (350 fish/ha) during June 1995. Large discharges of water during July and August of 1995 did not result in major losses of kokanee. Mid-winter flooding in February. March, and April of 1996: however, caused entrainment losses of 90% of all kokanee in the reservoir. The population declined to 140,000 kokanee. High flows during spring runoff used another 50% of the kokanee to be lost, further reducing the population to 71,000 fish (13 fish/ha). Entrainment losses were partially explainable by the distribution of kokanee in the reservoir. During winter, all age-classes of kokanee congregated near the dam making them susceptible to high releases of water. Kokanee appeared to be less susceptible to entrainment during summer and early fall because most kokanee were in other parts of the reservoir: adults were in the upper reservoir staging to spawn, fry were in the upper reservoir having emerged from tributary streams, and juvenile kokanee were spread throughout the reservoir.

  2. Dworshak Dam Impact (Impacts) Assessment and Fishery Investigation.

    Energy Technology Data Exchange (ETDEWEB)

    Mauser, Gregg

    1989-05-01

    Kokanee abundance, estimated from July trawl data, was 1.2 million fish in 1988, including 553,000 fry, 501,000 yearlings and 156,000 subadults. Spawning trend data indicated escapement was up threefold compared to 1987, despite a sport harvest of 207,000 kokanee averaging 258 mm caught at a rate of 1.5 fish per hour. An estimated 40,000 kokanee were counted during the September peak of spawning in five tributaries of the reservoir. Size of adult fish was below average at 293 mm. Zooplankton densities averaged 10.3 organisms/L in 1988 and ranged from 0.3 organisms/L during April at the Little North Fork station to 26.2 organisms/L in November at the Elk Creek station. Densities were similar to values obtained prior to the development of the primary kokanee fishery; however, cladocerans made up only 34.9% of the zooplankton sampled. Daphnia and Cyclops were the most important food items; Daphnia became the prime food organism as its seasonal abundance increased. Concentrations of ortho-phosphate and nitrate, lower than in the 1970s, indicated Dworshak may have become more oligotrophic. 13 refs., 24 figs., 4 tabs.

  3. Dworshak Dam Impact Assessment and Fishery Investigation, 1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Mauser, Gregg; Cannamela, David; Downing, Richard

    1990-06-01

    The Bonneville Power Administration (BPA) funded two 4-year research projects to develop recommendations for improving the sport fishery on Dworshak Reservoir. Research began during 1987 as a cooperative effort between the Idaho Department of Fish and Game (IDFG) and the Nez Perce Tribe of Idaho. The Nez Perce Tribe examined smallmouth bass and rainbow trout fisheries. The IDFG evaluated kokanee population dynamics and documented changes in reservoir productivity. 12 refs., 12 figs.

  4. Dworshak Dam Impact Assessment and Fishery Investigation and Trout, Bass and Forage Species: Combined Project Completion Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo; Statler, David P.; Elam, Steve

    1992-10-01

    The Nez Perce Tribe (NPT) and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative four-year effort to study impacts of Dworshak Dam operation on resident fisheries. The NPT Department of Fisheries Management focused on rainbow trout, smallmouth bass and forage fish. The IDFG's segment of the project was to document kokanee population dynamics, relate it to the changing nutrient status of the reservoir, evaluate kokanee losses through Dworshak Dam, and make kokanee management recommendations. This final report includes findings for 1990 and 1991 and relates these data to information previously presented in annual reports for 1987, 1988 and 1989.

  5. Strobe Light Testing and Kokanee Population Monitoring : Dworshak Dam Impacts Assessment and Fisheries Investigation Project, 87-99 : Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo A.; Harryman, Bill; Ament, Willaim J.

    1999-11-01

    We tested the response of kokanee Oncorhynchus nerka to strobe lights. Testing was conducted on wild, free-ranging fish in their natural environment (i.e., the pelagic region of two large Idaho lakes). Split-beam hydroacoustics were used to record the distance kokanee moved away from the lights, as well as the density of kokanee in the area near the lights. In control tests, where strobe lights were lowered into the lake but kept turned off, kokanee remained within a few meters of the lights. Once the lights began flashing, kokanee quickly moved away from the light source. Kokanee moved 20 to 40 m away from the lights in waters with Secchi transparencies from 3 to 5 m. Kokanee densities near the lights were significantly lower (p=0.07 to p=0.00) when the lights were turned on than in control samples with no lights flashing. Flash rates of 300, 360, and 450 flashes/min elicited strong avoidance responses from the fish. Kokanee remained at least 24 m from the lights during our longest test that lasted for 5 h 50 min. We also continued annual monitoring of the kokanee population in Dworshak Reservoir. Spawner counts in four tributary streams that were used as an index of the adult population reached a record low of 144 spawners. No age-1 or age-2 kokanee were caught in 15 trawl hauls used to make population estimates. The population estimate of fry was 65,000 fish, {+-} 76% (90% C.I.). Flooding during the spring of 1996 was responsible for the low kokanee population.

  6. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1990-07-01

    The Nez Perce Tribe and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative four-year effort to study impacts of Dworshak Dam operation on resident fisheries. This third annual report focuses on rainbow trout, smallmouth bass, and forage species. 22 refs., 19 figs., 11 tabs.

  7. Wildlife Protection, Mitigation, and Enhancement Planning Phase II, Dworshak Reservoir, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, H. Jerome; Martin, Robert C.

    1989-11-01

    The Pacific Northwest Electric Power Planning and Conservation Act of 1980 directed that measures be implemented to protect, mitigate, and enhance fish and wildlife to the extent affected by development and operation of hydropower projects on the Columbia River System. This Act created the Northwest Power Planning Council, which in turn developed the Columbia River Basin Fish and Wildlife Program. This program established a four-part process: wildlife mitigation status reports; wildlife impact assessments; wildlife protection, mitigation, and enhancement plans; and implementation of protection, mitigation, and enhancement projects. This mitigation plan for the Dworshak Reservoir Hydroelectric Facility was developed to fulfill requirements of Sections 1003(b)(2) and (3) of the Columbia River Basin Fish and Wildlife Program. Specific objectives of wildlife protection, mitigation, and enhancement planning for Dworshak Reservoir included: quantify net impacts to target wildlife species affected by hydroelectric development and operation of Dworshak Dam and Reservoir; develop protection, mitigation, and enhancement goals and objectives for the target wildlife species; recommend protection, mitigation, and enhancement actions for the target wildlife species; and coordination of project activities. 46 refs., 4 figs., 31 tabs.

  8. Brazil's Amazonian dams: Ecological and socioeconomic impacts

    Science.gov (United States)

    Fearnside, P. M.

    2016-12-01

    Brazil's 2015-2024 Energy Expansion Plan calls for 11 hydroelectric dams with installed capacity ≥ 30 MW in the country's Amazon region. Dozens of other large dams are planned beyond this time horizon, and dams with consumers. Population displacement is a major impact; for example, the Marabá Dam would displace 40,000 people, mostly traditional riverside dwellers (ribeirinhos). Various dams impact indigenous peoples, such as the Xingu River dams (beginning with Belo Monte) and the São Luiz do Tapajós and Chacorão Dams on the Tapajós River. Brazil has many energy options other than dams. Much energy use has little benefit for the country, such as exporting aluminum. Electric showerheads use 5% of the country's power. Losses in transmission lines (20%) are far above global averages and can be expected to increase as Amazonian hydroelectric dams far from consumer centers come on line. Brazil has tremendous wind and solar potential, but these do not have the same priority as dams. At the root of many questionable policies is a decision-making process in need of reform.

  9. Distributional Impacts of Large Dams in China

    Science.gov (United States)

    Bao, X.

    2010-12-01

    Dams on a river are believed to have heterogeneous impacts to the upstream, local and downstream areas. Generally, irrigation dams will bring benefits to the downstream by facilitating more irrigation, while it will bring negative impacts to upstream due to inundation or no impact to local area as a combination result of population dislocation and economic benefits. This paper checked the impacts of large dams (above 100 meters) on the upstream, downstream and local area, using 2000-2008 county level data in China. Robust heterogeneous impacts of different categories of dams (mainly dams serving for irrigation, hydropower, or other purposes) were found on different areas, using IV regression approaches. Dams higher than 100 meters are significantly and heterogeneously impacting agricultural production, urban employment and rural per capita income. Its beneficial impact on agriculture production is significant for downstream especially in continuous drought years. But its impacts on social welfare indicators, such as primary school enrollment and hospital beds, are not heterogeneously different across regions.

  10. Environmental impacts of increased hydroelectric development at existing dams

    Energy Technology Data Exchange (ETDEWEB)

    Railsback, S. F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cada, G. F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Petrich, C. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sale, M. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shaakir-Ali, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watts, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Webb, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1991-04-01

    This report describes the environmental impacts of a proposed U.S. Department of Energy (DOE) initiative to promote the development of hydropower resources at existing dams. Hydropower development at existing dams has, in general, fewer impacts than development of additional fossil-fueled resources or hydropower at new dams, although potential cumulative impacts of developing multiple hydropower projects have not been explicitly addressed. Environmental review of project impacts and mitigation needs can ensure that additional hydropower development at existing dams can provide a renewable resource with fewer impacts than alternative resources.

  11. Harvesting river water through small dams promote positive environmental impact.

    Science.gov (United States)

    Agoramoorthy, Govindasamy; Chaudhary, Sunita; Chinnasamy, Pennan; Hsu, Minna J

    2016-11-01

    While deliberations relating to negative consequences of large dams on the environment continue to dominate world attention, positive benefits provided by small dams, also known as check dams, go unobserved. Besides, little is known about the potential of check dams in mitigating global warming impacts due to less data availability. Small dams are usually commissioned to private contractors who do not have clear mandate from their employers to post their work online for public scrutiny. As a result, statistics on the design, cost, and materials used to build check dams are not available in public domain. However, this review paper presents data for the first time on the often ignored potential of check dams mitigating climate-induced hydrological threats. We hope that the scientific analysis presented in this paper will promote further research on check dams worldwide to better comprehend their eco-friendly significance serving society.

  12. Minidoka Dam Wildlife Impact Assessment: Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Robert C.; Meuleman, G. Allyn

    1989-03-01

    A wildlife impact assessment has been developed for the US Bureau of Reclamation's Minidoka Dam and Reservoir in south central Idaho. This assessment was conducted to fulfill requirements of the Fish and Wildlife Program. Specific objectives of this study included the following: select target wildlife species, and identify their current status and management goals; estimate the net effects on target wildlife species resulting from hydroelectric development and operation; recommend protection, mitigation, and enhancement goals for target wildlife species affected by hydroelectric development and operation; and consult and coordinate impact assessment activities with the Northwest Power Planning Council, Bonneville Power Administration, US Bureau of Reclamation, Bureau of Land Management, Shoshone-Bannock Tribes, US Fish and Wildlife Service, Pacific Northwest Utilities Conference Committee, and other entities expressing interest in the project. 62 refs., 2 figs., 11 tabs.

  13. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1987 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1988-05-01

    Dworshak Dam and Reservoir is a Corps of Engineers facility located on the North Fork Clearwater River 3.2 km upstream from the Mainstem Clearwater confluence. Since initial filling in 1971, conversion of 87 km of river habitat to a 6644 hectare impoundment has had a profound influence on resident fisheries. The Nez Perce Tribe and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative effort to study these impacts. The kokanee Oncorhynchus nerka assessment is included in the IDFG agreement, and is not addressed in this report. This project pertains primarily to rainbow trout Salmo gairdneri, smallmouth bass (Micropterus dolomieui), and forage species. For the period November 1987 through February 1988, an estimated 4339 angler-hours were expended to catch 430 rainbow trout. An estimated 20 bull trout Salvelinus confluentus, 4 smallmouth bass, and 4 suckers Catostomus spp. were also caught. Catch rates were generally poor through the period, at .091 fish per hour for all species combined (excluding kokanee). Shasta strain hatchery rainbow trout were dominant in the creel, comprising 53.9 percent of the catch, although this strain was last planted in the reservoir in June 1986. Bank anglers caught a higher percentage (93.5 percent) of the total catch of Shasta strain rainbows than Kamloops strain rainbows (33.3 percent). 11 refs., 4 figs., 6 tabs.

  14. Dworshak Reservoir Kokanee Population Monitoring, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo; Stark, Eric

    2003-03-01

    Onsite testing of strobe lights was conducted to determine if they repelled kokanee Oncorhynchus nerka away from the turbine intakes at Dworshak Dam. We tested a set of nine strobe lights flashing at a rate of 360 flashes/min placed near the intake of a 90 mW turbine. A split-beam echo sounder was used to determine the effect of strobe light operation on fish density (thought to be mostly kokanee) in front of the turbine intakes. On five nights between December 2001 and January 2002, fish density averaged 110 fish/ha when no lights were flashing. Mean density dropped to 13 fish/ha when the strobe lights were turned on during five additional nights of sampling. This 88% decline in density was significant at the P = 0.009 level of significance based on a paired Student's t test. There appeared to be no tendency for fish to habituate to the lights during the night. Test results indicate that a single set of nine lights may be sufficient to repel kokanee from a turbine intake during the night. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2001. Estimated abundance of kokanee has continued to increase since the spring of 1996 when high entrainment losses occurred. Based on hydroacoustic surveys, we estimated 3,276,000 kokanee in Dworshak Reservoir in early July 2001. This included 2,069,000 age-0 kokanee (90% CI {+-} 16.4%), 801,000 age-1 kokanee (90% CI {+-} 17.8%), and 406,000 age-2 kokanee (90% CI {+-} 20.5%). Entrainment sampling was also conducted with split-beam hydroacoustics a minimum of one continuous 24 h period per month. The highest entrainment rates occurred at night with lower discharges and shallower intake depths. Fish movement patterns suggested that they swam 'at will' in front of the intakes and may have chosen to move into the turbine intakes. Based on monthly hydroacoustic sampling in the forebay, we found that kokanee density was low in July and August during a period of high

  15. Dworshak Reservoir Kokanee Population Monitoring: Project Progress Report, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo; Vidergar, Dmitri T.; Harryman, Bill

    2001-08-01

    We used split-beam hydroacoustics and trawling to monitor the kokanee Oncorhynchus nerka population in Dworshak Reservoir during 1999. Estimated abundance of kokanee has continued to increase since the high entrainment losses in the spring of 1996. Based on hydroacoustic surveys, we estimated 1,545,000 kokanee and rainbow trout O. mykiss in Dworshak Reservoir during July 1999. This included 1,144,000 age-0 kokanee (90% CI {+-} 42%), 212,000 age-1 kokanee (90% CI {+-} 15%), and 189,000 age-2 kokanee and stocked rainbow trout (90% CI {+-} 39%). Rainbow trout could not be distinguished from the age-2 kokanee in the echograms since they were of similar size. Age-0 kokanee ranged in length from 40 mm to 90 mm, age-1 from 193 mm to 212 mm, and age-2 kokanee from 219 mm to 336 mm. These sizes indicated kokanee are still growing well. Discharge of water from Dworshak Dam during 1999 did not stop the expansion of the kokanee population based on these results. Counts of spawning kokanee in four tributary streams exceeded 11,000 fish. This index also showed a marked increase from last year's 660 spawning kokanee or the 1997 total of 144 spawning kokanee.

  16. Early Limnology of Dworshak Reservoir. Part 1. Limnology. Part 2. Impact of Log Leachates on Phytoplankton. Part 3. Fate of Phytoplankton and Zooplankton Dynamics. Part 4. Bacteriology.

    Science.gov (United States)

    1977-01-01

    Chemistry ....................... 1-55 Phytoplankton.......................1-64 Zooplankton.........................1-74 Regression Analyses...4 when 02 was 0. Hydrogen sulfide was never detected downstream of the dam. Water Chemistry Chemical composition of the North Fork of the Clearwater...growth tissue ( Schaum - burg 1972). Servizi et al. (1971) had similar results when comparing outer bark to actively growing inner bark. The highest

  17. A climate impact of dam lake and Recep Yazicioglu Gokpinar dam lake sample

    Directory of Open Access Journals (Sweden)

    Ülker Güner BACANLI

    2016-06-01

    Full Text Available Dams have both positive and negative effects on the environment. The most important effect can be defined as the regional climate change. In this study, the impact on Denizli city climate of Vali Recep Yazıcıoğlu Gökpınar Dam Lake was determined. In this study, Denizli city meteorological station (maximum, minimum and mean temperatures, total precipitation and wind speed data were used. Before and after from the dam construction; absolute changes are examined. After the dam construction; maximum, minimum and average temperature increase was observed in all months. A rainfall was observed to be increased in January, February and October on after dam construction, but another times was observed to be decreased. The evaporation and wind speed parameter has been little change. Linear regression, the Mann-Kendall and Sen’s Method for trend analysis were used. All techniques considered here consistently reveal that there are upward trend in maximum, minimum and mean temperatures, wind speed, no trend in precipitation and evaporation.

  18. The Aswan Dam: A Lesson on Man's Environmental Impact.

    Science.gov (United States)

    Peterson, Burnell

    This curriculum unit was prepared for senior high classroom use to teach geography, history, and environmental issues. The objective of the lesson is to illustrate the historical man/river relationship between Egypt and the Nile River, and the impact of the Aswan dam on the agricultural and economic needs of the country today. The lesson requires…

  19. Strobe Light Testing and Kokanee Population Monitoring : Dworshak Dam Impacts Assessment and Fisheries Investigation Project, 97-99 : annual Progress Report for 1998.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo A.; Harryman, Bill; Ament, William J.

    1999-12-01

    We tested the response of kokanee Oncorhynchus nerka to strobe lights. Testing was conducted on wild, free-ranging fish in their natural environment (i.e., the pelagic region of two large Idaho lakes). Split-beam hydroacoustics were used to record the distance kokanee moved away from the lights as well as the density of kokanee in the area near the lights. In control tests, where the strobe lights were lowered into the lake but kept turned off, kokanee remained within a few meters of the lights. Once the lights began flashing, kokanee quickly moved away from the light source. Kokanee were found to move an average of 30 to 136 m away from the lights in waters with Secchi transparencies from 2.8 to 17.5 m (p=0.00 to p=0.04). Kokanee densities near the lights were significantly lower (p=0.00 to p=0.07) when the lights were turned on than in control samples with no lights flashing. Flash rates of 300, 360, and 450 flashes/min elicited strong avoidance responses from the fish. Kokanee remained at least 24 m away from the lights during our longest test that lasted for 5 h 50 min. Kokanee appeared to be responding to flashes that were well less than 0.00016 lux above background lighting.

  20. How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation.

    Science.gov (United States)

    Fencl, Jane S; Mather, Martha E; Costigan, Katie H; Daniels, Melinda D

    2015-01-01

    Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0-15.3 km) or 287 wetted widths (136-437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic approach that has been applied to larger dams.

  1. 78 FR 35630 - Martin Dam Hydroelectric Project; Notice of Availability of the Draft Environmental Impact...

    Science.gov (United States)

    2013-06-13

    ... Energy Regulatory Commission Martin Dam Hydroelectric Project; Notice of Availability of the Draft Environmental Impact Statement for the Martin Dam Hydroelectric Project and Intention To Hold Public Meetings In... reviewed the application for license for the Martin Dam Hydroelectric Project (FERC No. 349), located...

  2. Perspectives on the Salience and Magnitude of Dam Impacts for Hydro Development Scenarios in China

    Directory of Open Access Journals (Sweden)

    Desiree Tullos

    2010-06-01

    Survey results indicate differences in the perceived salience and magnitude of impacts across both expert groups and dam scenarios. Furthermore, surveys indicate that stakeholder perceptions changed as the information provided regarding dam impacts became more specific, suggesting that stakeholder evaluation may be influenced by quality of information. Finally, qualitative comments from the survey reflect some of the challenges of interdisciplinary dam assessment, including cross-disciplinary cooperation, data standardisation and weighting, and the distribution and potential mitigation of impacts. Given the complexity of data and perceptions around dam impacts, decision-support tools that integrate the objective magnitude and perceived salience of impacts are required urgently.

  3. Impacts of Climate Change on Stream Temperatures in the Clearwater River, Idaho

    Science.gov (United States)

    Yearsley, J. R.; Chegwidden, O.; Nijssen, B.

    2016-12-01

    Dworshak Dam in northern Idaho impounds the waters of the North Fork of the Clearwater River, creating a reservoir of approximately 4.278 km3 at full pool elevation. The dam's primary purpose is for flood control and hydroelectric power generation. It also provides important water quality benefits by releasing cold water into the Clearwater River during the summer when conditions become critical for migrating endangered species of salmon. Changes in the climate may have an impact on the ability of Dworshak Dam and Reservoir to provide these benefits. To investigate the potential for extreme outcomes that would limit cold water releases from Dworshak Reservoir and compromise the fishery, we implemented a system of hydrologic and water temperature models that simulate daily-averaged water temperatures in both the riverine and reservoir environments. We used the macroscale hydrologic model, VIC, to simulate land surface water and energy fluxes, the one-dimensional, time-dependent stream temperature model, RBM, to simulate river temperatures and a modified version of CEQUAL-W2 to simulate water temperatures in Dworshak Reservoir. A long-term hydrologically based gridded data set of meteorological forcing provided the input for comparing model results with available observations of flow and water temperature. For purposes of investigating the impacts of climate change, we used the results from ten of the most recent Climate Model Intercomparison Project (CMIP5) climate change models scenarios in conjunction with the estimates of anthropogenic inputs of climate change gases from two representative concentration pathways (RCP). We compared the simulated results associated with a range of outcomes at critical river locations from the climate scenarios with existing conditions assuming that the reservoir would be operated under a rule curve based on the average reservoir elevation for the period 2006-2015 rule curve and for power demands represented by that same period.

  4. Wildlife Protection, Mitigation, and Enhancement Planning Phase I, Dworshak Reservoir, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, H. Jerome

    1988-02-01

    Under direction of the Pacific Northwest Electric Power Planning and Conservation Act of 1980, and the subsequent Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program, impacts to wildlife due to the development and operation of the US Army Corps of Engineers Dworshak Project have been examined. Using existing information, it has been determined that the project has resulted in the loss of 15,316 acres of elk habitat, 15,286 acres of white-tailed deer habitat, 16,986 acres of black bear habitat, 14,776 acres of ruffed grouse habitat, 13,616 acres of pileated woodpecker habitat, and 66 acres of yellow warbler habitat (scrub-shrub/red alder). Acreages of mallard, Canada goose, river otter, and beaver habitat could not be determined from existing information. The interagency work group has recommended that a HEP (Habitat Evaluation Procedure) be used to determine changes in the quantity and quality of target species habitat in the study area, due to the development and operation of Dworshak Reservoir. 60 refs., 3 figs., 6 tabs.

  5. IMPACT EVALUATION OF HAIZUKA DAM ON ITS UP STREAM:A CASE STUDY IN HIROSHIMA PREFECTURE, JAPAN

    Institute of Scientific and Technical Information of China (English)

    Forood AZARI DEHKORDI; Nobukazu NAKAGOSHI

    2004-01-01

    Japan ranks fifth in the world for the number of large dams. Environmental impacts of large dams are known, such as enormous losses of water or disruption of fish spawning, however, impacts of the dams on their up streams are functions of topography of the up stream. Haizuka Dam is located in Hiroshima Prefecture, Japan and its implementation will start in 2006. This large dam influences its up stream through dam making activities, which occurs in order and with different spatial presences that were categorized into chronological and spatial impacts. In this case study, spatial impacts were further divided into horizontal and vertical ones. The horizontal impacts were identified as new roads, diversion tunnel, dam lake, and submerged cultivated land, while vertical impacts were recognized as submerged historical monuments, slope protections, dam body, and deforested area in the reservoir. There were convergences of spatial and temporal impacts, however, the extent of the impacts was limited to the lake boundary.

  6. Examining the economic impacts of hydropower dams on property values using GIS.

    Science.gov (United States)

    Bohlen, Curtis; Lewis, Lynne Y

    2009-07-01

    While the era of dam building is largely over in the United States, globally dams are still being proposed and constructed. The articles in this special issue consider many aspects and impacts of dams around the world. This paper examines dam removal and the measurement of the impacts of dams on local community property values. Valuable lessons may be found. In the United States, hundreds of small hydropower dams will come up for relicensing in the coming decade. Whether or not the licenses are renewed and what happens to the dams if the licenses expires is a subject of great debate. Dams are beginning to be removed for river restoration and fisheries restoration and these "end-of-life" decisions may offer lessons for countries proposing or currently building small (and large) hydropower dams. What can these restoration stories tell us? In this paper, we examine the effects of dams along the Penobscot River in Maine (USA) on residential property values. We compare the results to findings from a similar (but ex post dam removal) data set for properties along the Kennebec river in Maine, where the Edwards Dam was removed in 1999. The Penobscot River Restoration Project, an ambitious basin-wide restoration effort, includes plans to remove two dams and decommission a third along the Penobscot River. Dam removal has significant effects on the local environment, and it is reasonable to anticipate that environmental changes will themselves be reflected in changes in property values. Here we examine historical real estate transaction data to examine whether landowners pay a premium or penalty to live near the Penobscot River or near a hydropower generating dam. We find that waterfront landowners on the Penobscot or other water bodies in our study area pay approximately a 16% premium for the privilege of living on the water. Nevertheless, landowners pay LESS to live near the Penobscot River than they do to live further away, contrary to the expectation that bodies of water

  7. Using causal maps to support ex-post assessment of social impacts of dams

    Energy Technology Data Exchange (ETDEWEB)

    Aledo, Antonio, E-mail: Antonio.Aledo@ua.es [Departamento de Sociología 1, Universidad de Alicante, Alicante 03080 (Spain); García-Andreu, Hugo, E-mail: Hugo.Andreu@ua.es [Departamento de Sociología 1, Universidad de Alicante, Alicante 03080 (Spain); Pinese, José, E-mail: pinese@uel.br [Centro de Ciências Exatas, UEL, Rodovia Celso Cid, Km 380, Campus Universitário, Londrina, PR 86057-970 (Brazil)

    2015-11-15

    - Highlights: • We defend the usefulness of causal maps (CM) for ex-post impact assessment of dams. • Political decisions are presented as unavoidable technical measures. • CM enable the identification of multiple causes involved in the dam impacts. • An alternative management of the dams is shown from the precise tracking of the causes. • Participatory CM better the quality of information and the governance of the research. This paper presents the results of an ex-post assessment of two important dams in Brazil. The study follows the principles of Social Impact Management, which offer a suitable framework for analyzing the complex social transformations triggered by hydroelectric dams. In the implementation of this approach, participative causal maps were used to identify the ex-post social impacts of the Porto Primavera and Rosana dams on the community of Porto Rico, located along the High Paraná River. We found that in the operation of dams there are intermediate causes of a political nature, stemming from decisions based on values and interests not determined by neutral, exclusively technical reasons; and this insight opens up an area of action for managing the negative impacts of dams.

  8. Impact of dams on flood occurrence of selected rivers in the United States

    Science.gov (United States)

    Mei, Xuefei; Van Gelder, P. H. A. J. M.; Dai, Zhijun; Tang, Zhenghong

    2016-10-01

    A significant large number of dams have been constructed in the past two centuries in the United States. These dams' ability to regulate downstream flooding has received world-wide attention. In this study, data from 38 rivers distributed over the entire conterminous Untied States with extensive pre- and post-dam annual peak discharge records, were collected to research the impacts of various dams on the flood behaviors at a national scale. The results indicate that dams have led to significant reductions in flood magnitude for nearly all of the sites; the decrease rate in the mean of annual peak discharge varies between 7.4% and 95.14%, except for the Dead River, which increased by 1.46%. Because of dams' effectiveness, the probability density curve of annual peak flow changes from a flat to peaked shape because both the range and magnitude of high discharges are decreased. Moreover, the potential impact of dams on flood characteristics were closely related to the dam's geographic location and function, the ratio of the storage capacity of the dam to the mean annual runoff of the river (C/R), and the ratio of reservoir storage capacity to the area of its drainage (C/D). Specifically, the effects of dams on annual peak flows were more related to latitude than longitude. Compared with dams built for other purposes, the dam exclusively used for flood management cut off more flood peaks. Increases in the ratios of C/R and C/D increased the degree of modification of annual maximum discharge.

  9. Large dams and alluvial rivers in the Anthropocene: The impacts of the Garrison and Oahe Dams on the Upper Missouri River

    Science.gov (United States)

    Skalak, Katherine; Benthem, Adam J.; Schenk, Edward R.; Hupp, Cliff R.; Galloway, Joel M.; Nustad, Rochelle A.; Wiche, Gregg J.

    2013-01-01

    The Missouri River has had a long history of anthropogenic modification with considerable impacts on river and riparian ecology, form, and function. During the 20th century, several large dam-building efforts in the basin served the needs for irrigation, flood control, navigation, and the generation of hydroelectric power. The managed flow provided a range of uses, including recreation, fisheries, and habitat. Fifteen dams impound the main stem of the river, with hundreds more on tributaries. Though the effects of dams and reservoirs are well-documented, their impacts have been studied individually, with relatively little attention paid to their interaction along a river corridor. We examine the morphological and sedimentological changes in the Upper Missouri River between the Garrison Dam in ND (operational in 1953) and Oahe Dam in SD (operational in 1959). Through historical aerial photography, stream gage data, and cross sectional surveys, we demonstrate that the influence of the upstream dam is still a major control of river dynamics when the backwater effects of the downstream reservoir begin. In the “Anthropocene”, dams are ubiquitous on large rivers and often occur in series, similar to the Garrison Dam Segment. We propose a conceptual model of how interacting dams might affect river geomorphology, resulting in distinct and recognizable morphologic sequences that we term “Inter-Dam sequence” characteristic of major rivers in the US.

  10. Impact of Dams on Riparian Frog Communities in the Southern Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Rohit Naniwadekar

    2014-08-01

    Full Text Available The Western Ghats is a global biodiversity hotspot and home to diverse and unique assemblages of amphibians. Several rivers originate from these mountains and hydropower is being tapped from them. The impacts of hydrological regulation of riparian ecosystems to wildlife and its habitat are poorly documented, and in particular the fate of frog populations is unknown. We examined the effects of dams on riparian frog communities in the Thamirabarani catchment in southern Western Ghats. We used nocturnal visual encounter surveys constrained for time, to document the species richness of frogs below and above the dam, and also at control sites in the same catchment. While we did not find differences in species richness below and above the dams, the frog community composition was significantly altered as a likely consequence of altered flow regime. The frog species compositions in control sites were similar to above-dam sites. Below-dam sites had a distinctly different species composition. Select endemic frog species appeared to be adversely impacted due to the dams. Below-dam sites had a greater proportion of generalist and widely distributed species. Dams in the Western Ghats appeared to adversely impact population of endemic species, particularly those belonging to the genus Nyctibatrachus that shows specialization for intact streams.

  11. Undamming rivers: a review of the ecological impacts of dam removal.

    Science.gov (United States)

    Bednarek, A T

    2001-06-01

    Dam removal continues to garner attention as a potential river restoration tool. The increasing possibility of dam removal through the FERC relicensing process, as well as through federal and state agency actions, makes a critical examination of the ecological benefits and costs essential. This paper reviews the possible ecological impacts of dam removal using various case studies. Restoration of an unregulated flow regime has resulted in increased biotic diversity through the enhancement of preferred spawning grounds or other habitat. By returning riverine conditions and sediment transport to formerly impounded areas, riffle/pool sequences, gravel, and cobble have reappeared, along with increases in biotic diversity. Fish passage has been another benefit of dam removal. However, the disappearance of the reservoir may also affect certain publicly desirable fisheries. Short-term ecological impacts of dam removal include an increased sediment load that may cause suffocation and abrasion to various biota and habitats. However, several recorded dam removals have suggested that the increased sediment load caused by removal should be a short-term effect. Pre-removal studies for contaminated sediment may be effective at controlling toxic release problems. Although monitoring and dam removal studies are limited, a continued examination of the possible ecological impacts is important for quantifying the resistance and resilience of aquatic ecosystems. Dam removal, although controversial, is an important alternative for river restoration.

  12. Study of the Environmental Impact of Constructing Dams on the Environment

    Directory of Open Access Journals (Sweden)

    Somayeh Babazadeh

    2016-06-01

    Full Text Available Undoubtedly, water is considered as one of the pivotal and fundamental bases for the development of communities in different countries. The development of water resources by constructing big and small dams in accordance with their situation and circumstances has been caused enormous environmental changes. Mutual impacts of dams on the environment can be assessed at two aspects of positive and negative effects. The dam as a barrier on the river creates different physical and chemical features in the place, shoal and mirage of the dam. despite various advantages which this function has had on the limitation of exploitation, such as decreasing the abundance and intensity of floodwaters and the accessibility to water in arid or drought years, but constructing such structures can strike the balance of natural systems and it would leave many short term and long term environmental impacts on that region or other regions which are affected by constructing dams. These impacts may have some influence on the condition and behavior of aerology, biology and hygienic, culture, monuments etc. and seriously will cause to change it . As a result, regarding the importance of positive effects of constructing dams, in order to stable development their negative environmental impacts should be minimized. In the present paper, the environmental impact of constructing dams on the environment has been assessed from different aspects .

  13. Dworshak Kokanee Population and Engrainment Assessment : 2006 Annual Report, March 1, 2006 - February 28, 2007.

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Eric J.

    2008-12-18

    During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. Strobe light tests were conducted on four nights from April 24-27, 2006, in front of the middle reservoir outlet (RO) 2. The density and distribution of fish, (thought to be mostly kokanee), were monitored with a split-beam echo sounder. We then compared fish counts and densities during nights when the lights were flashing to counts and densities during adjacent nights without the lights on. On two nights, April 25 and 27, 2006, when no lights were present, fish counts near RO 2 averaged 12.4 fish and densities averaged 31.0 fish/ha. When strobe lights were turned on during the nights of April 24 and 26, mean counts dropped to 4.7 fish and densities dropped to 0.5 fish/ha. The decline in counts (62%) and densities (99%) was statistically significant (p = 0.009 and 0.002, respectively). Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of a discharging reservoir outlet, which would be sufficient to improve sport fish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2006. Estimated abundance of kokanee increased from the 2005 population estimate. Based on hydroacoustic surveys, we estimated approximately 5,815,000 kokanee (90% CI {+-} 27.6%) in Dworshak Reservoir in August 2006. This included 2,183,000 age-0 (90% CI {+-} 24.2%), 1,509,000 age-1 (90% CI {+-} 29.0%), and 2,124,000 age-2 (90% CI {+-} 27.6%) kokanee. This resulted in a density of age-2 kokanee above the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site, split-beam hydroacoustics from May through September for a continuous 24 h period when dam operations permitted. The highest fish detection rates from entrainment assessments were found during dawn periods, unlike previous year's results

  14. Dworshak Kokanee Population and Entrainment Assessment 2005-2006 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Eric J. [Idaho Department of Fish and Game

    2008-11-06

    During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. We tested one set of nine strobe lights flashing at a rate of 360 flashes/min in front of turbine 3 while operating at higher discharges than previously tested. The density and distribution of fish, (thought to be mostly kokanee), were monitored with a split-beam echo sounder. We then compared fish counts and densities during nights when the lights were flashing to counts and densities during adjacent nights without the lights on. On five nights between January 31 and February 28, 2006, when no lights were present, fish counts near turbine 3 averaged eight fish and densities averaged 91 fish/ha. When strobe lights were turned on during five adjacent nights during the same period, mean counts dropped to four fish and densities dropped to 35 fish/ha. The decline in counts (49%) was not statistically significant (p = 0.182), but decline in densities (62%) was significant (p = 0.049). There appeared to be no tendency for fish to habituate to the lights during the night. Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of turbines operating at higher discharges, which would be sufficient to improve sportfish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2005. Estimated abundance of kokanee decreased from the 2004 population estimate. Based on hydroacoustic surveys, we estimated 3,011,626 kokanee (90% CI {+-} 15.2%) in Dworshak Reservoir, July 2005. This included 2,135,986 age-0 (90% CI {+-} 15.9%), 769,175 age-1 (90% CI {+-} 16.0%), and 107,465 age-2 (90% CI {+-} 15.2%). Poor survival of kokanee from age-1 to age-2 continued to keep age-2 densities below the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site split-beam hydroacoustics a minimum of two days

  15. Impact of Landslide Dams on River Profile Evolution

    Science.gov (United States)

    Safran, E. B.; Peden, D.; Harrity, K.; Anderson, S. W.; O'Connor, J. E.; Wallick, R.; House, P. K.; Ely, L.

    2008-12-01

    slow base level fall have little impact on long-term profile evolution. We conclude that the morphologic signature of landslide dams is context-dependent but can be significant; correct genetic interpretation of longitudinal profile morphology may hinge on recognizing such effects.

  16. 78 FR 43868 - Notice of Intent To Prepare a Draft Environmental Impact Statement for the Whittier Narrows Dam...

    Science.gov (United States)

    2013-07-22

    ... Statement for the Whittier Narrows Dam Safety Modification Study Report AGENCY: Department of the Army, U.S... Environmental Impact Statement (EIS) for the Whittier Narrows Dam Safety Modification Study (DSMS). Whittier Narrows Dam is located approximately 12 miles east of downtown Los Angeles, Los Angeles County, CA....

  17. Modelling the impact of dam removal on geomorphic channel response and sediment delivery: an Austrian case study

    NARCIS (Netherlands)

    Poppl, R.; Coulthard, T.; Keesstra, S.D.; Keiler, M.

    2015-01-01

    Dams are often considered to have the most significant impact on rivers as dam construction generally reduces
    downstream sediment fluxes which further involves geomorphic changes in the affected river reaches. Since many
    dams no longer fulfill their intended purpose (e.g. due to siltation),

  18. Using hydraulic modeling to address social impacts of small dam removals in southern New Jersey.

    Science.gov (United States)

    Wyrick, Joshua R; Rischman, Brian A; Burke, Christopher A; McGee, Craig; Williams, Chasity

    2009-07-01

    Small relic mill dams are common in the watersheds of southern New Jersey, dotting the landscape with many small neighborhood lakes. Originally built in the late 1800s, most of these dams have become increasingly unable to handle current design storms due to increased urbanization of the watersheds. Several of these dams have also been classified as "high hazard" by the New Jersey Department of Environmental Protection Dam Safety Division because their failure has the potential for loss of life or extensive property damage. The current private owners are generally unable to afford the high repair costs needed to rehabilitate the dams to current safety standards, and are therefore more inclined to remove them. This research analyses both the physical and social impacts of the removal of two small dams in southern New Jersey, and integrates the two seemingly disparate concepts. Using hydraulic modeling and previous case studies, it is predicted that there will be limited effects to the hydrological and biological characteristics of the stream corridor. A survey distributed to the affected homeowners that live on these lakes shows that the community, however, expects significant impacts to the bio-physical characteristics of the stream corridor, as well financial impacts to their property value and social impacts to their recreational activities. The current study exposes the widening gap between policy makers and landowners, and highlights where complete stakeholder interaction could and should occur.

  19. Historic human impact on low order mountain streams - what role did the dams play?

    Science.gov (United States)

    Larsen, Annegret; Fuelling, Alexander; Wilder, Nicole; Bork, Hans-Rudolf; Larsen, Joshua R.

    2014-05-01

    The historic damming of central European rivers is extensive, with the highest density concentrated on low-order streams. Construction of dams started mostly in medieval times (~ 1200 years ago) and peaked in the early nineteenth century, resulting in shifting dam densities with different ages and types. Early dams were mainly build for energy , but later their primary purpose shifted to floodplain irrigation . This legacy highlights the intense alteration of small streams by humans in a short time period relative to their Holocene evolution. However, our understanding of the impact of such high number of dams on the ecology, river morphology and sediment storage over longer time periods remains very limited. This knowledge gap becomes critical to address as dam removal and river restoration expands under the implementation of the Water Framework Directive, a European-wide legislative framework. In order to explore the possible effects of this framework on small order streams, we examine the changes that have occurred to a fluvial system since the onset of historic dam building. We combine the analysis of historic maps, chrono-stratigraphy and hydraulic modeling to understand the influence of the large number of dams along the low-order streams in two representative mountain catchments of 3rd and 4th order streams (Elsava and Sinn river in the Spessart and Rhön mountains, Germany). The datings and stratigraphical analysis indicate that the rivers were likely influenced by valley bottom damming before hillslope agriculture caused erosion and an increase of sediment delivery to the streams. Future work will examine the hydraulic behavior of the streams with and without dams in order to better understand their role in floodplain development.

  20. Marib Dam: the importance of environmental and health impact studies for development projects.

    Science.gov (United States)

    Basahi, I A

    2000-01-01

    Marib Dam was built without an environmental impact assessment study which created many conflicts. In 1995 and 1996 its impact on water quality, agriculture and groundwater recharge and socioeconomics was studied. Lake water could suffer severe eutrophication when floods are weak and algae growth is not controlled. Introducing Tilapia nilotica provided biological control of algae growth. The dam positively affected agriculture and groundwater within the designed irrigation scheme but negatively affected them beyond it. The dam also negatively affected health conditions and increased conflicts over water distribution. It positively affected women by allowing them to work in agriculture and participate in decision-making. The dam raised income levels of farmers and encouraged tourism.

  1. Impacts of Dams and Global Warming on Fish Biodiversity in the Indo-Burma Hotspot.

    Science.gov (United States)

    Kano, Yuichi; Dudgeon, David; Nam, So; Samejima, Hiromitsu; Watanabe, Katsutoshi; Grudpan, Chaiwut; Grudpan, Jarungjit; Magtoon, Wichan; Musikasinthorn, Prachya; Nguyen, Phuong Thanh; Praxaysonbath, Bounthob; Sato, Tomoyuki; Shibukawa, Koichi; Shimatani, Yukihiro; Suvarnaraksha, Apinun; Tanaka, Wataru; Thach, Phanara; Tran, Dac Dinh; Yamashita, Tomomi; Utsugi, Kenzo

    2016-01-01

    Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, and the proportion of threatened species as generating capacity increased. Projections from 126 global-warming scenarios included a rise in species richness, a reduction in habitable area, and an increase in the proportion of threatened species; however, there was substantial variation in the extent of these changes among warming projections. Projections from scenarios that combined the effects of dams and global warming were derived either by simply adding the two threats, or by combining them in a synergistic manner that took account of the likelihood that habitat shifts under global warming would be constrained by river fragmentation. Impacts on fish diversity under the synergistic projections were 10-20% higher than those attributable to additive scenarios, and were exacerbated as generating capacity increased-particularly if CO2 emissions remained high. The impacts of dams, especially those on river mainstreams, are likely to be greater, more predictable and more immediately pressing for

  2. Impacts of Dams and Global Warming on Fish Biodiversity in the Indo-Burma Hotspot

    Science.gov (United States)

    Nam, So; Samejima, Hiromitsu; Watanabe, Katsutoshi; Grudpan, Chaiwut; Grudpan, Jarungjit; Magtoon, Wichan; Musikasinthorn, Prachya; Nguyen, Phuong Thanh; Praxaysonbath, Bounthob; Sato, Tomoyuki; Shimatani, Yukihiro; Suvarnaraksha, Apinun; Tanaka, Wataru; Thach, Phanara; Tran, Dac Dinh; Yamashita, Tomomi

    2016-01-01

    Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world’s largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, and the proportion of threatened species as generating capacity increased. Projections from 126 global-warming scenarios included a rise in species richness, a reduction in habitable area, and an increase in the proportion of threatened species; however, there was substantial variation in the extent of these changes among warming projections. Projections from scenarios that combined the effects of dams and global warming were derived either by simply adding the two threats, or by combining them in a synergistic manner that took account of the likelihood that habitat shifts under global warming would be constrained by river fragmentation. Impacts on fish diversity under the synergistic projections were 10–20% higher than those attributable to additive scenarios, and were exacerbated as generating capacity increased—particularly if CO2 emissions remained high. The impacts of dams, especially those on river mainstreams, are likely to be greater, more predictable and more immediately

  3. The potential impact of new Andean dams on Amazon fluvial ecosystems.

    Science.gov (United States)

    Forsberg, Bruce R; Melack, John M; Dunne, Thomas; Barthem, Ronaldo B; Goulding, Michael; Paiva, Rodrigo C D; Sorribas, Mino V; Silva, Urbano L; Weisser, Sabine

    2017-01-01

    Increased energy demand has led to plans for building many new dams in the western Amazon, mostly in the Andean region. Historical data and mechanistic scenarios are used to examine potential impacts above and below six of the largest dams planned for the region, including reductions in downstream sediment and nutrient supplies, changes in downstream flood pulse, changes in upstream and downstream fish yields, reservoir siltation, greenhouse gas emissions and mercury contamination. Together, these six dams are predicted to reduce the supply of sediments, phosphorus and nitrogen from the Andean region by 69, 67 and 57% and to the entire Amazon basin by 64, 51 and 23%, respectively. These large reductions in sediment and nutrient supplies will have major impacts on channel geomorphology, floodplain fertility and aquatic productivity. These effects will be greatest near the dams and extend to the lowland floodplains. Attenuation of the downstream flood pulse is expected to alter the survival, phenology and growth of floodplain vegetation and reduce fish yields below the dams. Reservoir filling times due to siltation are predicted to vary from 106-6240 years, affecting the storage performance of some dams. Total CO2 equivalent carbon emission from 4 Andean dams was expected to average 10 Tg y-1 during the first 30 years of operation, resulting in a MegaWatt weighted Carbon Emission Factor of 0.139 tons C MWhr-1. Mercury contamination in fish and local human populations is expected to increase both above and below the dams creating significant health risks. Reservoir fish yields will compensate some downstream losses, but increased mercury contamination could offset these benefits.

  4. Impact of groundwater pumping vs. a large upstream dam on streamflows and temperature under varying climate

    Science.gov (United States)

    Risley, J. C.; Constantz, J. E.; Essaid, H.; Rounds, S. A.

    2009-12-01

    The relative impact of in-reach groundwater pumping versus a large upstream dam on streamflows and stream temperature was analyzed for humid, semiarid, and arid conditions with long dry seasons representing typical climate conditions where large dams are present, such as the western US or eastern Australia. A MODFLOW-2000 model, with the SFR1 stream-aquifer interaction module, the streamflow-routing package, and the grid-block rewetting option, was constructed to simulate monthly streamflows for 12 watershed scenarios described below. For each scenario streamflow output became input into a stream temperature simulation model. Stream temperatures were simulated using the CE-QUAL-W2 water quality model over a 110 km model grid, with the presence/absence of a dam at the top of the reach and pumping in the lower 60 km of the reach. Measured meteorological data from three representative locations in Oregon and California were used as model input to simulate the impact of varying climate conditions on streamflows and stream temperature. For each climate condition four hypothetical watershed scenarios were modeled: (1) natural [no dam or pumping], (2) large upstream dam present, (3) dam with in-reach pumping, and (4) no dam with pumping continued, resulting in 12 cases. Dam removal, in the presence or absence of pumping, created significant changes in streamflow resulting in significant changes in stream temperature throughout the year for all three climate conditions. From March to August, the presence of a dam caused monthly-mean stream temperatures to decrease on average by approximately 3.0, 2.5, and 2.0 oC for the humid, semiarid, and arid conditions, respectively; however, stream temperatures generally increased from September to February. Pumping caused stream temperatures to warm in summer and cool in winter by generally less than 0.5 oC. Though the impact of a large dam led to greater changes in stream temperature than the impact of pumping, ephemeral conditions

  5. The Influence of an EPS Concrete Buffer Layer Thickness on Debris Dams Impacted by Massive Stones in the Debris Flow

    Directory of Open Access Journals (Sweden)

    Xianbin Yu

    2015-01-01

    Full Text Available The failure of debris dams impacted by the massive stones in a debris flow represents a difficult design problem. Reasonable materials selection and structural design can effectively improve the resistance impact performance of debris dams. Based on the cushioning properties of expanded polystyrene (EPS concrete, EPS concrete as a buffer layer poured on the surface of a rigid debris dam was proposed. A three-dimensional numerical calculation model of an EPS concrete buffer layer/rigid debris dam was established. The single-factor theory revealed change rules for the thickness of the buffer layer concerning the maximal impact force of the rigid debris dam surface through numerical simulation. Moreover, the impact force-time/history curves under different calculation conditions for the rigid debris dam surface were compared. Simulation results showed that the EPS concrete buffer layer can not only effectively extend the impact time of massive stones affecting the debris dam but also reduce the impact force of the rigid debris dam caused by massive stones in the debris flow. The research results provide theoretical guidance for transferring the energy of the massive stone impact, creating a structural design and optimizing debris dams.

  6. DAM IMPACTS ON AND RESTORATION OF AN ALLUVIAL RIVER - RIO GRANDE, NEW MEXICO

    Institute of Scientific and Technical Information of China (English)

    Gigi RICHARD; Pierre JULIEN

    2003-01-01

    The impact of construction of dams and reservoirs on alluvial rivers extends both upstream and downstream of the dam. Downstream of dams, both the water and sediment supplies can be altered leading to adjustments in the river channel geometry and ensuing changes in riparian and aquatic habitats.The wealth of pre and post-regulation data on the Middle Rio Grande, New Mexico, provides an excellent case study of river regulation, channel adjustments, and restoration efforts. Cochiti Dam was constructed on the main stem of the Rio Grande in 1973 for flood control and sediment retention. Prior to dam construction, the Rio Grande was a wide, sandy braided river. Following dam construction, the downstream channel bed degraded and coarsened to gravel size, and the planform shifted to a more meandering pattern. Ecological implications of the geomorphic changes include detachment of the river from the floodplain, reduced recruitment of riparian cottonwoods, encroachment of non-native saltcedar and Russian olive into the floodplain, and degraded aquatic habitat for the Rio Grande silvery minnow.Recent restoration strategies include removal of non-native riparian vegetation, mechanical lowering of floodplain areas, and channel widening.

  7. Damming the Brahmaputra: Impacts on the Resilience of Local Communities to Floods and Climate Change

    Science.gov (United States)

    Rampini, C.

    2016-12-01

    Recurrent destructive floods along the Brahmaputra river basin are a major challenge for the people and state governments of Northeast India. Climate change is expected to further exacerbate this challenge, as melting Himalayan glaciers and changes in the South Asian monsoon lead to an increase in the frequency of severe floods. At the same time, the Brahmaputra has become the focus of India's hydropower development efforts, with 140 new dams planned along its main stem and tributaries. Though these dams could provide flood protection for downstream communities, political and economic factors have led dam builders to prioritize hydroelectricity generation over flood control. Using the Ranganadi Hydroelectric Project in Arunachal Pradesh as a case study, this research investigates the effects of dam building on the resilience of downstream communities to floods that are becoming increasingly severe as a result of climate change. Findings suggest that dams in Northeast are eroding downstream communities' resilience to floods by increasing their vulnerability and reducing their adaptive capacity to these natural hazards. The risk is that, as dams and climate change jointly make the floodplains of Northeast India increasingly hazardous, uninhabitable and unproductive, they will push local communities away from these landscapes and agricultural livelihoods and towards more carbon-intensive livelihoods. More broadly this research highlights the danger of pursuing climate change mitigation and renewable energy development projects without considering their impacts on the vulnerability and adaptability of affected communities to climate change.

  8. Cleaning up the big muddy: A meta-synthesis of the research on the social impact of dams

    NARCIS (Netherlands)

    Kirchherr, Julian; Pohlner, Huw; Charles, Katrina J.

    Scholars have been exploring the social impacts of dams for over 50 years, but a lack of systematic approaches has resulted in many research gaps remaining. This paper presents the first systematic review of the literature on the social impacts of dams. For this purpose, we built a sample of 217

  9. Using Choice Experiments to Assess Environmental Impacts of Dams in Portugal

    Directory of Open Access Journals (Sweden)

    Anabela Botelho

    2015-08-01

    Full Text Available Despite their well-known benefits in electricity production, dams are also responsible for some adverse environmental impacts affecting particularly the wellbeing of residents of the local communities. These environmental damages have not been included in the cost-benefit analysis of hydropower developments mainly because of the difficulty to determine their value. The prime objective of this paper is to measure the economic values of several environmental impacts due to the dams' activity in Portugal, using a discrete choice experiments approach. With the results of this research paper, we expect to contribute to a more efficient and thorough cost-benefit analysis within the complex process of deciding the optimal location of future dams to be built not only in Portugal, but elsewhere. The addition of this stage to the decision-making process allows the integration of economic, social and environmental dimensions, promoting a richer and more informed decision process.

  10. Impacts of beaver dams on hydrologic and temperature regimes in a mountain stream

    Directory of Open Access Journals (Sweden)

    M. Majerova

    2015-01-01

    Full Text Available Beaver dams affect hydrologic processes, channel complexity, and stream temperature by increasing inundated areas and influencing groundwater-surface water interactions. We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a three-year period spanning pre- and post-beaver colonization. Using continuous stream discharge, stream temperature, synoptic tracer experiments, and groundwater elevation measurements we documented pre-beaver conditions in the first year of the study. In the second year, we captured the initial effects of three beaver dams, while the third year included the effects of ten dams. After beaver colonization, reach scale discharge observations showed a shift from slightly losing to gaining. However, at the smaller sub-reach scale, the discharge gains and losses increased in variability due to more complex flow pathways with beaver dams forcing overland flow and increasing surface and subsurface storage. At the reach scale, temperatures were found to increase by 0.38 °C (3.8%, which in part is explained by a 230% increase in mean reach residence time. At the smallest, beaver dam scale, there were notable increases in the thermal heterogeneity where warmer and cooler niches were created. Through the quantification of hydrologic and thermal changes at different spatial and temporal scales, we document increased variability during post-beaver colonization and highlight the need to understand the impacts of beaver dams on stream ecosystems and their potential role in stream restoration.

  11. The impact of damming on riverine fluxes to the ocean: A case study from Eastern Iceland.

    Science.gov (United States)

    Eiriksdottir, Eydis Salome; Oelkers, Eric H; Hardardottir, Jorunn; Gislason, Sigurdur Reynir

    2017-04-15

    Anthropogenic water management has extensively altered the world's river systems through impoundments and channel diversions to meet the human's need for water, energy and transportation. To illuminate the effect of such activities on the environment, this study describes the impact of the installation of the Kárahnjúkar Dam in Eastern Iceland on the transport of riverine dissolved- and particulate material to the ocean by the Jökulsá á Dal and the Lagarfljót rivers. This dam, completed in 2007, collects water into the 2.2 km(3) Hálslón reservoir and diverts water from the glacial Jökulsá á Dal river into the partially glaciated Lagarfljót lagoon via a headrace tunnel. The impact of the damming was evaluated by sampling water from both the Jökulsá á Dal and the Lagarfljót rivers over a 15 year period spanning from 1998 to 2013. The annual flux of most dissolved elements increased substantially due to the damming. The fluxes of dissolved Zn, Al, Co, Ti and Fe increased most by damming; these fluxes increased by 46-391%. These differences can be attributed to changed saturation states of common secondary minerals in the Jökulsá á Dal due to reduced discharge, increased residence time and dissolution of suspended material, and, to a lesser degree, reduced photosynthesis due to less transparency in the Lagarfljót lagoon. The removal of particulate material and thus decreasing adsorption potential in the Jökulsá á Dal is the likely reason for the Fe flux increase. In contrast, approximately 85% of the original riverine transported mass of particulate material is trapped by the dam; that which passes tends to be relatively fine grained, increasing the average specific surface area of that which continues to flow towards the ocean. Consequently, the particulate geometric surface area flux is decreased by only 50% due to the damming. The blooming of silica diatoms during the spring consumes dissolved silica from the coastal waters until it becomes

  12. Comprehensive assessment of dam impacts on flow regimes with consideration of interannual variations

    Science.gov (United States)

    Zhang, Yongyong; Shao, Quanxi; Zhao, Tongtiegang

    2017-09-01

    Assessing the impact of human intervention on flow regimes is important in policy making and resource management. Previous impact assessments of dam regulation on flow regimes have focused on long-term average patterns, but interannual variations, which are important characteristics to be considered, have been ignored. In this study, the entire signatures of hydrograph variations of Miyun Reservoir in northern China were described by forty flow regime metrics that incorporate magnitude, variability and frequency, duration, timing, and rate of change for flow events based on a long-term synchronous observation series of inflow and outflow. Principal component analysis and cluster analysis were used to reduce the multidimensionality of the metrics and time and to determine impact patterns and their interannual shifts. Statistically significant driving factors of impact pattern variations were identified. We found that dam regulation resulted in four main impact classes on the flow regimes and that the regulated capacity was interannually attenuated from 1973 to 2010. The impact patterns alternated between the highly regulated class with extremely decreasing flow magnitude, slight variability, and extreme intermittency and the slightly regulated class with extremely increasing flow magnitude, slight variability, and extreme intermittency from 1973 to 1987 and then stabilized in the latter class from 1988 to 2001. After 2001, the pattern gradually changed from the moderately regulated class with moderately decreasing flow magnitude, extreme variability, and extreme intermittency to the slightly regulated class with slightly decreasing flow magnitude, slight variability, and no intermittency. Decreasing precipitation and increasing drought were the primary drivers for the interannual variations of the impact patterns, and inflow variability was the most significant factor affecting the patterns, followed by flow event frequency and duration, magnitude, and timing. This

  13. Integrative assessment of river damming impacts on aquatic fauna in a Portuguese reservoir.

    Science.gov (United States)

    Santos, R M B; Sanches Fernandes, L F; Cortes, R M V; Varandas, S G P; Jesus, J J B; Pacheco, F A L

    2017-12-01

    The impacts of river damming on aquatic fauna are assessed and then integrated across hierarchical scales, portrayed as nested circles. The outer circles characterize the studied site for habitat disturbance and hydrologic regime during the construction and filling phases. The inner circles characterize the construction and filling phase zones for water quality parameters and aquatic fauna. The procedure for integrating the impacts comprises two consecutive stages: in the task stage, inner circles are characterized through field and laboratory work involving sampling and analyses of water aliquots and aquatic fauna; in the impact assessment stage, circle data are processed in ecological and statistical algorithms, which allow identification of changes in abundance and composition of aquatic fauna communities and their integration with changes in water quality parameters across the construction and filling phase zones. The integrative assessment of river damming impacts on aquatic fauna was carried out in the Sabor River dam (Portugal). This dam created two reservoirs: primary and secondary. Changes in water quality caused by dam construction and stream water impoundment were significant, marked by increases in temperature and electric conductivity downstream, accumulation of phosphorus and nitrogen in the reservoirs triggering the growth of algae and the increase of chlorophyll a, and drop of transparency. These changes were aggravated in the secondary reservoir. The consequences of water deterioration for aquatic fauna were severe, marked by abrupt declines of native fish species and invasion of exotic species even upwards the reservoirs. The ecological status determined from ecological quality ratios of benthic macroinvertebrate assemblages were also affected, changing from good-fair in the unaffected watercourses to fair-poor in the lakes. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Hydrological and ecological impacts of dams on the Kafue Flats floodplain system, southern Zambia

    Science.gov (United States)

    Mumba, M.; Thompson, J. R.

    Developmental changes in river basins in Africa have become a reality. Many wetland ecosystems have been impacted by dams and other hydrological interventions resulting in both foreseen and unexpected consequences. The Kafue Flats in southern Zambia is an extensive floodplain system that lies within the middle Kafue river basin. The floodplain is about 255 km long and 60 km wide, covering an area of approximately 6,500 km 2. It is currently sandwiched between two large dams which are approximately 270 km apart. These dams have completely altered the hydrological regime of the system. Backwater from the downstream dam and releases from upstream have created a permanently flooded area within the floodplain that was not present in the past. Elsewhere, flooding has been reduced. The ecological consequences of these changes for the floodplain, which hosts two national parks (both Ramsar sites), have been extensive. Hydrological and vegetation changes have impacted the habitat for important wildlife communities including the endemic antelope, Kobus leche kafuensis. The most dramatic change in vegetation is associated with the colonisation of parts of the floodplain by the invasive alien plant, Mimosa pigra. This paper discusses these changes and their potential consequences.

  15. Modelling the impact of dam removal on geomorphic channel response and sediment delivery: an Austrian case study

    Science.gov (United States)

    Pöppl, Ronald; Coulthard, Tom; Keesstra, Saskia; Keiler, Margreth

    2015-04-01

    Dams are often considered to have the most significant impact on rivers as dam construction generally reduces downstream sediment fluxes which further involves geomorphic changes in the affected river reaches. Since many dams no longer fulfill their intended purpose (e.g. due to siltation), are dangerous (e.g. catastrophic dam failures) and/or are ecologically damaging (e.g. habitat destruction), within the last two decades several dams have been removed and many more are already proposed for removal. Unfortunately, there is still only little empirical knowledge about the geomorphic consequences of dam removals and the related sediment release which represents a big challenge for river management. Modelling is one way to approach this problem. In the presented study we modelled the impacts of dam removal on geomorphic channel processes, channel morphology and sediment delivery further considering the role of channel engineering measures and reservoir excavation within a river reach impacted by a series of dams using the landscape evolution model CAESAR-Lisflood. The model was run with data from a small catchment located in Lower Austria. Modelled geomorphic channel changes and sediment fluxes were spatio-temporally analyzed, related to real-world data and are discussed in the context of river management issues.

  16. Wildlife Habitat Impact Assessment, Chief Joseph Dam Project, Washington : Project Report 1992.

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Douglas; Berger, Matthew

    1992-01-01

    Under the Pacific Northwest Electric Power Planning and Conservation Act of 1980, and the subsequent Northwest Power Planning Council`s Columbia River Basin Fish and Wildlife Program, a wildlife habitat impact assessment and identification of mitigation objectives have been developed for the US Army Corps of Engineer`s Chief Joseph Dam Project in north-central Washington. This study will form the basis for future mitigation planning and implementation.

  17. Potential impacts of Three Gorges Dam in China on the ecosystem of East China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Baodong; BROCKMANN Uwe

    2008-01-01

    The Changjiang River in China was dammed in 2003.The possible changes in matters fluxes from the river downstream after the completion of Three Gorges Dam and their potential impacts on the ecosystem of the East China Sea are discussed.The estuarine and coastal waters in the East China Sea were heavily fertilized by the inflow of nutrient-rich freshwater from the Changjiang River, which has led to severe eutrophication and frequent harmful algal blooms,thus worsening the ecosystem health in this area.Analy- sis showed that the nutrient loadings are very likely to be reduced in the lower Changjiang River due to the construction of Three Gorges Dam.Especially for the total phosphorus,the discharges to the East China Sea will be reduced by one-third,which would relieve the severe eutrophication in this area.However,the expected decrease in the riverine silicate discharge would lead the ra- tio of silicon to nitrogen to be much less than 1 in the estuarine and coastal waters and thus may cause an elevation of flagellate growth.The changes in the annual water discharges and their seasonal distributions below the dam will be minor.Reduction of suspended particulate matter loading,due to the sedimentation behind the dam,will reduce the nutrient loadings of the particulate form especially for phosphorus,and decrease the turbidity of estuarine and coastal waters.On the other hand,this may enhance the erosion of the delta and the coasts as well as modifythe benthic ecosystem.

  18. Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae bionomics and malaria epidemiology

    Directory of Open Access Journals (Sweden)

    Jordi Sanchez-Ribas

    2012-08-01

    Full Text Available Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas. Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

  19. Potential Impact of Climate Changes on the Inundation Risk Levels in a Dam Break Scenario

    Directory of Open Access Journals (Sweden)

    Sudha Yerramilli

    2013-03-01

    Full Text Available The overall objective of the study is to generate information for an enhanced land use planning with respect to flood hazards. The study assesses the potential impact of climate change by simulating a dam break scenario in a high intensity rainfall event and evaluates the vulnerability risk in the downstream region by integrating ArcGIS and Hydrologic Engineering Centers River Analysis System (HEC-RAS technologies. In the past century, the evidence of climate changes are observed in terms of increase in high intensity rainfall events. These events are of high concern, as increased inflow rates may increase the probability of a dam failure, leading to higher magnitude flooding events involving multiple consequences. The 100 year historical rainfall data for the central Mississippi region reveals an increased trend in the intensity of rainfall rates after the 1970s. With more than 10% of high hazard dams in the central region, the damage can be far accumulative. The study determines occurrence of the high intensity rainfall event in the past 100 years for central Mississippi and simulates a Ross Barnett Reservoir dam break scenario and evaluates the vulnerability risks due to inundation in the immediate downstream region, which happens to be the State Capital. The results indicate that the inundation due to a Ross Barnett Reservoir failure under high intensity rainfall event is comparable to a catastrophic flood event experienced by the region in 1979, which almost equals a 200-year flood magnitude. The results indicate that the extent and depth of flood waters poses a significant destructive threat to the state capital, inundating various infrastructural and transportation networks.

  20. The impacts of wind power integration on sub-daily variation in river flows downstream of hydroelectric dams.

    Science.gov (United States)

    Kern, Jordan D; Patino-Echeverri, Dalia; Characklis, Gregory W

    2014-08-19

    Due to their operational flexibility, hydroelectric dams are ideal candidates to compensate for the intermittency and unpredictability of wind energy production. However, more coordinated use of wind and hydropower resources may exacerbate the impacts dams have on downstream environmental flows, that is, the timing and magnitude of water flows needed to sustain river ecosystems. In this paper, we examine the effects of increased (i.e., 5%, 15%, and 25%) wind market penetration on prices for electricity and reserves, and assess the potential for altered price dynamics to disrupt reservoir release schedules at a hydroelectric dam and cause more variable and unpredictable hourly flow patterns (measured in terms of the Richards-Baker Flashiness (RBF) index). Results show that the greatest potential for wind energy to impact downstream flows occurs at high (∼25%) wind market penetration, when the dam sells more reserves in order to exploit spikes in real-time electricity prices caused by negative wind forecast errors. Nonetheless, compared to the initial impacts of dam construction (and the dam's subsequent operation as a peaking resource under baseline conditions) the marginal effects of any increased wind market penetration on downstream flows are found to be relatively minor.

  1. Impacts of Karkheh Dam on Spatial Pattern of Riparian Zones in Karkheh National Park

    Directory of Open Access Journals (Sweden)

    H. Madadi

    2013-03-01

    Full Text Available Effective river ecosystem management requires that the existing hydrologic regime be characterized in terms of the natural hydrologic regime and the degree to which the human-altered regime differs from natural conditions. This is known as Range of Variation Approach (RVA and can be used for variation of stream flow, range of variation and appraisal of dam impacts on riparian zones. In this paper, we used 31 hydrologic parameters, classified into five groups, monthly flow indices, extreme flow indices, timing indices, high-flow and low-flow indices, and rate of change, to assess hydrologic regime alteration in downstream of Karkheh dam. For this, purpose the hydrologic parameters of Pay-Pol hydrometric station have been taken. into consideration. As the Riparian ecosystems are highly dependent on and sensitive to variation in the hydrological cycle, the focus of this study was the 50-meter buffer of the Karkheh River. To examine the impacts caused by the variation of hydrologic regime, we tested if this variation and 8 different landscape metrics in the study area are correlated. The results showed that variation of hydrologic regime had a significant impact on the landscape structure of riparian zone in Karkheh downstream and caused isolation in landscape pattern of the woodland cover. Therefore, landscape structure in Karkheh downstream is highly correlated to hydrologic processes of upstream of the river. It can be concluded that an effective water management strategy is keeping safe the ecological condition and integrity of the riparian zone of Karkheh. This happens when all the hydrologic parameters are in the natural range of variation as they were before dam construction.

  2. Potential impacts of damming the Juba Valley, western Somalia: Insights from geomorphology and alluvial history

    Science.gov (United States)

    Williams, Martin

    2014-05-01

    In 1988 plans were well advanced to dam the Juba River in western Somalia. The aims of the Baardheere Dam Project were to generate hydroelectric power for the capital Mogadishu, and to provide water for irrigation in the Juba Valley. A reconnaissance survey on foot along 500 km of the river upstream of the proposed dam site at Baardheere and detailed geomorphic mapping from air photos provided a basis for reconstructing the late Quaternary alluvial history of the river and for assessing the potential impact of the proposed dam. The Juba River rises in the Ethiopian Highlands and is the only river in Somalia that flows to the sea. Its history reflects climatic events in Ethiopia, where the Rift Valley lakes were very low during the LGM (21±2 ka), and high for about 5, 000 years before and after then. Cave deposits in Somalia indicate wetter conditions at 13, 10, 7.5 and 1.5 ka. Alluvial terraces in the Juba Valley range in age from late Pleistocene to late Holocene but only attain a few metres above the present floodplain. This is because the dry tributary valleys contain limestone caves and fissures that divert any high flows from the parent river underground, a process not known when the project was first approved. The oldest preserved terrace was cemented by calcrete by 40 ka. Alluvial gravels were deposited at the outlet of dry tributary valleys during times of episodic high-energy flow between 26 ka and 28 ka. Finely laminated shelly sands accumulated at 10 ka to form the 5 m terrace. The 2 m terrace was laid down 3.2 ka ago as a slackwater deposit. The lack of high-level alluvial terraces raises doubts over plans to dam the river, since rapid leakage would occur from side valleys and the reservoir would not attain the height needed to generate hydroelectric power. It would submerge all existing arable land along the river. Finally, the presence in the late Holocene alluvium of the sub-fossil gastropods Bulinus truncatus and Biomphalaria pfeifferi, which are

  3. Spatial extent and dynamics of dam impacts on tropical island freshwater fish assemblages

    Science.gov (United States)

    Cooney, Patrick B.; Kwak, Thomas J.

    2013-01-01

    Habitat connectivity is vital to the persistence of migratory fishes. Native tropical island stream fish assemblages composed of diadromous species require intact corridors between ocean and riverine habitats. High dams block fish migration, but low-head artificial barriers are more widespread and are rarely assessed for impacts. Among all 46 drainages in Puerto Rico, we identified and surveyed 335 artificial barriers that hinder fish migration to 74.5% of the upstream habitat. We also surveyed occupancy of native diadromous fishes (Anguillidae, Eleotridae, Gobiidae, and Mugilidae) in 118 river reaches. Occupancy models demonstrated that barriers 2 meters (m) high restricted nongoby fish migration and extirpated those fish upstream of 4-m barriers. Gobies are adapted to climbing and are restricted by 12-m barriers and extirpated upstream of 32-m barriers. Our findings quantitatively illustrate the extensive impact of low-head structures on island stream fauna and provide guidance for natural resource management, habitat restoration, and water development strategies.

  4. Little impact of the Three Gorges Dam on recent decadal lake decline across China's Yangtze Plain

    Science.gov (United States)

    Wang, Jida; Sheng, Yongwei; Wada, Yoshihide

    2017-05-01

    The ubiquitous lakes across China's Yangtze Plain (YP) are indispensable freshwater resources sustaining ecosystems and socioeconomics for nearly half a billion people. Our recent survey revealed a widespread net decline in the total YP lake inundation area during 2000-2011 (a cumulative decrease of ˜10%), yet its mechanism remained contentious. Here we uncover the impacts of climate variability and anthropogenic activities including (i) Yangtze flow and sediment alterations by the Three Gorges Dam (TGD) and (ii) human water consumption in agricultural, industrial, and domestic sectors throughout the downstream Yangtze Basin. Results suggest that climate variability is the dominant driver of this decadal lake decline, whereas studied human activities, despite varying seasonal impacts that peak in fall, contribute marginal fraction (˜10-20% or less) to the interannual lake area decrease. Given that the TGD impacts on the total YP lake area and its seasonal variation are both under ˜5%, we also dismiss the speculation that the TGD might be responsible for evident downstream climate change by altering lake surface extent and thus open water evaporation. Nevertheless, anthropogenic impacts exhibited a strengthening trend during the past decade. Although the TGD has reached its full-capacity water regulation, the negative impacts of human water consumption and TGD-induced net channel erosion, which are already comparable to that of TGD's flow regulation, may continue to grow as crucial anthropogenic factors to future YP lake conservation.

  5. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data

    Directory of Open Access Journals (Sweden)

    N. M. Velpuri

    2012-10-01

    Full Text Available Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in situ datasets. In this study, we used 12 yr (1998–2009 of existing multi-source satellite and model-assimilated global weather data. We used a calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of the Gibe III dam using three different approaches – a historical approach, a rainfall based approach, and a statistical approach to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the Gibe III dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 1–2 m (95% confidence compared to the lake level modeled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modeling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level at the time of

  6. Assessing the Potential Hydrological Impact of the Gibe III Dam on Lake Turkana Water Level Using Multi-Source Satellite Data

    Science.gov (United States)

    ,; Senai, G.B.

    2012-01-01

    Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in-situ datasets. In this study, we used 12 years (1998–2009) of existing multi-source satellite and model-assimilated global weather data. We use calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of Gibe III dam using three different approaches such as (a historical approach, a knowledge-based approach, and a nonparametric bootstrap resampling approach) to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 2 m (95% confidence) compared to the lake level modelled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modelling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level at the time of

  7. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data

    Directory of Open Access Journals (Sweden)

    N. M. Velpuri

    2012-03-01

    Full Text Available Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in-situ datasets. In this study, we used 12 years (1998–2009 of existing multi-source satellite and model-assimilated global weather data. We use calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of Gibe III dam using three different approaches such as (a historical approach, a knowledge-based approach, and a nonparametric bootstrap resampling approach to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 2 m (95% confidence compared to the lake level modelled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modelling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level

  8. Model analysis of check dam impacts on long-term sediment and water budgets in southeast Arizona, USA

    Science.gov (United States)

    Norman, Laura M.; Niraula, Rewati

    2016-01-01

    The objective of this study was to evaluate the effect of check dam infrastructure on soil and water conservation at the catchment scale using the Soil and Water Assessment Tool (SWAT). This paired watershed study includes a watershed treated with over 2000 check dams and a Control watershed which has none, in the West Turkey Creek watershed, Southeast Arizona, USA. SWAT was calibrated for streamflow using discharge documented during the summer of 2013 at the Control site. Model results depict the necessity to eliminate lateral flow from SWAT models of aridland environments, the urgency to standardize geospatial soils data, and the care for which modelers must document altering parameters when presenting findings. Performance was assessed using the percent bias (PBIAS), with values of ±2.34%. The calibrated model was then used to examine the impacts of check dams at the Treated watershed. Approximately 630 tons of sediment is estimated to be stored behind check dams in the Treated watershed over the 3-year simulation, increasing water quality for fish habitat. A minimum precipitation event of 15 mm was necessary to instigate the detachment of soil, sediments, or rock from the study area, which occurred 2% of the time. The resulting watershed model is useful as a predictive framework and decision-support tool to consider long-term impacts of restoration and potential for future restoration.

  9. Energy dissipation by submarine obstacles during landslide impact on reservoir - potentially avoiding catastrophic dam collapse

    Science.gov (United States)

    Kafle, Jeevan; Kattel, Parameshwari; Mergili, Martin; Fischer, Jan-Thomas; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

    2017-04-01

    Dense geophysical mass flows such as landslides, debris flows and debris avalanches may generate super tsunami waves as they impact water bodies such as the sea, hydraulic reservoirs or mountain lakes. Here, we apply a comprehensive and general two-phase, physical-mathematical mass flow model (Pudasaini, 2012) that consists of non-linear and hyperbolic-parabolic partial differential equations for mass and momentum balances, and present novel, high-resolution simulation results for two-phase flows, as a mixture of solid grains and viscous fluid, impacting fluid reservoirs with obstacles. The simulations demonstrate that due to the presence of different obstacles in the water body, the intense flow-obstacle-interaction dramatically reduces the flow momentum resulting in the rapid energy dissipation around the obstacles. With the increase of obstacle height overtopping decreases but, the deflection and capturing (holding) of solid mass increases. In addition, the submarine solid mass is captured by the multiple obstacles and the moving mass decreases both in amount and speed as each obstacle causes the flow to deflect into two streams and also captures a portion of it. This results in distinct tsunami and submarine flow dynamics with multiple surface water and submarine debris waves. This novel approach can be implemented in open source GIS modelling framework r.avaflow, and be applied in hazard mitigation, prevention and relevant engineering or environmental tasks. This might be in particular for process chains, such as debris impacts in lakes and subsequent overtopping. So, as the complex flow-obstacle-interactions strongly and simultaneously dissipate huge energy at impact such installations potentially avoid great threat against the integrity of the dam. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

  10. The impact of the provision of water for game on the basal cover of the herbaceous vegetation around a dam in the Kruger National Park

    Directory of Open Access Journals (Sweden)

    I. Thrash

    1991-09-01

    Full Text Available A line intercept survey was done on the herbaceous vegetation in permanently marked plots at distance intervals from the Wik-en-Weeg Dam, Kruger National Park, in 1973. The survey was repeated in 1990 so that changes in basal cover could be determined in relation to distance from the dam. Positive relationships with distance from the dam were found for the relative total percentage basal cover of the herbaceous vegetation, as well as for the relative basal cover of, respectively, grasses, forbs, decreasers and increasers. It was concluded that the provision of a permanent supply of drinking water for game in the Wik-en-Weeg Dam has had an impact on the nearby herbaceous community basal cover composition, as well as a negative impact on the basal cover of the herbaceous vegetation in the vicinity. The basal cover of the herbaceous stratum was more sensitive to the effect of the dam than parameters of the woody stratum.

  11. Impact of dam construction on river banks evolution and sediment dynamics. A case study from the Po River (Italy).

    Science.gov (United States)

    Maselli, V.; Pellegrini, C.; Crose, L.; Del Bianco, F.; Mercorella, A.

    2014-12-01

    Rivers draining densely populated landscapes are extremely impacted by modern human engineering: armored beds, artificial levees and dams modified natural fluvial dynamics, and consequently, the evolution of alluvial plains, deltas and coastal environments. Dams, in particular, segmented the longitudinal continuity of the river and reduced (or even interrupted) the export of sediment toward the sea. Here we investigate the impact of the Isola Serafini dam on the upstream portion of the Po River (Italy) influenced by backwater, by using an integrated approach of aerial and satellite images, longitudinal cross-sections, grain size analysis, backscatter data and multibeam bathymetry. The analysis of aerial photographs, acquired every 10 yr since the dam construction in 1960, and of longitudinal cross-sections, allows understanding how the river adjusts its profile in response to the backwater and quantifying areas of net river banks erosion and deposition in meanders. The drowning of the reaches influenced by backwater reduced the progradation of point bars and promoted the deposition of fine grained sediments, as highlighted by grain size analysis on surficial sediment sampled across and along the river course. Calibrated back-scatter data with grain-size distributions of two selected meanders, under the backwater effect and beyond, show how sands are progressively replaced by fine-grained sediments in the meander belt and in the river axis, mainly reflecting the reduction of flow velocity, inferred also by river bed roughness. The understanding of river and sediment dynamics under the influence of backwater due to dam construction is useful when studying pristine systems in which natural backwater affects their evolution, as in the case of the formation of standing water bodies during the drowning of an incised valley.

  12. Interim Columbia and Snake rivers flow improvement measures for salmon: Final Supplemental Environmental Impact Statement (SEIS)

    Energy Technology Data Exchange (ETDEWEB)

    1993-03-01

    Public comments are sought on this final SEIS, which supplements the 1992 Columbia River Salmon Flow Measures Options Analysis (OA)/Environmental Impact Statement (EIS). The Corps of Engineers, in cooperation with the Bonneville Power Administration and the Bureau of Reclamation proposes five alternatives to improve flows of water in the lower Columbia-Snake rivers in 1993 and future years to assist the migration of juvenile and adult anadromous fish past eight hydropower dams. These are: (1) Without Project (no action) Alternative, (2) the 1992 Operation, (3) the 1992 Operation with Libby/Hungry Horse Sensitivity, (4) a Modified 1992 Operation with Improvements to Salmon Flows from Dworshak, and (5) a Modified 1992 Operation with Upper Snake Sensitivity. Alternative 4, Modified 1992 Operations, has been identified as the preferred alternative.

  13. Impacts of Post-Dam Land-use/Land-cover Changes on Modification of Extreme precipitation in Contrasting Hydro-climate and Terrain Features

    Science.gov (United States)

    Woldemichael, A. T.; Hossain, F.

    2013-12-01

    Understanding the impact of post-dam climate feedbacks, due to land-use/land-cover (LULC) variability, on modification of extreme precipitation (EP) remains a challenge for a 21st century approach to dam design and operation. In this study, we used the Regional Atmospheric Modeling System (RAMS, version 6.0), involving a number of pre-defined LULC scenarios to address the important question regarding dams and their impoundments: How sensitive are the hydroclimatology and terrain features of a region in modulating the post-dam response of climate feedbacks to EP? The study region covered the Owyhee dam/reservoir on Owyhee River Watershed (ORW) -located in eastern Oregon. A systematic perturbation of the relative humidity in the initial and boundary condition of the model was carried out to simulate EP. Among the different LULC scenarios used in the simulation over the ORW, irrigation expansion in the post-dam era resulted in an increase in EP up to 6% in the 72-hr precipitation total. The contribution of the reservoir on EP added 8% to the 72-hr total when compared to the pre-dam LULC conditions. In order to address the science question, a previously completed investigation on the Folsom dam (American River Watershed, ARW) in California, was compared with the ORW findings on the basis of contrasting differences in hydroclimatology and terrain features. Our results indicate that the post-dam LULC change scenarios impact EP of ORW (Owyhee Dam) is much greater than the EP of the ARW (Folsom Dam) due to its semi-arid climate (leeward side) and flat terrain. LULC changes are found to be less sensitive to EP modification in the windward side of the mountainous terrain of ARW.

  14. Impacts of the Garafiri hydroelectric dam on the Konkoure estuary; Impacts du barrage hydroelectrique de Garafiri sur l'estuaire du Konkoure

    Energy Technology Data Exchange (ETDEWEB)

    Samoura, K. [Secretariat international francophone pour l' evaluation environnemental, Montreal, PQ (Canada); Waaub, J.P. [Quebec Univ., Montreal, PQ (Canada). Dept. de Geographie

    2008-09-15

    This article described the environmental impacts caused by the exploitation of one or several dams in tropical coastal basins. In particular, it proposed a methodological approach for analyzing the vulnerability of ecosystems to modifications caused by the exploitation of the Garafiri hydroelectric dam in Guinea. With an installed power capacity of 75 MW, this dam has been operational since 1999 and has supplied electricity to coastal and mid Guinea since 2000. Since then, the ecosystem of the Konkoure River has undergone important changes. This study focused primarily on impacts during the dry season. Data was collected at different hydroelectric stations along the Konkoure Basin to estimate changes in water flow in the estuary. The study showed several changes, including noticeable impacts on the soil salt content. In addition, changes in vegetation were attributed to changes in soil content. The study revealed that rice production has increased 65 per cent since 2000, while salt exploitation has been completely discontinued. It was concluded that the hydraulic management of the dam can have a significant impact on the region's ecosystem which can in turn influence ecological and social economic functions. It was concluded that the vulnerability of the ecosystem can be worsened in the context of climate change. 25 refs., 9 figs.

  15. Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in Changjiang River, China

    Science.gov (United States)

    Gao, Xin; Lin, Pengcheng; Li, Mingzheng; Duan, Zhonghua; Liu, Huanzhang

    2016-09-01

    Chinese sturgeon ( Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon.

  16. Impacts of hydroelectric dams on alluvial riparian plant communities in eastern Brazilian Amazonian

    Directory of Open Access Journals (Sweden)

    LEANDRO VALLE FERREIRA

    2013-09-01

    Full Text Available The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity.

  17. Impacts of Groundwater Recharge from Rubber Dams on the Hydrogeological Environment in Luoyang Basin, China

    Science.gov (United States)

    Dong, Shaogang; Liu, Baiwei; Liu, Huamin; Wang, Shidong; Wang, Lixin

    2014-01-01

    In the rubber dam's impact area, the groundwater total hardness (TH) has declined since 2000, ultimately dropping to 100–300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000–2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS) of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced. PMID:25126593

  18. Large Dams and Changes in an Agrarian Society: Gendering the Impacts of Damodar Valley Corporation in Eastern India

    Directory of Open Access Journals (Sweden)

    Kuntala Lahiri-Dutt

    2012-06-01

    Full Text Available This paper traces the gendered changes in agrarian livelihoods in the lower Damodar valley of eastern India and connects these changes to the large dam project of the Damodar Valley Corporation (DVC. The DVC, established in 1948, was one of the earliest dam projects in India. Although it was not fully completed, the DVC project has initiated unforeseen changes in the farming economy. The floods for which the Damodar river was notorious were not fully controlled, and the suffering of people living in the lower reaches of the valley never really diminished. This paper gives a brief description of the river and its history of water management practices and the roles of women and men in these practices. It traces the resultant impacts on gender roles, and outlines the new kinds of water management that emerged in response to the DVC’s failure to provide irrigation water when demanded. More specifically, the paper explores the changes in floods, changes in the farming economy, and the impacts of temporary sand dams or boro bandhs on the livelihoods of women and men from farming families in the Lower Damodar Valley. It observes that even over a longer temporal scale, the changes unleashed by large water control projects have significant and gendered impacts on agrarian societies.

  19. Landscape Evolution Modelling of naturally dammed rivers

    NARCIS (Netherlands)

    Gorp, van W.; Temme, A.J.A.M.; Baartman, J.E.M.; Schoorl, J.M.

    2014-01-01

    Natural damming of upland river systems, such as landslide or lava damming, occurs worldwide. Many dams fail shortly after their creation, while other dams are long-lived and therefore have a long-term impact on fluvial and landscape evolution. This long-term impact is still poorly understood and

  20. Landscape Evolution Modelling of naturally dammed rivers

    NARCIS (Netherlands)

    van Gorp, Wouter; Temme, Arnaud J. A. M.; Baartman, Jantiene E. M.; Schoorl, Jeroen M.

    2014-01-01

    Natural damming of upland river systems, such as landslide or lava damming, occurs worldwide. Many dams fail shortly after their creation, while other dams are long-lived and therefore have a long-term impact on fluvial and landscape evolution. This long-term impact is still poorly understood and la

  1. Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

    Science.gov (United States)

    Vinh, V. D.; Ouillon, S.; Thanh, T. D.; Chu, L. V.

    2014-10-01

    The Hoa Binh dam (HBD), located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although it is important for flood prevention, electricity production and irrigation in northern Vietnam, the Hoa Binh dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from a 50-year data set of water discharge and suspended sediment concentration (1960-2010), and the distribution of water and sediment across the nine mouths of the delta was simulated using the MIKE11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 9%, the yearly suspended sediment flux dropped, on average, by 61% at Son Tay near Hanoi (from 119 to 46 × 106 t yr-1). Along the coast, reduced sedimentation rates are coincident with the lower sediment delivery observed since the impoundment of the Hoa Binh dam. Water regulation has led to decreased water discharge in the wet season (-14% in the Red River at Son Tay) and increased water discharge in the dry season (+12% at the same station). The ratios of water and suspended sediment flows, as compared to the total flows in the nine mouths, increased in the northern and southern estuaries and decreased in the central, main Ba Lat mouth. The increasing volume of dredged sediments in the Haiphong harbour is evidence of the silting up of the northern estuary of Cam-Bach Dang. The effect of tidal pumping on enhanced flow occurring in the dry season and resulting from changed water regulation is discussed as a possible cause of the enhanced siltation of the estuary after Hoa Binh dam impoundment.

  2. Environmental Assessment and Finding of No Significant Impact: Pond B Dam Repair Project at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    1999-09-27

    The Department of Energy (DOE) has prepared an environmental assessment (EA) (DOE/EA-1285) for the proposed repair of the Pond B dam at the Savannah River Site (SRS), located near Aiken, South Carolina. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an environmental impact statement (EIS) is not required, and DOE is issuing this Finding of No Significant Impact (FONSI) and Floodplain Statement of Findings.

  3. Impact of rockfill deformation on stress-strain state on dam reinforced concrete face

    Directory of Open Access Journals (Sweden)

    Sainov Mikhail Petrovich

    2015-03-01

    Full Text Available The author considered the results of the numerical studies of stress-strain state of a 100 m high rockfill dam with a reinforced concrete face. In the analysis, the dam construction sequence and loads applied to it were considered; it was assumed that the reinforced concrete face was constructed after filling the dam. The calculations were carried out in the elastic formulation at various moduli of deformation and Poisson’s ratio. It was revealed that at rockfill settlement under the action of hydrostatic pressure the reinforced concrete face not only bends but also is subject to longitudinal force. The development of these forces is connected not only with rockfill shear deformation in horizontal direction. Depending on the value of rockfill Poisson’s ratio these longitudinal forces may be both compressive and tensile. At the Poisson’s ratio exceeding 0.25 the longitudinal forces are tensile, and when it is equal to 0.2 - they are compressive. Evidently these particular longitudinal forces are the course of crack formation in reinforced concrete faces of a number of constructed dams. The indirect confirmation of the development of tensile forces on the face is the fact that actually in all the dams with reinforced concrete face opening of perimeter joint was observed. Thus, in order to provide the strength of reinforced concrete it is important to increase rockfill shear modulus. Only the decrease of stone compressibility (i.e. increase of linear deformation modulus E will slightly improve the stress state of the face, as the value of E has less effect on settlements and shear of the dam than Poisson’s ratio. High rockfill dams with reinforced concrete face may have a favorable stress state only at narrow site when the face horizontal displacements are inconsiderable and due to the settlements of rockfill in the face the forces are compressive but not tensile longitudinal forces.

  4. Geographical Overview of the Three Gorges Dam and Reservoir, China - Geologic Hazards and Environmental Impacts

    Science.gov (United States)

    Highland, Lynn M.

    2008-01-01

    The Three Gorges Dam and Reservoir on the Yangtze River, China, has been an ambitious and controversial project. The dam, the largest in the world as of 2008, will provide hydropower, help to manage flood conditions, and increase the navigability of the Yangtze River. However, this massive project has displaced human and animal populations and altered the stability of the banks of the Yangtze, and it may intensify the seismic hazard of the area. It has also hindered archeological investigations in the reservoir and dam area. This report, originally in the form of a Microsoft PowerPoint presentation, gives a short history and overview of the dam construction and subsequent consequences, especially geologic hazards already noted or possible in the future. The report provides photographs, diagrams, and references for the reader's further research - a necessity, because this great undertaking is dynamic, and both its problems and successes continue to evolve. The challenges and consequences of Three Gorges Dam will be closely watched and documented as lessons learned and applied to future projects in China and elsewhere.

  5. Organic carbon and nitrogen export from a tropical dam-impacted floodplain system

    Directory of Open Access Journals (Sweden)

    R. Zurbrügg

    2012-06-01

    Full Text Available Tropical floodplains play an important role in organic matter transport, storage, and transformation between headwaters and oceans. However, the fluxes and quality of organic carbon (OC and organic nitrogen (ON in tropical river-floodplain systems are not well constrained. We explored the quantity and characteristics of dissolved and particulate organic matter (DOM and POM in the Kafue River flowing through the Kafue Flats (Zambia. The Kafue Flats are a tropical dam-impacted river-floodplain system in the Zambezi River basin. During the flooding season, >80% of the Kafue River water passed through the floodplain, mobilizing large quantities of OC and ON, which resulted in a net export of 75 kg OC km−2 d−1 and 2.9 kg ON km−2 d−1, 80% of which was in the dissolved form. Mass budget estimates showed that ON export, denitrification, and burial caused an annual deficit of ~21 000 t N yr−1 in the Kafue Flats. A N isotope balance and the δ15N of DON and PON suggest that N-fixation must level out the large N losses. The elemental C:N ratio of ~20, the δ13C values of higher than −24‰, and spectroscopic properties (excitation-emission matrices showed that DOM in the river was mainly of terrestrial origin. Despite a threefold increase in OC loads due to inputs from the floodplain, the river DOM characteristics remained relatively constant along the sampled 400-km river reach. This suggested that floodplain DOM had similar properties than DOM from the upstream reservoir. In contrast, based on its low δ13C of −29‰ and the C:N ratio of ~8, POM originated from phytoplankton production in the upstream reservoir and in the floodplain. While the reservoir had little impact on DOM properties, terrestrial POM was efficiently trapped and, instead, phytoplankton-derived POM was discharged to the downstream Kafue Flats.

  6. Wildlife Impact Assessment and Summary of Previous Mitigation Related to Hydroelectric Projects in Montana, Volume One, Libby Dam Project, Operator, U.S. Army Corps of Engineers.

    Energy Technology Data Exchange (ETDEWEB)

    Yde, Chris A.

    1984-10-01

    This assessment addresses the impacts to the wildlife populations and wildlife habitats due to the Libby Dam project on the Kootenai River and previous mitigation of these losses. The current assessment documents the best available information concerning the impacts to the wildlife populations inhabiting the project area prior to construction of the dam and creation of the reservoir. Many of the impacts reported in this assessment differ from those contained in the earlier document compiled by the Fish and Wildlife Service; however, this document is a thorough compilation of the available data (habitat and wildlife) and, though conservative, attempts to realistically assess the impacts related to the Libby Dam project. Where appropriate the impacts resulting from highway construction and railroad relocation were included in the assessment. This was consistent with the previous assessments.

  7. Impact of the Hoa Binh Dam (Vietnam on water and sediment budgets in the Red River basin and delta

    Directory of Open Access Journals (Sweden)

    D. V. Vu

    2014-01-01

    Full Text Available The Hoa Binh Dam, located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although being important for flood prevention, electricity production, and irrigation in northern Vietnam, the Hoa Binh Dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from 50 yr dataset of water discharge and suspended sediment concentration (1960–2010 and the distribution of water and sediment across the nine mouths of the delta was calculated using the MIKE 11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 8.8%, the yearly suspended sediment flux dropped, on average from 119 to 43 × 106 t yr−1 at Son Tay near Hanoi, and from 85 to 35 × 106 t yr−1 in the river mouths. Water regulation has led to decreased water discharge in the wet season and increased water discharge in the dry season. Suspended sediment discharge proportionally increased in northern and southern estuaries and decreased through the main and central Ba Lat mouth. Tidal pumping, which causes a net sediment flux from the coast to the estuary at low discharge, is high in the northern delta, as a consequence of the high tidal range (up to 4.5 m in spring tide; diurnal tide. The shifts in the dynamic and characteristics of the turbidity maximum zone in the Cam-Bach Dang estuary are probably the cause of the enhanced sediment deposition in the Haiphong harbor. Along the coast, the reduced sedimentation rates are coincident with the lower sediment delivery that has been observed since the impoundment of the Hoa Binh Dam.

  8. 78 FR 70295 - Intent to Prepare an Environmental Impact Statement for the Dam Safety Modification Report...

    Science.gov (United States)

    2013-11-25

    ... unacceptable erosion associated with overtopping of areas of the dam not designed to be overtopped. After a... begin detailed design and ] subsequent construction of the recommended alternative which included a 13... pavement for scour protection downstream of the hydropower penstocks. Ongoing construction on...

  9. Dams (National)

    Data.gov (United States)

    Department of Transportation — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands (NTAD 2015). The map layer was created by extracting dams...

  10. Impact of beaver dams on abundance and distribution of anadromous salmonids in two lowland streams in Lithuania.

    Science.gov (United States)

    Virbickas, Tomas; Stakėnas, Saulius; Steponėnas, Andrius

    2015-01-01

    European beaver dams impeded movements of anadromous salmonids as it was established by fishing survey, fish tagging and redd counts in two lowland streams in Lithuania. Significant differences in abundancies of other litophilic fish species and evenness of representation by species in the community were detected upstream and downstream of the beaver dams. Sea trout parr marked with RFID tags passed through several successive beaver dams in upstream direction, but no tagged fish were detected above the uppermost dam. Increase in abundances of salmonid parr in the stream between the beaver dams and decrease below the dams were recorded in November, at the time of spawning of Atlantic salmon and sea trout, but no significant changes were detected in the sections upstream of the dams. After construction of several additional beaver dams in the downstream sections of the studied streams, abundance of Atlantic salmon parr downstream of the dams decreased considerably in comparison with that estimated before construction.

  11. Flood Control Burlington Dam, Souris River, North Dakota. Final Environment Impact Statement.

    Science.gov (United States)

    1978-01-01

    Refuges (NWR’s), since the N4WR’s contain perhaps the key wildlife habitat along the Souris River, and since the NWR’s are of key environmental...are like Burlingtcr Dam in all the key characteristics. There are also no Puhlished res;icw articles which compare all these different conditions and...persisted for a few years since floodwater storage, is dominated by the thistles Sonchus and especially Cirsium, and appears rather stable and persistent

  12. Forecasting the Cumulative Impacts of Dams on the Mekong Delta: Certainties and Uncertainties

    Science.gov (United States)

    Kondolf, G. M.; Rubin, Z.; Schmitt, R. J. P.

    2016-12-01

    The Mekong River basin is undergoing rapid hydroelectric development, with 7 large mainstem dams on the upper Mekong (Lancang) River in China and 133 dams planned for the Lower Mekong River basin (Laos, Cambodia, Thailand, Vietnam), 11 of which are on the mainstem. Prior analyses have shown that all these dams built as initially proposed would trap 96% of the natural sediment load to the Mekong Delta. Such a reduction in sediment supply would compromise the sustainability of the delta itself, but there are many uncertainties in the timing and pattern of land loss. The river will first erode in-channel sediment deposits, partly compensating for upstream sediment trapping until these deposits are exhausted. Other complicating factors include basin-wide accelerated land-use change, road construction, instream sand mining, dyking-off floodplains, and changing climate, accelerated subsidence from groundwater extraction, and sea level rise. It is certain that the Mekong Delta will undergo large changes in the coming decades, changes that will threaten its very existence. However, the multiplicity of compounding drivers and lack of good data lead to large uncertainties in forecasting changes in the sediment balance on the scale of a very large network. We quantify uncertainties in available data and consider changes due to additional, poorly quantified drivers (e.g., road construction), putting these drivers in perspective with the overall sediment budget. We developed a set of most-likely scenarios and their implications for the delta's future. Uncertainties are large, but there are certainties about the delta's future. If its sediment supply is nearly completely cut off (as would be the case with `business-as-usual' ongoing dam construction and sediment extraction), the Delta is certainly doomed to disappear in the face of rising seas, subsidence, and coastal erosion. The uncertainty is only when and how precisely the loss will progress.

  13. Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology

    OpenAIRE

    Jordi Sanchez-Ribas; Gabriel Parra-Henao; Anthony Érico Guimarães

    2012-01-01

    Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). ...

  14. 78 FR 53494 - Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams

    Science.gov (United States)

    2013-08-29

    ... Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams AGENCY: Tennessee... preferred alternative in its final environmental impact statement (EIS) for the dam safety modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams. The notice of availability (NOA) of the...

  15. 75 FR 6004 - Notice of Intent To Prepare a Draft Environmental Impact Statement and Dam Safety Assurance...

    Science.gov (United States)

    2010-02-05

    ... upper 20 feet of the auxiliary dam's foundation is loose ] and might be subject to loss of shear... major rehabilitation of the auxiliary dam and evaluation of the main dam's overall earthquake... are necessary to prevent loss of life, extensive downstream damage, functional loss of the project...

  16. Damming the rivers of the Amazon basin

    Science.gov (United States)

    Latrubesse, Edgardo M.; Arima, Eugenio Y.; Dunne, Thomas; Park, Edward; Baker, Victor R.; D'Horta, Fernando M.; Wight, Charles; Wittmann, Florian; Zuanon, Jansen; Baker, Paul A.; Ribas, Camila C.; Norgaard, Richard B.; Filizola, Naziano; Ansar, Atif; Flyvbjerg, Bent; Stevaux, Jose C.

    2017-06-01

    More than a hundred hydropower dams have already been built in the Amazon basin and numerous proposals for further dam constructions are under consideration. The accumulated negative environmental effects of existing dams and proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin’s floodplains, estuary and sediment plume. We introduce a Dam Environmental Vulnerability Index to quantify the current and potential impacts of dams in the basin. The scale of foreseeable environmental degradation indicates the need for collective action among nations and states to avoid cumulative, far-reaching impacts. We suggest institutional innovations to assess and avoid the likely impoverishment of Amazon rivers.

  17. A stream of consciousness: the anti-dam movement' impact on rivers in the 20th century

    Energy Technology Data Exchange (ETDEWEB)

    McCully, P.

    2000-07-01

    It is argued that the 20th century devastated the world's rivers like no other period in history. In the past one hundred years some 40,000 large dams were built on the world's rivers; there are few rivers of any consequence left that remain dam-free. Dam reservoirs have flooded perhaps a million square kilometres of land and displaced up to 60 million people. The environmental toll has been equally shocking: estuaries were degraded, fisheries decimated, forest destroyed. This report describes a strong and growing people's counter-movement to save rivers and riverine communities. These actions by people and the poor economics of dam building, are making it increasingly difficult to build dams in most of the world. Construction of large dams is declining fast, from a peak of about 540 in the 1970s to 200 in the 1990s. In addition to the decline in the construction of new dams, the people's movement has been successful in forcing the decommissioning and removal of several major dams in recent years. Examples of the movement's success in bringing about the removal of some existing dams or halt the construction of new ones are cited from Hungary, India, and particularly the United States where nearly 500 dams were removed during the past 100 years. Specific examples of dam removal efforts are described, taken from Pennsylvania, Wisconsin, and from the Colombia/Snake River basin. The most exciting decommissioning effort involves taking on the dams that submerged Hetch Hetchy Valley in the Yosemite National Park and the Glen Canyon Dam on the Colorado River. A chronological table of the 'Boom Years of Dam Building' and 'The Rise of the People's Movement Against Dams' is attached.

  18. Dams: impacts on the aquatic mammals population of Amazonia; Barragens: consequencias sobre as populacoes de mamiferos aquaticos da Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Colares, Francisco Antonio Pinto [Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, AM (Brazil). Lab. de Mamiferos Aquaticos

    1996-12-31

    Many problems are caused by dam`s construction in the rivers for power generation. The elevation of the level of the water for dams formation destroys the habitat of otters and similar animals and can invades its hole and kill its young animals. The work talks about chinese experience in the dams of the river Yangtze (China) that make almost extinguished dolphins of the rivers of that country. For the herbivorous animals, the flora modification can cause problems to have enough food. In conclusion the work recommends a statistics of mammals animals population in dams places for future comparison 13 refs.

  19. The 2006 Project Progress Report for 1987-099-00 Dworshak Kokanee Population and Entrainment Assessment (contract # 26850) is attached to project 2007-003-00, contract #31598. [POINTER

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-18

    During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. Strobe light tests were conducted on four nights from April 24-27, 2006, in front of the middle reservoir outlet (RO) 2. The density and distribution of fish, (thought to be mostly kokanee), were monitored with a split-beam echo sounder. We then compared fish counts and densities during nights when the lights were flashing to counts and densities during adjacent nights without the lights on. On two nights, April 25 and 27, 2006, when no lights were present, fish counts near RO 2 averaged 12.4 fish and densities averaged 31.0 fish/ha. When strobe lights were turned on during the nights of April 24 and 26, mean counts dropped to 4.7 fish and densities dropped to 0.5 fish/ha. The decline in counts (62%) and densities (99%) was statistically significant (p = 0.009 and 0.002, respectively). Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of a discharging reservoir outlet, which would be sufficient to improve sport fish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2006. Estimated abundance of kokanee increased from the 2005 population estimate. Based on hydroacoustic surveys, we estimated approximately 5,815,000 kokanee (90% CI {+-} 27.6%) in Dworshak Reservoir in August 2006. This included 2,183,000 age-0 (90% CI {+-} 24.2%), 1,509,000 age-1 (90% CI {+-} 29.0%), and 2,124,000 age-2 (90% CI {+-} 27.6%) kokanee. This resulted in a density of age-2 kokanee above the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site, split-beam hydroacoustics from May through September for a continuous 24 h period when dam operations permitted. The highest fish detection rates from entrainment assessments were found during dawn periods, unlike previous year's results

  20. Modelling the impact of large dams on flows and hydropower production of the Sekong, Sesan and Srepok Rivers in the Mekong Basin

    Science.gov (United States)

    Piman, T.; Cochrane, T. A.; Arias, M. E.

    2013-12-01

    Water flow patterns in the Mekong River and its tributaries are changing due to water resources development, particularly as a result of on-going rapid hydropower development of tributaries for economic growth. Local communities and international observers are concerned that alterations of natural flow patterns will have great impacts on biodiversity, ecosystem services, food securing and livelihood in the basin. There is also concern that un-coordinated dam development will have an adverse impact on energy production potential of individual hydropower plants. Of immediate concern is the proposed hydropower development in the transboundary Srepok, Sesan and Srekong (3S) Basin, which contributes up to 20% of the Mekong's annual flows, has a large potential for energy production, and provides critical ecosystem services to local people and the downstream Tonle Sap Lake and the Mekong delta. To assess the magnitude of potential changes in flows and hydropower production, daily flows were simulated over 20 years (1986-2005) using the SWAT and HEC ResSim models for a range of dam development and operations scenarios. Simulations of all current and proposed hydropower development in the 3S basin (41 dams) using an operation scheme to maximize electricity production will increase average dry seasonal flows by 88.1% while average wet seasonal flows decrease by 24.7% when compared to the baseline (no dams) scenario, About 55% of dry season flows changes are caused by the seven largest proposed dams (Lower Srepok 3, Lower Srepok4, Lower Sesan 3, Lower Sesan and Srepok 2, Xekong 5, Xekong 4, and Xe Xou). The total active storage of the existing and ongoing hydropower projects is only 6,616 million m3 while the cumulative active storage of the seven large proposed dams is 17,679 million m3. The Lower Srepok 3 project causes the highest impact on seasonal flow changes. Average energy production of the existing and ongoing hydropower projects is 73.2 GWh/day. Additional benefits

  1. Environmental Impact Assessment of Kol-Dam Hydropower Project – A Case Study from Himachal Pradesh, India

    Directory of Open Access Journals (Sweden)

    Hukam Chand

    2016-04-01

    Full Text Available The study was conducted during 2011 to investigate the impacts of Kol-dam construction on people and their overall economy. There was a loss of total land holding per family in the range of 33.07 to 64.46 per cent in 5 affected villages selected for the study. However in case of cultivated land there was a loss in the range of 36.15 to 67.36 per cent in 5 sampled villages. Submergence of land resulted in the loss of different trees (fodder, timber, fuel wood and fruit from villages’ farmland in the range of 37.45 to 80.60 per cent in 5 affected village. There was a substantial decrease in the livestock population which ranged from 52.50 to 59.60 per cent. Construction of dam resulted in loss of assets to the extent of 33.33 to 45.45 percent in different villages. Overall there was a decrease in on-farm sectors (crop & livestock ranged from 42.86 to 81.17 per cent whereas an increase in off- farm income (jobs and private business ranges from 13.33 - 48.33 per cent has been observed from the affected villages. Hence it can be concluded that there was a loss of on-farm income resources like agriculture land and its associated resources i.e. important tree species and livestock. This might have serious impact on local biodiversity as well as on the life style of project affected families.

  2. Analysis of potential impacts of Flaming Gorge Dam hydropower operations on archaeological sites

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, K.L.; Malinowski, L.M.; Hoffecker, J.F.

    1955-12-01

    An archaeological field study was conducted along the Green River in the areas of Little Hole and Browns Park in Utah and Colorado. The purpose of the study was to measure the potential for hydropower operations at Flaming Gorge Dam to directly or indirectly affect archaeological sites in the study area. Thirty-four known sites were relocated, and six new sites were recorded. Information was collected at each site regarding location, description, geomorphic setting, sedimentary context, vegetation, slope, distance from river, elevation above river level, and site condition. Matching the hydrologic projections of river level and sediment load with the geomorphic and sedimentary context at specific site locations indicated that eight sites were in areas with a high potential for erosion.

  3. Impact of Geotechnical Factors on the Safety of Low Embankment Dams From the Perspective of Technical and Safety Supervision

    Directory of Open Access Journals (Sweden)

    Kasana Andrej

    2015-03-01

    Full Text Available Our research deals with a broad spectrum of problems concerning the variability of geotechnical factors and their influence on the safety of the biggest group of dam constructions in Slovakia, i.e., low earthfill dams. Its specific aim is the observation of their risk factors by using our experience and knowledge gained while working in the sector of technical and safety supervision. To achieve the aims of a research thesis, we analyzed 39 low earthfill dams. We performed observations and documented their conditions with the aim of clarifying the risk factors. After an analysis of the information materials that characterize dams and after a statistical analysis of the measurement results in situ, including measurements from technical and safety supervision databases, we performed an analysis by using mathematical modeling to evaluate the safety of the dam constructions. Out of the total number of 39 dam constructions, an analysis of the stability of the dam slopes was performed on 37 dams, and deformation problems were analyzed on 28 of the dams. Filtration problems were analyzed at 26 dams, and a complete evaluation of the intensity of filtration movements was performed on 19 of the constructions.

  4. Downstream environmental impacts of dams: case study Tucurui Hydroelectric Plant, PA; Impactos ambientais a jusante de hidreletricas: o caso da usina de Tucurui, PA

    Energy Technology Data Exchange (ETDEWEB)

    Manyari, Waleska Valenca

    2007-12-15

    The hydroelectric resources of the Amazon region are considered a competitive alternative despite the structural problems they entail. Concerning the latter, plans to build large-scale dams in the region have drawn criticism mainly on account of the loss of forest cover in areas flooded by dam reservoirs and the conflicts concerning the relocation of indigenous and riverside communities in the region. This study seeks to contribute to better understanding of the environmental issue in the Amazon by focusing attention on the downstream effects of dams, which have large-scale, hitherto neglected ecological repercussions. The impact of dams extends well beyond the area surrounding the artificial lakes they create, harming rich Amazon wetland ecosystems. The morphology of dammed rivers changes in response to new inputs of energy and matter, which may in turn destroy certain biotypes. This is a remote-sensing-based case study of the Tucurui hydroelectric scheme in the Amazon state of Para. Attention is drawn to the need to take into account effects on alluvial rivers downstream from hydroelectric power plants when it comes to making planning decisions, as part of a sustainable energy policy. (author)

  5. Organic carbon and nitrogen export from a tropical dam-impacted floodplain system

    Directory of Open Access Journals (Sweden)

    R. Zurbrügg

    2013-01-01

    Full Text Available Tropical floodplains play an important role in organic matter transport, storage, and transformation between headwaters and oceans. However, the fluxes and quality of organic carbon (OC and organic nitrogen (ON in tropical river-floodplain systems are not well constrained. We explored the quantity and characteristics of dissolved and particulate organic matter (DOM and POM, respectively in the Kafue River flowing through the Kafue Flats (Zambia, a tropical river-floodplain system in the Zambezi River basin. During the flooding season, > 80% of the Kafue River water passed through the floodplain, mobilizing large quantities of OC and ON, which resulted in a net export of 69–119 kg OC km−2 d−1 and 3.8–4.7 kg ON km−2 d−1, 80% of which was in the dissolved form. The elemental C : N ratio of ~ 20, the comparatively high δ13C values of −25‰ to −21‰, and its spectroscopic properties (excitation-emission matrices showed that DOM in the river was mainly of terrestrial origin. Despite a threefold increase in OC loads due to inputs from the floodplain, the characteristics of the riverine DOM remained relatively constant along the sampled 410-km river reach. This suggests that floodplain DOM displayed properties similar to those of DOM leaving the upstream reservoir and implied that the DOM produced in the reservoir was relatively short-lived. In contrast, the particulate fraction was 13C-depleted (−29‰ and had a C : N ratio of ~ 8, which indicated that POM originated from phytoplankton production in the reservoir and in the floodplain, rather than from plant debris or resuspended sediments. While the upstream dam had little effect on the DOM pool, terrestrial particles were retained, and POM from algal and microbial sources was released to the river. A nitrogen mass balance over the 2200 km2 flooded area revealed an annual deficit of 15 500–22 100 t N in

  6. Unusual salinity conditions in the Yangtze estuary in 2006: impacts of an extreme drought or of the Three Gorges Dam?

    Science.gov (United States)

    Dai, Zhijun; Chu, Ao; Stive, Marcel; Zhang, Xiaoling; Yan, Hong

    2011-07-01

    During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during 7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause.

  7. Sedimentation in the Three Gorges Dam and its impact on the sediment flux from the Changjiang (Yangtze River, China

    Directory of Open Access Journals (Sweden)

    B. Q. Hu

    2009-07-01

    Full Text Available After the operation of the Three Gorges Dam (TGD in 2003, the mean annual sediment load at Yichang station, 44 km downstream of the TGD, decreased drastically by 84% of that in the pre-TGD period (1986–2002. Annually, about 162 million tons (Mt sediment was trapped by the TGD in 2003–2007, of which 92% was deposited within the region from Cuntan to TGD site; the remaining 8% deposited in the upstream of Cuntan owing to the effect of the extended backwater region of TGD. The theoretical trapping efficiency of the cascade reservoir on the lower Jinshajiang was calculated and its impact on the Changjiang sediment in the coming decades discussed. The results show that the cascade reservoir will trap up to 91% of the sediment discharge coming from the Jinshajiang tributary, and then the sediment discharge from the Changjiang to the sea will continuously decrease to less than 90 Mt/yr in the coming decades. In the presence of low sediment discharge, profound impacts on the morphology of estuary, delta and coastal sea are expected.

  8. The impact of erosion protection by Stone Dams on Salt-Marsh vegetation on Two Wadden Sea Barrier Islands

    NARCIS (Netherlands)

    Loon-Steensma, van J.M.; Slim, P.A.

    2013-01-01

    This paper describes and quantifies the effect of low stone dams on the extent and composition of salt-marsh habitats on two Dutch Wadden islands: Terschelling and Ameland. The stone dams were built to prevent erosion of the salt-marsh edge. Analyses of a series of aerial photographs taken between 1

  9. Impact of Geotechnical Factors on the Safety of Low Embankment Dams From the Perspective of Technical and Safety Supervision

    Science.gov (United States)

    Kasana, Andrej; Minárik, Marian; Nikolaj, Maroš

    2015-03-01

    Our research deals with a broad spectrum of problems concerning the variability of geotechnical factors and their influence on the safety of the biggest group of dam constructions in Slovakia, i.e., low earthfill dams. Its specific aim is the observation of their risk factors by using our experience and knowledge gained while working in the sector of technical and safety supervision. To achieve the aims of a research thesis, we analyzed 39 low earthfill dams. We performed observations and documented their conditions with the aim of clarifying the risk factors. After an analysis of the information materials that characterize dams and after a statistical analysis of the measurement results in situ, including measurements from technical and safety supervision databases, we performed an analysis by using mathematical modeling to evaluate the safety of the dam constructions. Out of the total number of 39 dam constructions, an analysis of the stability of the dam slopes was performed on 37 dams, and deformation problems were analyzed on 28 of the dams. Filtration problems were analyzed at 26 dams, and a complete evaluation of the intensity of filtration movements was performed on 19 of the constructions. On the basis of a detailed analysis of the 39 dam constructions, we specified their problems and the concomitant consequences of the problems. Geotechnical risk factors and specific risks that determine the safety of water constructions were characterized. The analysis confirmed the importance of an engineer-geological and geotechnical checkup in the process of preparation and building (alternatively, during reconstructions and sanitation work) of such water constructions and also the importance of monitoring in the process of dam usage. Technical and safety checkups were also shown to be important when analyzing risk factors. The conclusions of the knowledge gained and the recommendations for the practice deal with recommendations to change the flow policy, develop a

  10. IMPACT OF THE ATATÜRK DAM LAKE ON AGRO-METEOROLOGICAL ASPECTS OF THE SOUTHEASTERN ANATOLIA REGION USING REMOTE SENSING AND GIS ANALYSIS

    Directory of Open Access Journals (Sweden)

    O. Ozcan

    2012-07-01

    Full Text Available The Atatürk Dam is the fourth largest clay-cored rock fill dam in the world. It was constructed on the Euphrates River located in semi-arid Southeastern Turkey in the 1980s as the central component of a large-scale regional development project for the Southeastern Anatolia region (referred to as GAP. The construction began in 1983 and was completed in 1990. The dam and the hydroelectric power plant, which went into service after filling up the reservoir was accomplished in 1992. The Atatürk Dam, which has a height of 169 m, a total storage capacity of 48.7 million m3, and a surface area of about 817 km2 plays an important role in the development of Turkey's energy and agriculture sectors. In this study, the spatial and temporal impacts of the Atatürk Dam on agro-meteorological aspects of the Southeastern Anatolia region have been investigated. Change detection and environmental impacts due to water-reserve changes in Atatürk Dam Lake have been determined and evaluated using multi-temporal Landsat satellite imageries and meteorological datasets within a period of 1984 to 2011. These time series have been evaluated for three time periods. Dam construction period constitutes the first part of the study. Land cover/use changes especially on agricultural fields under the Atatürk Dam Lake and its vicinity have been identified between the periods of 1984 to 1992. The second period comprises the 10-year period after the completion of filling up the reservoir in 1992. At this period, Landsat and meteorological time-series analyses are examined to assess the impact of the Atatürk Dam Lake on selected irrigated agricultural areas. For the last 9-year period from 2002 to 2011, the relationships between seasonal water-reserve changes and irrigated plains under changing climatic factors primarily driving vegetation activity (monthly, seasonal, and annual fluctuations of rainfall rate, air temperature, humidity on the watershed have been investigated

  11. The geomorphic legacy of small dams — An Austrian study

    NARCIS (Netherlands)

    Poeppl, R.E.; Keesstra, S.D.; Hein, T.

    2015-01-01

    Dams represent one of the most dominant forms of human impact upon fluvial systems during the Anthropocene, as they disrupt the downstream transfer of water and sediments. Removing dams restores river continuity and channel morphology. Both dam construction and dam removal induce geomorphic channel

  12. Dam Safety Concepts

    NARCIS (Netherlands)

    Duricic, J.

    2014-01-01

    The majority of dams constructed in the world are dams that can be categorized as embankment dams. Throughout history we can point to many failures of dams, and embankment dams in particular. Nowadays it is clear that the goal to construct stable dams has not been achieved, even with advanced techno

  13. Dam Safety Concepts

    NARCIS (Netherlands)

    Duricic, J.

    2014-01-01

    The majority of dams constructed in the world are dams that can be categorized as embankment dams. Throughout history we can point to many failures of dams, and embankment dams in particular. Nowadays it is clear that the goal to construct stable dams has not been achieved, even with advanced

  14. Dam Safety Concepts

    NARCIS (Netherlands)

    Duricic, J.

    2014-01-01

    The majority of dams constructed in the world are dams that can be categorized as embankment dams. Throughout history we can point to many failures of dams, and embankment dams in particular. Nowadays it is clear that the goal to construct stable dams has not been achieved, even with advanced techno

  15. Kokanee Impacts Assessment and Monitoring of Lake Pend Oreille and Dworshak Reservoir, Idaho, 1994 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fredericks, James P.; Elam, Steve; Maiolie, Melo A.

    1995-06-01

    In an effort to recover the declining kokanee Oncorhynchus nerka kennerlyi population in Lake Pend Oreille, a study was proposed to evaluate the benefits of a higher winter elevation, thus providing more spawning gravel for kokanee. This project was designed to collect and compile baseline information on the kokanee population and potential spawning gravel in Lake Pend Oreille that can be used to help evaluate the effectiveness of future changes in lake level management. We estimated the area of suitable quality spawning gravel at the current winter elevation (625.1 m) and at the proposed winter elevation (626.7 m). Gravels beneath the current winter elevation were generally characterized by a high percentage of fine sediments and a high degree of embeddedness. Of the total gravel available below the proposed elevation of 626.7 m, only 15% was available at current winter elevations. Kokanee population estimates were made with a midwater trawl and hydroacoustic surveys in August and September. September population estimates were 6,760,000 age O, 380,000 age 1 +, 700,000 age 2 +, 990,000 age 3 +, 760,000 age 4 +, and 70,000 age 5 + kokanee. Hydroacoustic surveys run alongside the trawl indicated that hydroacoustics can effectively estimate abundance of kokanee, with the exception of fry, which are too small to be completely distinguishable from opossum shrimp Mysis relicta. Historic estimates of wild kokanee fry indicate that winter elevations higher than 625 m and a stable elevation throughout the winter are positively correlated with kokanee fry abundance and survival.

  16. Records of pan (floodplain wetland) sedimentation as an approach for post-hoc investigation of the hydrological impacts of dam impoundment: The Pongolo river, KwaZulu-Natal.

    Science.gov (United States)

    Heath, S K; Plater, A J

    2010-07-01

    River impoundment by dams has far-reaching consequences for downstream floodplains in terms of hydrology, water quality, geomorphology, ecology and ecosystem services. With the imperative of economic development, there is the danger that potential environmental impacts are not assessed adequately or monitored appropriately. Here, an investigation of sediment composition of two pans (floodplain wetlands) in the Pongolo River floodplain, KwaZulu-Natal, downstream of the Pongolapoort dam constructed in 1974, is considered as a method for post-hoc assessment of the impacts on river hydrology, sediment supply and water quality. Bumbe and Sokhunti pans have contrasting hydrological regimes in terms of their connection to the main Pongolo channel - Bumbe is a shallow ephemeral pan and Sokhunti is a deep, perennial water body. The results of X-ray fluorescence (XRF) geochemical analysis of their sediment records over a depth of >1 m show that whilst the two pans exhibit similar sediment composition and variability in their lower part, Bumbe pan exhibits a shift toward increased fine-grained mineral supply and associated nutrient influx at a depth of c. 45 cm whilst Sokhunti pan is characterised by increased biogenic productivity at a depth of c. 26 cm due to enhanced nutrient status. The underlying cause is interpreted as a shift in hydrology to a 'post-dam' flow regime of reduced flood frequencies with more regular baseline flows which reduce the average flow velocity. In addition, Sokhunti shows a greater sensitivity to soil influx during flood events due to the nature of its 'background' of autochthonous biogenic sedimentation. The timing of the overall shift in sediment composition and the dates of the mineral inwash events are not well defined, but the potential for these wetlands as sensitive recorders of dam-induced changes in floodplain hydrology, especially those with a similar setting to Sokhunti pan, is clearly demonstrated. Copyright 2010 Elsevier Ltd. All

  17. Impacts of Groundwater Recharge from Rubber Dams on the Hydrogeological Environment in Luoyang Basin, China

    Directory of Open Access Journals (Sweden)

    Shaogang Dong

    2014-01-01

    Full Text Available In the rubber dam’s impact area, the groundwater total hardness (TH has declined since 2000, ultimately dropping to 100–300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000–2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced.

  18. Ecological consequences of hydropower development in Central America: Impacts of small dams and water diversion on neotropical stream fish assemblages

    Science.gov (United States)

    Anderson, Elizabeth P.; Freeman, Mary C.; Pringle, C.M.

    2006-01-01

    Small dams for hydropower have caused widespread alteration of Central American rivers, yet much of recent development has gone undocumented by scientists and conservationists. We examined the ecological effects of a small hydropower plant (Dona Julia Hydroelectric Center) on two low-order streams (the Puerto Viejo River and Quebradon stream) draining a mountainous area of Costa Rica. Operation of the Dona Julia plant has dewatered these streams, reducing discharge to ~ 10% of average annual flow. This study compared fish assemblage composition and aquatic habitat upstream and downstream of diversion dams on two streams and along a ~ 4 km dewatered reach of the Puerto Viejo River in an attempt to evaluate current instream flow recommendations for regulated Costa Rican streams. Our results indicated that fish assemblages directly upstream and downstream of the dam on the third order Puerto Viejo River were dissimilar, suggesting that the small dam (fishes. Along the ~ 4 km dewatered reach of the Puerto Viejo River, species count increased with downstream distance from the dam. However, estimated species richness and overall fish abundance were not significantly correlated with downstream distance from the dam. Our results suggested that effects of stream dewatering may be most pronounced for a subset of species with more complex reproductive requirements, classified as equilibrium-type species based on their life-history. In the absence of changes to current operations, we expect that fish assemblages in the Puerto Viejo River will be increasingly dominated by opportunistic-type, colonizing fish species. Operations of many other small hydropower plants in Costa Rica and other parts of Central America mirror those of Doha Julia; the methods and results of this study may be applicable to some of those projects.

  19. The combined impact on the flooding in Vietnam's Mekong River delta of local man-made structures, sea level rise, and dams upstream in the river catchment

    Science.gov (United States)

    Le, Thi Viet Hoa; Nguyen, Huu Nhan; Wolanski, Eric; Tran, Thanh Cong; Haruyama, Shigeko

    2007-01-01

    The Mekong River delta plays an important role in the Vietnamese economy and it has been severely impacted during this century by a series of unusually large floods. In the dry season the delta is also impacted by salinity intrusion and tides. These effects have caused severe human hardship. To mitigate these impacts, a large number of engineering structures, primarily dykes and weirs, have been built in the delta in recent years and are still being built, mainly to control floods and saltwater intrusion. These control measures are still being upgraded. A GIS-linked numerical model shows that the flood levels in the delta depend on the combined impacts of high river flows in the Mekong River, storm surges, sea level rise, and the likely, future siltation of the Mekong Estuary resulting from the construction of dams in China as well as many other dams proposed throughout the remaining river catchment. The model suggests that the engineering structures in the delta increase the flow velocities in the rivers and canals, increasing bank erosion, and cause the water to be deeper in the rivers and canals. This increases flooding in the non-protected areas of the delta and increases the risk of catastrophic failure of the dykes in the protected areas. The model also predicts that a sea level rise induced by global warming will enhance flooding in the Mekong River delta in Vietnam, and that flooding may worsen in the long term as a result of estuarine siltation resulting from the construction of dams. At the scale of the Mekong River basin, a multinational water resources management plan is needed that includes the hydrological needs of the delta. At the scale of the delta, a compromise is needed between allowing some flooding necessary for agriculture and preventing catastrophic flooding to alleviate human suffering.

  20. Assessment of dam impacts on river flow regimes and water quality: a case study of the Huai River Basin in P. R. China

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; ZHANG Yong-yong; WANG Gang-sheng

    2008-01-01

    The Huai River Basin is a unique area in P.R.China with the highest densities of population and water projects. It is also subject to the most serious water pollution. We proposed a distributional SWAT (Soil and Water Assessment Tool) model coupled with a water quality-quantity balance model to evaluate dam impacts on river flow regimes and water quality in the middle and upper reaches of the Huai River Basin. We calibrated and validated the SWAT model with data from 29 selected cross-sections in four typical years (1971, 1981, 1991 and 1999) and used scenario analysis to compensate for the unavailability of historical data regarding uninterrupted river flows before dam and floodgate construction, a problem of prediction for ungauged basins. The results indicate that dam and floodgate operations tended to reduce runoff, decrease peak value and shift peaking time.The contribution of water projects to river water quality deterioration in the concerned river system was between 0 to 40%, while pollutant discharge contributed to 60% to 100% of the water pollution. Pollution control should therefore be the key to the water quality rehabilitation in the Huai River Basin.

  1. Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River

    Science.gov (United States)

    Li, Mingzheng; Duan, Zhonghua; Gao, Xin; Cao, Wenxuan; Liu, Huanzhang

    2016-09-01

    Silver carp ( Hypophthalmichthys molitrix), bighead carp ( Aristichthys nobilis), grass carp ( Ctenopharyngodon idella), and black carp ( Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China. Reproduction of these carp has declined since the construction of the Three Gorges Dam (TGD) due to an altered water flow and thermal regime in the Changjiang (Yangtze) River. However, details of the changes in reproduction of the four species are not well understood. To assess the impact of the TGD on reproduction of the four carp, we investigated their eggs and larvae at Yidu City, which is 80 km below the TGD, during 2005-2012. We examined diff erences in larval abundance of the four species in the Jianli section (350 km downstream of the TGD) before (1997-2002) and after (2003-2012) construction of the TGD. Based on these observations, the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed. Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million, which were significant decreases since the 1980s. Moreover, larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction (ANCOVA, Pconserve these four major Chinese carps species.

  2. Impact of Kishnica and Badovci Flotation Tailing Dams on Levels of Heavy Metals in Water of Graçanica River (Kosovo

    Directory of Open Access Journals (Sweden)

    Fatbardh Gashi

    2017-01-01

    Full Text Available The main objective of this study was to perform assessment of water quality of Graçanica River (Kosovo, impacted by Kishnica and Badovci flotation tailing dams, using ICP-OES method. The obtained results show that the mean values of all heavy metals in studied river water samples were significantly high, with following maximal concentrations: As (0.033 mgL−1, Cd (0.002 mgL−1, Cr (0.225 mgL−1, Cu (0.015 mgL−1, Hg (0.004 mgL−1, Mn (15.66 mgL−1, Ni (0.255 mgL−1, Pb (0.013 mgL−1, and Zn (0.612 mgL−1, but only two samples from locations influenced by Kishnica and Badovci flotation tailing dams showed statistically anomalous values of Cr3+, Cu2+, Mn2+, Zn2+, and Hg2+. According to assessment based on Croatian standards, locations near both flotation tailing dams are significantly polluted with majority of studied metals, while downstream sampling stations are almost unpolluted or slightly polluted. Mercury is found to be the most significant contaminant. According to WHO recommended values for drinking water, on all locations values were within the limits for Al, Cd, Cu, and Zn, while for As, Cr, Hg, Mn, Ni, and Pb values exceed recommended values on some sampling stations. Further monitoring of water and possibly sediments of Graçanica River is advised, as well as performing of remediation of Kishnica and Badovci mine tailing dams.

  3. Mechanical effects of excavation rebound of arch dam bedrock and better concreting time of dam body

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In high ground stress zone, rebound deformation of excavation of arch dam bedrock has a significant impact on the structural behavior, design and construction of arch dam. Based on the analysis of mechanical effects of excavation rebound, with both stress and deformation as two constraint conditions and deformation modulus as a controlling condition, the method to determine a better concreting time of dam body was put forward. All of these play an important guiding role in the excavation of dam bedrock and the construction of dam body.

  4. Columbia River System Operation Review : Final Environmental Impact Statement, Appendix D: Exhibits.

    Energy Technology Data Exchange (ETDEWEB)

    Columbia River System Operation Review (U.S.)

    1995-11-01

    The Columbia River and its tributaries are the primary water system in the Pacific Northwest, draining some 219,000 square miles in seven states and another 39,500 square miles in British Columbia. Beginning in the 1930`s, the Columbia River has been significantly modified by construction of 30 major dams on the river and its tributaries, along with dozens of non-Federal projects. Construction and subsequent operation of these water development projects have contributed to eight primary uses of the river system, including navigation, flood control, irrigation, electric power generation, fish migration, fish and wildlife habitat, recreation, and water supply and quality considerations. Increasing stress on the water development of the Columbia River and its tributaries has led primary Federal agencies to undertake intensive analysis and evaluation of the operation of these projects. These agencies are the U.S. Army Corps of Engineers and the Bureau of Reclamation, who operate the large Federal dams on the river, and the Bonneville Power Administration who sells the power generated at the dams. This review, termed the System Operation Review (SOR), has as its ultimate goal to define a strategy for future operation of the major Columbia River projects which effectively considers the needs of all river uses. This volume, Appendix D: Cultural resources appendix, Technical imput includes the following: Development of geomorphology based framework for cultural resources management, Dworshak Reservoir, Idaho; Impact profiles for SOR reservoirs; comments from the following Native American tribes: Burns Paiute Tribe; Coville Confederated Tribes; Confederated Tribes of the Warm Springs Indian Reservation; Confederated Tribes and bands of the Yakama Indian Nation (comments); Nez Perce Tribe; Coeur D`Alene Tribe; Spokane Tribe of Indians; The confederated Tribes of the Umatilla Indian Reservation.

  5. Design of adaptation actions to compensate the hydrological impact of the river regulation by dams on the Ebro Delta (Spain): combining modeling and field work.

    Science.gov (United States)

    Contreras, Darío; Jurado, Alicia; Carpintero, Miriam; Rovira, Albert; Polo, María J.

    2016-04-01

    River regulation by dams for both flood control and water storage has allowed to decrease both uncertainty and risks associated to extreme hydrological events. However, the alteration of the natural river flow regime and the detraction of high water volumes usually lead to significant effects downstream on the morphology, water quality, ecological status of water… and this is particularly relevant in the transitional waters since the sea level rise poses an additional threat on such conditions. The Ebro River, in northeastern Spain, is one of the highly regulated rivers in Spain with the dams located in the mainstream. Besides an estimated decrease of a 30% of the freshwater inputs, the sediment delivery to the final delta in the Mediterranean has dramatically been decreased up to a 99%, with environmental risks associated to the reduction of the emerged areas from the loss of sediment supply, the impact on the subsidence dynamics, and the sea level rise. The Ebro Delta suffers a mean regression of 10 m per year, and the persistence of macrophyte development in the final reach of the river due to the low water mean flow regime. The project LIFE EBRO-ADMICLIM (ENV/ES/001182), coordinated by the IRTA in Catalonia (Spain), puts forwards pilot actions for adaptation to and mitigation of climate change in the Ebro Delta. An integrated approach is proposed for managing water, sediment and habitats (rice fields and wetlands), with the multiple aim of optimizing ground elevation, reducing coastal erosion, increasing the accumulation (sequestration) of carbon in the soil, reducing emissions of greenhouse gases (GHG), and improving water quality. This work presents the pilot actions included in the project to mitigate the loss of water flow and sediment supply to the delta. Sediment injections at different points upstream have been designed to calibrate and validate a sediment transport model coupled to a 2D-hydrodinamic model of the river. The combination of an a

  6. Geomorphic response to large-dam removal: Impacts of a massive sediment release to the Elwha River, Washington

    Science.gov (United States)

    Magirl, C. S.; Ritchie, A.; Bountry, J.; Randle, T. J.; East, A. E.; Hilldale, R. C.; Curran, C. A.; Pess, G. R.

    2015-12-01

    The 2011-2014 staged removals of two nearly century-old dams on the Elwha River in northwest Washington State, the largest dam-removal project in the United States, exposed 21 million m3 of reservoir-trapped sand and gravel to potential fluvial transport. The river downstream from the dams is gravel bedded with a pool-riffle morphology. The river flows 20 km to the marine environment through a riparian corridor lined with large wood and having relatively few anthropogenic alterations. This moderately natural pre-dam-removal condition afforded an unprecedented opportunity to study river response to an anticipated massive sediment release. Four years into the project, 12 million m3 of sediment eroded from the former reservoirs with about 90% of the total load transported to the marine environment. Annualized sediment discharge was as great as 20 times the background natural load. Initial river response to the arrival of the first large sediment pulse was the nearly complete filling of the river's previously sediment-starved pools, widespread filling of side channels, and increased braiding index. In year 2, during maximum aggradation, the river graded to a plane-bedded system, efficiently conveying sediment to the marine environment. Modest peak flows (<2-yr return period) in year 2 promoted sediment transport but caused little large-scale geomorphic disturbance by channel migration or avulsions. As the river processed the sediment pulse, pools returned and the braiding index decreased in years 3-4. Higher peak flows in year 4 caused localized channel widening and migration but no major avulsions. Gauging indicated sand dominated the first stages of sediment release, but fluvial loads coarsened through time with progressive arrival of larger material. The literature suggests the Elwha River sediment wave should have evolved through dispersion with little translation. However, morphologic measurements and data from a stage-gauge network indicated patterns of

  7. Alleviating dam impacts along the transboundary Se San River in northeast Cambodia : a review of the rapid environmental impact assessment on the Cambodian part of the Se San River due to hydropower development in Vietnam (July 2007 version)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-02-15

    Probe International has reviewed 2 reports regarding the environmental impact assessment (EIA) on the Cambodian part of the Se San River resulting from hydropower development in Vietnam. Both reports were prepared for Electricity of Vietnam (EVN), the project owner and developer. The operation of 3 large hydro dams on the upper Se San River has disrupted flow in downstream Cambodia where more than 28,000 people depend on the river for drinking water, irrigation, fishing, livestock watering and transportation. Probe International's focus is on mitigating and compensating for affected communities in downstream Cambodia. Their review of the EIAs recommends that Electricity of Vietnam consider switching from peaking to base load operations at its upper Se San hydro dams to mitigate the impacts in downstream Cambodia. The downstream impacts of EVN dams on the Se San River include loss of life, property, livelihood and habitat; malnutrition; loss of wet season rice production; reduced fish catches; food security at risk; loss of fish protein; loss of river bank agriculture; reduced availability of plants for food and medicine; river bank erosion; reservoir erosion and downstream turbidity; increased transportation risks; loss of fisheries habitat; increased pressure on upland forests; disrupted riverine ecosystem; and disrupted fish migration. The EIA recommendations include the re-regulation of the Se San 4A reservoir; operational changes to reduce downstream fluctuations and erosion; monitoring impact of operations on water quantity and quality downstream; algal monitoring; establishment of early warning system for spillway release; prolonging the wet season filling of the reservoir; reducing nutrient inputs to the rivers and reservoirs and a fish stocking program. 6 figs., 1 appendix.

  8. Experimental research on the dam-break mechanisms of the Jiadanwan landslide dam triggered by the Wenchuan earthquake in China.

    Science.gov (United States)

    Xu, Fu-gang; Yang, Xing-guo; Zhou, Jia-wen; Hao, Ming-hui

    2013-01-01

    Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.

  9. Geomorphic impacts, age and significance of two giant landslide dams in the Nepal Himalayas: Ringmo-Phoksundo (Dolpo District) and Dhampu-Chhoya (Mustang District).

    Science.gov (United States)

    Fort, Monique; Braucher, Regis; Bourlès, Didier; Guillou, Valery; Nath Rimal, Lila; Gribenski, Natacha; Cossart, Etienne

    2014-05-01

    Large catastrophic slope failures have recently retained much attention in the northern dry Himalayas (1). They play a prominent role in the denudation history of active orogens at a wide range of spatial and time scales (2), and they impact durably landforms and process evolution in upstream catchments. Their occurrence mostly results from three different potential triggers: earthquakes, post-glacial debuttressing, and permafrost melting. We focus on two examples of giant rock slope failures that occurred across and north of the Higher Himalaya of Nepal and assess their respective influence on the regional, geomorphic evolution. The Ringmo rockslide (4.5 km3) results from the collapse of a mountain wall (5148 m) cut into palaeozoic dolomites of the Tethysian Himalayas. It caused the damming of the Suli Gad River at the origin of the Phoksumdo Lake (3600 m asl). The presence of glacial till at the very base of the sequence suggests the rockslide event is post-glacial, a field assumption confirmed by cosmogenic dating. Two consistent 36Cl ages of 20,885 ±1675 argue for a single, massive event of paraglacial origin that fits well with the last chronologies available on the Last Glacial Maximum in the Nepal Himalaya. The persistence of the Phoksumdo Lake is due to its dam stability (i.e. high lime content of landslide components) and to low sediment flux from the arid, upper Suli Gad catchment. The Dhampu-Chhoya rock avalanche (about 1 km3, area extent 10 km2) was derived from the northward failure of the Kaiku ridge, uphold by north-dipping, upper crystallines of the Higher Himalaya. It dammed the Kali Gandaki River, with complex interactions with the Late Pleistocene ice tongues derived from the Dhaulagiri (8167 m) and Nilgiris (7061 m) peaks. Both the rock avalanche and glaciers controlled the existence and level of the "Marpha Lake" (lacustrine deposits up to Kagbeni). Again, consistent 10Be ages of 29,680 ± 1015 ka obtained from two large blocks (>1000 m3

  10. Dams and transnational advocacy: Political opportunities in transnational collective action

    Science.gov (United States)

    Fu, Teng

    Possible arguments to explain the gradual decline in big dam development and its site transferring from developed to developing countries include technical, economic, and political factors. This study focuses on the political argument---the rise of transnational anti-dam advocacy and its impact on state policy-making. Under what conditions does transnational anti-dam advocacy matter? Under what conditions does transnational advocacy change state dam policies (delay, scale down, or cancel)? It examines the role of transnational anti-dam actors in big dam building in a comparative context in Asia. Applying the social movement theory of political opportunity structure (POS) and using the qualitative case-study method, the study provides both within-case and cross-case analyses. Within-case analysis is utilized to explain the changing dynamics of big dam building in China (Three Gorges Dam and proposed Nu/Salween River dam projects), and to a lesser extent, Sardar Sarovar Project in India and Nam Theun 2 Dam in Laos. Different domestic and international POS (DPOS and IPOS) impact the strategies and outcomes of anti-dam advocacies in these countries. The degree of openness of the POS directly affects the capacity of transnational efforts in influencing state dam policies. The degree of openness or closure is measured by specific laws, institutions, discourse, or elite allies (or the absence of these) for the participation of non-state actors on big dam issues at a particular moment. This degree of openness is relative, varying over time, across countries and regions. This study finds that the impact of transnational anti-dam activism is most effective when both DPOS and IPOS are relatively open. Transnational anti-dam advocacy is least effective in influencing state dam policies when both DPOS and IPOS are relatively closed. Under a relatively open DPOS and closed IPOS, transnational anti-dam advocacy is more likely to successfully change state dam policies and even

  11. Alpine dams

    Directory of Open Access Journals (Sweden)

    Alain Marnezy

    2009-03-01

    Full Text Available Les barrages-réservoirs de montagne ont été réalisés initialement dans les Alpes pour répondre à la demande d’énergie en période hivernale. Une certaine diversification des usages de l’eau s’est ensuite progressivement développée, en relation avec le développement touristique des collectivités locales. Aujourd’hui, la participation des ouvrages d’Électricité De France à la production de neige de culture représente une nouvelle étape. Dans les régions où les aménagements hydroélectriques sont nombreux, les besoins en eau pour la production de neige peuvent être résolus par prélèvements à partir des adductions EDF. Les gestionnaires de stations échappent ainsi aux inconvénients liés à la construction et à la gestion des « retenues collinaires ». Cette évolution, qui concerne déjà quelques régions alpines comme la haute Maurienne ou le Beaufortin, apparaît comme une forme renouvelée d’intégration territoriale de la ressource en eau.Mountain reservoirs were initially built in the Alps to meet energy needs in the winter. A certain diversification in the uses of water then gradually developed, related to tourism development in the local communities. Today, the use of facilities belonging to EDF (French Electricity Authority to provide water for winter resorts to make artificial snow represents a new phase. By taking water from EDF resources to supply snow-making equipment, resort managers are thus able to avoid the problems related to the construction and management of small headwater dams. This new orientation in the use of mountain water resources already affects a number of alpine regions such as the Upper Maurienne valley and Beaufortain massif and represents a renewed form of the territorial integration of water resources.

  12. Iran funds dam completion

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Iran has signed a contract with unnamed foreign financiers for US$300M to fund two half-finished dam schemes, according to Tehran radio. The schemes are the Ostur dam in Mianeh in East Azerbaijan province and the Molla Sadra dam in Fars province. The Ostur dam will have a storage capacity of 2B m3 and a 160 MW hydro power station.

  13. Hoover Dam Learning Packet.

    Science.gov (United States)

    Bureau of Reclamation (Dept. of Interior), Washington, DC.

    This learning packet provides background information about Hoover Dam (Nevada) and the surrounding area. Since the dam was built at the height of the Depression in 1931, people came from all over the country to work on it. Because of Hoover Dam, the Colorado River was controlled for the first time in history and farmers in Nevada, California, and…

  14. Expectations of immortality: dam safety management into the next millennium

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, M.D. [Tonkin and Taylor International Ltd., Auckland, (New Zealand)

    1999-07-01

    Topics concerning the problems associated with older and aging dams are considered including: what can be done to extent the lifetime of an old dam, the decision to decommission a dam based on a value judgment that the risk of maintaining the dam is too great for society's acceptance, the possibility of change in the level of risk tolerance with time in a technological environment, traditional surveillance methods used by dam owners in the Y2K situation, and the unreality of dam immortality. Trends and means for preserving older dams for their owner's purposes are outlined, as well as their lifetime compared to that of the downstream systems they serve. Despite the fact that we live in a throwaway society, dam owners cannot just leave their dam asset when they are through with using it. Someone has to maintain the dam, or ensure that it is safely decommissioned when the owner is finished with it. On a worldwide scale the available pool of experienced dam engineers is shrinking. This problem needs to be addressed by a shift towards operating and dam safety management skills based on a firm awareness of dam design principles. A shift in society's expectations has occurred such that dam designers and owners must now recognize the impact a dam can have both on its natural and social environments. Because of the increasing emphasis on paying attention to the impacts of people's activities on the planet, engineers more than anyone else must have a significant influence in that direction. 9 refs.

  15. Sustainability of dams-an evaluation approach

    Science.gov (United States)

    Petersson, E.

    2003-04-01

    Situated in the stream bed of a river, dams and reservoirs interrupt the natural hydrological cycle. They are very sensitive to all kinds of changes in the catchment, among others global impacts on land use, climate, settlement structures or living standards. Vice versa dams strongly affect the spatially distributed, complex system of ecology, economy and society in the catchment both up- and downstream of the reservoir. The occurrence of negative impacts due to large dams led to serious conflicts about future dams. Nevertheless, water shortages due to climatic conditions and their changes, that are faced by enormous water and energy demands due to rising living standards of a growing world population, seem to require further dam construction, even if both supply and demand management are optimised. Although environmental impact assessments are compulsory for dams financed by any of the international funding agencies, it has to be assumed that the projects lack sustainability. Starting from an inventory of today's environmental impact assessments as an integral part of a feasibility study the presentation will identify their inadequacies with regard to the sustainability of dams. To improve the sustainability of future dams and avoid the mistakes of the past, the planning procedures for dams have to be adapted. The highly complex and dynamical system of interrelated physical and non-physical processes, that involves many different groups of stakeholders, constitutes the need for a model-oriented decision support system. In line with the report of the World Commission of Dams an integrated analysis and structure of the complex interrelations between dams, ecology, economy and society will be presented. Thus the system, that a respective tool will be based on, is analysed. Furthermore an outlook will be given on the needs of the potential users of a DSS and how it has to be embedded in the overall planning process. The limits of computer-based decision-support in the

  16. Do we need construct more dams?

    Science.gov (United States)

    Chen, J.; Shi, H.

    2013-12-01

    This paper reviews global dam development in association with the growths of global population, economy, and energy consumption in the past several decades, and also evaluates contributions of dam development to future world sustainable development. Eventually, this paper answers whether we need more dams in the future or not. The world population has rapidly increased from 1.6 billion in 1900, 2.5 billion in 1950, 6.1 billion in 2000, to 7.0 billion in 2011, and is projected to reach 9.5 billion in 2050; similarly, the world economy has dramatically expanded. To maintain socioeconomic development, the consumption of water, food and energy has increased rapidly as well. However, the total volume of available water resource over the world is limited, the food production largely depends on water supply, and the main energy sources are still oil, coal and gas at present, which are regarded as non-renewable resources. Accordingly, it is expected that we will face serious problems to deal with the challenges of water crisis, food security and energy shortage in the near future. In order to enhance the capability of regulating water resource, a great number of global dams (and related reservoirs) have been constructed in the last one hundred years; currently, almost all large rivers over the world have been regulated by dams. The reservoirs can supply sufficient water for irrigated land to ensure food production, and the associated hydropower stations can generate electricity. This article collects the dam data from the ICOLD (International Commission on Large Dams) and GRanD (Global Reservoir and Dam) databases, and some socioeconomic data, including population, economy, and consumptions of water, food and energy over the world. Analysis of these data reveals that global dam development has a great impact on the world sustainable development. Further, it is concluded that we need further dam development to maintain our future development.

  17. The Effects of the Anti-Dam Movement on the Environmental Protection in American West

    Institute of Scientific and Technical Information of China (English)

    赵倩

    2009-01-01

    This paper examines the far - reaching influence of anti - dam movement on the protection of environment in the second half of the 20th century in American West. It first introduces the historical background of dams built along the Colorado Biver - the most important river in the West, especially the construction of Hoover Dam and Glen Canyon Dam. Then, the criticism of dams on the Colorado is examined with the emphasis on the anti - dam movement resulting from the awareness of the negative ecological impacts on the Colorado. In the conclusion, the author demonstrates the unparallel historical significance of the anti -dam movement in the en-vironmentalism in developing the American West.

  18. Dam removal: Listening in

    Science.gov (United States)

    Foley, Melissa M.; Bellmore, James; O'Connor, James E.; Duda, Jeff; East, Amy E.; Grant, Gordon G.; Anderson, Chauncey; Bountry, Jennifer A.; Collins, Mathias J.; Connolly, Patrick J.; Craig, Laura S.; Evans, James E.; Greene, Samantha; Magilligan, Francis J.; Magirl, Christopher S.; Major, Jon J.; Pess, George R.; Randle, Timothy J.; Shafroth, Patrick B.; Torgersen, Christian; Tullos, Desiree D.; Wilcox, Andrew C.

    2017-01-01

    Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (methods in the U.S.

  19. Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake; Effects of Operation of Kerr and Hungry Horse Dam on Reproductive Success, 1983 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Decker-Hess, Janet; McMullin, Steve L.

    1983-11-01

    Domrose (1968) found live eggs and fry only in shoreline spawning areas wetted by groundwater seeps. Impacts of the operation of Kerr Dam on lakeshore spawning have not been quantified. Recent studies have revealed that operation of Hungry Horse Dam severely impacted successful kokanee spawning and incubation in the Flathead River above Flathead Lake (Graham et al. 1980, McMullin and Graham 1981, Fraley and Graham 1982 and Fraley and McMullin 1983). Flows from Hungry Horse Dam to enhance kokanee reproduction in the river system have been voluntarily met by the Bureau of Reclamation since 1981. In lakeshore spawning areas in other Pacific Northwest systems, spawning habitat for kokanee and sockeye salmon was characterized by seepage or groundwater flow where suitable substrate composition existed (Foerster 1968). Spawning primarily occurred in shallower depths (<6 m) where gravels were cleaned by wave action (Hassemer and Rieman 1979 and 1980, Stober et al. 1979a). Seasonal drawdown of reservoirs can adversely affect survival of incubating kokanee eggs and fry spawned in shallow shoreline areas. Jeppon (1955 and 1960) and Whitt (1957) estimated 10-75 percent kokanee egg loss in shoreline areas of Pend Oreille Lake, Idaho after regulation of the upper three meters occurred in 1952. After 20 years of operation, Bowler (1979) found Pend Oreille shoreline spawning to occur in fewer areas with generally lower numbers of adults. In studies on Priest Lake, Idaho, Bjornn (1957) attributed frozen eggs and stranded fry to winter fluctuations of the upper three meters of the lake. Eggs and fry frozen during winter drawdown accounted for a 90 percent loss to shoreline spawning kokanee in Donner Lake, California (Kimsey 1951). Stober et al. (1979a) determined irrigation drawdown of Banks Lake, Washington reduced shoreline survival during five of the seven years the system was studied. The goal of this phase of the study was to evaluate and document effects of the operation of Kerr Dam

  20. Seismic Analysis of Morrow Point Dam

    Energy Technology Data Exchange (ETDEWEB)

    Noble, C R

    2002-04-01

    The main objective of this study is to perform nonlinear dynamic earthquake time history analyses on Morrow Point Dam, which is located 263 km southwest of Denver, Colorado. This project poses many significant technical challenges, one of which is to model the entire Morrow Point Dam/Foundation Rock/Reservoir system which includes accurate geology topography. In addition, the computational model must be initialized to represent the existing dead loads on the structure and the stress field caused by the dead loads. To achieve the correct dead load stress field due to gravity and hydrostatic load, the computer model must account for the manner in which the dams were constructed. Construction of a dam finite element model with the correct as-built geometry of the dam structure and simply ''turning on'' gravity in the computer model will generally lead to an incorrect initial stress field in the structure. The sequence of segmented lifts typical of dam construction has a significant impact on the static stress fields induced in the dam. In addition, the dam model must also account for the interaction between the adjacent dam segments across the dam contraction joints. As a result of these challenges, it was determined that a significant amount of code development was required in order to accurately simulate the motion of the dam structure. Modifications to the existing slide surfaces are needed to allow for appropriate modeling of the shear keys across the contraction joints. Furthermore, a model for hydrodynamic interaction was also implemented into NIKE3D and DYNA3D for fluid representation in the 3D dam system finite element model. Finally, the modeling of the 3D dam system results in a very large computational model, which makes it difficult to perform a static initialization using an implicit code. Traditionally, for these large models, the model has been initialized over a long time scale using an explicit code. However, recent advancements

  1. Impact of the Low Head Dam/Barrage on Fisheries – A Case Study of Giri River of Yamuna Basin (India

    Directory of Open Access Journals (Sweden)

    Rumana Harcharan Singh

    2015-12-01

    Full Text Available Shannon’s diversity index H’ = pi log2 pi was calculated for 16 fish species. The index was resolved into its components, species richness and relative abundance, to determine which components played a larger role in the determination of diversity pattern. Changes in diversity were correlated with species richness (r, habitat heterogeneity, and hydrological regimes in a longitudinal stretch of 35 km along the river Giri, a major tributary of the Yamuna River system, in Western Himalayas. Abundance differs with change in habitat structures, habitat preference of fish species and water regimes. The decrease in diversity in the lower stretch of about 3-4 km upstream of the barrage was found to be associated with habitat fragmentation and as well as d/s with loss of biotic integrity of aquatic ecosystem due to water scarcity. Species richness was found to be maximum at upper and middle reaches (elevation 650-800 m, msl of the river, whereas it was low in lower reaches. Change in water chemistry was also noticed at Jatan barrage-low head dam due to impoundment of river water. It is inferred that the regulation of water has an impact on species richness and relative abundance, and on habitat heterogeneity which has decreased due to the change in environmental condition.

  2. Dam to the Rescue

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Three Gorges Dam relieves the summer drought in south and central China,but may contribute to other problems The Three Gorges Dam played an important role in relieving China’s drought in central and eastern prov-inces that had been using increased water discharges from the Dam to irrigate dry farmlands facing the worst drought int he last 60 years in 2011.

  3. Impacts of the dam-orientated water-sediment regulation scheme on the lower reaches and delta of the Yellow River (Huanghe): A review

    Science.gov (United States)

    Wang, Houjie; Wu, Xiao; Bi, Naishuang; Li, Song; Yuan, Ping; Wang, Aimei; Syvitski, James P. M.; Saito, Yoshiki; Yang, Zuosheng; Liu, Sumei; Nittrouer, Jeffrey

    2017-10-01

    The water-sediment regulation scheme (WSRS), beginning in 2002, is an unprecedented engineering effort to manage the Yellow River with the aims to mitigate the siltation both in the lower river channel and within the Xiaolangdi Reservoir utilizing the dam-regulated flood water. Ten years after its initial implementation, multi-disciplinary indicators allow us to offer a comprehensive review of this human intervention on a river-coastal system. The WSRS generally achieved its objective, including bed erosion in the lower reaches with increasing capacity for flood discharge and the mitigation of reservoir siltation. However, the WSRS presented unexpected disturbances on the delta and coastal system. Increasing grain size of suspended sediment and decreasing suspended sediment concentration at the river mouth resulted in a regime shift of sediment transport patterns that enhanced the disequilibrium of the delta. The WSRS induced an impulse delivery of nutrients and pollutants within a short period ( 20 days), which together with the altered hydrological cycle, impacted the estuarine and coastal ecosystem. We expect that the sediment yield from the loess region in the future will decrease due to soil-conservation practices, and the lower channel erosion will also decrease as the riverbed armors with coarser sediment. These, in combination with uncertain water discharge concomitant with climate change, increasing water demands and delta subsidence, will put the delta and coastal ocean at high environmental risks. In the context of global change, this work depicts a scenario of human impacts in the river basin that were transferred along the hydrological pathway to the coastal system and remotely transformed the different components of coastal environment. The synthesis review of the WSRS indicates that an integrated management of the river-coast continuum is crucially important for the sustainability of the entire river-delta system. The lessons learned from the WSRS in

  4. Living with dams

    NARCIS (Netherlands)

    H.L.F. Saeijs (Henk); K.D. Schuijt (Kirsten)

    2002-01-01

    textabstractDams have proven their usefulness in preventing and mitigating floods, and water scarcity and generating electricity. They are indispensable in present society. But at the same time, they cause serious ecological, social and economical problems. Consequently we have to live with a dams

  5. The Nahal Oz Reservoir dam-break flood: Geomorphic impact on a small ephemeral loess-channel in the semi-arid Negev Desert, Israel

    Science.gov (United States)

    Roskin, Joel; Bergman, Nathaniel; Shaulker, Ofer; Greenbaum, Noam

    2014-05-01

    and as distance from the source area increases, available energy is substantially reduced due to high transmission losses, gentler valley gradients, very wide shallow flow and the ability of the drainage network to accommodate large discharges. Consequently, the geomorphic impact was limited to the first 2.6 km with only minor erosional or depositional evidence downstream. The current natural flow regime has only minor impact on the newly formed channel geometry below the breached dam. Accordingly, the channel geometry may be preserved for a relatively long time. However, channel recovery in this segment was rapid and within a few years all bare loess surfaces exposed during the flood have been covered by dense vegetation. The analysis also shows that Nahal Oz Reservoir's dam-break flood transmission losses and flood attenuation rates were extreme in comparison to other case studies. This artificial flood event in a desert environment offers a rare opportunity to quantify channel and bank erosion evolution processes during an extremely high magnitude flood within highly erodible fine sediment as well as to detect the recovery processes a few years later.

  6. Estimating flood inundation caused by dam failures

    Energy Technology Data Exchange (ETDEWEB)

    Mocan, N. [Crozier and Associates Inc., Collingwood, ON (Canada); Joy, D.M. [Guelph Univ., ON (Canada). School of Engineering; Rungis, G. [Grand River Conservation Authority, Cambridge, ON (Canada)

    2006-01-15

    Recent advancements in modelling inundation due to dam failures have allowed easier and more illustrative analyses of potential outcomes. This paper described new model and mapping capabilities available using the HEC-RAS hydraulic model in concert with geographic information systems (GIS). The study area was the upper reaches of Canagagigue Creek and the Woolwich Dam near Elmira, Ontario. A hydraulic analysis of a hypothetical dam failure was developed based on the summer probable maximum flood (PMF) event. Limits extended from Woolwich Dam to downstream of the Town of Elmira. An incoming summer PMF hydrograph was set as the upstream boundary condition in the upstream model. Simulation parameters include simulation time-step; implicit weighting factor; water surface calculation tolerance; and output calculation interval. Peak flows were presented, as well as corresponding flood inundation results through the Town of Elmira. The hydraulic model results were exported to a GIS in order to develop inundation maps for emergency management planning. Results from post-processing included inundation maps for each of the simulated time-steps as well as an inundation animation for the duration of the dam breach. It was concluded that the modelling tools presented in the study can be applied to other dam safety assessment projects in order to develop effective and efficient emergency preparedness plans through public consultation and the establishment of impact zones. 1 tab., 2 figs.

  7. Role of the Small Intestine in Developmental Programming: Impact of Maternal Nutrition on the Dam and Offspring.

    Science.gov (United States)

    Meyer, Allison M; Caton, Joel S

    2016-01-01

    Small-intestinal growth and function are critical for optimal animal growth and health and play a major role in nutrient digestion and absorption, energy and nutrient expenditure, and immunological competence. During fetal and perinatal development, the small intestine is affected by the maternal environment and nutrient intake. In ruminants, altered small-intestinal mass, villi morphology, hypertrophy, hyperplasia, vascularity, and gene expression have been observed as a result of poor gestational nutrition or intrauterine growth restriction. Although many of these data come from fetal stages, data have also demonstrated that nutrition during mid- and late gestation affects lamb small-intestinal growth, vascularity, digestive enzyme activity, and gene expression at 20 and 180 d of age as well. The small intestine is known to be a highly plastic tissue, changing with nutrient intake and physiological state even in adulthood, and the maternal small intestine adapts to pregnancy and advancing gestation. In ruminants, the growth, vascularity, and gene expression of the maternal small intestine also adapt to the nutritional plane and specific nutrient intake such as high selenium during pregnancy. These changes likely alter both pre- and postnatal nutrient delivery to offspring. More research is necessary to better understand the role of the offspring and maternal small intestines in whole-animal responses to developmental programming, but programming of this plastic tissue seems to play a dynamic role in gestational nutrition impacts on the whole animal.

  8. Geophysical methods for the assessment of earthen dams

    Science.gov (United States)

    Dams and levees are an integral part of the fluvial system in watersheds. Their stability is of utmost concern to the Nation and to those directly impacted should failure occur. There are some 88,000 dams and 110,000 miles of levees in the USA. Many of those are earthen embankments and structures su...

  9. Impulsive force of debris flow on a curved dam

    Institute of Scientific and Technical Information of China (English)

    Chjeng-Lun SHIEH; Chia-Hsien TING; Hung-Wen PAN

    2008-01-01

    Although Sabo dams are an efficient method for river and basin management,traditional Sabo dams have a great impact on ecology and landscape.Moreover,such dams are hit and often damaged by great impulsive force when they block the debris flow.Therefore,alternative shapes for Sabo dam deserve thorough investigation.In this investigation,a curved dam was designed by changing the upstream-dam-surface geometric shape to reduce the impulsive force of the debris flow,with enhanced stability and reduced concrete mass being the anticipated outcomes.In this study,the flume and laboratory facilities simulated the impulsive force of the debris flow to the Sabo dams.Three geometric forms,including vertical,slanted and curved Sabo dams,were used to determine the impulsive force.Impulsive force theories of the debris flow were derived from the momentum equation and the Bernoulli equation.In these,the impulsive force was balanced by the friction force of the Sabo dam and the opposite force of the load cell behind the dam as it was hit by the debris flow.Positive correlations were found when comparing the experimental data with the theoretical results.These findings suggest that our impulsive force theory has predictive validity with regard to the experimental data.The results from both theory and experimental data clearly show that curved dams were sustained less force than the other dams under the same debris flow.This comparison demonstrates the importance of curved geometry for a well-designed Sabo dam.

  10. A continous Bayesian network for earth dams' risk assessment: methodology and quantification

    NARCIS (Netherlands)

    Morales-Napoles, O.; Delgado-Hernadez-D.J.; De-Leon-Escobedo, D.; Arteaga-Arcos, J.C.

    2013-01-01

    Dams’ safety is highly important for authorities around the world. The impacts of a dam failure can be enormous. Models for investigating dam safety are required for helping decision-makers to mitigate the possible adverse consequences of flooding. A model for earth dam safety must specify clearly p

  11. 76 FR 20707 - Cle Elum Dam Fish Passage Facilities and Fish Reintroduction Project; Kittitas County, WA

    Science.gov (United States)

    2011-04-13

    ... Bureau of Reclamation Cle Elum Dam Fish Passage Facilities and Fish Reintroduction Project; Kittitas... Environmental Impact Statement (FEIS) for the Cle Elum Dam Fish Passage Facilities and Fish Reintroduction... FEIS on the proposed Cle Elum Dam Fish Passage Facilities and Fish Reintroduction Project....

  12. A continous Bayesian network for earth dams' risk assessment: methodology and quantification

    NARCIS (Netherlands)

    Morales-Napoles, O.; Delgado-Hernadez-D.J.; De-Leon-Escobedo, D.; Arteaga-Arcos, J.C.

    2013-01-01

    Dams’ safety is highly important for authorities around the world. The impacts of a dam failure can be enormous. Models for investigating dam safety are required for helping decision-makers to mitigate the possible adverse consequences of flooding. A model for earth dam safety must specify clearly p

  13. Allegheny County Dam Locations

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the point locations of dams in Allegheny County. If viewing this description on the Western Pennsylvania Regional Data Center’s open data portal...

  14. Dams: Pros and Cons

    African Journals Online (AJOL)

    Steve

    The Dam was built for the main purpose of water supply to university community. Data on .... The decision on who is to participate in a full EIA on a water ... METHOD AND MATERIALS ..... Development”, Encyclopedia of Life Support Systems,.

  15. Factors influencing movement of two migratory fishes within the tailrace of a large neotropical dam and their implications for hydropower impacts

    Science.gov (United States)

    Suzuki, F. M.; Dunham, Jason; Silva, L. G. M.; Alves, C. B. M.; Pompeu, P.S.

    2017-01-01

    Fish attempting to move upstream through hydroelectric dams can be trapped and killed in turbines. Understanding fish movement patterns can provide useful insights for how to manage dam operations to minimize fish kill in turbines. We evaluated the movements of two migratory fish (Curimba-Prochilodus argenteus and Mandi-Pimelodus maculatus) using acoustic telemetry in the tailrace of Três Marias Dam (São Francisco River, Brazil) from 31 October 2011 to 16 February 2012. The majority of tagged fish left the tailrace in less than one week; however, some individuals returned, performing several visits to the tailrace. Mandi remained longer in the tailrace than Curimba. The number of visits was influenced by diel period, turbine and spillway discharge. Although the diel period was the only important contributor to the visits performed by Curimba, the movements of Mandi were significantly influenced by three factors. We found that whereas Curimba was predominantly diurnal, Mandi showed nocturnal habits. Additionally, visits of Mandi were significantly greater during higher turbine and spillway discharge. We discuss the implications of these results for understanding fish movements in the Três Marias Dam tailrace and their potential implications for adapting hydroelectric operations to minimize fish kills.

  16. Three Gorges Dam: Impact of Water Level Changes on the Density of Schistosome-Transmitting Snail Oncomelania hupensis in Dongting Lake Area, China.

    Science.gov (United States)

    Wu, Jin-Yi; Zhou, Yi-Biao; Chen, Yue; Liang, Song; Li, Lin-Han; Zheng, Sheng-Bang; Zhu, Shao-ping; Ren, Guang-Hui; Song, Xiu-Xia; Jiang, Qing-Wu

    2015-01-01

    Schistosomiasis remains an important public health issue in China and worldwide. Oncomelania hupensis is the unique intermediate host of schistosoma japonicum, and its change influences the distribution of S. japonica. The Three Gorges Dam (TGD) has substantially changed the ecology and environment in the Dongting Lake region. This study investigated the impact of water level and elevation on the survival and habitat of the snails. Data were collected for 16 bottomlands around 4 hydrological stations, which included water, density of living snails (form the Anxiang Station for Schistosomiasis Control) and elevation (from Google Earth). Based on the elevation, sixteen bottomlands were divided into 3 groups. ARIMA models were built to predict the density of living snails in different elevation areas. Before closure of TGD, 7 out of 9 years had a water level beyond the warning level at least once at Anxiang hydrological station, compared with only 3 out of 10 years after closure of TGD. There were two severe droughts that happened in 2006 and 2011, with much fewer number of flooding per year compared with other study years. Overall, there was a correlation between water level changing and density of living snails variation in all the elevations areas. The density of living snails in all elevations areas was decreasing after the TGD was built. The relationship between number of flooding per year and the density of living snails was more pronounced in the medium and high elevation areas; the density of living snails kept decreasing from 2003 to 2014. In low elevation area however, the density of living snails decreased after 2003 first and turned to increase after 2011. Our ARIMA prediction models indicated that the snails would not disappear in the Dongting Lake region in the next 7 years. In the low elevation area, the density of living snails would increase slightly, and then stabilize after the year 2017. In the medium elevation region, the change of the density of

  17. Evaluation Model of Life Loss Due to Dam Failure

    Science.gov (United States)

    Huang, Dongjing

    2016-04-01

    Dam failure poses a serious threat to human life, however there is still lack of systematic research on life loss which due to dam failure in China. From the perspective of protecting human life, an evaluation model for life loss caused by dam failure is put forward. The model building gets three progressive steps. Twenty dam failure cases in China are preferably chosen as the basic data, considering geographical location and construction time of dams, as well as various conditions of dam failure. Then twelve impact factors of life loss are selected, including severity degree of flood, population at risk, understanding of dam failure, warning time, evacuation condition, number of damaged buildings, water temperature, reservoir storage, dam height, dam type, break time and distance from flood area to dam. And through principal component analysis, it gets four principal components consisting of the first flood character principle component, the second warning system principle component, the third human character principle component and the fourth space-time impact principle component. After multivariate nonlinear regression and ten-fold validation in combination, the evaluation model for life loss is finally established. And the result of the proposed model is closer to the true value and better in fitting effect in comparison with the results of RESCDAM method and M. Peng method. The proposed model is not only applied to evaluate life loss and its rate under various kinds of dam failure conditions in China, but also provides reliable cause analysis and prediction approach to reduce the risk of life loss.

  18. 闸坝对河流水质水量影响评估及调控能力识别研究框架%Research Framework of Assessment of Dams' Impact on Water Quality and Quantity and Identification of Regulation Ability

    Institute of Scientific and Technical Information of China (English)

    左其亭; 刘子辉; 窦明; 高军省

    2011-01-01

    The Huaihe River Basin has the characteristics of multitudinous dams, frequent water pollution accidents and prominent issues in terms of flood prevention and control as well as water pollution. Assessment of dams' impact on water quality and quantity and identification of dams' regulation ability are the science foundation and precondition of tackling water pollution accidents. In this paper, key scientific problems on assessment of dams' impact on water quality and quantity and identification of dams' regulation ability are discussed. Specifically,the problems include the techniques to assess dams' impact on water quality and quantity, the approaches to simulate the quantitative relationships among dams ' regulation pollution load into rivers and water quality variations,and the methods to id entify dams' regulation ability. Finally,combined with the national and technological demands of National scientific and technological major project of water pollution control and treatment of China, this paper puts forward the research framework of assessment of dams' impact on water quality and quantity and identification of regulate ability with the case study of Huaihe River Base, in the purpose of providing theoretical foundation for joint regulation of dams on water quality and quantity.%针对重污染河流闸坝众多、水污染事故多发、防洪防污矛盾突出等问题,评估闸坝对河流水质水量影响,识别闸坝调控能力,是解决河流突发性水污染事故的科学基础和前提条件.探讨了当前闸坝对河流水质水量影响评估及调控能力识别技术研究面临的关键科学问题,包括闸坝对河流水质水量影响评估技术方法,闸坝调控、入河污染负荷和河流水质变化之间量化关系模拟技术方法,闸坝对河流水质水量调控能力识别技术;并以淮河流域为例,结合淮河重大水专项国家需求和科技需求,初步提出闸坝对河流水质水量影响评估及调控能力

  19. The Impact of “Man-Made Hydrological Drought” on Plant Species Abundance in the Low-Flow Channel Downstream from the Matawin Dam, Quebec

    OpenAIRE

    Ghassen Ibrahim; Édith Gravel; Émilie Simard; Ali Assani; Stéphane Campeau

    2013-01-01

    The interannual variability of streamflow affects the composition and species richness of vegetation in low-flow channels and alluvial plains. Although climate conditions in 2003 and 2004 were nearly identical, large differences in streamflow were observed downstream from the Matawin dam. These differences resulted in numerous days without flow (no water release) during the growing period (May to August) in 2003, leading to man-made hydrological drought. While this drought had no effect on ab...

  20. Sediment settling in the Latian Dam in Iran

    Institute of Scientific and Technical Information of China (English)

    Farhang BEHRANGI; Mohammad Ali BANIHASHEMI; Shayesteh MAHANI; Mohammad Reza RAHMANIAN

    2014-01-01

    Among the difficulties that influence future dam operations, reservoir sedimentation is the most problematic for engineers. This study predicted the amount and pattern of sedimentation for use in estimation of the useful lifespan of reservoirs and identification of optimal locations for outlets and intakes at the initial stages of dam design. Hydrographic surveys of different dams can provide better insight into this phenomenon. Latian Dam in Iran has conducted hydrographic surveys during 7 time periods. The amount and process of sedimentation in this reservoir were determined, and predictions of distribution of sediments were validated by well-known, common methods. The formation of a delta in the reservoir was investigated for different time periods after operation. Future problems due to the impacts of sedimentation on dam operation and the useful lifespan of the reservoir were predicted. In addition, the study results may be used for developing empirical methods to predict sedimentation patterns in other reservoirs.

  1. Multiple issues of a hydroelectric dam project in west Africa and integrated evaluation of human and environmental impacts; Pluralite des enjeux d'un projet de barrage en Afrique de l'Ouest et evaluation integree des impacts humains et environnementaux

    Energy Technology Data Exchange (ETDEWEB)

    Circe, M. [Tecsult Inc., Montreal, PQ (Canada)

    2007-07-01

    The energy and sustainable development plan of the Niger Government involves the construction of the Kandadji dam to regulate the flow of the Niger River and to produce electricity in order to meet the energy needs of the population. The Kandadji dam project is also considered a vital infrastructure investment to ensure water resources for irrigation purposes for food security and to improve health conditions in the Niger River valley. Niger's energy plan is intended to ensure environmental protection in the exploitation and consumption of energy resources, the promotion of new and renewable energy sources and access to energy by all citizens. An environmental impact assessment was conducted as part of the project feasibility study. This presentation highlighted the environmental problems that have affected the river in recent years which could possibly cause ecological and socio-economic problems in the short term, such as conservation of natural heritage. It was determined that there are no technical or geological challenges facing the construction of the Kandadji dam. A seismic study has established the safety of the proposed earth dam, which would be built using local material. 20 figs.

  2. The Political Ecology of Chinese Large Dams in Cambodia: Implications, Challenges and Lessons Learnt from the Kamchay Dam

    Directory of Open Access Journals (Sweden)

    Giuseppina Siciliano

    2016-09-01

    Full Text Available Given the opportunities offered by foreign investment in energy infrastructure mostly by Chinese firms, the Government of Cambodia is giving high priority to developing hydropower resources for reducing energy poverty and powering economic growth. Using a “Political ecology of the Asian drivers” framework, this paper assesses China’s involvement in the development of large dams’ in Cambodia and its impacts on the access of natural resources such as water and energy by dam builders, local communities and the government. This analysis is based on 61 interviews and 10 focus group discussions with affected communities, institutional actors, Chinese dam builders and financiers in relation to the first large Chinese dam built in Cambodia: the Kamchay dam. Based on the results of the analysis this paper makes recommendations on how to improve the planning, implementation and governance of future large dams in Cambodia.

  3. Dam safety in British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, H.M.; Round, R.P.D.

    1978-01-01

    Many dams in British Columbia were built before 1900, and a comprehensive inspection and surveillance program has been developed. The background and implementation of this program are described. Topics discussed include program responsibilities, classification of dams, organization, the dam safety program, and coordination with other agencies. (PMA)

  4. Institutionalizing the option of dam removal: the New Hampshire initiative.

    Science.gov (United States)

    Lindloff, S D

    2003-01-01

    For two years, the State of New Hampshire has worked to institutionalize the option of dam removal. The high gradient streams that flow through the granite hills and mountains of this small northeastern state provided ideal conditions for dam construction, particularly during America's Industrial Revolution of the 1800s when mills were constructed throughout the area. With more than 4,800 dams in the state's database, there are many opportunities for the removal of dams that no longer serve a useful purpose, have become a public safety hazard and impact the river environment. Efforts to facilitate removal of dams in New Hampshire include the formation of a River Restoration Task Force and the creation of a dam removal program within the state agency responsible for regulating dams. This has led to the removal of two dams in the past year, with approximately ten additional projects in various stages of planning. A history of this agency-led initiative, as well as a discussion of the program's strengths, challenges and goals for the future are presented.

  5. Resilience scales of a dammed tropical river

    Science.gov (United States)

    Calamita, Elisa; Schmid, Martin; Wehrli, Bernhard

    2017-04-01

    Artificial river impoundments disrupt the seasonality and dynamics of thermal, chemical, morphological and ecological regimes in river systems. These alterations affect the aquatic ecosystems in space and time and specifically modify the seasonality and the longitudinal gradients of important biogeochemical processes. Resilience of river systems to anthropogenic stressors enables their recovery along the flow path; however little is known about the longitudinal distance that rivers need to partially restore their physical, chemical and biological integrity. In this study, the concept of a "resilience scale" will be explored for different water quality parameters downstream of Kariba dam, the largest artificial lake in the Zambezi basin (South-East Africa). The goal of this project is to develop a modelling framework to investigate and quantify the impact of large dams on downstream water quality in tropical context. In particular, we aim to assess the degree of reversibility of the main downstream alterations (temperature, oxygen, nutrients) and consequently the quantification of their longitudinal extent. Coupling in-situ measurements with hydraulic and hydrological parameters such as travel times, will allow us to define a physically-based parametrization of the different resilience scales for tropical rivers. The results will be used for improving future dam management at the local scale and assessing the ecological impact of planned dams at the catchment scale.

  6. Proceedings of the Canadian Dam Association conference 2010: partnering for a safer future

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    New and numerous challenges faced by the the dam safety community and dams were discussed at this conference. Hydraulic resources availability, the durability of the installations, modes of operation and processes, the business environment and human resources in the dam safety community are factors which will influence and impact these challenges. New types of dams have been constructed or are being built. Research is needed and knowledge sharing needs to be promoted to ensure the development of safe and reliable projects. This conference brought together samll dam owners and larger utilities looking for the latest in technology developments.

  7. The impact of an industrial effluent on the water quality, submersed macrophytes and benthic macroinvertebrates in a dammed river of Central Spain.

    Science.gov (United States)

    Gonzalo, Cristina; Camargo, Julio A

    2013-10-01

    This research was conducted in the middle Duratón River (Central Spain), in the vicinity of Burgomillodo Reservoir. An industrial effluent enters the river 300 m downstream from the dam. Fluoride and turbidity levels significantly increased downstream from the effluent, these levels being to some extent affected by differential water releases from the dam. The community of submersed macrophytes exhibited slighter responses and, accordingly, lower discriminatory power than the community of benthic macroinvertebrates, this indicating that metrics and indices based on macroinvertebrates may be more suitable for the biological monitoring of water pollution and habitat degradation in dammed rivers receiving industrial effluents. However, in relation to fluoride bioaccumulation at the organism level, macrophytes (Fontinalis antipyretica and Potamogeton pectinatus) were as suitable bioindicators of fluoride pollution as macroinvertebrates (Ancylus fluviatilis and Pacifastacus leniusculus). Fluoride bioaccumulation in both hard and soft tissues of these aquatic organisms could be used as suitable bioindicator of fluoride pollution (even lower than 1 mg F(-)L(-1)) in freshwater ecosystems. Echinogammarus calvus exhibited a great sensitivity to the toxicity of fluoride ions, with a 96 h LC₅₀ of 7.5 mg F(-)L(-1) and an estimated safe concentration of 0.56 mg F(-)L(-1). The great capacity of E. calvus to take up and retain fluoride during exposures to fluoride ions would be a major cause of its great sensitivity to fluoride toxicity. It is concluded that the observed fluoride pollution might be partly responsible for the absence of this native amphipod downstream from the industrial effluent.

  8. Impact of smoking on guided tissue regeneration using a biocomposite poly (lactic-co-glycolic) acid/sub-micron size hydroxyapatite with a rubber dam as an alternative barrier.

    Science.gov (United States)

    Stramazzotti, D; Coiana, C; Zizzi, A; Spazzafumo, L; Sauro, S; D'Angelo, A B; Rubini, C; Aspriello, S D

    2015-03-01

    The purpose of our study was to critically evaluate the results obtained from a guided tissue regeneration technique after 12 months using a bocomposite poly (lactic-co-glycolic) acid/sub-micron size hydroxyapatite (PLGA/HA) with a rubber dam as a barrier in smoking and non-smoking patients. We selected 36 patients (18 current smokers and 18 non-smokers) diagnosed with chronic advanced periodontitis with a periodontal site (probing depth [PD] >5) amenable to regenerative surgery. Twelve months after surgery, the periodontal parameters were found to have statistically improved, when non-smokers were compared with smokers, in: PD reduction (6.3 ± 2.1 mm vs. 3.6 ± 1.9 mm); CAL gain (4.4 ± 1.1 vs. 2.8 ± 2.2 mm); recession (1.8 ± 1.4 mm vs. 0.8 ± 0.9 mm); and hard tissue fill (4.7 ± 0.8 mm vs. 2.8 ± 2.1 mm). Furthermore, since we found PD baseline differences between groups, smoking seemed not to influence the outcomes achieved (CAL gain and ΔREC) 12 months post surgery with respect to PD baseline. The use of PLGA/HA with a rubber dam significantly improved the periodontal parameters in both smoking and non-smoking subjects. This improvement was nevertheless lower in smokers than the non-smokers, confirming the negative impact of smoking on periodontal regeneration.

  9. Accuracy Analysis of a Dam Model from Drone Surveys

    OpenAIRE

    Elena Ridolfi; Giulia Buffi; Sara Venturi; Piergiorgio Manciola

    2017-01-01

    This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs) used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D) model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a...

  10. The Impact of “Man-Made Hydrological Drought” on Plant Species Abundance in the Low-Flow Channel Downstream from the Matawin Dam, Quebec

    Directory of Open Access Journals (Sweden)

    Ghassen Ibrahim

    2013-06-01

    Full Text Available The interannual variability of streamflow affects the composition and species richness of vegetation in low-flow channels and alluvial plains. Although climate conditions in 2003 and 2004 were nearly identical, large differences in streamflow were observed downstream from the Matawin dam. These differences resulted in numerous days without flow (no water release during the growing period (May to August in 2003, leading to man-made hydrological drought. While this drought had no effect on abiotic variables (grain-size distribution and nutrient concentrations in sediments, a significant decrease in the number of terrestrial species was observed in 2004 (year without drought relative to 2003 (drought year on three sand bars studied. This decrease is interpreted to result from prolonged submergence of the sites in 2004. Principal component analysis highlighted the effect of individual sites (first principal component and of the interannual variability of streamflow (second component on the number of species. The study suggests that, from a flow management standpoint, it is advisable to release enough water downstream from the dam during the growing season to prevent low-flow channel colonization by invasive terrestrial species.

  11. Mitigation of negative ecological and socio-economic impacts of the Diama dam on the Senegal River Delta wetland (Mauritania, using a model based decision support system

    Directory of Open Access Journals (Sweden)

    S. Duvail

    2003-01-01

    Full Text Available Abstract: The delta of the River Senegal was modified substantially by the construction of the Diama dam in 1986 and the floodplain and estuarine areas on the Mauritanian bank were affected severely by the absence of floods. In 1994, managed flood releases were initiated in the Bell basin (4000 ha of the Diawling National Park, as part of a rehabilitation effort. The basin was designated as a joint management area between traditional users and the Park authority and a revised management plan was developed through a participatory approach based on a topographical, hydro-climatic, ecological and socio-economic data. Hydraulic modelling was developed as a tool to support stakeholder negotiations on the desired characteristics of the managed flood releases. Initially, a water balance model was developed. The data were then integrated into a one-dimensional hydraulic model, MIKE 11 (DHI, 2000. When associated with a Digital Elevation Model and a Geographic Information System, (Arc View, the model provided a dynamic description of floods. Flood extent, water depth and flood duration data were combined with ecological and socio-economic data. The water requirements of the different stakeholders were converted to flood scenarios and the benefits and constraints analysed. A consensus scenario was reached through a participatory process. The volume of flood release required to restore the delta does not affect hydro-power generation, navigation or intensive irrigation, for which the dams in the basin were constructed. Hydraulic modelling provided useful inputs to stakeholder discussions and allows investigation of untested flood scenarios. Keywords: wetland restoration, water use conflicts, equity, Senegal River delta, Mauritania, Diawling National Park

  12. Tourism, water resources and urban sustainability A case study of the impact of tourism on development Agchay dam, sustainability and income in Chayparhcity

    Directory of Open Access Journals (Sweden)

    Ghahraman Rostami

    2014-07-01

    Full Text Available Thehigh number of towns and settlements has a very top of their undeniable role inthe lives of the vast expanse of land, which is so important in the study andplanning of sustainable development and more measured information should be decided.However, the use of past experiences and proper planning for the futurerequires a correct summation of past experiences and needs logical assessmentof the situation in the future. Therefore, Recognition of villages and citiescan be considered as one of the most important parts of sustainable development.Nowadays The researches ofrural and urban community are important  in knowing the advancing the country's development goals So, to reviewthe  (QarezyaaddinCity has been studiedfrom the viewpoint of economy and living conditions. (Qarezyaaddin center ofChayparh city has been chosen as one of the target cities due to Bastam  historic castles and   Agh Chai dam,which is  the first aristocraticarch dam disclosed tofertile lands.to do this study, library and field methods through interviewswith target groups has been used.These results indicate that Qarezyaaddin has arich economic  potential of the  city  native livestock and agricultural fields.This result indicates that theincreased revenue from tourism, livestock and agriculture sectors stronglyinfluenced the city.And it has become a dynamic city So that rapid changes inurban development in recent years  isvery impressive compared to surrounding towns.satellite maps shows this fact.

  13. Estimates o the risks associated with dam failure

    Energy Technology Data Exchange (ETDEWEB)

    Ayyaswamy, P.; Hauss, B.; Hseih, T.; Moscati, A.; Hicks, T.E.; Okrent, D.

    1974-03-01

    The probabilities and potential consequences of dam failure in California, primarily due to large earthquakes, was estimated, taking as examples eleven dams having a relatively large population downstream. Mortalities in the event of dam failure range from 11,000 to 260,000, while damage to property may be as high as $720 million. It was assumed that an intensity IX or X earthquake (on the Modified Mercalli Scale) would be sufficient to completely fail earthen dams. Predictions of dam failure were based on the recurrence times of such earthquakes. For the dams studied, the recurrence intervals for an intensity IX earthquake varied between 20 and 800 years; for an intensity X between 50 and 30,000 years. For the Lake Chabot and San Pablo dams (respectively 20, 30 years recurrent earthquake times for a intensity X) the associated consequences are: 34,000 (Lake Chabot) and 30,000 (San Pablo) people killed; damage $140 million and $77 million. Evaculation was found to ameliorate the consequences slightly in most cases because of the short time available. Calculations are based on demography, and assume 10 foot floodwaters will drown all in their path and destroy all one-unit homes in the flood area. Damage estimates reflect losses incurred by structural damage to buildings and do not include loss of income. Hence the economic impact is probably understated.

  14. Regional energy markets and the cost of natural flow dam operation

    Energy Technology Data Exchange (ETDEWEB)

    Sparrow, F.T.; Preckel, P.V.; Gotham, D.J. [Purdue University, Energy Center at Discovery Park, West Lafayette, IN (United States); Bowen, B.H. [American University in Kosovo, Pristina (RS); Yu, Z. [EmberClear, Inc., Houston, TX (United States)

    2011-11-15

    With the proliferation of electricity markets for the purchase and sale of firm and non-firm power and capacity, the possibility exists for using trade in these commodities to minimize the cost impact of operating dams to restore downstream flows to pre-dam patterns - so called Run of River (ROR) dam operation. We examine the impact of such markets on the incremental costs of ROR operation relative to least cost operation via a stochastic, dynamic optimization model. We identify features of the dam structure and of the economic environment that are critical to achieving ROR operation at modest incremental cost. (orig.)

  15. USGS Dam Removal Science Database

    Science.gov (United States)

    Bellmore, J. Ryan; Vittum, Katherine; Duda, Jeff J.; Greene, Samantha L.

    2015-01-01

    This database is the result of an extensive literature search aimed at identifying documents relevant to the emerging field of dam removal science. In total the database contains 179 citations that contain empirical monitoring information associated with 130 different dam removals across the United States and abroad. Data includes publications through 2014 and supplemented with the U.S. Army Corps of Engineers National Inventory of Dams database, U.S. Geological Survey National Water Information System and aerial photos to estimate locations when coordinates were not provided. Publications were located using the Web of Science, Google Scholar, and Clearinghouse for Dam Removal Information.

  16. FULCRUM - A dam safety management and alert system

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Cameron; Greenaway, Graham [Knight Piesold Ltd., Vancouver, (Canada)

    2010-07-01

    Efficient management of instrumentation, monitoring and inspection data are the keys to safe performance and dam structure stability. This paper presented a data management system, FULCRUM, developed for dam safety management. FULCRUM is a secure web-based data management system which simplifies the process of data collection, processing and analysis of the information. The system was designed to organize and coordinate dam safety management requirements. Geotechnical instrumentation such as piezometers or inclinometers and operating data can be added to the database. Data from routine surveillance and engineering inspection can also be incorporated into the database. The system provides users with immediate access to historical and recent data. The integration of a GIS system allows for rapid assessment of the project site. Customisable alerting protocols can be set to identify and respond quickly to significant changes in operating conditions and potential impacts on dam safety.

  17. Greenhouse gas emissions from Brazil’s Amazonian hydroelectric dams

    Science.gov (United States)

    Fearnside, Philip M.

    2016-01-01

    Tropical dams are often falsely portrayed as ‘clean’ emissions-free energy sources. The letter by de Faria et al (2015 Environ. Res. Lett. 10 124019) adds to evidence questioning this myth. Calculations are made for 18 dams that are planned or under construction in Brazilian Amazonia and show that emissions from storage hydroelectric dams would exceed those from electricity generation based on fossil fuels. Fossil fuels need not be the alternative, because Brazil has vast potential for wind and solar power as well as opportunities for energy conservation. Because dam-building is rapidly shifting to humid tropical areas, where emissions are higher than in other climatic zones, the impact of these emissions needs to be given proper weight in energy-policy decisions.

  18. Evaluating segregation in granular filters for earth dams

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, K. [Cambridge Univ., Cambridge (United Kingdom); Grabinsky, M. [Toronto Univ., ON (Canada)

    2003-07-01

    This paper presented some case studies to illustrate the relationship between seepage problems encountered with earth dams and segregation of the dams' granular filters during construction. A literature review of segregation mechanisms was presented along with a laboratory investigation. The case studies showed that the current understanding of the impact of a given degree of segregation is relatively poor. The literature reveals that although segregation mechanisms are identified and analyzed, very few are likely to be predominant during earth dam construction. Laboratory studies show that a mathematical relationship can be established between the filter's grain size distribution curve and the potential degree of segregation. Therefore, a mathematical relationship can also be established with the potential for adverse dam performance. The authors proposed a field procedure which allows for the monitoring of segregation during construction by contractors and engineers. It also helps in deciding whether any segregated zones require replacement. 5 refs., 7 figs.

  19. 泥石流冲击荷载下拦挡坝的动力响应分析%Dynamic response analysis for a dam against impact load of debris flow

    Institute of Scientific and Technical Information of China (English)

    周勇; 刘贞良; 王秀丽; 周凤玺

    2015-01-01

    选取典型的泥石流冲击荷载,把钢筋混凝土拦挡坝简化成悬臂梁,建立其动力偏微分方程,运用数学物理方程中的变量分离法和结构动力学中的振型叠加法求得动力偏微分方程的解析解,最后根据材料力学得到相应的应力以及应变。算例分析表明解析解是可靠的,且在拦挡坝的坝顶处有最大的位移,为实际工程力学计算提供一种思路。%Here,the typical impact load of debris flow was chosen,and a reinforced concrete dam against debris flow was simplified into a cantilevered beam,its dynamic partial differential equation was established.Then,the variable separation method in mathematical physics equations and the modal superposition method in the structural dynamics were used to get the analytical solution to the dynamic partial differential equation.According to the mechanics of materials,the corresponding stress and strain of the beam were obtained.The example analysis showed that the analytical solution to the dynamic equation is reliable,and the top of the dam against debris flow has the largest displacement.The study results provided an idea for practical engineering mechanical calculation.

  20. Combating Poverty by Irrigation from Large Dams in Arid Countries: A Case Study of Minab Dam, Iran

    Directory of Open Access Journals (Sweden)

    ALI ASGHAR IRAJ POOR

    2010-10-01

    Full Text Available A set of indicators for sustainable development were identified to be employed in developing countries. The selected indicators provided a good understanding of social and engineering outputs of a water resources project. Results of the study revealed that there are significant positive impacts of dam construction but they were not same as the targeted objectives envisaged in the feasibility report of the project. It means that after construction of the dam and irrigation system, development didn?t match with the targeted goals of the project. This study argues the world-wide controversy against construction of dam in arid zone which is ill-founded and based on a few short term, mitigable negative impacts, ignoring many positive long term inputs alleviating chronic poverty in arid regions. The study meticulously looks into the pre dam bio-physical and socio-economic conditions in one of the arid region of Iran under the area commanded by Minab dam. This dam was constructed in Hormozgan province of Iran in 1983 and its irrigation system was completed in 1986 which was followed by progressive expansion of irrigated agriculture which almost doubled in year 2006. Literacy rate has increased from 41% (pre-project to 74% in 2006. Similarly, significant improvements were observed in health care, sanitation, education, and other disciplines.

  1. The dam design of Three Gorges Project

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaomao; Xu Linxiang; Liao Renqiang

    2011-01-01

    The dam of Three Gorges Project is a concrete gravity dam with the crest elevation of 185 m, the maximum height of 181 m and dam axis length of 2 309.5 m. The dam consists of spillway, powerhouse, non-over flow, ship-lift, temporary ship-lock, left diversion wall and longitudinal cofferdam blocks. Some key techniques relating to dam structure design are presented, including hydraulics of flood discharge structure, dam joint design, layout and structural type of penstock, deep anti-sliding stability of dam foundation, reconstruction of temporary ship-lock and closed drainage and pumping of dam foundation.

  2. Tarbela Dam Project

    Energy Technology Data Exchange (ETDEWEB)

    Khan, B.A. [WAPDA Tarbela Dam Project (Pakistan); Ahmad, W. [Siemens Pakistan Ltd., Islamabad (Pakistan)

    1999-07-01

    Construction of one of the world's largest water resource development project is discussed. The Tarbela project is built on the Indus River, (itself one of the largest rivers of the world) and consists of a 9,000 feet long and 465 feet high earth and rockfill embankment across the entire width of the river with two spillways cutting through the left bank. On the left bank valley there are two auxiliary embankment dams to close the gap. A total of five tunnels, each a mile long, have been constructed for irrigation releases and power generation. Electricity is being generated by two power generating plants constructed on three of these tunnels. They have a generating capacity of 3,478 MW, supplying 40 per cent of all Pakistani demand. Several 'firsts' are identified. For example, the dam is the world's largest, containing over 200 million cubic yards of earth and rock, as are the five tunnels (14 meters in diameter), as well as the outlet gates. The energy release by the water gushing through the five tunnels at maximum level is more than 13 million KW, approximately equivalent to 10 million horsepower. 1 ref.

  3. Repair, Evaluation, Maintenance, and Rehabilitation Research Program. Underwater Stilling Basin Repair Techniques Using Precast or Prefabricated Elements

    Science.gov (United States)

    1991-12-01

    Stilling Basins* Training Wall Estimated Low Height Water Depth** Dam ft ft Old River Low Sill Structure 45 16 Arkabutla Dam 29 Enid Dam 30 Pomme De... Terre Dam 32 Pomona Dam 20 ruttle Creek Dam 48 18t Curwensville Lake Dam 32 28 Lac Qui Parle Dam 23 Chief Joseph Dam - 26 Libby Dam 69 20t Dworshak Dam 67

  4. Determination of Seepage and Analysis of Earth Dams (Case Study: Karkheh Dam)

    OpenAIRE

    A. Kamanbedast; M. Shahosseini

    2011-01-01

    Because of the increasing trend of building dam throughout Iran; it is necessary to optimize dam buildings and operations. Dam or Hydropower industry has two types of buildings; normally: (1) Concrete dams (2) Embankment (earth) dams. Generally, scientists and engineers use different methods to enhance safety and decrease any errors in calculation due to maintenance of water storage especially hydro structure of the dam. It is necessary to investigate the dam seepage control; commonly use...

  5. The World Commission on Dams + 10: Revisiting the Large Dam Controversy

    Directory of Open Access Journals (Sweden)

    Deborah Moore

    2010-06-01

    Full Text Available The World Commission on Dams (WCD was an experiment in multi-stakeholder dialogue and global governance concerned with a subject area – large dams – that was fraught with conflict and controversy. The WCD Report, Dams and Development: A New Framework for Decision-Making, was published in 2000 and accompanied by hopes that broad-based agreements would be forged on how to better manage water and energy development. Ten years later, this special issue of Water Alternatives revisits the WCD and its impacts, exploring the question: Is the WCD still relevant? The editorial team and the Guest Editors of this special issue of Water Alternatives have selected a range of 20 papers, 6 viewpoints, and 4 book reviews that help to illustrate the evolution in the dams debate. The goal of this special issue is to examine the influence and the impacts of the WCD on the dam enterprise, in general, and on the policies and practices of key stakeholders and institutions, and on the development outcomes for affected communities and environments, in particular. In this introduction, the Guest Editors provide an overview of the special issue, exploring the new drivers of dam development that have emerged during the last decade, including climate change and new financiers of dams, and describing the themes emerging from this diverse set of papers and viewpoints. This special issue demonstrates the need for a renewed multi-stakeholder dialogue at multiple levels. This would not be a redo of the WCD, but rather a rekindling and redesigning of processes and forums where mutual understanding, information-sharing, and norm-setting can occur. One of the most promising developments of the last decade is the further demonstration, in case studies described here, that true partnership amongst key stakeholders can produce transformative resource-sharing agreements, showing that many of the WCD recommendations around negotiated decision making are working in practice. We hope

  6. Assessing Otter Presence In Dams: A Methodological Proposal

    Directory of Open Access Journals (Sweden)

    Margarida Santos-Reis

    2009-10-01

    Full Text Available Standard otter survey methodology proposed by the IUCN Otter Specialist Group enables comparisons in present/absence data in different countries or in different regions. However, otter presence and distribution assessment in dry areas, such as the Mediterranean region, which are characterized by highly marked seasonal climate with intermittent water flow coupled with different types of habitats or systems such as dams, may gain from adjustment to the methodology. Pressure for dam building still occurs in these regions and the need for studies on ecological communities and species protection is increasing. Dams are very different from usual otter riverine habitat and we need to understand their influence on otter populations. Variation of dam location, reservoir characteristics and season will all influence spraint detectability. Environmental Impact Assessment Studies and ecological studies are frequently limited by both budget and time requiring field researchers to apply more efficient methodologies. Based on experience from studies conducted in Portugal we propose adjustments to the standard survey methodology (using spraints surveying otter presence in dams to be applied specifically to Mediterranean-type ecosystems. We define aspects to be considered regarding survey season, survey length and width, number and location of survey sites, among others. This paper will allow researchers to plan more effective field surveys based on standard otter survey methodology for the purpose of dam surveys, be that to detect otter presence/absence, a more in-depth comparative studies of otter presence, or simply improving the collecting of fresh spraints for molecular spraint analysis.

  7. The importance of cultural aspects in impact assessment and project: developmentreflections from a case study of a hydroelectric dam in Brazil

    NARCIS (Netherlands)

    Hanna de Almeida Oliveira, Philippe; Vanclay, Frank; Langdon, Esther Jean; Arts, Jos

    2016-01-01

    Failure to consider the cultural and social factors of projects can lead to situations where mitigation does not effectively address the impacts they were intended to alleviate, and can even create other impacts. We critically analyse the processes of designing and implementing a social and

  8. The importance of cultural aspects in impact assessment and project: developmentreflections from a case study of a hydroelectric dam in Brazil

    NARCIS (Netherlands)

    Hanna de Almeida Oliveira, Philippe; Vanclay, Frank; Langdon, Esther Jean; Arts, Jos

    2016-01-01

    Failure to consider the cultural and social factors of projects can lead to situations where mitigation does not effectively address the impacts they were intended to alleviate, and can even create other impacts. We critically analyse the processes of designing and implementing a social and environm

  9. Risk analysis model for landslide mass of high slope in dam area

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to identify the threat of reservoir bank landslide to dam safety and reduce the risk of dam failure,impact factors of the landslide are analyzed.The concept of landslide risk degree is put forward to measure the threat of landslide to dam safety.The monotony of the landslide risk assessment function which changes with different affecting factors is analyzed qualitatively.Based on gene automatic programming,a data mining model of the landslide risk assessment function is constructed combined with impact factors of reservoir bank landslide on dam safety.And the assessment function of landslide risk has been excavated and established according to practical project information,which provides a valuable reference for analyzing the impact of landslide on dam risk.

  10. Prediction for supersaturated total dissolved gas in high-dam hydropower projects

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The supersaturated total dissolved gas(TDG)generated during high dam spills may cause gas bubble disease for fish and ultimately endanger their existence.As more and more high-dam hydropower projects have been constructed in China,the environmental assessment of the supersaturated TDG is becoming more and more important.It is of great importance for quantitative impact assessment of the supersaturated TDG of high dams and for the construction of ecological friendly high-dam hydropower projects.Based on the conceptual summarization of the TDG production process,the TDG prediction model for high-dam projects,in which the ski-jump energy dissipation is adopted,is developed in the paper.The model is validated by field data and employed in the TDG prediction of a high-dam hydropower project to be built in southwest China.

  11. The Changing Political Dynamics of Dam Building on the Mekong

    Directory of Open Access Journals (Sweden)

    Philip Hirsch

    2010-06-01

    Full Text Available This paper explores political dynamics surrounding dam building in the Mekong river basin, prior to, and following, the World Commission on Dams (WCD. Since the 1950s, dam building in the Mekong river basin has been enmeshed in a complex and shifting geopolitical and eco-political landscape. The broad geopolitical sweep of US hegemony, Cold War, regional rapprochement and the rise of China has been superimposed on eco-political shifts between modernist belief in progress as mastery over nature, concerns of global and national environmental movements over dams and their impacts, and a galvanised Mekong environmentalism. During the first decade of the 21st century, mainstream dams on the Lower Mekong have returned to the agenda after having almost disappeared in favour of tributary projects. The growing strength and assertiveness of regional economic players has fundamentally altered the context of energy demand, planning and investment. New sources of finance have relocated the points of political leverage. Environment has been mustered in favour of, as well as in opposition to, dam construction in the contexts of climate-change discourses, protected-area linkage with dam projects, and an industry push for sustainability protocols and certification. Despite the Mekong being one of its focal basins, WCD has not played a prominent role in this transformed arena, yet many of the social and environmental concerns, stakeholder-based processes and safeguard-oriented approaches to hydropower planning that WCD brought to the fore have persisted in the wider ethos of politics around dams in the region.

  12. 33 CFR 222.6 - National Program for Inspection of Non-Federal Dams.

    Science.gov (United States)

    2010-07-01

    ..., etc., for defining a comprehensive national dam safety program. (G) Responding to Congressional, media... significant economic, social or political impacts and technical uncertainties in evaluating the dams, advice..., division and district Engineers are encouraged to take advantage of suitable opportunities to provide...

  13. Assessing post-dam removal sediment dynamics using the CONCEPTS computer model

    Science.gov (United States)

    Dam removal will impact stream morphology not just locally, but both far upstream and downstream. There is a critical need for tools to predict the rates, magnitudes, and mechanisms by which sediment is removed from a reservoir following dam removal, as well as for tools to predict where this sedime...

  14. Watershed restoration: planning and implementing small dam removals to maximize ecosystem services

    Science.gov (United States)

    Tonitto, C.; Riha, S. J.

    2016-12-01

    River restoration and enhancing watershed connectivity is of growing concern in industrialized nations. The past two decades have seen a number of small dam removals, though many removals remain unstudied and poorly documented. We summarize socio-economic and biophysical lessons learned during the past two decades of accelerated activity regarding small dam removals throughout the United States. We present frameworks for planning and implementing removals developed by interdisciplinary engagement. Toward the goal of achieving thorough dam removal planning, we present outcomes from well-documented small dam removals covering ecological, chemical, and physical change in rivers post-dam removal, including field observation and modeling methodologies. Guiding principles of a dam removal process should include: 1) stakeholder engagement to navigate the complexity of watershed landuse, 2) an impacts assessment to inform the planning process, 3) pre- and post-dam removal observations of ecological, chemical and physical properties, 4) the expectation that there are short- and long-term ecological dynamics with population recovery depending on whether dam impacts were largely related to dispersion or to habitat destruction, 5) an expectation that changes in watershed chemistry are dependent on sediment type, sediment transport and watershed landuse, and 6) rigorous assessment of physical changes resulting from dam removal, understanding that alteration in hydrologic flows, sediment transport, and channel evolution will shape ecological and chemical dynamics, and shape how stakeholders engage with the watershed.

  15. Geomorphic and Ecological Issues in Removal of Sediment-Filled Dams in the California Coast Ranges (Invited)

    Science.gov (United States)

    Kondolf, G. M.; Oreilly, C.

    2010-12-01

    Water-supply reservoirs in the actively eroding California Coast Ranges are vulnerable to sediment filling, thus creating obsolete impounding dams (Minear & Kondolf 2009). Once full of sediment, there is more impetus to remove dams for public safety and fish passage, but managing accumulated sediments becomes a dominant issue in dam removal planning. We analyzed the planning process and sediment management analyses for five dams, all of which have important ecological resources but whose dam removal options are constrained by potential impacts to downstream urban populations. Ringe Dam on Malibu Ck, Matilija Dam on the Ventura River, Searsville Dam on San Francisquito Ck, and Upper York Creek Dam on York Ck cut off important habitat for anadromous steelhead trout (Oncorhynchus mykiss). San Clemente Dam on the Carmel River has a working fish ladder, but only some of the migratory steelhead use it. By virtue of having filled with sediment, all five dams are at greater risk of seismic failure. San Clemente Dam is at greater risk because its foundation is on alluvium (not bedrock), and the poor-quality concrete in Matilija Dam is deteriorating from an akali-aggregate reaction. Simply removing the dams and allowing accumulated sediments to be transported downstream is not an option because all these rivers have extremely expensive houses along downstream banks and floodplains, so that allowing the downstream channel to aggrade with dam-dervied sediments could expose agencies to liability for future flood losses. Analyses of potential sediment transport have been based mostly on application of tractive force models, and have supported management responses ranging from in-situ stabilization (San Clemente and Matilija) to removal of stored sediment (York) to annual dredging to maintain capacity and prevent sediment passing over the dam (proposed for Searsville).

  16. Owyhee River intracanyon lava flows: does the river give a dam?

    Science.gov (United States)

    Ely, Lisa L.; Brossy, Cooper C.; House, P. Kyle; Safran, Elizabeth B.; O'Connor, Jim E.; Champion, Duane E.; Fenton, Cassandra R.; Bondre, Ninad R.; Orem, Caitlin A.; Grant, Gordon E.; Henry, Christopher D.; Turrin, Brent D.

    2013-01-01

    Rivers carved into uplifted plateaus are commonly disrupted by discrete events from the surrounding landscape, such as lava flows or large mass movements. These disruptions are independent of slope, basin area, or channel discharge, and can dominate aspects of valley morphology and channel behavior for many kilometers. We document and assess the effects of one type of disruptive event, lava dams, on river valley morphology and incision rates at a variety of time scales, using examples from the Owyhee River in southeastern Oregon. Six sets of basaltic lava flows entered and dammed the river canyon during two periods in the late Cenozoic ca. 2 Ma–780 ka and 250–70 ka. The dams are strongly asymmetric, with steep, blunt escarpments facing up valley and long, low slopes down valley. None of the dams shows evidence of catastrophic failure; all blocked the river and diverted water over or around the dam crest. The net effect of the dams was therefore to inhibit rather than promote incision. Once incision resumed, most of the intracanyon flows were incised relatively rapidly and therefore did not exert a lasting impact on the river valley profile over time scales >106 yr. The net long-term incision rate from the time of the oldest documented lava dam, the Bogus Rim lava dam (≤1.7 Ma), to present was 0.18 mm/yr, but incision rates through or around individual lava dams were up to an order of magnitude greater. At least three lava dams (Bogus Rim, Saddle Butte, and West Crater) show evidence that incision initiated only after the impounded lakes filled completely with sediment and there was gravel transport across the dams. The most recent lava dam, formed by the West Crater lava flow around 70 ka, persisted for at least 25 k.y. before incision began, and the dam was largely removed within another 35 k.y. The time scale over which the lava dams inhibit incision is therefore directly affected by both the volume of lava forming the dam and the time required for sediment

  17. 76 FR 12094 - Whitman River Dam, Inc.

    Science.gov (United States)

    2011-03-04

    ... Federal Energy Regulatory Commission Whitman River Dam, Inc. Notice of Application Tendered for Filing.... Applicant: Whitman River Dam, Inc. e. Name of Project: Crocker Dam Hydro Project. f. Location: On the... analysis at this time. n. The Crocker Dam Hydro Project would consist of: (1) The existing...

  18. FORMATION AND FAILURE OF NATURAL DAMS.

    Science.gov (United States)

    Costa, John E.; Schuster, Robert L.

    1988-01-01

    Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and late-neoglacial moraines present the greatest threat to people and property. Landslide dams form a wide range of physiographic settings. The most common types of mass movements that form landslide dams are rock and debris avalanches; rock and soil slumps and slides; and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam. Although data are few, for the same potential energy at the dam site, downstream flood peaks from the failure of glacier-ice dams are smaller than those from landslide, moraine, and constructed earth-fill and rock-fill dam failures.

  19. Big Lake Dam Inspection Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes an inspection of the Big Lake Dam that was done in September of 1983. The inspection did not reveal any conditions that constitute and...

  20. A river might run through it again: criteria for consideration of dam removal and interim lessons from California.

    Science.gov (United States)

    Pejchar, L; Warner, K

    2001-11-01

    Resource managers are increasingly being challenged by stakeholder groups to consider dam removal as a policy option and as a tool for watershed management. As more dam owners face high maintenance costs, and rivers as spawning grounds for anadromous fish become increasingly valuable, dam removal may provide the greatest net benefit to society. This article reviews the impact of Endangered Species Act listings for anadromous fish and recent shifts in the Federal Energy Regulatory Commission's hydropower benefit-costs analysis and discusses their implications for dam removal in California. We propose evaluative criteria for consideration of dam removal and apply them to two case studies: the Daguerre and Englebright Dams on the Yuba River and the Scott and Van Horne Dams on the South Eel River, California.

  1. Economic Efficiency and Equity in Dams Removal: Case studies in Northeastern Massachusetts Doina Oglavie, Ellen Douglas, David Terkla

    Science.gov (United States)

    Oglavie, D. R.; Douglas, E. M.; Terkla, D.

    2009-12-01

    According to American Rivers (www.americanrivers.org), Massachusetts has almost 3,000 dams under state regulation, 296 of which have been classified as high hazard, meaning they pose a serious threat to human life if they should fail. Most of these dams, however, are low head, “run-of-the-river” dams that no longer serve the purpose for which they were built. The presence of these dams has fragmented aquatic and riparian ecosystems, impeded fish passage and generally impacted the natural ecological and hydrological functioning of the streams in which they reside. Dam removal should be considered when a dam no longer serves its function. Although in many cases, the removal of a dam is environmentally beneficial (at least over the long term), sometimes the removal of a dam can incur environmental costs, such as release of contaminants that were sequestered behind the dam. Dam removal is a complex issue especially with respect to privately owned dams. In many cases, dam removal is less costly than dam maintenance or upgrade, hence dam removal decisions tend to be based on purely monetary considerations, and the environmental costs or benefits associated with the dam are not considered. Typically, the main objective for the dam owner is to incur the lowest possible cost (private cost), whether it be operating and maintenance or removal; external costs (environmental degradation) are rarely, if ever, considered, hence the true cost to society is not included in the economic analysis. If dam operation and removal decisions are to be economically efficient, then they have to include both the private costs as well as the external (environmental) costs. The purpose of this work is to 1) attempt to quantify the externalities associated with the maintenance and the removal of dams, 2) assess whether or not the current dam removal evaluation process maximizes social welfare (efficiency and equity) and 3) suggest ways in which this process can be improved by including the

  2. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  3. Dam overtopping risk using probabilistic concepts – Case study: The Meijaran Dam, Iran

    Directory of Open Access Journals (Sweden)

    Ehsan Goodarzi

    2013-06-01

    Full Text Available Hydrologic risk assessment and uncertainty analysis by mathematical and statistical methods provide useful information for decision makers. This study presents the application of risk and uncertainty analysis to dam overtopping due to various inflows and wind speeds for the Meijaran Dam in the north of Iran. The procedure includes univariate flood and wind speed frequency analyses, reservoir routing, and integration of wind set-up and run-up to calculate the reservoir water elevation. Afterwards, the probability of overtopping was assessed by applying two uncertainty analysis methods (Monte Carlo simulation and Latin hypercube sampling, and considering the quantile of flood peak discharge, initial depth of water in the reservoir, and spillway discharge coefficient as uncertain variables. The results revealed that rising water level in the reservoir is the most important factor in overtopping risk analysis and that wind speed also has a considerable impact on reservoirs that are placed in windy areas.

  4. Geophysical evaluation of the Success Dam foundation, Porterville, California

    Science.gov (United States)

    Hunter, L.E.; Powers, M.H.; Haines, S.; Asch, T.; Burton, B.L.; Serafini, D.C.

    2006-01-01

    Success Dam is a zonedearth fill embankment located near Porterville, CA. Studies of Success Dam by the recent Dam Safety Assurance Program (DSAP) have demonstrated the potential for seismic instability and large deformation of the dam due to relatively low levels of earthquake shaking. The U.S. Army Corps of Engineers conducted several phases of investigations to determine the properties of the dam and its underlying foundation. Detailed engineering studies have been applied using a large number of analytical techniques to estimate the response of the dam and foundation system when subjected to earthquake loading. Although a large amount of data have been acquired, most are 'point' data from borings and results have to be extrapolated between the borings. Geophysical techniques were applied to image the subsurface to provide a better understanding of the spatial distribution of key units that potentially impact the stability. Geophysical investigations employing seismic refraction tomography, direct current (DC) resistivity, audio magnetotellurics (AMT) and self-potential (SP) were conducted across the location of the foundation of a new dam proposed to replace the existing one. Depth to bedrock and the occurrence of beds potentially susceptible to liquefaction were the focus of the investigations. Seismic refraction tomography offers a deep investigation of the foundation region and looks at compressional and shear properties of the material. Whereas resistivity surveys determines conductivity relationships in the shallow subsurface and can produce a relatively high-resolution image of geological units with different electrical properties. AMT was applied because it has the potential to look considerably deeper than the other methods, is useful for confirming depth to bedrock, and can be useful in identifying deep seated faults. SP is a passive electrical method that measures the electrical streaming potential in the subsurface that responds to the movement of

  5. River Restoration by Dam Removal: Assessing Riverine Re-Connectivity Across New England

    Science.gov (United States)

    Magilligan, F. J.; Nislow, K. H.; Graber, B.; Sneddon, C.; Fox, C.; Martin, E.

    2014-12-01

    The impacts of dams in New England are especially acute as it possesses one of the highest densities of dams in the US, with the NID documenting more than 4,000 dams, and state agency records indicating that >14,000 dams are peppered throughout the landscape. This large number of dams contributes to pervasive watershed fragmentation, threatening the ecological integrity of rivers and streams, and in the case of old, poorly maintained structures, posing a risk to lives and property. These concerns have generated active dam removal efforts throughout New England. To best capture the geomorphic, hydrologic, and potential ecological effects of dam removal at a regional level, we have compiled a dataset of 127 removed dams in New England, which includes information about structural characteristics, georectified locations, and key watershed attributes (including basin size, distance to next upstream obstacle, and number of free-flowing river kms opened up). Our specific research questions address (1) what is the spatial distribution of removed dams and how does this pattern relate to stated management goals of restoring critical habitat for native resident freshwater and diadromous fish, (2) what are the structural or management commonalities in dam types that have been removed, and (3) what has been the incremental addition of free-flowing river length? Rather than reflecting an overall management prioritization strategy, results indicate that dam removals are characterized more by opportunistic removals. For example, despite a regional emphasis on diadromous fish protection and restoration, most removals are inland rather than coastal settings. Most of the removed dams were small (~ 45% 2,300 river kms over the past several decades, with implication for both resident and diadromous fish, and with many removals located in mid-sized rivers that are a key link between upstream and downstream/coastal aquatic ecosystems.

  6. Simulation of morphological changes due to dam removal

    Science.gov (United States)

    In this chapter, a brief review of numerical models and their applications for impact assessment of dam removal on sediment transport and morphological changes in alluvial rivers is given. As an example, a one-dimensional river flow and sediment transport model, CCHE1D, is applied to assess morpholo...

  7. Conflicts Associated with Dam Removal in Sweden

    Directory of Open Access Journals (Sweden)

    Anna G. C. Lejon

    2009-12-01

    Full Text Available The increasing number of deteriorating old dams that need renovation or have lost their function make dam removal a viable management option. There are at least four major reasons for dam removal: safety, law and policy, economy, and ecology. Here we discuss 17 Swedish dams that were recently considered for removal. Because dam removal usually causes controversy, dam removal initiatives may succeed, fail, or result in a compromise such as a bypass channel for migrating fish. We identify and discuss three major obstructions to dam removal: funding, cultural-historical values, and threatened species. To facilitate dam removal, the reasons for, and the effects of, dam removal must be carefully explained, and the public and stakeholders must be kept informed. In complicated cases in which compromise solutions may be the most feasible outcome, the integration of the knowledge of different stakeholders is crucial. The involvement of diverse stakeholders increases their willingness to find compromises, thus avoiding conflicts and failures.

  8. Effects of upstream dams versus groundwater pumping on stream temperature under varying climate conditions

    National Research Council Canada - National Science Library

    John C. Risley; Jim Constantz; Hedeff Essaid; Stewart Rounds

    2010-01-01

      The relative impact of a large upstream dam versus in-reach groundwater pumping on stream temperatures was analyzed for humid, semiarid, and arid conditions with long dry seasons to represent typical...

  9. Social Discounting of Large Dams with Climate Change Uncertainty

    Directory of Open Access Journals (Sweden)

    Marc Jeuland

    2010-06-01

    This paper reviews the recent discounting controversy and examines its implications for the appraisal of an illustrative hydropower project in Ethiopia. The analysis uses an integrated hydro-economic model that accounts for how the dam’s transboundary impacts vary with climate change. The real value of the dam is found to be highly sensitive to assumptions about future economic growth. The argument for investment is weakest under conditions of robust global economic growth, particularly if these coincide with unfavourable hydrological or development factors related to the project. If however long-term growth is reduced, the value of the dam tends to increase. There may also be distributional or local arguments favouring investment, if growth in the investment region lags behind that of the rest of the globe. In such circumstances, a large dam can be seen as a form of insurance that protects future vulnerable generations against the possibility of macroeconomic instability or climate shocks.

  10. Dam risk assistant analysis system design

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to reduce the labor intensity and task difficulty of dam risk analysis and to meet the actual requirement of dam risk analysis,it is necessary to establish a dam risk assistant analysis system.The program structure and the implementation ways of the dam risk assistant analysis system are analyzed,and a procedural framework with "three-tier and multi-database" structure and "level structure" is established.The concept of dam risk assessment system modular development is proposed and the coupled mode of function module and data is improved.Finally,the dam risk assistant analysis system is developed using Delphi visual programming language.

  11. Assessment of dam construction impact on hydrological regime changes in lowland river – A case of study: the Stare Miasto reservoir located on the Powa River

    Directory of Open Access Journals (Sweden)

    Sojka Mariusz

    2016-09-01

    Full Text Available The purpose of the presented research is analysis and assessment of the Stare Miasto reservoir impact on the hydrological regime changes of the Powa River. The reservoir was built in 2006 and is located in the central part of Poland. The total area of inundation in normal conditions is 90.68 ha and its capacity is 2.159 mln m3. Hydrological regime alteration of the Powa River is analysed on the basis of daily flows from the Posoka gauge station observed during period 1974–2014. Assessment of hydrological regime changes is carried out on the basis of Range of Variability Approach (RVA method. All calculations are made by means of Indicators of Hydrologic Alteration (IHA software version 7.1.0.10. The analysis shows that the Stare Miasto reservoir has a moderate impact on hydrological regime of the Powa River. Construction of the reservoir has positive effect on stability of minimal flows, which are important for protection of river ecosystems. The results obtained indicate that the Stare Miasto reservoir reduces a spring peak flow and enables to moderate control of floods.

  12. Amazon dams and waterways: Brazil's Tapajós Basin plans.

    Science.gov (United States)

    Fearnside, Philip M

    2015-09-01

    Brazil plans to build 43 "large" dams (>30 MW) in the Tapajós Basin, ten of which are priorities for completion by 2022. Impacts include flooding indigenous lands and conservation units. The Tapajós River and two tributaries (the Juruena and Teles Pires Rivers) are also the focus of plans for waterways to transport soybeans from Mato Grosso to ports on the Amazon River. Dams would allow barges to pass rapids and waterfalls. The waterway plans require dams in a continuous chain, including the Chacorão Dam that would flood 18,700 ha of the Munduruku Indigenous Land. Protections in Brazil's constitution and legislation and in international conventions are easily neutralized through application of "security suspensions," as has already occurred during licensing of several dams currently under construction in the Tapajós Basin. Few are aware of "security suspensions," resulting in little impetus to change these laws.

  13. Douglas County Dam Breach Inundation Areas

    Data.gov (United States)

    Kansas Data Access and Support Center — Dam breach analysis provides a prediction of the extent and timing of flooding from a catastrophic breach of the dams. These results are sufficient for developing...

  14. VT High Risk Dam Inundation Areas

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Preliminary release Storm-Day dam inundation areas digitized from various source Emergency Action Plans. These dams were prioritized for...

  15. Dams and Obstructions along Iowa's Canoe Routes

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This dataset represents obstruction to canoe and boat users of the canoe routes of Iowa. This may represent actual dams, rock dams (natural or man made), large...

  16. EVALUASI KEAMANAN DAM JATILUHUR BERBASIS INDEKS RESIKO

    Directory of Open Access Journals (Sweden)

    Avazbek Ishbaev

    2014-12-01

    Full Text Available The dams have very important roles to agricultural activities. Especially, West Java with 240,000 hectares of agricultural land, needs a good dam structure that can be used sustainably. Jatiluhur dam in Purwakarta, West Java is one of big dams in Indonesia which has important rules not only for Purwakarta but also for Jakarta, Karawang and Bekasi residents. A study and observation about safety and dam stability is needed to prevent any damage. The purpose of this research were to identify parameters that influenced dam safety and to evaluate dam reliability based on index tools. Analysis was done using risk index tools. The result showed that the condition of the dam of Jatiluhur is still satisfied with indicators, "Idam"-750. The total index risk was 127.22 and the safety factor was 83.04 out of 100. Therefore, Jatiluhur dam could be classified as safe and no need for particular treatments. Jatiluhur dam can be operated in normal condition or abnormal condition with periodic monitoring. Keywords: dam safety, evaluation, Jatiluhur Dam, risk index tools

  17. Webinar: Stepped chute design for embankment dams

    Science.gov (United States)

    Changing demographics in the vicinity of dams have led to hazard creep in a number of dams worldwide. Many of these dams now have insufficient spillway capacity as a result of these changes in hazard classification from low to significant or high hazard. Stepped chutes applied to the embankment da...

  18. Dams life; La vie des barrages

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The paper reports on the conclusions of decennial and annual inspections of French dams. Dams surveillance is performed by the operators and consists in visual examinations and measurements. Concrete dams, in particular, always have more or less developed fissures with water sweating threw the concrete mass or the foundations. Old concrete often show low swelling phenomena which are measured too. (J.S.)

  19. Viewpoint – Brazil’s Madeira River Dams: A Setback for Environmental Policy in Amazonian Development

    Directory of Open Access Journals (Sweden)

    Philip Martin Fearnside

    2014-02-01

    Full Text Available Decisions on hydroelectric dam construction will be critical in shaping the future of Amazonia, where planned dams would convert most tributaries into chains of reservoirs. The Santo Antônio and Jirau dams, now nearing completion on the Madeira River, have created dangerous precedents in a trend towards weakening environmental protection in Brazil. Political appointees have overruled the technical staff of the Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA, which is responsible for evaluating the environmental impact study (EIA and for licensing dams. Installation licences were granted without satisfying many of the 'conditions' that had been established as prerequisites. This feature and several others of the licensing process for the Madeira River dams have now been repeated in licensing the controversial Belo Monte Dam on the Xingu River. Brazil plans to build 30 large dams in its Amazon region in a decade, and others are to be financed and built by Brazil in Peru, Bolivia, Ecuador and Guyana. These plans affect virtually all water resources in an area larger than Western Europe. The Madeira River dams indicate the need to reform the decision-making process in Brazil.

  20. 使用橡皮障对牙体牙髓科患者舒适度的影响%Impact of the use of rubber dam on patient comfort in the department of cariology and endodontology

    Institute of Scientific and Technical Information of China (English)

    刘思毅; 刘婧寅; 刘木清; 董艳梅

    2015-01-01

    AIM: To investigate the patients′ acceptance of rubber dam use and the influencing factors of rubber dam during restorative and endodontic treatment. METHODS:Rubber dam was used during restorative or en-dodontic treatment in 202 patients (85 males and 117 females) aged 14 to 78 year-old (36. 5 on average) in this ques-tionnaire study. Patients′acceptance rate of rubber dam usage and whether tooth position, type of treatment and local anesthesia would affect the use of rubber dam were studied. RESULTS:Of all the patients questioned, 88. 1% would like to use rubber dam again during dental treatment. The acceptance rate of patients who had maxillary anterior teeth treatment was higher (97. 1%, P0. 05). CON-CLUSION:Patients' acceptance rate of rubber dam use was high in the department of cariology and endodontology. Tooth position and local anesthesia may influence patients' degree of comfort during rubber dam use.%目的:调查患者在进行牙体牙髓治疗时使用橡皮障的接受度及不适感来源。方法:对202名在牙体牙髓治疗时使用橡皮障的14~78岁患者(男性85名,女性117名)进行问卷调查;统计并分析患者对橡皮障的接受度以及牙位、方法、是否局麻等对橡皮障使用舒适度的影响。结果:88.1%的患者愿意下次治疗时再次使用橡皮障;治疗上颌前牙的患者对橡皮障接受度较其他治疗部位高(97.1%)(P0.05)。结论:牙体牙髓治疗时患者对橡皮障术野隔离法的接受度高,牙位、是否局麻会影响患者对橡皮障的接受度。

  1. The formation and failure of natural dams

    Science.gov (United States)

    Costa, J.E.; Schuster, R.L.

    1987-01-01

    Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and neoglacial moraines present the greatest threat to people and property. The most common types of mass movements that form landslide dams are rock and debris avalanches, rock and soil slumps and slides, and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Landslide dams can be classified into six categories based on their relation with the valley floor. Type I dams (11%) of the 81 landslide dams around the world that were classifed do not reach from one valley side to the other. Type II dams (44%) span the entire valley flood, occasionally depositing material high up on opposite valley sides. Type III dams (41%) move considerable distances both upstream and downstream from the landslide failure. Type IV dams (1%) are rare and involve the contemporaneous failure of material from both sides of a valley. Type V dams (1%) are also rare, and are created when a single landslide sends multiple tongues of debris into a valley forming two or more landslide dams in the same surfaces, that extend under the stream or valley and emerge on the opposite valley side. Many landslide dams fail shortly after formation. Overtopping is by far the most common cause of failure. Glacial ice dams can produce at least nine kinds of ice-dammed lakes. The most dangerous are lakes formed in main valleys dammed by tributary glaciers. Failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam. Cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel. Warmer temperate-ice dams tend to fail by sudden englacial or subglacial breaching and drainage. Late neoglacial moraine-dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several

  2. Environmental risk assessment of a dam during construction phase

    Directory of Open Access Journals (Sweden)

    S. Rezaian

    2016-12-01

    Full Text Available The present study was conducted to assess the possible risks induced by construction of Gavi Dam in Ilam Province; western part of Iran, using MIKE-11 model and technique for order of preference by similarity to ideal solution. For this purpose, vulnerable zone of the dam site against the flooding risk of Gavi River was calculated for different return periods. The flooding zones were stimulated by MIKE-11 model. In order to check whether or not the dam construction could affect the quality of the Gavi River, the physicochemical quality of the river water was also tested. Afterwards, a questionnaire was prepared containing an inventory of possible risks supposed to be induced by construction of Gavi Dam. The questionnaires were placed at disposal of experts to score the items based on their importance. The questionnaires were then analyzed using SPSS Software, version 16. According to which, a total number of 12 risk factors were identified. The dam construction risks were qualitatively assessed by preliminary hazard analysis. Based on the results, 3 of 12 identified risks were recognized unacceptable. The shortlisted risks were prioritized at final step using technique for order of preference by similarity to ideal solution. "Habitat fragmentation" with a weight of 0.3002, "water pollution" with a weight of 0.295, and "impacts on aquatics" with a weight of 0.293 were identified as three top priority flooding risks. Among the most important corrective measures for mitigation of the risks at construction phase can be pointed to "restoration of the land cover", “conservation of areas surrounding the dam as a new wildlife habitat", “prevention of water contamination”, and "conservation of fish spawning sites".

  3. Impact Analysis of Aggraded Sediment on Dam-break Flood in Reservoir%某水库库区淤沙对溃坝洪水影响分析

    Institute of Scientific and Technical Information of China (English)

    郭维东; 康国亮; 胡志华; 谢方芳

    2011-01-01

    为分析某淤积型水库淤沙对溃坝洪水计算的影响,将MIKE21中的水动力模块与输沙模块耦合构建了二维溃坝水沙模型、分别模拟了不考虑淤沙与考虑淤沙运动水库的溃坝洪水演进过程.模拟结果表明,与不考虑淤沙运动水库溃坝相比,考虑淤沙的水库溃坝洪水下游各断面洪峰流量减小,洪水过后水位升高,水深变化不明显.%In order to analyze the influence of sediment in reservoir sedimentation on routing process of dam break flood, two-dimensional water-silt dam-break model is established by coupling hydrodynamic module (HD) and sand transport module (ST) in MIKE21 software. The dam-break flood routing process is simulated with or without considering the scouring and aggrading process of sediment in a reservoir. The results show that simulation considering the slit downstream sections have smaller peak flow discharge, lower water level after the dam break flood, water depth also changes in comparison with the simulation not considering the slit.

  4. Research on shape optimization of CSG dams

    Directory of Open Access Journals (Sweden)

    Xin CAI

    2011-12-01

    Full Text Available The multi-objective optimization method was used for shape optimization of cement sand and gravel (CSG dams in this study. The economic efficiency, the sensitivities of maximum horizontal displacement and maximum settlement of the dam to water level changes, the overall stability, and the overall strength security were taken into account during the optimization process. Three weight coefficient selection schemes were adopted to conduct shape optimization of a dam, and the case studies lead to the conclusion that both the upstream and downstream dam slope ratios for the optimal cross-section equal 1:0.7, which is consistent with the empirically observed range of 1:0.6 to 1:0.8 for the upstream and downstream dam slope ratios of CSG dams. Therefore, the present study is of certain reference value for designing CSG dams.

  5. Future directions of dam safety in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Verzeni, Gerard [Hydro Quebec, QC, (Canada)

    2010-07-01

    Gerard Verzeni, former director of the dam safety & environment at Hydro-Quebec introduced the future directions of dam safety in Canada. New and numerous challenges are emerging for the dam safety community. Measurable effects of climate changes illustrate that hydraulic forecasts would change drastically. Loads with times and amplitudes which are different from the actual knowledge will apply on dams. The development of new types of dams using recent technologies raises several issues, for example the longevity of such installations. The installations are becoming old and soon will require complete renovation and update for regulation and standards compliance. Concrete dams already need efforts and investment to maintain then in a safe state. Various factors will influence these challenges such as human resources in the dam safe community. In these conditions, it is important that organizations like CDA play an important role in providing support and reference and in being a driver for the whole industry.

  6. The Influence of Ground Water on Stream Restoration Following Dam Removal

    Science.gov (United States)

    Constantz, J.; Essaid, H.

    2003-12-01

    With the exception of ground-water seepage beneath dams and the resulting impact on structural failure, there is a void of work directly examining the downstream impacts of dams from the perspective of ground-water/surface-water interaction. This work considers alterations in an alluvial basin caused by: (1) erection of a dam upstream, (2) followed by ground-water pumping in the basin, and (3) dam removal. Theoretical results predict that when dams are removed in developed ground-water basins, downstream baseflows may be greatly reduced relative to natural baseflows, as a result of lower water table elevations in the developed basin relative to the natural setting. Without the dam as a `safety valve' providing extra streamflow during low-flow seasons, there is a real potential for ephemeral conditions downstream of the previous location of the dam as the dry season progresses. MODFLOW simulations are used to test these theoretical results, by quantifying the impact of dam removal on downstream surface water and ground water. The simulations incorporate an improved stream-aquifer interaction and streamflow routing package to represent movement of water in the vadose zone between the stream and a lowered water table. An idealized MODFLOW model with the new stream package has been constructed, which extends from the upland bedrock headwaters of a stream to the downstream sediment-filled basin. The model domain is 180 km long, 15 km wide, and 2.2 km deep, including a stream with a potential length of 180 km. In the upper reaches, the stream is divided into a north, south, and main stem with their confluence upstream of a dam situated in the domain above the bedrock/basin contact. Horizontal discretization is 1000 m in the direction parallel to the stream, 200 to 600 m perpendicular to the stream, and vertical discretization is 100 m. This modeling framework affords the opportunity to examine a variety of cases with and without the presence of an upstream dam. Initial

  7. Study of Dam-break Due to Overtopping of Four Small Dams in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Zakaraya Alhasan

    2015-01-01

    Full Text Available Dam-break due to overtopping is one of the most common types of embankment dam failures. During the floods in August 2002 in the Czech Republic, several small dams collapsed due to overtopping. In this paper, an analysis of the dam break process at the Luh, Velký Bělčický, Melín, and Metelský dams breached during the 2002 flood is presented. Comprehensive identification and analysis of the dam shape, properties of dam material and failure scenarios were carried out after the flood event to assemble data for the calibration of a numerical dam break model. A simple one-dimensional mathematical model was proposed for use in dam breach simulation, and a computer code was compiled. The model was calibrated using the field data mentioned above. Comparison of the erodibility parameters gained from the model showed reasonable agreement with the results of other authors.

  8. Management of dams for the next Millennium: proceedings of the 1999 Canadian Dam Association

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The meeting featured seven sessions with 18 papers abstracted/indexed therein as follows: keynote address: tailings dams safety - implications for the dam safety community; 1 - design and performance: performance monitoring of dams: are we doing what we should be doing?; tailings dams from the perspective of conventional dam engineering; and design overview of Syncrude's Mildred Lake east toe berm; 2 - design and modelling: use of a 2D model for a dam break study on the ALCAN hydroelectric complex in Quebec; and spillway design implications resulting from changes in rainfall extremes; 3 - risk and dam safety I: closing the gaps in the dam safety guidelines; the reality of life safety consequence classification; and surveillance practices for the next millenium; 4 - risk and dam safety II: quantitative risk-assessment using the capacity-demand analysis; and new guidelines for dam safety classification; 5 - millenium issues: expectations of immortality, dam safety management into the next millenium; 6 - rehabilitation techniques: the unconventional application of conventional materials; nondestructive testing technology to characterize concrete dam/bedrock interface; method and instrument for detecting crack in concrete; and grouting of the cracks in the Arch 5-6 - Daniel Johnson Dam; and 7 - case studies: rehabilitation of an 80 year old Ambursen type dam; and debris booms for the protection of spillways.

  9. Experimental study of debris flow caused by domino failures of landslide dams

    Institute of Scientific and Technical Information of China (English)

    Hua-Yong CHEN; Peng CUI; Gordon G.D.ZHOU; Xing-Hua ZHU; Jin-Bo TANG

    2014-01-01

    The formation of landslide dams is often induced by earthquakes in mountainous areas. The failure of a landslide dam typically results in catastrophic flash floods or debris flows downstream. Significant attention has been given to the processes and mechanisms involved in the failure of individual landslide dams. However, the processes leading to domino failures of multiple landslide dams remain unclear. In this study, experimental tests were carried out to investigate the domino failure of landslide dams and the consequent enlargement of downstream debris flows. Different blockage conditions were considered, including complete blockage, partial blockage and erodible bed (no blockage). The mean velocity of the flow front was estimated by videos. Total stress transducers (TSTs) and Laser range finders (LRFs) were employed to measure the total stress and the depth of the flow front, respectively. Under a complete blockage pattern, a portion of the debris flow was trapped in front of each retained landslide dam before the latter collapsed completely. This was accompanied by a dramatic decrease in the mean velocity of the flow front. Conversely, under both partial blockage and erodible bed conditions, the mean velocity of the flow front increased gradually downward along the sloping channel. Domino failures of the landslide dams were triggered when a series of dams (complete blockage and partial blockage) were distributed along the flume. However, not all of these domino failures led to enlarged debris flows. The modes of dam failures have significant impacts on the enlargement of debris flows. Therefore, further research is necessary to understand the mechanisms of domino failures of landslide dams and their effects on the enlargement of debris flows.

  10. Differences in survival and growth in hatchery and stream environments, and in maturation of residuls in a stream, between progeny of hatchery and wild steelhead (Study sites: Brushy Fork Creek and Dworshak Hatchery; Stocks:Dworshak hatchery and Fish Creek wild; Year classes: 1992 and 1993): Chapter 1

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hensleigh, Jay E.; Leonetti,; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    Freshwater survival in hatchery and natural rearing environments was compared between progeny of hatchery (H) and wild (W) steelhead Oncorhynchus mykiss from the Clearwater River drainage in Idaho. Adults from Dworshak National Fish Hatchery and wild adults from Fish Creek fish were artificially spawned, and their progeny were genetically marked at the PEPA allozyme locus and released together as unfed fry in production facilities at the hatchery and in Brushy Fork Creek, also in the Clearwater River drainage, in a common garden design. Survival was higher for H than for W progeny at the hatchery but lower for H than for W progeny in Brushy Fork, indicating reduced fitness of the hatchery population for natural rearing and suggesting domestication as the cause. Survival at the hatchery was lower than is typical due to disease outbreaks. Survival of the first year-class of experimental fish to smolt release was only 18%. Survival of H fish was 3.8 times that of W fish under these poor survival conditions. All fish from the second year-class died halfway through the scheduled 10 month rearing period. Survival of H fish was 5.2 times that of W fish to when 1% of the initial fry were still alive indicating that W fish succumbed to the epizootic sooner than did H fish. Emigrants from the Brushy Fork study reach were sampled for three years and fish residing in the study reach were sampled for six years following fry release. Most emigrants were one or two years old and too small to be smolts (mean fork length at age-2 = 93 mm). Survival in Brushy Fork was lower for H than for W fish of the first year-class. Survival of the second year-class was higher for H than for W fish during the first two months in the stream but was lower for H than for W fish thereafter, and net survival from release to ages 3 and older was also lower for H than for W fish if our emigrant samples were representative (periods of inoperative emigrant traps prevented certainty about this

  11. Predicted time from fertilization to maximum wet weight for steelhead alevins based on incubation temperature and egg size (Study site: Western Fishery Research Center, Seattle; Stock: Dworshak hatchery; Year class: 1996): Chapter 4

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Slatton, Stacey L.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    The accuracy of a model that predicts time between fertilization and maximum alevin wet weight (MAWW) from incubation temperature was tested for steelhead Oncorhynchus mykiss from Dworshak National Fish Hatchery on the Clearwater River, Idaho. MAWW corresponds to the button-up fry stage of development. Embryos were incubated at warm (mean=11.6°C) or cold (mean=7.3°C) temperatures and time between fertilization and MAWW was measured for each temperature. Model predictions of time to MAWW were within 1% of measured time to MAWW. Mean egg weight ranged from 0.101-0.136 g among females (mean = 0.116). Time to MAWW was positively related to egg size for each temperature, but the increase in time to MAWW with increasing egg size was greater for embryos reared at the warm than at the cold temperature. We developed equations accounting for the effect of egg size on time to MAWW for each temperature, and also for the mean of those temperatures (9.3°C).

  12. Effects of the Ben Franklin Dam on the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Harty, H.

    1979-04-01

    A previous assessment of the effects of a Ben Franklin Dam on the Hanford Site made in 1967 was updated so that the potential adverse effects may be better understood in light of existing operations, current environmental and safety standards, and proposed facilities and operations. The major effects would probably arise from flooding of portions of the site by the reservoir associated with the dam and by the raising of the ground water table under the site. A preliminary analysis of the effects of the dam is presented, and a number of studies are recommended in order to fully evaluate and understand these potential impacts. The following seven tasks are identified and discussed: groundwater - hydrology analysis; soil liquefaction analysis; hydrostatic uplift and soil effects on structures; assessment of the potential for landsliding and sloughing; facility decommissioning; hydrothermal analysis; and, meteorological effects. Four other aspects commented upon in this report are: aquatic ecology, terrestrial ecology, socioeconomic effects, and public interaction. Possible effects on ongoing DOE-sponsored R and D are also noted. To the extent possible, cost estimates are developed for corrective actions which must be taken on the Hanford Site to accommodate the dam. Where this was not possible, appropriate courses of action leading to cost estimates are presented.

  13. Accuracy Analysis of a Dam Model from Drone Surveys.

    Science.gov (United States)

    Ridolfi, Elena; Buffi, Giulia; Venturi, Sara; Manciola, Piergiorgio

    2017-08-03

    This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs) used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D) model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a correct GCPs location choice to properly georeference the images and thus, the model. To this end, a high number of GCPs configurations were investigated, building a series of dense point clouds. The accuracy of these resulting dense clouds was estimated comparing the coordinates of check points extracted from the model and their true coordinates measured via traditional topography. The paper aims at providing information about the optimal choice of GCPs placement not only for dams but also for all surveys of high-rise structures. The knowledge a priori of the effect of the GCPs number and location on the model accuracy can increase survey reliability and accuracy and speed up the survey set-up operations.

  14. Accuracy Analysis of a Dam Model from Drone Surveys

    Directory of Open Access Journals (Sweden)

    Elena Ridolfi

    2017-08-01

    Full Text Available This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a correct GCPs location choice to properly georeference the images and thus, the model. To this end, a high number of GCPs configurations were investigated, building a series of dense point clouds. The accuracy of these resulting dense clouds was estimated comparing the coordinates of check points extracted from the model and their true coordinates measured via traditional topography. The paper aims at providing information about the optimal choice of GCPs placement not only for dams but also for all surveys of high-rise structures. The knowledge a priori of the effect of the GCPs number and location on the model accuracy can increase survey reliability and accuracy and speed up the survey set-up operations.

  15. Geomorphic and ecological disturbance and recovery from two small dams and their removal.

    Science.gov (United States)

    Tullos, Desirée D; Finn, Debra S; Walter, Cara

    2014-01-01

    Dams are known to impact river channels and ecosystems, both during their lifetime and in their decommissioning. In this study, we applied a before-after-control-impact design associated with two small dam removals to investigate abiotic and biotic recovery trajectories from both the elimination of the press disturbance associated with the presence of dams and the introduction of a pulse disturbance associated with removal of dams. The two case studies represent different geomorphic and ecological conditions that we expected to represent low and high sensitivities to the pulse disturbance of dam removal: the 4 m tall, gravel-filled Brownsville Dam on the wadeable Calapooia River and the 12.5 m tall, sand and gravel-filled Savage Rapids Dam on the largely non-wadeable Rogue River. We evaluated both geomorphic and ecological responses annually for two years post removal, and asked if functional traits of the macroinvertebrate assemblages provided more persistent signals of ecological disturbance than taxonomically defined assemblages over the period of study. Results indicate that: 1) the presence of the dams constituted a strong ecological press disturbance to the near-downstream reaches on both rivers, despite the fact that both rivers passed unregulated flow and sediment during the high flow season; 2) ecological recovery from this press disturbance occurred within the year following the restoration action of dam removal, whereas signals of geomorphic disturbance from the pulse of released sediment persisted two years post-removal, and 3) the strength of the press disturbance and the rapid ecological recovery were detected regardless of whether recovery was assessed by taxonomic or functional assemblages and for both case studies, in spite of their different geomorphic settings.

  16. Geomorphic and ecological disturbance and recovery from two small dams and their removal.

    Directory of Open Access Journals (Sweden)

    Desirée D Tullos

    Full Text Available Dams are known to impact river channels and ecosystems, both during their lifetime and in their decommissioning. In this study, we applied a before-after-control-impact design associated with two small dam removals to investigate abiotic and biotic recovery trajectories from both the elimination of the press disturbance associated with the presence of dams and the introduction of a pulse disturbance associated with removal of dams. The two case studies represent different geomorphic and ecological conditions that we expected to represent low and high sensitivities to the pulse disturbance of dam removal: the 4 m tall, gravel-filled Brownsville Dam on the wadeable Calapooia River and the 12.5 m tall, sand and gravel-filled Savage Rapids Dam on the largely non-wadeable Rogue River. We evaluated both geomorphic and ecological responses annually for two years post removal, and asked if functional traits of the macroinvertebrate assemblages provided more persistent signals of ecological disturbance than taxonomically defined assemblages over the period of study. Results indicate that: 1 the presence of the dams constituted a strong ecological press disturbance to the near-downstream reaches on both rivers, despite the fact that both rivers passed unregulated flow and sediment during the high flow season; 2 ecological recovery from this press disturbance occurred within the year following the restoration action of dam removal, whereas signals of geomorphic disturbance from the pulse of released sediment persisted two years post-removal, and 3 the strength of the press disturbance and the rapid ecological recovery were detected regardless of whether recovery was assessed by taxonomic or functional assemblages and for both case studies, in spite of their different geomorphic settings.

  17. National Program of Inspection of Non-Federal Dams.

    Science.gov (United States)

    1982-05-01

    inhabitants were informed by the media or local officials, the inspection program had little impact. When downstream residents were made fully aware of the... edad of A inet’ca ipt Coe~re aseiN , That the te rme ibts grs f ton. adagn" u used in thia Act means any artificial barrier, iiicludire *po is perit...performance, etc., for defining a comprehensive national dam safety program. (g) Responding to Congressional, media , scientific and engineering

  18. Detrital Zircon Record of a Dammed River in Texas - Implications for Modern River Provenance Stories and Sediment Budgets

    Science.gov (United States)

    Dafov, L. N.; Stockli, D. F.; Mohrig, D. C.; Olariu, C.

    2016-12-01

    rivers and coastal processes after dam construction. Importantly, this study is a cautionary tale for the use of DZ U-Pb provenance studies of modern rivers and the impact of dams and anthropogenic perturbations, as the downstream DZ record does not appear to reflect the pre-dam provenance signature of the Colorado River of Texas.

  19. Quantifying Channel Morphology Changes in Response to the Removal of the Glines Canyon Dam, Elwha River, Washington

    Science.gov (United States)

    Free, B. J.; Ely, L. L.; Hickey, R.; Flake, R.; Baumgartner, S.

    2014-12-01

    The removal of two dams on the Elwha River, Washington, is the largest dam-removal project in history. Our research documents the sediment deposition, erosion, and channel changes between the dams following the initial sediment release from the removal of the upstream Glines Canyon Dam. Within the first year following the dam removal, the pulse of coarse sediment and large woody debris propagated downstream well over 6 km below the dam. The sediment deposition and altered channel hydraulics caused lateral channel migration where anabranching channels merge around new mid-channel bars and at large bends in the river channel. Documenting the river channel response to this exceptional sediment pulse could improve models of the impacts of future dam removals on similar gravel-bed rivers. We quantified the sediment flux and channel changes at four field sites 2-6 km downstream of Glines Canyon Dam. Topographic changes were surveyed with a terrestrial laser scanner (TLS) on an annual basis from August 2012 - August 2014 and the surface sediment distribution was quantified with bimonthly sediment counts. Differencing the annual TLS data yielded an overall increase in sediment throughout the study reach, with a minimum of 20,000 m3 of deposition on bars and banks exposed above the water surface in each 700-m-long TLS survey reach. The surface sediment distribution decreased from ~18 cm to dam removal began to re-emerge due to the remobilizing of sediment through the system.

  20. After Three Gorges Dam: What have we learned?

    Science.gov (United States)

    Natali, J.; Williams, P.; Wong, R.; Kondolf, G. M.

    2013-12-01

    China is at a critical point in its development path. By investing heavily in large-scale infrastructure, the rewards of economic growth weigh against long-term environmental and social costs. The construction of Three Gorges Dam, the world's largest hydroelectric project, began in 1994. Between 2002 and 2010, its 660 kilometer reservoir filled behind a 181 meter dam, displacing at least 1.4 million people and transforming Asia's longest river (the Yangtze) while generating nearly 100 billion kWh/yr of electricity -- 2.85% of China's current electric power usage. As the mega-project progenitor in a cascade of planned dams, the Three Gorges Dam emerges as a test case for how China will plan, execute and mitigate its development pathway and the transformation of its environment. Post-Project Assessments (PPA) provide a systematic, scientific method for improving the practice of environmental management - particularly as they apply to human intervention in river systems. In 2012, the Department of Landscape Architecture and Environmental Planning at University of California, Berkeley organized a symposium-based PPA for the Three Gorges Dam on the Yangtze River. Prior to this symposium, the twelve invited Chinese scientists, engineers and economists with recent research on Three Gorges Dam had not had the opportunity to present their evaluations together in an open, public forum. With a 50-year planning horizon, the symposium's five sessions centered on impacts on flows, geomorphology, geologic hazards, the environment and socioeconomic effects. Three Gorges' project goals focused on flood control, hydropower and improved navigation. According to expert research, major changes in sediment budget and flow regime from reservoir operation have significantly reduced sediment discharge into the downstream river and estuary, initiating a series of geomorphic changes with ecological and social impacts. While the dam reduces high flow stages from floods originating above the

  1. Evaporation Ponds or Recharge Structures ? the Role of Check Dams in Arkavathy River Basin, India

    Science.gov (United States)

    Jeremiah, K.; Srinivasan, V.; R, A.

    2014-12-01

    "Watershed development" has been the dominant paradigm for water management in India for the last two decades. Current spending on watershed development programmes rivals spending on large dams. In practice, watershed development involves a range of soil and water conservation measures including building check dams, gully plugs, contour bunds etc. Despite their dominance in water management paradigms, relatively little empirical data exists on these structures. Importantly, even though the benefits of individual watershed structures are recognized, the cumulative impact of building hundreds of such structures on hydrologic partitioning of a watershed remains unknown. We investigated the role of check dams in two small milli-watersheds in the Arkavathy River basin in South India. We conducted a comprehensive census of all check dams in the two milli-watersheds with a total area of 26 sq km. 40 check dams (representing a density of 1.35/sq km of watershed area) were geotagged, photographed, measured and their condition was recorded. We then selected twelve check dams and monitored the water stored using capacitance sensors. We also set up Automatic Weather Stations in each watershed. Inflows, evaporation and infiltration were calculated at each site to evaluate how check dams alter hydrologic partitioning in the watershed as a whole.

  2. Experimental study of breach process of landslide dams by overtopping and its initiation mechanisms

    Institute of Scientific and Technical Information of China (English)

    杨阳; 曹叔尤; 杨克君; 李文萍

    2015-01-01

    The present paper studies the physics of the breach erosion process, particularly, the breach initiation process in over- topped landslide dams. Due to great complexities involved, only homogeneous landslide dams are considered. The flume experime- nts of dam overtopping are conducted to study the breach growth process. And in order to reveal the effects of the seepage during the breach development, the permeability characteristics of the dam materials are also taken into consideration. With the experimental observation, the details of the breach growth are examined, and the whole breach process could be distinguished into five stages, i.e., Stage I, the seepage erosion, Stage II, the formation of the initial breach, Stage III, the erosion toward the head, Stage IV, the expan- sion and incision of the breach, and Stage V, the re-equilibration of the river channel through the breach. It is shown that once trigge- red the entire breach process goes continually without stop, which highlights the significant impact of the early stages on the later deformation of the dam. Evidence shows that the initial breach of the dam is most likely to take place in the downstream slope of the dam, near the upper edge of the seepage face. The experimental results show a “headcut” mechanism of the breach initiation.

  3. Exporting dams: China's hydropower industry goes global.

    Science.gov (United States)

    McDonald, Kristen; Bosshard, Peter; Brewer, Nicole

    2009-07-01

    In line with China's "going out" strategy, China's dam industry has in recent years significantly expanded its involvement in overseas markets. The Chinese Export-Import Bank and other Chinese financial institutions, state-owned enterprises, and private firms are now involved in at least 93 major dam projects overseas. The Chinese government sees the new global role played by China's dam industry as a "win-win" situation for China and host countries involved. But evidence from project sites such as the Merowe Dam in Sudan demonstrates that these dams have unrecognized social and environmental costs for host communities. Chinese dam builders have yet to adopt internationally accepted social and environmental standards for large infrastructure development that can assure these costs are adequately taken into account. But the Chinese government is becoming increasingly aware of the challenge and the necessity of promoting environmentally and socially sound investments overseas.

  4. Dam safety review, classification of dams for the Novia Scotia Power Inc. Black River hydroelectric system

    Energy Technology Data Exchange (ETDEWEB)

    Alderman, Aaron; Small, Andy [AMEC Earth and environmental, Fredericton, (Canada); O' Neil, Ellis [Nova Scotia Power Inc., Halifax, (Canada)

    2010-07-01

    In 2009, AMEC was retained by Nova Scotia Power Inc. (NSPI) to conduct a dam safety review of the dams that are part of the Black River Hydroelectric System. This paper presented the results of this dam classification exercise which was carried out for the Bear River hydroelectric system in Nova Scotia, based on the 2007 Canadian Dam Association (CDA) dam safety guidelines. Flood mapping and dam-break analysis were performed for events ranging from the 1:100 year to PMF flood events, including cascading events. These results were used to draw up a classification of the dams. Associated design criteria were then developed. Following the assessment of the dam sites, conclusions and recommendations were discussed. The recommendations were presented in terms of regular maintenance items and reconstruction items, which are now used by NSPI to determine the party responsible for undertaking the recommendation and for evaluation of the maintenance and reconstruction schedules.

  5. Dam Inventory, dams, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Dam Inventory dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'dams'. Data...

  6. A review of proposed Glen Canyon Dam interim operating criteria

    Energy Technology Data Exchange (ETDEWEB)

    LaGory, K.; Hlohowskyj, I.; Tomasko, D.; Hayse, J.; Durham, L.

    1992-04-01

    Three sets of interim operating criteria for Glen Canyon Dam on the Colorado River have been proposed for the period of November 1991, to the completion of the record of decision for the Glen Canyon Dam environmental impact statement (about 1993). These criteria set specific limits on dam releases, including maximum and minimum flows, up-ramp and down-ramp rates, and maximum daily fluctuation. Under the proposed interim criteria, all of these parameters would be reduced relative to historical operating criteria to protect downstream natural resources, including sediment deposits, threatened and endangered fishes, trout, the aquatic food base, and riparian plant communities. The scientific bases of the three sets of proposed operating criteria are evaluated in the present report:(1) criteria proposed by the Research/Scientific Group, associated with the Glen Canyon Environmental Studies (GCES); (2) criteria proposed state and federal officials charged with managing downstream resources; and (3) test criteria imposed from July 1991, to November 1991. Data from Phase 1 of the GCES and other sources established that the targeted natural resources are affected by dam operations, but the specific interim criteria chosen were not supported by any existing studies. It is unlikely that irreversible changes to any of the resources would occur over the interim period if historical operating criteria remained in place. It is likely that adoption of any of the sets of proposed interim operating criteria would reduce the levels of sediment transport and erosion below Glen Canyon Dam; however, these interim criteria could result in some adverse effects, including the accumulation of debris at tributary mouths, a shift of new high-water-zone vegetation into more flood-prone areas, and further declines in vegetation in the old high water zone.

  7. Measurement of Dam Deformations: Case Study of Obruk Dam (Turkey)

    Science.gov (United States)

    Gulal, V. Engin; Alkan, R. Metin; Alkan, M. Nurullah; İlci, Veli; Ozulu, I. Murat; Tombus, F. Engin; Kose, Zafer; Aladogan, Kayhan; Sahin, Murat; Yavasoglu, Hakan; Oku, Guldane

    2016-04-01

    In the literature, there is information regarding the first deformation and displacement measurements in dams that were conducted in 1920s Switzerland. Todays, deformation measurements in the dams have gained very different functions with improvements in both measurement equipment and evaluation of measurements. Deformation measurements and analysis are among the main topics studied by scientists who take interest in the engineering measurement sciences. The Working group of Deformation Measurements and Analysis, which was established under the International Federation of Surveyors (FIG), carries out its studies and activities with regard to this subject. At the end of the 1970s, the subject of the determination of fixed points in the deformation monitoring network was one of the main subjects extensively studied. Many theories arose from this inquiry, as different institutes came to differing conclusions. In 1978, a special commission with representatives of universities has been established within the FIG 6.1 working group; this commission worked on the issue of determining a general approach to geometric deformation analysis. The results gleaned from the commission were discussed at symposiums organized by the FIG. In accordance with these studies, scientists interested in the subject have begun to work on models that investigate cause and effect relations between the effects that cause deformation and deformation. As of the scientist who interest with the issue focused on different deformation methods, another special commission was established within the FIG engineering measurements commission in order to classify deformation models and study terminology. After studying this material for a long time, the official commission report was published in 2001. In this prepared report, studies have been carried out by considering the FIG Engineering Surveying Commission's report entitled, 'MODELS AND TERMINOLOGY FOR THE ANALYSIS OF GEODETIC MONITORING OBSERVATIONS

  8. Study on dynamic anti-sliding stability of a high gravity dam considering complex dam foundation

    OpenAIRE

    Deng-hong CHEN; Cheng-bin DU

    2011-01-01

    There existed some limitations when analyzing the anti-sliding seismic stability of dam-foundation system by traditional pseudo-static method and response spectrum method. The dynamic strength reduction method was used to study on the deep anti-sliding stability of a high gravity dam considering complex dam foundation under strong earthquake-induced ground action. The static analysis was firstly carried out by reducing the shear strength parameters of the dam foundation’s rock mass with equal...

  9. Environment Changes of Lampao Dam Communities in Northeast Thailand

    Directory of Open Access Journals (Sweden)

    Winyoo Sata

    2008-01-01

    community realized the problems. Together they turned around, changing the direction of their development from money-oriented economy back to environment rehabilitation in the community. Starting in 1997 they adopted the King's philosophy of Sufficiency Economy. This concept of development did help to revive the environment of Sa-Adnathom community-their farm land, natural water resource and forest. They engaged in organic farming, reduced mono-crop growing and returned to reliance on natural means to meet their four basic needs in life. Conclusion: This research yielded a recommendation regarding policy guidelines for community development in Thailand. That is, the environment impact on the adjacent community of the dam should be given a careful consideration before such a project would be launched.

  10. 78 FR 60271 - Hollow Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of Application for Transfer of...

    Science.gov (United States)

    2013-10-01

    ... Federal Energy Regulatory Commission Hollow Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of..., Hollow Dam Power Company (transferor) and Ampersand Hollow Dam Hydro, LLC (transferee) filed an application for transfer of license for the Hollow Dam Project, FERC No. 6972, located on the West Branch...

  11. Numerical modelling for stability of tailings dams

    OpenAIRE

    Auchar, Muhammad; Mattsson, Hans; Knutsson, Sven

    2013-01-01

    A tailings dam is a large embankment structure that is constructed to store the waste from the mining industry. Stability problems may occur in a tailings dam due to factors such as quick rate of raising, internal erosion and liquefaction. The failure of a tailings dam may cause loss of human life and environmental degradation. Tailings Dams must not only be stable during the time the tailings storage facility is in operation, but also long time after the mine is closed. In Sweden, the licens...

  12. Debris Flow Dam Formation in Southeast Tibet

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; WU Jishan; GENG Xueyong

    2005-01-01

    Glaciers with their deposits abound in the alpine areas of Southeast Tibet. Large debris flows occur frequently from these deposits and form dams that block streams. In this paper, 3 events of large debris flows reported in Peilong Valley located in Southeast Tibet, and which resulted 2 blocking dams resulted, are discussed in details, focusing on the major factors controlling dam formation. The results shows that the first surge group caused by snow and ice avalanches, ice-lake breaks, and large-scale landslides, with a high peak discharge and high velocity, and an abundance of boulders, are most likely to form blocking dams.

  13. Comprehensive evaluation methods for dam service status

    Institute of Scientific and Technical Information of China (English)

    WU ZhongRu; XU Bo; GU ChongShi; LI ZhanChao

    2012-01-01

    More than 87000 dams have been built in China,and about one third of them are risky projects.A number of high and ultra-high dams are being constructed in China's western region.The current dam construction practice tends to focus on socio-economic benefits and neglect the environment and ecology.Furthermore,periodic examinations are intended to ensure the structural safety of dams.This paper proposes a general evaluation principle for dam service.This principle stipulates that dam projects should have maximum socio-economic benefits and minimum negative effects on the environment and ecology.To satisfy the general principle of mutual harmony,socio-economic benefits,dam safety,environment,and ecology are analyzed,and the evaluation methods for dam service status are discussed.Then,a fusion algorithm of interlayer assessment is proposed on the basis of evidence theory and the fuzzy comprehensive analysis method.Finally,a comprehensive evaluation model is established.Example analysis shows that the proposed theories and methods can fulfill scientific assessment of the service status of dams.

  14. Correlating check dam sedimentation and rainstorm characteristics on the Loess Plateau, China

    Science.gov (United States)

    Li, Xungui; Wei, Xia; Wei, Ning

    2016-07-01

    On the Loess Plateau, China, check dams are necessary for soil and water conservation. In this study, the relationships between check dam sedimentation and storm characteristics were investigated, and rainstorm events for an area of data scarcity were reconstructed using optimal regression models. Four typical check dams of the Loess Plateau (the Shipanmao, Hualiang, No. 3 Guandigou, and No. 4 Guandigou dams) were selected for case studies. Soil profiles behind the four dams were divided into 21, 25, 31, and 31 layers, respectively. The one-to-one link between sediment layers and corresponding storm characteristics were considered based on the peak fallout of 137Cs and on the principle that higher flow corresponds to higher sediment deposition volume. Analysis showed that the layered sediment volume (V) was closely related to rainfall erosivity (R), and to the maximum rainfall intensity over 30 min (I30). A statistically significant power regression model between V and R was observed, along with an exponential regression model between V and I30. Based on the power regression model between V and R, a new approach was developed in order to reconstruct rainfall erosivity in rainfall data-scarcity areas. Different hysteresis patterns (counterclockwise, clockwise, and hybrid) at the single storm scale were observed between V and R for the Shipanmao dam deposition wedge (depositional area behind a dam), and these impacted differently on the scale reconstruction results. However, the distance between the reconstructed dams and the known dams had an even stronger influence. The scale method developed in this study was shown to perform well and was able to reconstruct rainstorm events for adjacent regions with similar climatic and geomorphological conditions. Furthermore, the results of this study have improved our understanding of single rainstorm dynamics and soil erosion mechanisms on the Loess Plateau.

  15. Development and implementation of a dam safety program for Manitoba Infrastructure and Transportation

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Ninel S.; McLean, Angela D. [Manitoba infrastructure and transportation, Winnipeg, (Canada)

    2010-07-01

    Responsibility for the operation and maintenance of provincial dams has been transferred, at the province's initiative, to Manitoba Infrastructure and Transportation (MIT). MIT used the 2007 CDA guidelines as reference in the development of a dam safety program for provincial dams in response to the lack of provincial legislation for the regulation and management of dams in Manitoba. This paper presented the work of the MIT to develop and implement a management system, with emphasis on the planning and implementation elements. MIT focused on both the prioritization of work and the implementation of an inspection program. To develop a prioritization scheme, a risk assessment was performed with the estimation of risk based on the impact of an event occurring and integrating the quality of the controls in place. Multiple account analysis (MAA) was also used to develop a second prioritization plan.

  16. Hydrologic response of streams restored with check dams in the Chiricahua Mountains, Arizona

    Science.gov (United States)

    Norman, Laura M.; Brinkerhoff, Fletcher C.; Gwilliam, Evan; Guertin, D. Phillip; Callegary, James B.; Goodrich, David C.; Nagler, Pamela L.; Gray, Floyd

    2016-01-01

    In this study, hydrological processes are evaluated to determine impacts of stream restoration in the West Turkey Creek, Chiricahua Mountains, southeast Arizona, during a summer-monsoon season (June–October of 2013). A paired-watershed approach was used to analyze the effectiveness of check dams to mitigate high flows and impact long-term maintenance of hydrologic function. One watershed had been extensively altered by the installation of numerous small check dams over the past 30 years, and the other was untreated (control). We modified and installed a new stream-gauging mechanism developed for remote areas, to compare the water balance and calculate rainfall–runoff ratios. Results show that even 30 years after installation, most of the check dams were still functional. The watershed treated with check dams has a lower runoff response to precipitation compared with the untreated, most notably in measurements of peak flow. Concerns that downstream flows would be reduced in the treated watershed, due to storage of water behind upstream check dams, were not realized; instead, flow volumes were actually higher overall in the treated stream, even though peak flows were dampened. We surmise that check dams are a useful management tool for reducing flow velocities associated with erosion and degradation and posit they can increase baseflow in aridlands.

  17. Economic evaluation of the Diamer-Basha dam: Analysis with an integrated economic/water simulation model of Pakistan:

    OpenAIRE

    Robinson, Sherman; Gueneau, Arthur

    2014-01-01

    This paper describes the potential impact on the economy of Pakistan of building the Diamer-Basha dam. An integrated system of economic and water simulation models is applied to Pakistan to analyze the economywide impacts of changes in water resources in the Indus river basin, focusing on agricultural and hydropower benefits provided by the Diamer-Basha dam under different climate scenarios. The model framework links separate economic and water models, drawing on the strengths of both approac...

  18. Safety Aspects of Sustainable Storage Dams and Earthquake Safety of Existing Dams

    Directory of Open Access Journals (Sweden)

    Martin Wieland

    2016-09-01

    Full Text Available The basic element in any sustainable dam project is safety, which includes the following safety elements: ① structural safety, ② dam safety monitoring, ③ operational safety and maintenance, and ④ emergency planning. Long-term safety primarily includes the analysis of all hazards affecting the project; that is, hazards from the natural environment, hazards from the man-made environment, and project-specific and site-specific hazards. The special features of the seismic safety of dams are discussed. Large dams were the first structures to be systematically designed against earthquakes, starting in the 1930s. However, the seismic safety of older dams is unknown, as most were designed using seismic design criteria and methods of dynamic analysis that are considered obsolete today. Therefore, we need to reevaluate the seismic safety of existing dams based on current state-of-the-art practices and rehabilitate deficient dams. For large dams, a site-specific seismic hazard analysis is usually recommended. Today, large dams and the safety-relevant elements used for controlling the reservoir after a strong earthquake must be able to withstand the ground motions of a safety evaluation earthquake. The ground motion parameters can be determined either by a probabilistic or a deterministic seismic hazard analysis. During strong earthquakes, inelastic deformations may occur in a dam; therefore, the seismic analysis has to be carried out in the time domain. Furthermore, earthquakes create multiple seismic hazards for dams such as ground shaking, fault movements, mass movements, and others. The ground motions needed by the dam engineer are not real earthquake ground motions but models of the ground motion, which allow the safe design of dams. It must also be kept in mind that dam safety evaluations must be carried out several times during the long life of large storage dams. These features are discussed in this paper.

  19. Genetic differences between hatchery and wild steelhead for survival, growth, dispersal, and male maturation in a natural stream (Study site: Twenty-Mile Creek; Stocks: Dworshak hatchery and Selway River wild; Year classes: 1994 and 1995): Chapter 3

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Hensleigh, Jay E.; Wetzel, Lisa A.; Baker, Bruce M.; Leonetti,; Stenberg, Karl D.; Slatton, Stacey L.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    This study was initiated in the early 1990s to provide managers with data comparing genetic fitness for natural rearing, as measured by survival of juveniles in freshwater, between steelhead Oncorhynchus mykiss from Dworshak National Fish Hatchery and wild steelhead from the Clearwater River, Idaho. We artificially spawned hatchery steelhead and wild steelhead from the Selway River, a Clearwater River tributary, released the resulting genetically marked (at the PEPA allozyme locus) progeny (HxH, HxW from hatchery females and wild males, and WxW) as unfed fry in a second order tributary of the South Fork Clearwater River, and monitored fish residing in the stream or emigrating from it for five years. Barrier falls prevented access to the stream by naturally produced steelhead. Over 90% of the emigrants were one or two years of age and too small to be smolts (mean fork length at age-2 = 103 mm). Per fry released, the HxH cross produced 0.64-0.83 times as many emigrants as the WxW cross (P<0.05). The HxH cross produced 0.63 times as many age-4 residuals as the WxW cross for one year-class (P=0.051) and 0.68 times as many for the other (ns). Survival from age-1 to age-4 was lower for HxH than for WxW residuals of one year-class (P<0.05) and survival from age-2 to age-4 may have been lower for HxH than for WxW residuals of the other (P=0.062). Collectively, these results indicate lower survival for HxH than for WxW fish. Size was often greater for HxH than for WxW fish indicating faster growth for the former, and condition factor was also usually greater for HxH than for WxW fish. Dispersal of fry from release sites and emigration of one- and two-year olds from the study stream were greater for WxW than for HxH fish, and apparently neither was from competitive displacement of small by larger fish. Incidence of flowing milt was higher for HxH than for WxW fish at age-2. Peak incidence of flowing milt for older residuals was similar among crosses (about 50%), but the peak

  20. McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program; 1996 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hillson, Todd; Lind, Sharon; Price, William (Washington Department of Fish and Wildlife, Olympia, WA)

    1997-07-01

    The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996, Smolt Monitoring Program activities also began at the new juvenile collection facility located at Ice Harbor Dam. This report summarizes the 1996 Smolt Monitoring work at all three sites. The work at Ice Harbor consisted of Gas Bubble Trauma (GBT) monitoring only. In general, the 1996 passage season at both the McNary and Lower Monumental sites can be characterized by reduced passage of juveniles through the collection systems due to elevated river flows and spill, and low (<1%) overall facility mortality rates most likely resulting from cooler water temperatures. In accordance with the National Marine Fisheries Service recommendations (NMFS, 1995) all spring migrants were bypassed at McNary Dam in 1996. Mechanical problems within the McNary collection system resulted in collection and sampling activities being delayed until April 18 at this site, while sampling and collection began on the scheduled starting date of April 1 at Lower Monumental Dam. Monitoring operations were conducted through December 14 at McNary Dam and through October 28 at Lower Monumental Dam. An ongoing transportation evaluation summer migrant marking program was conducted at McNary Dam in 1996 by the NMFS. This necessitated the sampling of 394,211 additional fish beyond the recommended sampling guidelines. All total, 509,237 and 31,219 juvenile salmonids were anesthetized and individually counted, examined for scale loss, injuries, and brands by WDFW Smolt Monitoring personnel in 1996 at McNary Dam and Lower Monumental Dam, respectively.

  1. Measurement of Creep on the Calaveras Fault at Coyote Dam using Terrestrial Radar Interferometry (TRI).

    Science.gov (United States)

    Baker, B.; Cassotto, R.; Fahnestock, M. A.; Werner, C. L.; Boettcher, M. S.

    2015-12-01

    The Calaveras fault in central California is part of the San Andreas fault system. Coyote Dam, an earthen dam that straddles the fault ~13km northeast of Gilroy, experiences creep style deformation that ranges from 10 to 15 mm/yr. Uncertainty in the location of the fault, coupled with the historic rate of deformation, affect the dam's safety factor. Assessing the impact of fault creep on the dam's stability is paramount to its safety evaluation, but is difficult to resolve due to limited spatial and temporal sampling of conventional methods. Terrestrial radar interferometry (TRI), like satellite-based observations, produces high spatial resolution maps of ground deformation. Unlike space-based sensors, TRI can be readily deployed and the observation geometry selected to get the maximum line of sight (LOS) signal. TRI also benefits from high temporal sampling which can be used to reduce errors related to atmospheric phase delays and high temporal sampling also facilitates tracking rapidly moving features such as landslides and glaciers. GAMMA Portable Radar Interferometer (GPRI) measurements of Coyote Dam rock faces were made from concrete piers built upstream and downstream of the dam. The GPRI operates at a radar frequency of 17.2 GHz with a spatial resolution at the dam of approximately 0.9 m x 2.0 m. Changes in LOS path length smaller than 0.1mm can be measured. Data were acquired approximately every 2 to 3 weeks over a 7-month period to map the fault trace through the dam faces. Our study exploits the dense record of observations obtained, and the relatively short distance of the radar to the dam to minimize atmospheric affects. We investigate how the deformation evolves in time and the orientation of fault through the dam, including the strike and dip as measured along the dam surface. Our results show rates consistent with GPS data and regional satellite observations, but produce a much more detailed map of the fault on the dam than possible with GPS or

  2. Adaptability to geological faulted foundation of Hardfill dam

    Institute of Scientific and Technical Information of China (English)

    Kun XIONG; Yunlong HE; Yunfeng PENG

    2008-01-01

    Hardfill dam is a new type of dam which has the advantages of low stress level and even stress distri-bution in a dam body, resulting in low demands to foun-dations. Based on 2D linear elastic and elasto-plastic calculations of gravity dam and Hardfill dam using finite element method (FEM), the stress distribution in a dam body and anti-sliding stabilization is analyzed on the geo-logical faulted foundations with weak weathered rock and soft interlayers. It is concluded that Hardfill dams have better adaptability to geological faulted foundations than gravity dams and is more secure and economically sound.

  3. Vulnerability of aged concrete gravity dams

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, I. [Assam Engineering Institute, Guwahati (India). Dept. of Civil Engineering; Maity, D. [Indian Institute of Technology, Guwahati (India). Dept. of Civil Engineering

    2004-07-01

    This paper presented an analysis procedure to predict the effects of aging on the behavior of concrete gravity dams. A time dependent isotropic damage index was determined, presenting the performance of the dam with increasing age. Results revealed that the degradation process is dependent on the design life of the structure. The influence of damage along the dam height was greater than damage observed along its width. In order to consider the time dependent degradation of concrete owing to environmental factors and mechanical loading, an algorithm was presented in order to forecast the behavior of existing dams and to assess the necessity of retrofitting or decommissioning. It was concluded that dam behavior during seismic excitation is influenced by the effects of both the dam reservoir system and initial earthquake damage. With increasing age, dam displacement increases, but hydrodynamic pressures and stresses exerted by reservoirs decrease. It was recommended that more accurate behavior could be determined if further research into the coupled effect of foundation-dam-reservoir interaction with material non-linearity was considered. 15 refs.,15 figs.

  4. Comparison of Natural Dams from Lava Flows and Landslides on the Owyhee River, Oregon

    Science.gov (United States)

    Ely, L. L.; Brossy, C. C.; Othus, S. M.; Orem, C.; Fenton, C.; House, P. K.; O'Connor, J. E.; Safran, E. B.

    2008-12-01

    Numerous large lava flows and mass movements have temporarily dammed the Owyhee River in southeastern Oregon at various temporal and spatial scales. These channel-encroaching events potentially play a significant role in creating and maintaining the geomorphic features of river canyons in uplifted volcanic terranes that compose a significant part of the western U.S. Abundant landslides and lava flows have the capacity to inhibit incision by altering channel slope, width, and bed character, and burying valley- bottom bedrock under exogenous material; or promote incision by generating cataclysmic floods through natural dam failures. The natural dams vary in their source, morphology, longevity and process of removal, which in turn affects the extent and duration of their impact on the river. The 3 most recent lava flows filled the channel 10-75 m deep and flowed up to 26 kilometers downvalley, creating long, low dams that were subject to gradual, rather than catastrophic, removal. In the last 125 ka, the Saddle Butte and West Crater lava dams created reservoirs into which 10-30 meters of silt and sand were deposited. The river overtopped the dams and in most reaches eventually cut a new channel through the adjacent, less resistant bedrock buttresses. Terraces at several elevations downstream and upstream of the West Crater dam indicate periods of episodic incision ranging from 0.28 to 1.7 mm/yr., based on 3He exposure ages on strath surfaces and boulder-rich fluvial deposits. In contrast to the lava dams, outburst flood deposits associated with landslide dams are common along the river. The mechanisms of failure are related to the geologic setting, and include rotational slump complexes, cantilevered blocks and block slides, and massive earthflows. Most large-scale mass movements occur in reaches where the Owyhee canyon incises through stacks of interbedded fluviolacustrine sediments capped with lava flows. The frequently observed association of landslides and flood

  5. Upgrading of Boundary Dam spillway

    Energy Technology Data Exchange (ETDEWEB)

    McPhail, Gordon; MacMillan, Dave; Smith, Bert [KGS Group, Winnipeg, (Canada); Lacelle, Justin [SaskPower, Regina, (Canada)

    2010-07-01

    An initial dam safety review was performed in 2005 and identified a number of concerns; the most critical were insufficient spillway capacity and deficiencies in the condition of the existing spillways. This paper described the challenges faced by the upgrading operation on the 50 year old Boundary Dam spillway started in 2008. SaskPower retained the KGS Group to increase the design spillway capacity to 1200 m3/s and remedy observed defects. The construction project involved maintaining the reservoir at full supply level while the 20m long spillway chute and stilling basin below were completely replaced. The difficulties came from the need to complete each year's construction such that the spillway could potentially pass spring flood flows. This paper showed that the upgrade measures selected for implementation were developed through close dialogue between the owner and the designer, with valuable input provided by a panel of external experts as well as from contractors participating in the design process.

  6. The Three Gorges Dam: Does it accelerate or delay the progress towards eliminating transmission of schistosomiasis in China?

    Science.gov (United States)

    Zhou, Yi-Biao; Liang, Song; Chen, Yue; Jiang, Qing-Wu

    2016-07-05

    The Three Gorges Dam, located in the largest endemic area of schistosomiasis in China, is one of the world's largest hydroelectric projects to date. Some large-scale hydro projects have resulted in schistosomiasis emergence or re-emergence. Therefore, the dam's potential impact on the transmission of Schistosoma japonicum has raised concerns from medical researchers worldwide. A systematic literature review, coupled with an analysis of data on the water level and snail density in the Yangtze River was conducted to assess the impact of the dam on schistosomiasis transmission after more than 10 years of operation. The dam has significantly altered the water levels in the Yangtze River according to different seasons. These changes directly impact the ecology of the schistosome snail host. Due to the dam, there has been a reduction in the density of Oncomelania snails and/or changes in the distribution of snails. The prevalence of infection with S. japonicum has decreased in the downstream areas of the dam, including in the Dongting and Poyang Lakes. The prevalence of infection with S. japonicum in humans has decreased from 6.80 % in 2002 (before the dam began operating) to 0.50 % in 2012, and the number of people infected with S. japonicum have decreased from 94 208 in 2002 to 59 200 in 2011 in the Poyang Lake region. The presence of the dam does not seem to affect snail breeding or the prevalence of schistosomiasis in the Three Gorges Reservoir. Overall, the Three Gorges Dam has significantly contributed to changes in hydrology after more than 10 years of the dam operating. The changes caused by the dam, together with integrated control of schistosomiasis, might be accelerating the progress towards eliminating the transmission of S. japonicum in the middle and lower reaches of the Yangtze River. Despite the positive effect the dam is having in controlling S. japonicum transmission, continued surveillance is required to monitor the future ecological impacts of the

  7. Restoring Environmental Flows by Modifying Dam Operations

    Directory of Open Access Journals (Sweden)

    Gregory A. Thomas

    2007-06-01

    Full Text Available The construction of new dams has become one of the most controversial issues in global efforts to alleviate poverty, improve human health, and strengthen regional economies. Unfortunately, this controversy has overshadowed the tremendous opportunity that exists for modifying the operations of existing dams to recover many of the environmental and social benefits of healthy ecosystems that have been compromised by present modes of dam operation. The potential benefits of dam "re-operation" include recovery of fish, shellfish, and other wildlife populations valued both commercially and recreationally, including estuarine species; reactivation of the flood storage and water purification benefits that occur when floods are allowed to flow into floodplain forests and wetlands; regaining some semblance of the naturally dynamic balance between river erosion and sedimentation that shapes physical habitat complexity, and arresting problems associated with geomorphic imbalances; cultural and spiritual uses of rivers; and many other socially valued products and services. This paper describes an assessment framework that can be used to evaluate the benefits that might be restored through dam re-operation. Assessing the potential benefits of dam re-operation begins by characterizing the dam's effects on the river flow regime, and formulating hypotheses about the ecological and social benefits that might be restored by releasing water from the dam in a manner that more closely resembles natural flow patterns. These hypotheses can be tested by implementing a re-operation plan, tracking the response of the ecosystem, and continually refining dam operations through adaptive management. The paper highlights a number of land and water management strategies useful in implementing a dam re-operation plan, with reference to a variety of management contexts ranging from individual dams to cascades of dams along a river to regional energy grids. Because many of the

  8. Research progress on dam-break floods

    KAUST Repository

    Wu, Jiansong

    2011-08-01

    Because of the catastrophic effects downstream of dam-break failure, more and more researchers around the world have been working on the study of dam-break flows to accurately forecast the downstream inundation mapping. With the rapid development of computer hardware and computing techniques, numerical study on dam-break flows has been a popular research subject. In the paper, the numerical methodologies used to solve the governing partial differential equations of dam-break flows are classified and summarized, and their characteristics and applications are discussed respectively. Furthermore, the fully-developed mathematical models developed in recent decades are reviewed, and also introduced the authors\\' on-going work. Finally, some possible future developments on modeling the dam-break flows and some solutions are presented and discussed. © 2011 IEEE.

  9. Seismic failure modes and seismic safety of Hardfill dam

    Institute of Scientific and Technical Information of China (English)

    Kun XIONG; Yong-hong WENG; Yun-long HE

    2013-01-01

    Based on microscopic damage theory and the finite element method, and using the Weibull distribution to characterize the random distribution of the mechanical properties of materials, the seismic response of a typical Hardfill dam was analyzed through numerical simulation during the earthquakes with intensities of 8 degrees and even greater. The seismic failure modes and failure mechanism of the dam were explored as well. Numerical results show that the Hardfill dam remains at a low stress level and undamaged or slightly damaged during an earthquake with an intensity of 8 degrees. During overload earthquakes, tensile cracks occur at the dam surfaces and extend to inside the dam body, and the upstream dam body experiences more serious damage than the downstream dam body. Therefore, under the seismic conditions, the failure pattern of the Hardfill dam is the tensile fracture of the upstream regions and the dam toe. Compared with traditional gravity dams, Hardfill dams have better seismic performance and greater seismic safety.

  10. Impact of River Damming on the Characteristics of Riverine Chromophoric Dissolved Organic Matter%拦河大坝对河流有色溶解有机质赋存特征的影响初探

    Institute of Scientific and Technical Information of China (English)

    向元婧; 黄清辉

    2014-01-01

    The dissolved organic matter ( DOM) in natural waters plays an important role in global biogeochemical cycles and the microbial loop that is sequestering carbon on a global scale.Chromophoric ( or colored) dissolved organic matter ( CDOM) , a significant fraction of total DOM, absorbs light over a broad range of ultraviolet ( UV) and visible wavelengths.The primary sources of DOM in rivers include surface runoff, wastewater discharge and phytoplankton exudates.It has been reported that the DOM of reservoirs is influenced by the tributary inflow.Res-ervoirs, depending on residence time, can become more lacustrine and significantly alter phytoplankton and plank-tonic bacteria communities and nutrient dynamics but the influence on CDOM is not clear.In this study, we report the spatial dynamics of riverine CDOM in the reaches above and below Three Gorges Dam to provide preliminarily findings on the influence of river impoundment on the characteristics of CDOM.Water samples were collected along five transects from the Xiangxi River estuary (31 km above Three Gorges Dam) to Nanjinguan (38km below Three Gorges Dam) on June 3, 2008.Samples were filtered on site and transported to the laboratory for analysis using ul-traviolet-visible and fluorescence spectroscopy.In situ CDOM concentrations were also determined in the upper rea-ches of the Xiangxi River Bay and the Miaohe section of the Yangtze River.The absorption coefficient for CDOM atλ=355 nm ( a355 ) was measured by UV-vis spectroscopy and the composition of fluorescent components ( FDOM) was analyzed using three-dimensional fluorescence ( EEM) spectroscopy.From the upper reaches of Xiangxi River Bay to the Three Gorges Dam, the absorption coefficient increased from 1.30 m-1 to 5.21 m-1 .Fluorescence in-tensities also increased due to the increase in tyrosine ( protein-like) substances (25%in upper Xiangxi River Bay to 62%near Three Gorges Dam) and decrease in humic-like substances.At Huanglingmiao, just below the

  11. Dynamic simulation based optimized design method of concrete production system for RCC dam

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chunju; ZHOU Yihong

    2007-01-01

    The construction system of roller compacted concrete (RCC) dam is running according to a series of connected procedures which are highly impacted and interacted consisting with the resource level.Therefore,a dynamic simulation model of the construction system for RCC dam is presented.With this model,the design of concrete production system is placed in the whole system and tested with related dynamic impactions and interactions under complicated boundaries.Moreover,if several simulation experiments were conducted,plenty of detailed information throughout the construction duration is obtained.Consequently,the optimal one should be chosen on the basis of actual requirement and situation.

  12. Influence of groundwater pumping on streamflow restoration following upstream dam removal

    Science.gov (United States)

    Constantz, J.; Essaid, H.

    2007-01-01

    We compared streamflow in basins under the combined impacts of an upland dam and groundwater pumping withdrawals, by examining streamflow in the presence and absence of each impact. As a qualitative analysis, inter-watersbed streamflow comparisons were performed for several rivers flowing into the east side of the Central Valley, CA. Results suggest that, in the absence of upland dams supporting large reservoirs, some reaches of these rivers might develop ephemeral streamflow in late summer. As a quantitative analysis, we conducted a series of streamflow/ groundwater simulations (using MODFLOW-2000 plus the streamflow routing package, SFR1) for a representative hypothetical watershed, with an upland dam and groundwater pumping in the downstream basin, under humid, semi-arid, and and conditions. As a result of including the impact of groundwater pumping, post-dam removal simulated streamflow was significantly less than natural streamflow. The model predicts extensive ephemeral conditions in the basin during September for both the arid and semi-arid cases. The model predicts continued perennial conditions in the humid case, but spatially weighted, average streamflow of only 71% of natural September streamflow, as a result of continued pumping after dam removal.

  13. Flow regulation and river fragmentation in large basins due to global dam development (Invited)

    Science.gov (United States)

    Grill, G. O.; Lehner, B.

    2013-12-01

    Dam construction has recently received new interest as an alternative and renewable source of energy, especially in developing countries, and as a means to provide water security in regions with naturally variable water flows. On the other hand, the negative effects from increased fragmentation of the world's large rivers through hydropower and irrigation dams is a matter of great concern for ecologists and conservationists. The main negative effects of dams result from their role as a barrier for migratory fish species, as well as the alteration of the natural flow regime owing to artificial water release schedules. While the trade-offs between these antagonistic effects are usually assessed locally by conducting environmental impact assessments at and in the vicinity of the construction site, the cumulative effects of multiple dams located in the same basin are generally neglected in such plans. To address the cumulative effects at the scale of large river networks, we developed a new impact assessment approach by combining state-of-the-art global scale hydrographic (HydroSHEDS) and hydrological models (WaterGAP) with a river routing scheme (HydroROUT). This combination enables modelers to simulate scenarios for historic, current and future conditions that allow for comparisons between the large river basins of the world. We derive indices that can describe the relative impact of individual and multiple dams regarding flow alteration and habitat fragmentation at a global scale. Our model also allows for the application of tailor-made weighting schemes to include information of eco-hydrological classifications, as well as species richness and diversity. Furthermore, we include natural barriers such as waterfalls, and examine their effect on river network connectivity. Results for the Greater Mekong Region show that ecosystem connectivity and flow alteration are most strongly affected by dams located at the mainstream rivers, particularly for basins where the main

  14. Seeking more Opportunities of Check Dams' harmony with nearby Circumstances via Design Thinking Process

    Science.gov (United States)

    Lin, Huan-Chun; Chen, Su-Chin; Tsai, Chen-Chen

    2014-05-01

    The contents of engineering design should indeed contain both science and art fields. However, the art aspect is too less discussed to cause an inharmonic impact with natural surroundings, and so are check dams. This study would like to seek more opportunities of check dams' harmony with nearby circumstances. According to literatures review of philosophy and cognition science fields, we suggest a thinking process of three phases to do check dams design work for reference. The first phase, conceptualization, is to list critical problems, such as the characteristics of erosion or deposition, and translate them into some goal situations. The second phase, transformation, is to use cognition methods such as analogy, association and metaphors to shape an image and prototypes. The third phase, formation, is to decide the details of the construction, such as stable safety analysis of shapes or materials. According to the previous descriptions, Taiwan's technological codes or papers about check dam design mostly emphasize the first and third phases, still quite a few lacks of the second phase. We emphases designers shouldn't ignore any phase of the framework especially the second one, or they may miss some chances to find more suitable solutions. Otherwise, this conceptual framework is simple to apply and we suppose it's a useful tool to design a more harmonic check dam with nearby natural landscape. Key Words: check dams, design thinking process, conceptualization, transformation, formation.

  15. Test system calibrate used in DAM%DAM测试系统校准

    Institute of Scientific and Technical Information of China (English)

    张思敏; 盛永鑫

    2013-01-01

    The test system used in DAM is the critical equipment of the DAM, its performance has a direct impact on DAM. In order to solve the problem of the system calibration is not comprehensive and the automated calibration is not high, the in-site calibration idea is put forward. Through the analysis of the principle and the work process of the test system used in DAM,the calibration system of test system used in DAM is set up,the calibration adapter diagram and software composition are stated . This method has been proved to be good in versatility and high automation,can meet the calibration needs of the test system used in DAM .%DAM测试系统是DAM关键测试设备,它的性能会对DAM的性能指标有直接的影响,为了解决系统校准不全面和自动化程度不高的问题,提出了原位校准思路.通过对DAM测试系统原理和工作流程分析,构建DAM测试系统校准装置,阐述了校准适配网络组成和软件组成框图.经过实际应用证明,该方法通用性好,自动化程度高,满足DAM测试系统校准需求.

  16. A virtual reality approach to public protection and emergency preparedness planning in dam safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Assaf, H.; Hartford, D.N.D. [BC Hydro, Burnaby, BC (Canada)

    2002-12-01

    BC Hydro has developed a new approach to analyze and assess the consequences of dam emergencies on human communities. The Life Safety Model (LSM) was designed to enable the electric utility to provide different response agencies with realistic dynamic models of a wide range of emergency scenarios that require a response in the event of a dam failure. LSM is pertinent to public safety because it enables response agencies to develop emergency plans and provides insight into the design of risk mitigation measures through its ability to simulate high risk locations. The model can create representations of downstream communities in potentially impacted areas and can geographically illustrate the potential dam breach events with reference to flood propagation and the movement of people on foot or in vehicles. A wide range of downstream dam operation conditions is presented. LSM merges state of the art technologies and recent scientific advances in environmental simulation and modelling, GIS, artificial intelligence, real time modelling of 2-dimensional dam breach flooding scenarios, structural reliability analysis, and human behaviour characterisation. This paper describes the modular architecture of the model and demonstrates how to generate the vital information needed to characterize a dam failure emergency. 2 refs., 1 tab., 7 figs.

  17. 3D Simulation of Dam-break effect on a Solid Wall using Smoothed Particle Hydrodynamics

    CERN Document Server

    Suprijadi,; Naa, Christian; Putra, Anggy Trisnawan

    2013-01-01

    Dam is built for water supply, water flow or flooding control and electricity energy storage, but in other hand, dam is one of the most dangerous natural disaster in many countries including in Indonesia. The impact of dam break in neighbour area and is huge and many flooding in remote area, as happen in Dam Situ Gintung in Tangerang (close to Jakarta) in 2009. Smoothed Particle Hydrodynamics (SPH), is one of numerical method based on Lagrangian grid which is ap- plied in astrophysical simulation may be used to solve the simulation on dam break effect. The development of SPH methods become alternative methods to solving Navier Stokes equation, which is main key in fluid dynamic simulation. In this paper, SPH is developed for supporting solid par- ticles in use for 3D dam break effect (3D-DBE) simulation. Solid particle have been treated same as fluid particles with additional calculation for converting gained position became translation and rotation of solid object in a whole body. With this capability, the r...

  18. Fish navigation of large dams emerges from their modulation of flow field experience.

    Science.gov (United States)

    Goodwin, R Andrew; Politano, Marcela; Garvin, Justin W; Nestler, John M; Hay, Duncan; Anderson, James J; Weber, Larry J; Dimperio, Eric; Smith, David L; Timko, Mark

    2014-04-08

    Navigating obstacles is innate to fish in rivers, but fragmentation of the world's rivers by more than 50,000 large dams threatens many of the fish migrations these waterways support. One limitation to mitigating the impacts of dams on fish is that we have a poor understanding of why some fish enter routes engineered for their safe travel around the dam but others pass through more dangerous routes. To understand fish movement through hydropower dam environments, we combine a computational fluid dynamics model of the flow field at a dam and a behavioral model in which simulated fish adjust swim orientation and speed to modulate their experience to water acceleration and pressure (depth). We fit the model to data on the passage of juvenile Pacific salmonids (Oncorhynchus spp.) at seven dams in the Columbia/Snake River system. Our findings from reproducing observed fish movement and passage patterns across 47 flow field conditions sampled over 14 y emphasize the role of experience and perception in the decision making of animals that can inform opportunities and limitations in living resources management and engineering design.

  19. Numerical Simulation of Downstream Flooding due to a Flexible-Dam Collapse. The case of "La Esperanza" dam, Hidalgo-México: Implication on Hazard Assessment.

    Science.gov (United States)

    Areu Rangel, O. S., Sr.; Mendoza-Sanchez, I.; Bonasia, R.

    2015-12-01

    The risk of flooding of settlements located downstream of a dam is high due to the large number of people living on natural waterways. Risk assessment of flooding could help in projecting containment and protection in case of a dam-break. For projecting containment and protection works, the assessment should take into account velocities, densities and impact pressure of the water on the villages in risk. Therefore, it is appealing to conduct a series of numerical simulations of downstream flooding including velocity and pressure fields, and their temporal and spatial fluctuations. The present work focuses on the real case of "La Esperanza" dam, located in the state of Hidalgo (Mexico). The dam was built 70 years ago and currently two thirds of its capacity is covered with silt, which implies a very high horizontal thrust. The simulation of the flood due to failure of the dam was carried on using the DualSPHysics code, a new implementation of the mesh-free Lagrangian Smoothed Particle Hydrodynamic (SPH) method. For the boundary conditions, a Digital Elevation Model of the potentially affected area was built using satellite images, the actual bathymetry of the dam and cross sections of the channel. In order to evaluate the hazard posed to the villages located downstream of the dam, different collapse scenarios were simulated, with particular focus on the consequences of the temporal variation of rainfall. Preliminary results show acceleration and dynamic pressure values of water in especially selected areas that are subjected to high risk for the elevated number of inhabitant.

  20. SCENARIO OF AN ACCIDENT OF SOIL DAMS IN CASE OF WATER SPILL OVER A DAM CREST BY USING FAULT TREE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Kuznetsov Dmitriy Viktorovich

    2016-04-01

    Full Text Available The scenario of a hydrodynamic accident of water flow over a crest of a soil dam is considered by the method of fault tree analysis, for which the basic reasons and controlled diagnostic indicators of an accident have been defined. Logical operators “AND”/”OR” were used for creation of a sequence of logically connected events, leading to an undesired event in the scenario of accident. The scenario of the accident was plotted in case of three basic reasons - an excessive settling of a dam crest, an excess flood, an inoperable spillway, taking into account the sequence of the events’ development and with observance of the necessary conditions leading to an accident. “Technical” reasons were observed in the present scenario, force majeure events were not considered. The provided scenario of the accident consists of two branches of events’ development: the left one that depends on an upstream level, and the right one that depends on settling of a dam crest. In each of the considered events an accident “the water spill over a crest of a soil dam” is possible only in case of execution of two different conditions at the same time, i.e. in case of an appropriate upstream level and the appropriate mark of a crest of a soil dam. The conditions of the accident are defined by diagnostic indices - the upstream level and settling of a dam crest, which at the same time are safety criteria of the hydraulic structure for soil dams. They allow defining the technical condition of the construction. Four possible technical conditions are suggested for the definition of technical statuses - normative, operable, limited operable, abnormal. Criteria of safety are the boundaries of the state: for loading and impact - it is the upstream level, for geometrical compliance of the construction - it is a dam crest mark.

  1. Wind-Driven Ecological Flow Regimes Downstream from Hydropower Dams

    Science.gov (United States)

    Kern, J.; Characklis, G. W.

    2012-12-01

    Conventional hydropower can be turned on and off quicker and less expensively than thermal generation (coal, nuclear, or natural gas). These advantages enable hydropower utilities to respond to rapid fluctuations in energy supply and demand. More recently, a growing renewable energy sector has underlined the need for flexible generation capacity that can complement intermittent renewable resources such as wind power. While wind power entails lower variable costs than other types of generation, incorporating it into electric power systems can be problematic. Due to variable and unpredictable wind speeds, wind power is difficult to schedule and must be used when available. As a result, integrating large amounts of wind power into the grid may result in atypical, swiftly changing demand patterns for other forms of generation, placing a premium on sources that can be rapidly ramped up and down. Moreover, uncertainty in wind power forecasts will stipulate increased levels of 'reserve' generation capacity that can respond quickly if real-time wind supply is less than expected. These changes could create new hourly price dynamics for energy and reserves, altering the short-term financial signals that hydroelectric dam operators use to schedule water releases. Traditionally, hourly stream flow patterns below hydropower dams have corresponded in a very predictable manner to electricity demand, whose primary factors are weather (hourly temperature) and economic activity (workday hours). Wind power integration has the potential to yield more variable, less predictable flows at hydro dams, flows that at times could resemble reciprocal wind patterns. An existing body of research explores the impacts of standard, demand-following hydroelectric dams on downstream ecological flows; but weighing the benefits of increased reliance on wind power against further impacts to ecological flows may be a novel challenge for the environmental community. As a preliminary step in meeting this

  2. Lower Granite Dam Smolt Monitoring Program, 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Morrill, Charles; Ross, Doug; Mensik, Fred

    2000-01-01

    The 2000 fish collection season at Lower Granite was characterized by lower than average spring flows and spill, low levels of debris, cool water temperatures, increased unclipped yearling and subyearling chinook smolts, and 8,300,546 smolts collected and transported compared to 5,882,872 in 1999. With the continued release of unclipped supplementation chinook and steelhead above Lower Granite Dam, we can no longer accurately distinguish wild chinook, steelhead, and sockeye/kokanee in the sample. Although some table titles in this report still show ''wild'' column headings, the numbers in these columns for 1999 and 2000 include wild and unclipped hatchery origin smolts. The increases over previous years reflect the increased supplementation. A total of 8,300,546 juvenile salmonids were collected at Lower Granite Dam. Of these, 187,862 fish were bypassed back to the river and 7,950,648 were transported to release sites below Bonneville Dam, 7,778,853 by barge and 171,795 by truck. A total of 151,344 salmonids were examined in daily samples. Nine research projects conducted by four agencies impacted a total of 1,361,006 smolts (16.4% of the total collection).

  3. CFD modelling approach for dam break flow studies

    Directory of Open Access Journals (Sweden)

    C. Biscarini

    2009-11-01

    Full Text Available This paper presents numerical simulations of free surface flows induced by a dam break comparing the shallow water approach to fully three-dimensional simulations. The latter are based on the solution of the complete set of Reynolds-Averaged Navier-Stokes (RANS equations coupled to the Volume of Fluid (VOF method.

    The methods assessment and comparison are carried out on a dam break over a flat bed without friction and a dam break over a triangular bottom sill. Experimental and numerical literature data are compared to present results.

    The results demonstrate that the shallow water approach loses some three-dimensional phenomena, which may have a great impact when evaluating the downstream wave propagation. In particular, water wave celerity and water depth profiles could be underestimated due to the incorrect shallow water idealization that neglects the three-dimensional aspects due to the gravity force, especially during the first time steps of the motion.

  4. TYPOLOGY OF LARGE DAMS. A REVIEW

    Directory of Open Access Journals (Sweden)

    Gheorghe ROMANESCU

    2015-06-01

    Full Text Available The dams represent hydrotechnical constructions meant to ensure a judicious use of water resources. The international literature is extremely rich in data regarding the large dams on Earth. In this context, a hierarchy of the main dams is attempted and the role they play in the economic development of the regions they were built in is underlined. The largest dams are built on the big rivers in Asia, North America, South America and Africa. The reservoirs have multiple roles: electricity production, drinking or industrial water supply, irrigations, recreation, etc. High costs and land fragility do not allow the construction of dams in the places most affected by drought or flood. This is why they are usually built in mountainous areas, at great distance from the populated centres. On the Romanian territory, there are 246 large dams, built in the hydrographical basins of Siret, Olt, Arges, Somes, etc. The largest rivers on Earth, by discharge, (Amazon and Zair do not also include the largest dams because the landform and the type of flow have not allowed such constructions.

  5. Nonlinear Seismic Analysis of Morrow Point Dam

    Energy Technology Data Exchange (ETDEWEB)

    Noble, C R; Nuss, L K

    2004-02-20

    This research and development project was sponsored by the United States Bureau of Reclamation (USBR), who are best known for the dams, power plants, and canals it constructed in the 17 western states. The mission statement of the USBR's Dam Safety Office, located in Denver, Colorado, is ''to ensure Reclamation dams do not present unacceptable risk to people, property, and the environment.'' The Dam Safety Office does this by quickly identifying the dams which pose an increased threat to the public, and quickly completing the related analyses in order to make decisions that will safeguard the public and associated resources. The research study described in this report constitutes one element of USBR's research and development work to advance their computational and analysis capabilities for studying the response of dams to strong earthquake motions. This project focused on the seismic response of Morrow Point Dam, which is located 263 km southwest of Denver, Colorado.

  6. Ririe Dam Release Test Assessment

    Science.gov (United States)

    2013-06-01

    72 Lyme Road Hanover, NH 03755-1290 Stephen Hall and Jeremy Giovando US Army Engineer District, Walla Walla 201 North Third Avenue Walla Walla...11/2013 at 0330 2/12/2013 at 1410 10120114 95th St. (1) 10120115 55th St. (2) 2/11/2013 at 1010 2/12/2013 at 2120 10120111 55th St. (1) 9737377...Ririe Dam 2/10/2013 at 1440 0 hr 64,700 N 95th E 2/12/2013 at 1410 47 hr 30 min 0.32 0.32 33,020 55th St. Bridge 2/12/2013 at 2120 54 hr 40 min

  7. Mechanical analysis of a gravity dam

    OpenAIRE

    Bergant, Urša

    2012-01-01

    In the first part of our work we will present the water supply project in Obala and backend Karst regions. The use of the river Reka and its tributary Suhorka is essential, since an amassment is going to be built on it. We decided to build the dam from rolled concrete, which is economically and environmentally better than a paved barrier or a classic concrete dam. The second part of our work includes tension and stability program calculations. The primary dimensions of the dam-taken from a te...

  8. Geophysics Methods in Electrometric Assessment of Dams

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, V. A., E-mail: davydov-va@yandex.ru; Baidikov, S. V., E-mail: badikek@mail.ru; Gorshkov, V. Yu., E-mail: vitalaa@yandex.ru; Malikov, A. V., E-mail: alex.mal.1986@mail.ru [Russian Academy of Sciences, Geophysical Institute, Ural Branch (Russian Federation)

    2016-07-15

    The safety assessment of hydraulic structures is proposed to be conducted via geoelectric measurements, which are capable of assessing the health of earth dams in their natural bedding without intervention in their structure. Geoelectric measurements are shown as being capable of pinpointing hazardous parts of a dam, including areas of elevated seepage. Applications of such methods are shown for a number of mini-dams in the Sverdlovsk region. Aparameter (effective longitudinal conductivity) that may be used to monitor the safety of hydraulic structures is proposed. Quantitative estimates of this parameter are given in terms of the degree of safely.

  9. Integral stability of Hardfill dam%Hardfill坝的整体稳定安全度

    Institute of Scientific and Technical Information of China (English)

    熊堃; 何蕴龙; 刘俊林

    2011-01-01

    根据Hardfill坝的设计理念,研究适合Hardfill坝的整体稳定安全度考察方法,基于弹塑性有限元方法对典型Hardfill坝进行了计算,并就Hardfill坝材料参数及结构特征对大坝整体稳定安全度的影响进行了敏感性分析.结果表明:以强度储备为主的综合法考察大坝的整体安全度,Hardfill 坝一般存在沿坝基面的整体失稳破坏机理,其破坏模式为剪切屈服区自坝趾开始,沿坝基面向上游扩展,从而导致大坝滑移失稳;与相同地基条件下的重力坝结构相比,梯形结构的Hardfill坝的整体稳定安全度有较大提高;坝体与坝基的弹性模量比对Hardfill坝的破坏模式及整体安全度影响较小,而坝体的抗剪强度对其则有显著的影响,同时坝坡坡比和坝高对Hardfill坝的破坏模式影响也较小;坝趾部位为大坝安全的薄弱部位,在设计与施工中应在该位置适当加大水泥用量以提高其强度.%An appropriate dam safety evaluation method was studied according to the design concept of the Hardfill dam. Based on the elasto-plastic finite element method, the integral stability of a typical Hardfill dam was analyzed, and the sensitivity analysis was made to assess the effects of the material parameters and structural characteristics on the integral stability of the dam. The results show that the failure mode of the Hardfill dam is mostly integral sliding along the interface between the dam and foundation when the synthesis method based on the intensity reserve is used. The shear yield zone expands from the dam toe towards upstream along the interface, which leads to the slide failure of the dam. Compared with the gravity dam on the same foundation, the trapezoid Hardfill dam is much more stable. The failure mode and integral stability of the Hardfill dam are affected little by elastic modulus, but dramatically by shear strength of the dam. The slope radio and height of the dam have small impact on the

  10. Effects of Large Dam Removal and Groundwater Pumping on Stream Temperature under Humid, Semiarid, and Arid Conditions

    Science.gov (United States)

    Risley, J. C.; Constantz, J. E.; Essaid, H.; Rounds, S. A.

    2010-12-01

    The effects of large upstream dam removal and in-reach groundwater pumping on streamflows and stream temperature was analyzed for humid, semiarid, and arid conditions with long dry seasons representing typical climate conditions where large dams are present, such as the western US or eastern Australia. A MODFLOW-2000 model, with options for stream-aquifer interaction and grid-block rewetting, was constructed to simulate monthly streamflows for 12 watershed scenarios described below. For each scenario, streamflow output became input into a stream temperature simulation model. Stream temperatures were simulated using the CE-QUAL-W2 water quality model over a 110 km model grid, with the presence and removal of a dam at the top of the reach and pumping in the lower 60 km of the reach. Measured meteorological data from three locations in Oregon and California representing the three meterologic conditions were used as model input to simulate the impact of varying climate conditions on streamflows and stream temperature. For each climate condition, four hypothetical watershed scenarios were modeled: (1) natural (no dam or pumping), (2) large upstream dam present, (3) dam with in-reach pumping, and (4) no dam with pumping continued, resulting in 12 cases. Dam removal, in the presence or absence of pumping, created significant changes in streamflow characteristics, resulting in significant changes in stream temperature throughout the year for all three climate conditions. From March to August, the presence of a dam caused monthly mean stream temperatures to decrease on average by approximately 3.0°C, 2.5°C, and 2.0°C for the humid, semiarid, and arid conditions, respectively; however, stream temperatures generally increased from September to February. Pumping caused stream temperatures to warm in summer and cool in winter by generally less than 0.5°C. Though dam removal led to greater changes in stream temperature than pumping, ephemeral conditions were increased both

  11. Reliablity analysis of gravity dams by response surface method

    Science.gov (United States)

    Humar, Nina; Kryžanowski, Andrej; Brilly, Mitja; Schnabl, Simon

    2013-04-01

    A dam failure is one of the most important problems in dam industry. Since the mechanical behavior of dams is usually a complex phenomenon existing classical mathematical models are generally insufficient to adequately predict the dam failure and thus the safety of dams. Therefore, numerical reliability methods are often used to model such a complex mechanical phenomena. Thus, the main purpose of the present paper is to present the response surface method as a powerful mathematical tool used to study and foresee the dam safety considering a set of collected monitoring data. The derived mathematical model is applied to a case study, the Moste dam, which is the highest concrete gravity dam in Slovenia. Based on the derived model, the ambient/state variables are correlated with the dam deformation in order to gain a forecasting tool able to define the critical thresholds for dam management.

  12. Discussion on construction and type selection of China high dams

    Institute of Scientific and Technical Information of China (English)

    Zhou Jianping; Yang Zeyan; Chen Guanfu

    2009-01-01

    At the beginning of 21st century, with the rapid and steady development of China economy, a lot of large scale hydropower projects with large dams from 200 m to 300 m high are being or to be buih. China dam constructions are reaching the level of 300 m high arch dam, 250 high CFRD (concrete face rockfill dam) and 200 m high RCC (roller compacted concrete) gravity dam. Due to the safety and the economy, the type selection for high dams has become the key issue during the argumentation for the hydropower projects, and further efforts are still needed in this aspect for high dams. After reviewing the high dam constructions in China and abroad, authors proposed some advices for the selection of dam types, and hope that it can provide some helpful information for the researches and the design of high dams.

  13. 76 FR 34799 - Permanent Dam Safety Modification at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams, TN

    Science.gov (United States)

    2011-06-14

    ... Permanent Dam Safety Modification at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams, TN AGENCY... various alternatives for permanent modifications to the existing dam facilities at Cherokee, Fort Loudoun, Tellico, and Watts Bar dams in Tennessee. The level of review will be determined after the public...

  14. A conceptual model of check dam hydraulics for gully control

    Directory of Open Access Journals (Sweden)

    C. Castillo

    2013-09-01

    Full Text Available There is little information in scientific literature regarding the modifications induced by check dam systems in flow regimes in restored gully reaches, despite it being a crucial issue for the design of conservation measures. Here, we develop a conceptual model to classify flow regimes in straight rectangular channels for initial and dam-filling conditions as well as a method of estimating efficiency in order to provide guidelines for optimal design. The model integrates several previous mathematical approaches for assessing the main processes involved (hydraulic jump HJ, impact flow, gradually varied flows. Its performance was compared with the simulations obtained from IBER, a bi-dimensional hydrodynamic model. The impact of check dam spacing (defined by the geometric factor of influence c on efficiency was explored. Eleven main classifications of flow regimes were identified depending on the element and level of influence. The model produced similar results when compared with IBER, but led to higher estimations of HJ and impact lengths. Total influence guaranteed maximum efficiency and HJ control defining the location of the optimal c. Geometric total influence (c = 1 was a valid criterion for the different stages of the structures in a wide range of situations provided that hydraulic roughness conditions remained high within the gully, e.g. through revegetation. Our total influence criterion involved shorter spacing than that habitually recommended in technical manuals for restoration, but was in line with those values found in spontaneous and stable step-pools systems, which might serve as a reference for man-made interventions.

  15. Determination of Seepage and Analysis of Earth Dams (Case Study: Karkheh Dam

    Directory of Open Access Journals (Sweden)

    A. Kamanbedast

    2011-01-01

    Full Text Available Because of the increasing trend of building dam throughout Iran; it is necessary to optimize dam buildings and operations. Dam or Hydropower industry has two types of buildings; normally: (1 Concrete dams (2 Embankment (earth dams. Generally, scientists and engineers use different methods to enhance safety and decrease any errors in calculation due to maintenance of water storage especially hydro structure of the dam. It is necessary to investigate the dam seepage control; commonly used by several methods. Seepage is one of the important issues for design, build and maintenance of dams awareness. Seepage problem and its rules helps scientist to select a suitable method of monitoring and solving such problem. These methods of analysis were carried out at civil and construction project. In this study, one of latest method of investigation of seepage behavior were analytically evaluated and compared with the actual rules. Based on determine results; several suggestions and optimization method were suggested. Therefore, an optimum method was scientifically selected. Besides that, flow condition of porous environment with application of numeric program was analyzed. Finally, all the results were lunched out from seep/w soft which is the most significant program about this matter; use of finite elements method is specified for saturated and unsaturated environment. Thus; leakage and seepage were defined as function of (time and position. Subsequently, the best seepage solutions for the dam constructing were scientifically identified.

  16. Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

    Science.gov (United States)

    Zhang, Jingkui; Zhang, Liaojun

    2014-06-01

    Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

  17. Long-term dam safety monitoring of Punt dal Gall arch dam in Switzerland

    Institute of Scientific and Technical Information of China (English)

    M.WIELAND[1; G.F.KIRCHEN[2

    2012-01-01

    The 130 m high Punt dal Gall dam is located at the Swiss-Italian border in the South-eastern part of Switzerland and was completed in 1969.The dam is founded on highly folded and partially crushed dolomite and limestone formations.A grout curtain with an area of 120,000 m 2 was provided for controlling seepage.For the monitoring of the dam deformations five inverted pendulums were installed in the dam and three in the rock foundation of the right abutment outside of the dam.For a seasonal water level fluctuation in the reservoir of about 60 m the maximum amplitude of the radial displacement is 25 mm,which includes both the effects of the water load and temperature effects.Furthermore a comprehensive geodetic network was established,57 joint meters were installed and cracks in the crest gallery are monitored by crack meters.There are also thermometers,piezometers and rocmeters.Springs at the left and right banks of the dam are monitored and chemical analyses of the seepage water and springs are performed regularly.The dam is equipped with strong motion instruments and several near-field earthquakes have been recorded in the past.The paper describes the long-term safety monitoring of this 42 years old arch dam.A short description of the Swiss practice in dam safety monitoring and emergency planning is also given.

  18. Numerical Study of Two-Dimensional Viscous Flow over Dams

    Institute of Scientific and Technical Information of China (English)

    王利兵; 刘宇陆; 涂敏杰

    2003-01-01

    In this paper, the characteristics of two-dimensional viscous flow over two dams were numerically investigated. The results show that the behavior of the vortices is closely related to the space between two dams, water depth, Fr number and Reynolds number. In addition, the flow properties behind each dam are different, and the changes over two dams are more complex than over one dam. Finally, the relevant turbulent characteristics were analyzed.

  19. Research on Dam Simulation System Based on OpenGL

    Science.gov (United States)

    Li, Kairong; Wang, Juanni; Zuo, Kui; Yun, Jian

    Dam, not only has great ability to alleviate water shortages especially during the dry season which improve hydropower capacity, but also plays an imporant rule in the river ecosystem. Dam has significant effect in improving our water environment and protecting ecological system.This paper copes with the three-dimensional model of dams and discusses OpenGL modeling, lighting, material, model transformation, perspective transformation technologies to achieve visualization of the dam, and eventually we visualize the dam through concrete examples.

  20. Final Design Analysis : Lake Ladora Dam Repair

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is intended to present Rocky Mountain Arsenal with details concerning the remedial repair for Ladora Dam to meet the geotechnical concerns and hydrologic...

  1. Chemical - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  2. Dams life; La vie des barrages

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper summarizes the conclusions of the annual inspections of French dams in operation (fissures, water oozing, concrete swelling etc..). Only the observations which require a special attention are reported. (J.S.)

  3. White Sturgeon Passage at The Dalles Dam

    Science.gov (United States)

    ,

    2008-01-01

    Researchers at the USGS Western Fisheries Research Center's Columbia River Research Laboratory, working with the U.S. Army Corps of Engineers, sought to better understand upstream and downstream passage of white sturgeon at dams. A study at The Dalles Dam provided the opportunity to compare two fish ladders; one that passes sturgeon upstream to one that does not, to determine if subtle differences in construction result in better passage of white sturgeon. Researchers conducted a study using a combination of acoustic and radio telemetry technologies to obtain information on juvenile and adult white sturgeon near The Dalles Dam, with the objectives of characterizing the distribution and movements of white sturgeon in the immediate vicinity of the dam and to determine timing and routes of upstream and downstream passage.

  4. Physical - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  5. Biological - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  6. Anthropocene streams and base-level controls from historic dams in the unglaciated mid-Atlantic region, USA

    Science.gov (United States)

    Merritts, Dorothy; Walter, Robert; Rahnis, Michael; Hartranft, Jeff; Cox, Scott; Gellis, Allen; Potter, Noel; Hilgartner, William; Langland, Michael; Manion, Lauren; Lippincott, Caitlin; Siddiqui, Sauleh; Rehman, Zain; Scheid, Chris; Kratz, Laura; Shilling, Andrea; Jenschke, Matthew; Datin, Katherine; Cranmer, Elizabeth; Reed, Austin; Matuszewski, Derek; Voli, Mark; Ohlson, Erik; Neugebauer, Ali; Ahamed, Aakash; Neal, Conor; Winter, Allison; Becker, Steven

    2011-01-01

    Recently, widespread valley-bottom damming for water power was identified as a primary control on valley sedimentation in the mid-Atlantic US during the late seventeenth to early twentieth century. The timing of damming coincided with that of accelerated upland erosion during post-European settlement land-use change. In this paper, we examine the impact of local drops in base level on incision into historic reservoir sediment as thousands of ageing dams breach. Analysis of lidar and field data indicates that historic milldam building led to local base-level rises of 2-5 m (typical milldam height) and reduced valley slopes by half. Subsequent base-level fall with dam breaching led to an approximate doubling in slope, a significant base-level forcing. Case studies in forested, rural as well as agricultural and urban areas demonstrate that a breached dam can lead to stream incision, bank erosion and increased loads of suspended sediment, even with no change in land use. After dam breaching, key predictors of stream bank erosion include number of years since dam breach, proximity to a dam and dam height. One implication of this work is that conceptual models linking channel condition and sediment yield exclusively with modern upland land use are incomplete for valleys impacted by milldams. With no equivalent in the Holocene or late Pleistocene sedimentary record, modern incised stream-channel forms in the mid-Atlantic region represent a transient response to both base-level forcing and major changes in land use beginning centuries ago. Similar channel forms might also exist in other locales where historic milling was prevalent.

  7. Risk assessment of tailings facility dam failure

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Stefanova, Violeta

    2011-01-01

    This paper presents the consequences of tailings facility dam failure and therefore the needs for its risk assessment. Tailings are fine-grained wastes of the mining industry, output as slurries, due to mixing with water during mineral processing. Tailings dams vary a lot as it is affected by: tailings characteristics and mill output, site characteristics as: topography, hydrology, geology, groundwater, seismicity and available material and disposal methods. The talings which accumulat...

  8. Stability and performance of older dams

    Energy Technology Data Exchange (ETDEWEB)

    Dharmawardene, W.; Herbig, A.; Morrison, J. [Alberta Environment, AB (Canada); Chan, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2003-07-01

    There are 1300 licensed dams in Alberta. Most were designed and constructed between the late 1940s and the early 1960s. As a rule, compacted earthfill in preglacial and interglacial valleys in southern Alberta was used to construct all dams of moderate height. At these dam sites, the foundations are of valley infill alluvial soils underlain by weak rocks. The best prevailing engineering practices at the time were used to design these dams. It included drilling, soil testing prior to and during construction, and some stability analyses. Despite these measures, a number of the dams built on soft clays suffered significant deformations and cracking of the embankment during construction. A re-examination of the stability of some of the older dams in Alberta, owned by the provincial department of the Environment, was undertaken six years ago using currently accepted design practices. Allowance was made in the new analyses for the presence of shear zones and fissures in the foundation soils, as well as softening caused by wetting. Despite many years of apparently satisfactory service, Factors of Safety that were marginal or deficient were discovered at many dams. The authors presented case histories of three older dams (North and South McGregor, and North Ridge, all located in southern Alberta) for which the long term Factors of Safety were marginal under normal loading. A number of criteria, such as deformation, stress strain curves of foundation materials and the consequence of failure were taken into consideration in assessing and confirming the requirement for repair before any structural modifications were undertaken. Some of the repairs that were carried out were also briefly described. 12 refs., 4 tabs., 5 figs.

  9. Walter Bouldin Dam failure and reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-09-01

    Walter Bouldin is one of several hydroelectric developments of Alabama Power Company. On February 10, 1975, an earth embankment section of Walter Bouldin Dam was breached, causing total evacuation of the forebay reservoir and rendering the 225-MW power plant inoperable. The Federal Power Commission instituted an investigation of the dam failure, and a report on the investigation was published in February 1976. Subsequently, an evidentiary hearing was held before an administrative law judge who issued his initial decision on August 19, 1976. The Commission, on April 21, 1977, issued its Opinion No. 795 in which it adopted the initial decision with modifications and terminated the investigation of failure of Walter Bouldin Dam. Opinion No. 795 directs the staff of the Bureau of Power to prepare, for the future guidance of the Commission, a report on the deficiencies which were found in its investigation, together with advice as to how such deficiencies have been and should be remedied. Also, it directs the staff of the Bureau of Power to address certain general recommendations included in the initial decision. This report was prepared in response to that directive and summaries information on the dam failure and its investigation; the evidentiary hearing; the judge's recommendations, the reconstruction of the Bouldin Dam; and the evalution and status of the Federal Energy Regulatory Commission Dam safety program. (LCL)

  10. Reliability Analysis of High Rockfill Dam Stability

    Directory of Open Access Journals (Sweden)

    Ping Yi

    2015-01-01

    Full Text Available A program 3DSTAB combining slope stability analysis and reliability analysis is developed and validated. In this program, the limit equilibrium method is utilized to calculate safety factors of critical slip surfaces. The first-order reliability method is used to compute reliability indexes corresponding to critical probabilistic surfaces. When derivatives of the performance function are calculated by finite difference method, the previous iteration’s critical slip surface is saved and used. This sequential approximation strategy notably improves efficiency. Using this program, the stability reliability analyses of concrete faced rockfill dams and earth core rockfill dams with different heights and different slope ratios are performed. The results show that both safety factors and reliability indexes decrease as the dam’s slope increases at a constant height and as the dam’s height increases at a constant slope. They decrease dramatically as the dam height increases from 100 m to 200 m while they decrease slowly once the dam height exceeds 250 m, which deserves attention. Additionally, both safety factors and reliability indexes of the upstream slope of earth core rockfill dams are higher than that of the downstream slope. Thus, the downstream slope stability is the key failure mode for earth core rockfill dams.

  11. OVERVIEW OF DAM GULLY EROSION RESEARCH

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Traditionally gully erosion has been identified with the dissection of the landscape in agricultural settings but it is also recognized as a prevalent erosion feature in earthen dam auxiliary spillways and embankments. Flows through earthen spillways and over dam embankments, due to large rainfall events, have the potential to erode and breach the dam or spillway and result in catastrophic releases from the reservoir. The gully erosion process in an earthen spillway or on an embankment can be characterized by stages of initiation, development, and migration of a headcut. A headcut is defined as a near vertical drop at the upstream end of a gully. The rate of headcut migration is important in determining the breach potential of an earthen spillway and dam embankment. A research program is being conducted to examine the gully erosion processes of earthen dam auxiliary spillways and embankments. This paper describes: 1) the unique test facilities constructed to examine the dominant factors affecting the erosion of earthen spillways and embankments; 2) the observations of the erosion processes and results to date; and 3) the predictive relationships that have been developed for dam gully erosion research at the ARS Hydraulic Engineering Research Unit laboratory in Stillwater, OK.

  12. Use and application of inflatable dam seals in large concrete dams

    Energy Technology Data Exchange (ETDEWEB)

    Dickes, G. [Structural Preservation Systems Inc., Hanover, MD (United States)

    2001-10-01

    The successful installation of inflatable dam seals has been accomplished at several large concrete dams in the United States. This accomplishment was recently realized for the first time in Canada. The minimization of water intrusion caused by failed water stops in monolithic dams by a small diameter inflatable seal is one of the many uses for the device. Many problems encountered at large concrete dams are related to stress control of alkali-aggregate or alkali silica reaction (AAR, ASR), and the inflatable dam seal fits in as part of this control system. Many of the problems with concrete dams are due to AAR which causes concrete to expand, resulting in cracking of concrete and misalignment of equipment as two of the most important issues. A transverse vertical saw cut through the upper section of the concrete structure was one of the methods used to alleviate the stresses brought about by AAR. This method has been used on a number of occasions in both Canada and the United States. Once the saw cut is complete, from the upstream face to the downstream face, controlling the water flow in the kerf (13-19 millimeter) presents a major challenge. Successfully sealing failed water stops and saw cuts was accomplished by installing inflatable dam seals with vertical heights in excess of 38 meters. A specific seal must be designed in each case. Several elements of the composite construction seal meet the engineering requirements set forth by Dam Safety Officials and Engineers and Owners. Some case histories were presented, namely the Harry S. Truman Dam in Missouri, the Tennessee Valley Authority at several sites, the Hiwassee Dam in North Carolina, the Fontana Dam in Tennessee, and the Mactaquac Generating Station in New Brunswick. 10 refs., 11 figs.

  13. Grouting of the cracks in the Arch 5-6 Daniel Johnson dam

    Energy Technology Data Exchange (ETDEWEB)

    Lariviere, R.; Routhier, L.; Roy, V.; Saleh, K.; Tremblay, S.

    1999-07-01

    The Daniel-Johnson dam is located 800 km northeast of Montreal, PQ, and is 1314 m in length and 214 m high. Just after completion of dam construction different types of cracks started to appear on the upstream and downstream faces. During and after the construction of the dam, numerous cracks and joints were grouted in order to reduce water infiltration. In some cases, as a result of high injection pressures and inaccurate methods, the injections provoked the propagation of the existing cracks or the initiation of new ones. Because of this situation and to determine the contribution of injection to dam safety, in 1985, Hydro-Quebec applied a moratorium on all future injection work on the dam. Research work was initiated in 1986 in the areas of grouting materials, methods, equipment and behavioral analysis to establish a safe method for the injection of the cracks. A committee was formed in 1993 with members from various groups, in order to: carry out extensive behavioral analysis of the Arch 5-6 dam, carry out an investigation program in order to determine the cause of the increase of the water infiltration, undertake a structural analysis program in order to evaluate the impact of an injection on the safety of the dam, and identify the proper method and injection products to use. In 1997, as a result of the progress of the structural analysis studies and the injection research project, a decision was made to proceed with the injection of the dam. A description is included of the results of the investigation, recommendations and results of the injection research project, as well as some details of the grouting campaign carried out in January 1999. On the whole, a better knowledge was acquired of the structure, of the plunging cracks and the behaviour of the dam during the injection. In the field of injection methods, materials and equipment, research work was invaluable when it came to the injection of micro-fine cracks in concrete dams. 5 refs., 8 figs.

  14. 75 FR 439 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

    Science.gov (United States)

    2010-01-05

    ... Plan and Socio-economic workshops, updates from the public outreach ad hoc group, and a report from the... Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement to comply with... environmental assessment that will be used to evaluate the effects of the protocol. Other agenda items...

  15. Hydrologic response of streams restored with check dams in the Chiricahua Mountains

    Science.gov (United States)

    In this study, hydrological processes are evaluated to determine impacts of stream restoration in the West Turkey Creek, Chiricahua Mountains, southeast Arizona, during a summer-monsoon season (June–October of 2013). A paired-watershed approach was used to analyze the effectiveness of check dams to ...

  16. Development and validation of a 2D dam break process model

    Science.gov (United States)

    Flooding due to dam or levee breach often results in detrimental impact on the people and their properties in the flooding zone. The embankment breach process is often caused by overtopping or internal erosion due to excessive water in a reservoir or a river. This study is to develop a practical nu...

  17. Grand Coulee Dam Wildlife Mitigation Program : Pygmy Rabbit Programmatic Management Plan, Douglas County, Washington.

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, Paul

    1992-06-01

    The Northwest Power Planning Council and the Bonneville Power Administration approved the pygmy rabbit project as partial mitigation for impacts caused by the construction of Grand Coulee Dam. The focus of this project is the protection and enhancement of shrub-steppe/pygmy rabbit habitat in northeastern Washington.

  18. Wildlife Protection, Mitigation, and Enhancment Plan: Minidoka Dam: Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Meuleman, G. Allyn; Martin, Robert C.; Hansen, H. Jerome

    1991-04-01

    A wildlife protection, mitigation, and enhancement plan has been developed for the US Bureau of Reclamation's Minidoka Dam and Reservoir in south-central Idaho. Specific objectives of this study included the following: Develop protection, mitigation, and enhancement goals and objectives for target wildlife species; identify potential protection, mitigation, and enhancement opportunities to achieve the mitigation objectives; and coordinate project activities with agencies, tribes, and the public. The interagency work group previously assessed the impacts of Minidoka Dam on wildlife. There were estimated losses of 10,503 habitat units (HU's) for some target wildlife species and gains of 5,129 HU's for other target species. The work group agreed that mitigation efforts should be directed toward target species that were negatively impacted by Minidoka Dam. They developed the following prioritized mitigation goals: 1,531 river otter HU's in riparian/river habitat, 1,922 sage grouse HU's in shrub-steppe (sagebrush-grassland) habitat, 1,746 mule deer HU's in shrub-steppe habitat, and 175 yellow warbler HU's in deciduous scrub-shrub wetland habitat. The work group proposed the following preferred mitigation options, in priority order: Provide benefits of 1,706 river otter and yellow warbler HU's by protecting and enhancing riparian/river habitat in south central Idaho; and provide benefits of 3,668 sage grouse and mule deer HU's by protecting and enhancing shrub-steppe (sagebrush-grassland) habitat. 38 refs., 2 figs., 5 tabs.

  19. HIGH-SPEED FLOW EROSION ON A NEW ROLLER COMPACTED CONCRETE DAM DURING CONSTRUCTION

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; LUO Shao-ze; HU Ya-an; YUAN Qiang; WANG He-sheng; ZHAO Lan-hao

    2012-01-01

    A new roller compacted concrete dam of Fengman Hydropower Station is to be built in the toe of the old dam,which was identified as a dangerous dam.The new dam during construction would be influenced by the high-speed flow discharged from the old dam,which is an important problem to be considered for the first time in China,and which would affect the construction of the whole project.Therefore,a series of erosion experiments were conducted in this article.A high-speed flow erosion test apparatus was developed for the erosion experiments of the new dam materials.The maximum jet velocity goes up to 40 m/s and the section area of the nozzle is 0.0025 m2.In the process of experiments,the equipment shows a good performance.Erosive wear tests for two types of materials used in the new dam,a roller compacted concrete and a distorted concrete with four kinds of ages were carried out with the flow velocity in the range of 30 m/s-35 m/s.Erosion parameters and erosion laws for the two types of concretes with different ages were determined,and a general relationship between the erosion rate and the flow velocity is obtained as:N =cvP,with the velocity exponent P between 3.33 and 3.93.It is concluded that the erosion resistance of the distorted concrete is better than that of the roller compacted concrete and the mechanical properties of the concretes of over 14 d age are influenced slightly by the water impact.The test results might serve as a practical technique guide for the safety of this project during its construction in the flood season.

  20. Game model of safety monitoring for arch dam deformation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Arch dam deformation is comprehensively affected by water pressure,temperature,dam’s structural behavior and material properties as well as other factors.Among them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam’s structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance factors.Therefore,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of dam.On the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

  1. The interplay of activists and dam developers : the case of Myanmar’s mega-dams

    NARCIS (Netherlands)

    Kirchherr, Julian; J. Charles, Katrina; Walton, Matthew J.

    2017-01-01

    Scholars investigating activism against large dam developments in Asia usually focus on those campaigning, but not on those the campaigns are aimed at–the dam developers. Yet the developers’ perspective is crucial to comprehensively understand the dynamics of social and environmental activism in

  2. Challenges of high dam construction to computational mechanics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chuhan

    2007-01-01

    The current situations and growing prospects of China's hydro-power development and high dam construction are reviewed,giving emphasis to key issues for safety evaluation of large dams and hydro-power plants,especially those associated with application of state-of-the-art computational mechanics.These include but are not limited to:stress and stability analysis of dam foundations under external loads;earthquake behavior of dam-foundation-reservoir systems,mechanical properties of mass concrete for dams,high velocity flow and energy dissipation for high dams,scientific and technical problems of hydro-power plants and underground structures,and newly developed types of dam-Roll Compacted Concrete (RCC) dams and Concrete Face Rock-fill (CFR)dams.Some examples demonstrating successful utilizations of computational mechanics in high dam engineering are given,including seismic nonlinear analysis for arch dam foundations,nonlinear fracture analysis of arch dams under reservoir loads,and failure analysis of arch dam-foundations.To make more use of the computational mechanics in high dam engineering,it is pointed out that much research including different computational methods,numerical models and solution schemes,and verifications through experimental tests and filed measurements is necessary in the future.

  3. A New Approach for Structural Monitoring of Large Dams with a Three-Dimensional Laser Scanner.

    Science.gov (United States)

    González-Aguilera, Diego; Gómez-Lahoz, Javier; Sánchez, José

    2008-09-24

    Driven by progress in sensor technology, computer methods and data processing capabilities, 3D laser scanning has found a wide range of new application fields in recent years. Particularly, monitoring the static and dynamic behaviour of large dams has always been a topic of great importance, due to the impact these structures have on the whole landscape where they are built. The main goal of this paper is to show the relevance and novelty of the laserscanning methodology developed, which incorporates different statistical and modelling approaches not considered until now. As a result, the methods proposed in this paper have provided the measurement and monitoring of the large "Las Cogotas" dam (Avila, Spain).

  4. How stakeholders frame dam removal: The role of current and anticipated future ecosystem service use

    Science.gov (United States)

    Reilly, Kate; Adamowski, Jan

    2016-04-01

    Many river restoration projects, including dam removal, are controversial and can trigger conflicts between stakeholders who are for and against the proposed project. The study of environmental conflicts suggests that differences in how stakeholders 'frame', or make sense of a situation based on their prior knowledge and experiences, can perpetuate conflicts. Understanding different stakeholders' frames, particularly how they converge, can form the basis of successful conflict resolution. In the case of dam removals, it is often assumed that emphasising increased provision of ecosystem services can be a point of convergence between those advocating for ecological restoration and those opposed to removal because of negative human impacts. However, how exactly stakeholders frame a contentious proposed dam removal and how those frames relate to ecosystem services has been little studied. Here we used the case of a potential dam removal in New Brunswick to investigate how people frame the issue and how that relates to their current and anticipated future use of ecosystem services. Based on in-depth interviews with 30 stakeholders in the area, including both people for and against dam removal, we found that both groups currently used ecosystem services and were in favour of ecosystem protection. However, they differed in how they framed the issue of the potential dam removal. The group against dam removal framed the issue as one of loss and risk - they thought that any potential benefits to the ecosystem would be outweighed by the high risk of negative social impacts caused by a loss of access to ecosystem services, such as recreation and aesthetic enjoyment. By contrast, the group in favour of the dam framed the issue as one of opportunity and justice. They thought that following a short transition period, all stakeholders would benefit from the restored river, particularly from a restored salmon fishery, improved aesthetic appeal and the long-term sustainability of an

  5. Design and construction of Nemiscau-1 Dam, the first asphalt core rockfill dam in North America

    Energy Technology Data Exchange (ETDEWEB)

    Alicescu, V.; Tournier, J.P. [Hydro-Quebec, Montreal, PQ (Canada); Vannobel, P. [Societe d' Energie de la Baie James, Montreal, PQ (Canada)

    2008-07-01

    The concept of asphalt as a waterproofing medium inside embankment dams was originally developed in Germany in the 1960s. More than 100 asphalt core rockfill (ACRD) dams have been completed or are under construction. They all have a strong record without any seepage problems or required maintenance. After using the glacial till as waterproofing material for its embankment dams for more than 50 years, Hydro-Quebec is now looking to develop new dam concepts, mainly for the zones where natural waterproofing materials do not exist. In order to do so, the company has decided to design and construct the Nemiscau-1 Dam as a prototype ACRD. This paper presented the detailed design criteria, technical specifications as well as some information concerning the construction of the dam such as asphalt mix design. The given dam site, geology and materials is well suited for a dam with an asphalt core and the chosen core thickness of minimum 400 mm was found to be appropriate, given the small net water head. The main reservoir levels as well as the characteristics of the dam were also listed. Information on the general construction of the dam was provided. It was concluded that the longitudinal profile of the rock excavation and concrete plinth must be optimized, with an optimum balance between the rock excavation, the volume and shape of the concrete plinth and finally, the placement of the asphalt core with the manual method. Several combinations of these 3 elements must be analyzed at the design stage and the most cost effective one should be applied on site. 5 tabs., 7 figs.

  6. Particle-bound metal transport after removal of a small dam in the Pawtuxet River, Rhode Island, USA.

    Science.gov (United States)

    Katz, David R; Cantwell, Mark G; Sullivan, Julia C; Perron, Monique M; Burgess, Robert M; Ho, Kay T

    2016-10-06

    The Pawtuxet River in Rhode Island, USA, has a long history of industrial activity and pollutant discharges. Metal contamination of the river sediments is well documented and historically exceeded toxicity thresholds for a variety of organisms. The Pawtuxet River dam, a low-head dam at the mouth of the river, was removed in August 2011. The removal of the dam was part of an effort to restore the riverine ecosystem after centuries of anthropogenic impact. Sediment traps were deployed below the dam to assess changes in metal concentrations and fluxes (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) from the river system into Pawtuxet Cove. Sediment traps were deployed for an average duration of 24 days each, and deployments continued for 15 months after the dam was removed. Metal concentrations in the trapped suspended particulate matter dropped after dam removal (e.g., 460 to 276 mg/kg for Zn) and remained below preremoval levels for most of the study. However, particle-bound metal fluxes increased immediately after dam removal (e.g., 1206 to 4248 g/day for Zn). Changes in flux rates during the study period indicated that river volumetric flow rates acted as the primary mechanism controlling the flux of metals into Pawtuxet Cove and ultimately upper Narragansett Bay. Even though suspended particulate matter metal concentrations initially dropped after removal of the dam, no discernable effect on the concentration or flux of the study metals exiting the river could be associated with removal of the Pawtuxet River dam. Integr Environ Assess Manag 2016;00:000-000. Published 2016. This article is a US Government work and is in the public domain in the USA.

  7. Flood effects provide evidence of an alternate stable state from dam management on the Upper Missouri River

    Science.gov (United States)

    Skalak, Katherine; Benthem, Adam J.; Hupp, Cliff R.; Schenk, Edward R.; Galloway, Joel M.; Nustad, Rochelle A.

    2017-01-01

    We examine how historic flooding in 2011 affected the geomorphic adjustments created by dam regulation along the approximately 120 km free flowing reach of the Upper Missouri River bounded upstream by the Garrison Dam (1953) and downstream by Lake Oahe Reservoir (1959) near the City of Bismarck, ND, USA. The largest flood since dam regulation occurred in 2011. Flood releases from the Garrison Dam began in May 2011 and lasted until October, peaking with a flow of more than 4200 m3 s−1. Channel cross-section data and aerial imagery before and after the flood were compared with historic rates of channel change to assess the relative impact of the flood on the river morphology. Results indicate that the 2011 flood maintained trends in island area with the loss of islands in the reach just below the dam and an increase in island area downstream. Channel capacity changes varied along the Garrison Segment as a result of the flood. The thalweg, which has been stable since the mid-1970s, did not migrate. And channel morphology, as defined by a newly developed shoaling metric, which quantifies the degree of channel braiding, indicates significant longitudinal variability in response to the flood. These results show that the 2011 flood exacerbates some geomorphic trends caused by the dam while reversing others. We conclude that the presence of dams has created an alternate geomorphic and related ecological stable state, which does not revert towards pre-dam conditions in response to the flood of record. This suggests that management of sediment transport dynamics as well as flow modification is necessary to restore the Garrison Segment of the Upper Missouri River towards pre-dam conditions and help create or maintain habitat for endangered species. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  8. Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin

    Energy Technology Data Exchange (ETDEWEB)

    Dugan, Patrick J. [WorldFish Center; Barlow, Chris [Australian Center for International Agricultural Research (ACIAR); Agostinho, Angelo A. [Fundacao University, Parana Brazil; Baran, Eric [WorldFish Center; Cada, Glenn F [ORNL; Chen, Daqing [Yangtze River Fisheries Research Institute, People' s Republic of China; Cowx, Ian G. [Hull International Fisheries Research Institute, England; Ferguson, John W. [North West Fisheries Science Center, Seattle, WA; Jutagate, Tuantong [Ubon Ratchathani University, Ubon Ratchathani, Thailand; Mallen-Cooper, Martin [Fishway Consulting Service, Australia; Marmulla, Gerd [Food and Agriculture Organization of the United Nations (FAO), Rome, Italy; Nestler, John [USA Corps Engineers, Concord, MA USA; Petrere, Miquel [Universidade Estadual Paulista, Rio Claro, Brazil; Winemiller, Kirk O. [Texas A& M University

    2010-06-01

    The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin's fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur

  9. Monitoring of small and medium embankment dams on permafrost in a changing climate

    Institute of Scientific and Technical Information of China (English)

    Rudolf V.Zhang

    2014-01-01

    Global climate warming which began in the second half of the twentieth century is continuing. It is associated with in creased risks for ecological management, especially in permafrost areas comprising over 65% of Russia. Of special con cern are dams constructed on permafrost. They are subject not only to climatic impacts, but also to additional hydrothermal loads from water reservoirs. This paper presents the concept of geocryological monitoring of dams and other water re source projects and substantiates its necessity in view of climatic change. It also presents methods, scope and implemen tation of geocryological monitoring at medium and small dams, considering the specific nature of Far Northern areas, as well as the complicated geotechnical, hydrogeological and permafrost conditions.

  10. Effects of Flaming Gorge Dam hydropower operations on downstream flow, stage, and sediment transport

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.C.L.; Tomasko, D.; Cho, H.E.; Williams, G. [Argonne National Lab., IL (United States); McCoy, J.; Palmer, C. [USDOE Western Area Power Administration, Salt Lake City, UT (United States)

    1996-11-01

    Hydropower operations at Flaming Gorge Dam, located on the Green River in Utah, can produce rapid downstream changes in flow and stage. These changes can in turn affect sediment transport and ecologic resources below the dam. To evaluate these effects, four hydropower operational scenarios with varying degrees of hydropower-release fluctuations were examined. This study demonstrates that the combined use of river-flow routing, water-surface profile, and sediment-transport models can provide useful information for evaluating the potential impacts of hydropower-operations on ecological and other resources downstream of the dam. Study results show that flow fluctuations may or may not persist for a long distance, depending on the initial magnitude of fluctuation and the duration of hydropower peaking. Stage fluctuations depend not only on flow fluctuations but also on river channel characteristics, such as channel width and longitudinal slope.

  11. Chixoy Dam Legacies: The Struggle to Secure Reparation and the Right to Remedy in Guatemala

    Directory of Open Access Journals (Sweden)

    Barbara Rose Johnston

    2010-06-01

    Full Text Available The World Commission on Dams brought global attention to the adverse costs of large dam development, including the disproportionate displacement of indigenous peoples and ethnic minorities and the extreme impoverishment of development refugees. The WCD recommended that governments, industry and financial institutions accept responsibility for flawed development and make proper reparation, including remedial activities such as the restoration of livelihood and land compensation for relocated communities. One exemplary case cited is Guatemala’s Chixoy dam. Completed in 1982, this internationally financed dam was built during a time when military dictatorships deployed policies of state-sponsored violence against a Mayan citizenry. Construction occurred without a resettlement plan, and forced displacement occurred through violence and massacre. This paper describes an attempt to implement WCD reparation recommendations in a context where no political will existed. To clarify events, abuses and meaningful remedy, an independent assessment process was established in 2003, auditing the development record, assessing consequential damages and facilitating the community articulation of histories and needs. The resulting 2005 study played a key role in reparation negotiations. The Chixoy case illustrates some of the more profound impacts of the WCD review. The WCD served as a catalyst in social movement formation and a force that expanded rights-protective space for dam-affected communities to negotiate an equitable involvement in development.

  12. Fish community response to dam removal in a Maine coastal river tributary

    Science.gov (United States)

    Zydlewski, Joseph; Hogg, Robert S.; Coghlan Jr., Stephen M.; Gardner, Cory

    2016-01-01

    Sedgeunkedunk Stream, a third-order tributary to the Penobscot River in Maine, historically has supported several anadromous fishes including Atlantic Salmon Salmo salar, Alewife Alosa pseudoharengus, and Sea Lamprey Petromyzon marinus. Two small dams constructed in the 1800s reduced or eliminated spawning runs entirely. In 2009, efforts to restore marine–freshwater connectivity in the system culminated in removal of the lowermost dam (Mill Dam) providing access to 4.7 km of lotic habitat and unimpeded passage into the lentic habitat of Fields Pond. In anticipation of these barrier removals, we initiated a modified before-after-control-impact study, and monitored stream fish assemblages in fixed treatment and reference sites. Electrofishing surveys were conducted twice yearly since 2007. Results indicated that density, biomass, and diversity of the fish assemblage increased at all treatment sites upstream of the 2009 dam removal. No distinct changes in these metrics occurred at reference sites. We documented recolonization and successful reproduction of Atlantic Salmon, Alewife, and Sea Lamprey in previously inaccessible upstream reaches. These results clearly demonstrate that dam removal has enhanced the fish assemblage by providing an undisrupted stream gradient linking a small headwater lake and tributary with a large coastal river, its estuary, and the Atlantic Ocean.

  13. Experimental Study on Mechanism and Shape Characteristics of Suspended Flexible Dam

    Institute of Scientific and Technical Information of China (English)

    王建中; 范红霞; 朱立俊

    2014-01-01

    Hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structural form. With brush and stone as building materials, this kind of structure has an obvious engineering effect. However, it not only requires huge capital investments, but also has negative impacts on the ecological environment. The suspended flexible dam is an innovative engineering measure, and few theoretical and experimental researches of this type dam can be found at present. This paper studies the mechanism and shape characteristics of this dam and obtains the dynamic equilibrium equation of flexible dam, the float buoyancy expression, and the condition for transformation among three forms of the underwater shape of the dam. The results are valuable in engineering application and can be used as the reference for the future work due to the distinctive design philosophy, the small negative effects on environment and the consistency for sustainable development.

  14. Understanding the role of farm dams in the Murray-Darling Basin in Australia through hydrological analysis coupled with stakeholder interviews

    Science.gov (United States)

    Kuil, Linda; Winnubst, Madelinde; van Dijk, Albert

    2013-04-01

    Climate predictions suggest that surface water availability in the Murray-Darling Basin (MDB) in Australia is more likely to decline than to increase in the next decades. In 2000, farm dams were first recognized as a significant risk to future flows in the MDB and have since been the subject of hydrological research. This study was conducted to provide insight into the role of farm dams in the Yass catchment, which is a subcatchment of the MDB close to Canberra, in order to indentify obstacles for integrated water management. The role of farm dams was investigated from both a hydrological and social perspective. Model prediction and data inference were used to estimate the impact of farm dams on streamflow. The density of farm dams in the catchment was estimated at 5.7 dams km-2. The impact on the Yass River was simulated to be in the order of 20 percent of mean annual streamflow. To understand why farm dams are used, semi-structured interviews were conducted to capture views and opinions of land holders. Research found that farm dams play a very important role in terms of individuals' water supply, although other systems are also used. Furthermore, land holders are responsible for their own water supply for drinking and agricultural water needs. Water rights are based on a right to rainfall or groundwater that is present on an individual's property. This means that landholders have both a need and a right to collect and store runoff. Current legislation put in place by the New South Wales government to restrict the amount of rain water to be captured does not seem to affect most people. If additional policy to minimize the impact of farm dams on streamflow were to be introduced, this has to be based on well-thought-out arguments based on a long term vision as the interview results indicate that farm dams are deeply embedded in Australian rural culture.

  15. SEFIDROOD RIVER SUB-WATERSHED-DAM-ESTUARY AND DEGRADATION MODEL: A HOLISTIC APPROACH IN IRAN

    Institute of Scientific and Technical Information of China (English)

    Forood AZARI DEHKORDI; Majid F MAKHDOUM; Nobukazu NAKAGOSHI

    2003-01-01

    The major concern of this article is to address the shortcoming and outgoing effects of the human activities on the landscape patterns and their consequences in the Sefidrood River watershed in Iran. A flow of data includes three inputs; each of them belongs to one part of three zones of a fluvial system. The three parts of the Sefidrood River fluvial system include Zone 1, a sub-watershed as degradation modeling site, Zone 2, Sefidrood Dam as dam site, and Zone 3, 17km away from the Sefidrood River path to the Caspian Sea as ending point site. The degradation model in the Zone 1 provides a suitable mean for decision support system to decrease the human impacts on each small district. The maximum number for degradation coefficient belongs to the small district with the highest physiographic density, relatively cumulative activities, and a lower figure for the habitat vulnerability. The human degradation impact were not limited to the upstream. The investigation to the Sefldrood Dam and ending point of the Sefldrood River depicts that sedimentation continues as a significant visual impact in the Sefidrood Dam reservoir and the estuary.

  16. The future role of dams in the United States of America

    Science.gov (United States)

    Ho, Michelle; Lall, Upmanu; Allaire, Maura; Devineni, Naresh; Kwon, Hyun Han; Pal, Indrani; Raff, David; Wegner, David

    2017-02-01

    xml:id="wrcr22481-sec-1001" numbered="no">Storage and controlled distribution of water have been key elements of a human strategy to overcome the space and time variability of water, which have been marked by catastrophic droughts and floods throughout the course of civilization. In the United States, the peak of dam building occurred in the mid-20th century with knowledge limited to the scientific understanding and hydrologic records of the time. Ecological impacts were considered differently than current legislative and regulatory controls would potentially dictate. Additionally, future costs such as maintenance or removal beyond the economic design life were not fully considered. The converging risks associated with aging water storage infrastructure and uncertainty in climate in addition to the continuing need for water storage, flood protection, and hydropower result in a pressing need to address the state of dam infrastructure across the nation. Decisions regarding the future of dams in the United States may, in turn, influence regional water futures through groundwater outcomes, economic productivity, migration, and urban growth. We advocate for a comprehensive national water assessment and a formal analysis of the role dams play in our water future. We emphasize the urgent need for environmentally and economically sound strategies to integrate surface and groundwater storage infrastructure in local, regional, and national water planning considerations. A research agenda is proposed to assess dam failure impacts and the design, operation, and need for dams considering both paleo and future climate, utilization of groundwater resources, and the changing societal values toward the environment.

  17. EXPERIMENTAL INVESTIGATION OF THE FAILURE OF CASCADE LANDSLIDE DAMS

    Institute of Scientific and Technical Information of China (English)

    NIU Zhi-pan; XU Wei-lin; LI Nai-wen; XUE Yang; CHEN Hua-yong

    2012-01-01

    This paper preseuts results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel.The dams were designed to be regular trapezoid with fine sand.A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures.Under two differem inflow discharges,the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated.The results indicate that when the inflow discharge is large,the deformation pattern of the downstream dam is similar to that of the upstream dam,and both dams are characterized with the overtopping scour throughout the dam failure process.When the inflow discharge is small,the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision,and the downstream dam is characterized with the overtopping scour.The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.

  18. Toward policies and decision-making for dam removal.

    Science.gov (United States)

    Doyle, Martin W; Harbor, Jon M; Stanley, Emily H

    2003-04-01

    Dam removal has emerged as a critical issue in environmental management. Agencies responsible for dams face a drastic increase in the number of potential dam removals in the near future. Given limited resources, these agencies need to develop ways to decide which dams should be removed and in what order. The underlying science of dam removal is relatively undeveloped and most agencies faced with dam removal lack a coherent purpose for removing dams. These shortcomings can be overcome by the implementation of two policies by agencies faced with dam removal: (1) the development and adoption of a prioritization scheme for what constitutes an important dam removal, and (2) the establishment of minimum levels of analysis prior to decision-making about a dam removal. Federal and state agencies and the scientific community must encourage an initial experimental phase of dam removal during which only a few dams are removed, and these are studied intensively. This will allow for the development of the fundamental scientific understanding needed to support effective decision-making in the future and minimize the risk of disasters arising from poorly thought out dam removal decisions.

  19. Understanding Hydrological Regime Alterations Caused by dams: the Santiago River case in the Andean Region of the Amazon Basin.

    Science.gov (United States)

    Rosero-Lopez, D.; Flecker, A.; Walter, M. T.

    2016-12-01

    Water resources in South America have been clearly targeted as key sources for hydropower expansion over the next 30 years. Ecuador, among the most biologically diverse countries in the world, has the highest density of hydropower dams, either operational, under construction, or planned, in the Amazon Basin. Ecuador's ambitious plan to change its energy portfolio is conceived to satisfy the country's demand and to empower the country to be the region's first hydroelectric energy exporter. The Santiago watershed located in the southeast part of the country has 39 facilities either under construction or in operation. The Santiago River and its main tributaries (Zamora and Upano) are expected to be impounded by large dams over the next 10 years. In order to understand the magnitude and potential impacts of regional dam development on hydrological regimes, a 35-year historical data set of stream discharge was analyzed. We examined flow regimes for time series between the construction of each dam, starting with the oldest and largest built in 1982 up until the most recent dam built in 2005. Preliminary results indicate a systematic displacement in flow seasonality following post-dam compared to pre-dam conditions. There are also notable differences in the distributions of peaks and pulses in post-dam flows. The range of changes from these results shows that punctuated and cumulative impacts are related to the size of each new impoundment. These observations and their implications to the livelihoods, biota, and ecosystems services in the Santiago watershed need to be incorporated into a broader cost-benefit analysis of hydropower generation in the western Amazon Basin.

  20. International small dam safety assurance policy benchmarks to avoid dam failure flood disasters in developing countries

    Science.gov (United States)

    Pisaniello, John D.; Dam, Tuyet Thi; Tingey-Holyoak, Joanne L.

    2015-12-01

    In developing countries small dam failure disasters are common yet research on their dam safety management is lacking. This paper reviews available small dam safety assurance policy benchmarks from international literature, synthesises them for applicability in developing countries, and provides example application through a case study of Vietnam. Generic models from 'minimum' to 'best' practice (Pisaniello, 1997) are synthesised with the World Bank's 'essential' and 'desirable' elements (Bradlow et al., 2002) leading to novel policy analysis and design criteria for developing countries. The case study involved 22 on-site dam surveys finding micro level physical and management inadequacies that indicates macro dam safety management policy performs far below the minimum benchmark in Vietnam. Moving assurance policy towards 'best practice' is necessary to improve the safety of Vietnam's considerable number of hazardous dams to acceptable community standards, but firstly achieving 'minimum practice' per the developed guidance is essential. The policy analysis/design process provides an exemplar for other developing countries to follow for avoiding dam failure flood disasters.

  1. Re-grouting of Maroon Dam foundation

    Energy Technology Data Exchange (ETDEWEB)

    Palassi, M. [Tehran Univ. (Iran, Islamic Republic of). Dept. of Civil Engineering; Sharghi, A. [JTMA Co., Tehran (Iran, Islamic Republic of)

    2003-07-01

    The Maroon dam, built on the Maroon River in the Khoozestan province (southwest) of Iran, has a height of 176 metres and a 1.2 billion cubic metre reservoir. It is one of the largest embankment dams in Iran. A number of unpredicted inflows of water into tunnels and other underground openings occurred during the first impoundment of the Maroon dam. Impoundment was halted and the reservoir was emptied to correct the problem. This paper reviews the measures that were implemented during the remediation process, and presented an evaluation of the effectiveness of the process. The foundation treatment involved placing concrete in the caverns, constructing a concrete lining, and extending the grout curtain. The grouting procedure was also described. The overall effectiveness of the concrete work and grouting resulted in a reduction in leakage from 8.5 cubic metres per second to a more acceptable 10 litres per second. 8 figs.

  2. Channel changes downstream from a dam

    Science.gov (United States)

    Hadley, R.F.; Emmett, W.W.

    1998-01-01

    A flood-control dam was completed during 1979 on Bear Creek, a small tributary stream to the South Platte River in the Denver, Colorado, area. Before and after dam closure, repetitive surveys between 1977 and 1992 at five cross sections downstream of the dam documented changes in channel morphology. During this 15-year period, channel width increased slightly, but channel depth increased by more than 40 percent. Within the study reach, stream gradient decreased and median bed material sizes coarsened from sand in the pools and fine gravel on the riffle to a median coarse gravel throughout the reach. The most striking visual change was from a sparse growth of streamside grasses to a dense growth of riparian woody vegetation.

  3. Design of tailing dam using red mud

    Science.gov (United States)

    Rout, Subrat; Sahoo, Tapaswini; Das, Sarat

    2013-06-01

    Red mud, waste industrial product from aluminum industries produced approximately 75 million tonnes every year with less than half of this is used. Storage of this unutilized red mud takes vast tracts of usable land and pollutes, land, air and water. Construction of high embankments, under passes, flyovers, tailing dams uses vast tract of natural resources (top soil) is also matter of concern as its takes thousands of years to form the natural soil. This paper discusses use of red mud for construction of tailing dam based on laboratory findings and finite element analysis. The geotechnical properties such as plasticity, compaction, permeability, shear strength characteristics and dispersion of red mud are presented. Stability and seepage analysis of tailing dams as per finite element analysis using the above geotechnical parameters is presented.

  4. Numerical Modeling of Debris Flow Force Caused by Climate Change and Its application to Check Dam

    Science.gov (United States)

    KIM, S. D.; Jun, K.; JUN, B. H.; Lee, H. J.; TAK, W. J.

    2016-12-01

    Due to global warming, climate change cause a super hurricane and heavy rainfall frequently. Heavy rainfall cause by debris flow in mountainous terrains, and disasters by debris flow force have continuously increased. The purpose of this study is to analyze the characteristics of debris flow force acting on the check dam. The numerical approach to the debris flow force was performed by the Finite Difference Method (FDM) based on the erosion-deposition combination model including the equation of continuity, mass conservation, and momentum conservation. In order to investigate behavior of the debris flow force according to the variance of supplying water discharge and channel slope angle, a rectangular straight channel and one closed type check dam was set up for conducting numerical simulations. As the supply water discharges increase, the curve of the impact force by debris flow becomes unstable and fluctuation with high impact force occurred as time passes. And the peak impact force showed a steeper slope and appeared more quickly, the high impact force undergoes a fluctuation with high speed, and acting on the check dam. At the mountainous upstream, strong rainfall energy provoke a repeat erosion and deposition which results in debris flow force causing much damage along the check dam at the mountainous place. The analyses of the present study help provide information to predict future debris flow force and how to design for the check dam. This research was supported by a grant [MPSS-NH-2014-74] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government

  5. Wildlife Impact Assessment and Summary of Previous Mitigation Related to Hydroelectric Projects in Montana, Phase 1, Volume Two (B), Clark Fork River Projects, Cabinet Gorge and Noxon Rapids Dams, Operator, Washington Water Power Company.

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Marilyn

    1984-06-01

    This report documents best available information concerning the wildlife species impacted and the degree of the impact. A target species list was developed to focus the impact assessment and to direct mitigation efforts. Many non-target species also incurred impacts but are not discussed in this report. All wildlife habitats inundated by the two reservoirs are represented by the target species. It was assumed the numerous non-target species also affected will be benefited by the mitigation measures adopted for the target species. Impacts addressed are limited to those directly attributable to the loss of habitat and displacement of wildlife populations due to the construction and operation of the two hydroelectric projects. Secondary impacts, such as the relocation of railroads and highways, and the increase of the human population, were not considered. In some cases, both positive and negative impacts were assessed; and the overall net effect was reported. The loss/gain estimates reported represent impacts considered to have occurred during one point in time except where otherwise noted. When possible, quantitative estimates were developed based on historical information from the area or on data from similar areas. Qualitative loss estimates of low, moderate, or high with supporting rationale were assessed for each species or species group.

  6. Challenges to natural process restoration: common dam removal management concerns

    Science.gov (United States)

    Collins, M. J.; Tullos, D. D.; Bellmore, J. R.; Bountry, J.; Connolly, P. J.; Shafroth, P. B.; Wilcox, A. C.

    2015-12-01

    Practitioners must make dam removal decisions in spite of uncertainty about physical and ecological responses. This can result in implementing structural controls or other interventions at a site to avoid anticipated negative effects, sometimes even if a given concern is not warranted. We used a newly available dam removal science database and other information sources to explore seven frequently raised issues we call "Common Management Concerns" (CMCs), investigating their occurrence and the contributing biophysical controls. We describe these controls to enable managers to better assess if further analyses are warranted at their sites before interventions are planned and implemented. The CMCs addressed are: rate and degree of reservoir sediment erosion; drawdown impacts on local water infrastructure; excessive channel incision; downstream sediment aggradation; elevated turbidity; colonization of reservoir sediments by non-native plants; and expansion of invasive fish. The relative dearth of case studies available for many CMCs limited the generalizable conclusions we could draw about prevalence, but the available data and established understanding of relevant processes revealed important biophysical phenomena controlling the likelihood of CMC occurrence. To assess CMC risk, we recommend managers concurrently evaluate if site conditions suggest the ecosystem, infrastructure, or other human uses will be negatively affected if the biophysical phenomenon producing the CMC occurs. We show how many CMCs have one or more controls in common, facilitating the identification of multiple risks at a site, and demonstrate why CMC risks should be considered in the context of other important factors like watershed disturbance history, natural variability, and dam removal tradeoffs. Better understanding CMCs and how to evaluate them will enable practitioners to avoid unnecessary interventions and thus maximize opportunities for working with natural processes to restore river

  7. Study on dynamic anti-sliding stability of a high gravity dam considering complex dam foundation

    Directory of Open Access Journals (Sweden)

    Deng-hong CHEN

    2011-06-01

    Full Text Available There existed some limitations when analyzing the anti-sliding seismic stability of dam-foundation system by traditional pseudo-static method and response spectrum method. The dynamic strength reduction method was used to study on the deep anti-sliding stability of a high gravity dam considering complex dam foundation under strong earthquake-induced ground action. The static analysis was firstly carried out by reducing the shear strength parameters of the dam foundation’s rock mass with equal proportion. Then, the time-history seismic analysis was carried out based on the static analysis. It was proposed as one of dynamic instability criterions that the peak values of the dynamic displacements and plastic strain energy change suddenly with increasing strength reduction coefficient. The elasto-plastic behavior of the dam foundation was idealized using Drucker–Prager yield criterion based on associated flow rule assumption. Through the static, dynamic strength reduction analysis and dynamic linear elastic analysis of the overflow dam monolith of a high gravity dam, the results’ reliability of elastic-plastic time history analysis was confirmed. The results also showed that the rock mass strength of the high gravity dam foundation has higher strength reserve coefficient. The instability criterions of dynamic strength reduction method proposed were feasible. Although the static anti-slide analysis methods and standards of gravity dam based on the numerical methods are being discussed at present, the dynamic calculation method and instability criterions proposed in this paper would provide some meaningful suggestions for the dynamic analysis of the similar projects.

  8. Optimizing the dammed: water supply losses and fish habitat gains from dam removal in California.

    Science.gov (United States)

    Null, Sarah E; Medellín-Azuara, Josué; Escriva-Bou, Alvar; Lent, Michelle; Lund, Jay R

    2014-04-01

    Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0-2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

  9. Predicting Water Levels at Kainji Dam Using Artificial Neural Networks

    African Journals Online (AJOL)

    Predicting Water Levels at Kainji Dam Using Artificial Neural Networks. ... The aim of this study is to develop artificial neural network models for predicting water levels at Kainji Dam, which supplies water to Nigeria's largest ... Article Metrics.

  10. Inventory of Dams in the State of Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Permitted dams in Iowa and associated attributes, as recorded by the Floodplain Section of the DNR. The dams regulated are those with the parameters listed below: a....

  11. National Inventory of Dams Coastal California Extract 2010

    Data.gov (United States)

    California Department of Resources — The National Inventory of Dams (NID) is a congressionally authorized database, which documents dams in the U.S. and its territories. The NID was most recently...

  12. Research review of the cement sand and gravel (CSG) dam

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The cement sand and gravel (CSG) dam is a new style of dam that owes the advantages both of the concrete faced rock-fill dam (CRFD) and roller compacted concrete (RCC) gravity dam,because of which it has attracted much attention of experts home and abroad.At present,some researches on physic-mechanical property of CSG material and work behavior of CSG dam have been done.This paper introduces the development and characteristics of CSG dam systematically,and summarizes the progress of the study on basic tests,constitutive relation of CSG material and numerical analysis of CSG dam,in addition,indicates research and application aspect of the dam.

  13. Computational Aspects of Dam Risk Analysis: Findings and Challenges

    Directory of Open Access Journals (Sweden)

    Ignacio Escuder-Bueno

    2016-09-01

    Full Text Available In recent years, risk analysis techniques have proved to be a useful tool to inform dam safety management. This paper summarizes the outcomes of three themes related to dam risk analysis discussed in the Benchmark Workshops organized by the International Commission on Large Dams Technical Committee on “Computational Aspects of Analysis and Design of Dams.” In the 2011 Benchmark Workshop, estimation of the probability of failure of a gravity dam for the sliding failure mode was discussed. Next, in 2013, the discussion focused on the computational challenges of the estimation of consequences in dam risk analysis. Finally, in 2015, the probability of sliding and overtopping in an embankment was analyzed. These Benchmark Workshops have allowed a complete review of numerical aspects for dam risk analysis, showing that risk analysis methods are a very useful tool to analyze the risk of dam systems, including downstream consequence assessments and the uncertainty of structural models.

  14. Lac Courte Oreilles Hydro Dam Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Jason [Lac Courte Oreilles, Hayward, WI (United States); Meyers, Amy [Kiser Hydro, LLC, Norway, MI (United States)

    2014-12-31

    The main objective of this project was to investigate upgrading the existing hydro power generating system at the Winter Dam. The tribe would like to produce more energy and receive a fair market power purchase agreement so the dam is no longer a drain on our budget but a contributor to our economy. We contracted Kiser Hydro, LLC Engineering for this project and received an engineering report that includes options for producing more energy with cost effective upgrades to the existing turbines. Included in this project was a negotiation of energy price sales negotiations.

  15. Research on Dam Perspective Based on Numerical Solution

    Institute of Scientific and Technical Information of China (English)

    WANGZi-ru; ZHOUHui-cheng; LIMing-qiu

    2005-01-01

    The numerical solution of dam toe line is solved based on the dam data and topographic map of dam located. The display of dam perspective is also realized by programming of using VC++ and OpenGL. The research results above provide the foundation of construction design, construction lofting and information inquiry, which avoids the drawbacks of only using blueprints to do the same work in the past. The method used is useful in practical engineering.

  16. Investigation on the Causes of Cracking in Earth Dams (Case study: Mahmood-Abad Earth Dam

    Directory of Open Access Journals (Sweden)

    H. Rahimi

    2016-09-01

    Full Text Available Introduction: Cracking of earth dams is a one of the main threat causes of stability of embankment dams. In this research by modeling of the behavior of an embankment dam and employing conditions of the earthquake, the reasons of cracking were inspected using by modeling of earth dam behavior. Based on the literature, one of the main causes of dam failures is sliding and cracking of the dam structure during earthquake. Localized liquefaction of foundation soils was one of the causes of the observed post-earthquake distress within these dams. Material and Methods: In order to study the causes and the results of crack on earth dams, Mahmoodabad earthen dam with a height of 19 m, is located in Zanjan province, northwest of Iran, which suffered a longitudinal crack on the crest and slight sliding of the upstream slope due to 2001 Avaj earthquake was studied. This dam has faced earthquake two times with an interval of two years. During the first earthquake with the magnitude about 6.6 in Richter scale small longitudinal cracks had created on the crest. The developed cracks had been repaired by injecting the cement and then has been hidden by passing the time. After the second earthquake with the magnitude about 6.5 in Richter scale the hidden cracks had been appeared again and the slight movement of the upper slopes of dam reported. Based on the site investigation and documented information about dam, including maps and parameter data, the behavior of the dam has modeled by using Plaxis as a finite element model. In order to check the accuracy of the design of dam, the stability analysis has been conducted using by Xslope as a limit equilibrium model. The foundation conditions and the Geotechnical properties of the layer beneath the dam has been inspected by open excavation. Results and Discussion: Underground investigation about Geotechnical properties of dam foundation has showed that there is a thin sandy layer confined in alluvium material of the

  17. Major dams of the United States, Geographic NAD83, USGS (2006) [dams00x020_USGS_2006

    Data.gov (United States)

    Louisiana Geographic Information Center — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands. The map layer was created by extracting dams 50 feet or...

  18. 43 CFR 418.18 - Diversions at Derby Dam.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Diversions at Derby Dam. 418.18 Section... Operations and Management § 418.18 Diversions at Derby Dam. (a) Diversions of Truckee River water at Derby Dam must be managed to maintain minimum terminal flow to Lahontan Reservoir or the Carson River...

  19. 25 CFR 173.16 - Reserved area, Coolidge Dam.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Reserved area, Coolidge Dam. 173.16 Section 173.16... area, Coolidge Dam. No permit for any commercial business or other activity (except boating concessions...-fourths of a mile from the center of the Coolidge Dam, Arizona....

  20. 21 CFR 872.6300 - Rubber dam and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rubber dam and accessories. 872.6300 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6300 Rubber dam and accessories. (a) Identification. A rubber dam and accessories is a device composed of a thin sheet of latex with a hole in...

  1. SEISMIC RESPONSE OF DAM WITH SOIL-STRUCTURE INTERACTION.

    Science.gov (United States)

    Bycroft, G.N.; Mork, P.N.

    1987-01-01

    An analytical solution to the response of a long trapezoidal-section dam on a foundation consisting of an elastic half-space and subjected to simulated earthquake motion is developed. An optimum seismic design is achieved when the cross section of the dam is triangular. The effect of soil structure interaction is to lower the strain occurring in the dam.

  2. Evaporação líquida no lago de Sobradinho e impactos no escoamento devido à construção do reservatório Net evaporation in Sobradinho dam and impacts on runoff due to the construction of the reservoir

    Directory of Open Access Journals (Sweden)

    Silvio B. Pereira

    2009-06-01

    Full Text Available Um dos problemas que dificultam a gestão de recursos hídricos, são as perdas de água por evaporação nos reservatórios de regularização, fazendo com que estimativas confiáveis de evaporação nos reservatórios sejam essenciais, tanto no planejamento e gerenciamento dos recursos hídricos, quanto em estudos de impacto ambiental. Com base neste enfoque objetivou-se, através do trabalho ora apresentado, estimar a evaporação líquida no lago de Sobradinho por meio da metodologia do tanque Classe A e dos modelos Linacre (1993, Kohler et al. (1955 e CRLE, além dos impactos ocorridos nas condições de escoamento devido à construção do reservatório. Os resultados permitiram concluir que: a construção do reservatório de sobradinho alterou sensivelmente o comportamento hidrológico do rio São Francisco à jusante da mesma; os valores obtidos pelo modelo Kohler et al. (1955 podem ser utilizados como base de referência para a estimativa da evaporação média anual do lago de Sobradinho; o coeficiente de tanque Classe A que melhor representou a variação sazonal de evaporação no lago de Sobradinho foi de 0,57; finalmente, a vazão média anual correspondente à evaporação líquida do reservatório de Sobradinho foi de 132 m³ s-1.Losses of water by evaporation in regulatory reservoirs are one of the problems that exist in water resources management, the reliable estimates of evaporation in the reservoirs becoming essential not only in the planning and administration of the water resources but also in studies of environmental impact. The objective of this paper was to estimate the net evaporation in the Sobradinho dam through the Class A tank methodology and the Linacre (1993, Kohler et al. (1955 and CRLE models, as well as to verify the impacts on the flow conditions due to the construction of the reservoir. The results showed that: the construction of the Sobradinho reservoir, associated to the other activities developed in the

  3. The expected collapse of a large dam Saddam Dam in Iraq; Un grand barrage a haut risque Saddam Dam en Irak

    Energy Technology Data Exchange (ETDEWEB)

    Mesny, M. [Conseil general du genie rural, des eaux et des forets, 75 - Paris (France)

    2004-07-01

    The Saddam dam is a very large dam in Iraq on the Tigris River, 80 kilometres upstream from the city of Mosul. It is a fill dam with a clayey silt core. The height of the dam is 120 meters and the capacity of the reservoir is 11 billions m3. But this dam has been built on foundations of gypsum that is a rock soluble in water. The impounding of the reservoir in 1986 has shown that, in spite of the grout curtain, substantial seepage has occurred (up to 1.4 m{sup 3}/s), as well as the dissolution of minerals from foundations (up to 80 tons per day). The substantial increase in permeability and seepage through the dam foundations results in a severe concern about the stability of the dam. The program of injection has been stopped in 1991, due to the circumstances. So there is a real risk that this dam would collapse through a quickly developing leak in the dike, resulting in the devastation of the rich agricultural valley of the Tigris River and in potential human losses at Mosul. A 10 to 20-meter high submersion wave would reach this town 3 to 4 hours after the collapse of the dam. An international action is urgently required to check the conditions of the dam and to propose remedial solutions, which may be a 120-meter deep concrete wall down to the calcareous floor existing below the soluble layers of the foundations. (author)

  4. Immediate changes in stream channel geomorphology, aquatic habitat, and fish assemblages following dam removal in a small upland catchment

    Science.gov (United States)

    Magilligan, F. J.; Nislow, K. H.; Kynard, B. E.; Hackman, A. M.

    2016-01-01

    downstream reach. Post-removal, but pre-flood, bed surveys indicate 2 m of incision had migrated 25 m upstream of the former reservoir before encountering the exhumed dam, which now acts as the new grade control, limiting progressive headcutting. Approximately 1000 m3 of sediment was evacuated in the first year, with 67% of the volume occurring by pre-flood, process-driven (e.g., changes in base level) controls. The combination of changes in channel-bed sedimentology, the occurrence of a large magnitude flood, and the emergence of the new crib dam that is a likely barrier to fish movement was associated with major reductions in abundance and richness in sites downstream and immediately upstream adjacent to the former dam in post-removal sampling. At the same time, we documented the presence of four species of fish, including sea lamprey, which were not present above the dam prior to removal, indicating that upstream passage has been achieved; and we also documented lamprey spawning activity at sites immediately below the dam, which had previously been unsuitable owing to an excessively coarse and armored riverbed. Our results point to the importance of interactions between dam removal and flood disturbance effects, with important implications for short- and long-term monitoring and assessment of dam impacts to river systems.

  5. Synthesis of common management concerns associated with dam removal

    Science.gov (United States)

    Tullos, Desiree D.; Collins, Mathias J.; Bellmore, J. Ryan; Bountry, Jennifer A.; Connolly, Patrick J.; Shafroth, Patrick B.; Wilcox, Andrew C.

    2016-01-01

    Managers make decisions regarding if and how to remove dams in spite of uncertainty surrounding physical and ecological responses, and stakeholders often raise concerns about certain negative effects, regardless of whether or not these concerns are warranted at a particular site. We used a dam-removal science database supplemented with other information sources to explore seven frequently-raised concerns, herein Common Management Concerns (CMCs). We investigate the occurrence of these concerns and the contributing biophysical controls. The CMCs addressed are: degree and rate of reservoir sediment erosion, excessive channel incision upstream of reservoirs, downstream sediment aggradation, elevated downstream turbidity, drawdown impacts on local water infrastructure, colonization of reservoir sediments by non-native plants, and expansion of invasive fish. Biophysical controls emerged for some of the concerns, providing managers with information to assess whether a given concern is likely to occur at a site. To fully assess CMC risk, managers should concurrently evaluate site conditions and identify the ecosystem or human uses that will be negatively affected if the biophysical phenomenon producing the CMC occurs. We show how many CMCs have one or more controls in common, facilitating the identification of multiple risks at a site, and demonstrate why CMC risks should be considered in the context of other factors like natural watershed variability and disturbance history.

  6. Local Climate Sensitivity of the Three Gorges Dam

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Norman L.; Jin, Jiming; Tsang, Chin-Fu

    2005-02-18

    Two simulations, control and land use change, were performed for an eight week period (2 April-16 May 1990) to determine the net sensitivity of the local climate around the Three Gorges Dam. The analysis indicates that the large reservoir acts as a potential evaporating surface that decreases the surface temperature, cools the lower atmosphere, decreasing upward motion, and increasing sinking air mass. Such sinking results in low level moisture divergence, decreasing cloudiness, and increasing net downward radiation, which increases the surface temperature. However, results indicate that evaporative cooling dominates radiative warming in this initial study. The strong evaporation also supplies moisture to the atmosphere, suggesting an increase in precipitation, but the sinking moist air diverges away from the TGD region with no net change in precipitation. This numerical study represents an initial methodology for quantification of the impact of the Three Gorges Dam on the local climate and a more comprehensive, fine-scale set of multi-season simulations with additional observational data is needed for a more complete analysis.

  7. Dams life. Dams in operation; La vie des barrages. Barrages en exploitation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper summarizes the conclusions of the annual inspections of French dams in operation (fissures, water oozing, concrete swelling etc..). Only the observations which require a special attention are reported. (J.S.)

  8. DAM-LAKEFRONT PLAZA: Revitalization of an Agriculture Reservoir Dam in Kashar-Tirana/Albania

    Directory of Open Access Journals (Sweden)

    Valbona Koçi

    2014-12-01

    Full Text Available The Dam-Lakefront Plaza in Kashar-Tirana/Albania is a research project that proposes not only the re-consideration and reinforcement of the artificial Reservoirs Dams built during Socialism in Albania, but envisions the maintenance of dams and revitalization of the lakeside area promoting the public-private collaboration. In addition, it envisions the generation of qualitative and lively public spaces in sub-urban areas as well. Admitting the artificial lakes as specific nodes of man-made infrastructure in the landscape, and consequently the dams (together with the drainage channels as important hydrotechnic elements of the flood protection infrastructure, this research intends to elaborate on one type of landscape infrastructure - the vertical screens, offering a mediation between the natural and built landscape.

  9. Formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes for gas separations

    KAUST Repository

    Xu, Liren

    2014-06-01

    This paper reports the formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes. 6FDA-polyimides are of great interest for advanced gas separation membranes, and 6FDA-DAM polyimide is a representative polymer in this family with attractive dense film properties for several potential applications. The work reported here for the 6FDA-DAM polyimide provides insight for the challenging fabrication of defect-free asymmetric hollow fiber membranes for this class of 6FDA-polyimides, which behave rather different from lower free volume polymers. Specifically, the 6FDA based materials show relatively slow phase separation rate in water quench baths, which presents a challenge for fiber spinning. For convenience, we refer to the behavior as more "non-solvent resistant" in comparison to other lower free volume polymers, since the binodal phase boundary is displaced further from the conventional position near the pure polymer-solvent axis on a ternary phase diagram in conventional polymers like Matrimid® and Ultem®. The addition of lithium nitrate to promote phase separation has a useful impact on 6FDA-DAM asymmetric hollow fiber formation. 6FDA-DAM phase diagrams using ethanol and water as non-solvent are reported, and it was found that water is less desirable as a non-solvent dope additive for defect-free fiber spinning. Phase diagrams are also reported for 6FDA-DAM dope formulation with and without the addition of lithium nitrate, and defect-free asymmetric hollow fiber membranes are reported for both cases. The effect of polymer molecular weight on defect-free fiber spinning was also investigated. Gas transport properties and morphology of hollow fibers were characterized. With several thorough case studies, this work provides a systematic guideline for defect-free fiber formation from 6FDA-polymers. © 2014 Elsevier B.V.

  10. Postpartum behavioral profiles in Wistar rats following maternal separation - altered exploration and risk-assessment behavior in MS15 dams

    Directory of Open Access Journals (Sweden)

    Loudin Daoura

    2010-06-01

    Full Text Available The rodent maternal separation (MS model is frequently used to investigate the impact of early environmental factors on adult neurobiology and behavior. The majority of MS studies assess effects in the offspring and few address the consequences of repeated pup removal in the dam. Such studies are of interest since alterations detected in offspring subjected to MS may, at least in part, be mediated by variations in maternal behavior and the amount of maternal care provided by the dam. The aim of this study was to investigate how daily short (15 min; MS15 and prolonged (360 min; MS360 periods of MS affects the dam by examining postpartum behavioral profiles using the multivariate concentric square field™ (MCSF test. The dams were tested on postpartum days 24-25, i.e. just after the end of the separation period and weaning. The results reveal a lower exploratory drive and lower risk-assessment behavior in MS15 dams relative to MS360 or animal facility reared dams. The present results contrast some of the previously reported findings and provide new information about early post-weaning behavioral characteristics in a multivariate setting. Plausible explanations for the results are provided including a discussion how the present results fit into the maternal mediation hypothesis.

  11. Assessing potential removal of low-head dams in urban settings: an example from the Ottawa River, NW Ohio.

    Science.gov (United States)

    Roberts, Sheila J; Gottgens, Johan F; Spongberg, Alison L; Evans, James E; Levine, Norman S

    2007-01-01

    This is a study of the scientific component of an effort to restore an urban river by removing a low-head dam. The Secor Dam is owned by a local government entity near Toledo, Ohio. The proposed removal of the last structure impeding flow on the Ottawa River has broad appeal, but the owner is concerned about liability issues, particularly potential changes to the flood regime, the presence of contaminated sediments behind the dam, and possible downstream transport of reservoir sediments. Assessing sediment contamination involved sediment sampling and analysis of trace metals and organic contaminants. Forecasting sediment transport involved field methods to determine the volume and textural properties of reservoir and upstream sediment and calculations to determine the fate of reservoir sediments. Forecasting changes in the flood regime involved HEC-RAS hydrological models to determine before and after dam removal flood scenarios using LiDAR data imported into an ArcGIS database. The resulting assessment found potential sediment contamination to be minor, and modeling showed that the removal of the dam would have minimal impacts on sediment transport and flood hazards. Based on the assessment, the removal of the dam has been approved by its owners.

  12. Blending the Analytic Hierarchy Process and Fuzzy Logical Systems in Scenic Beauty Assessment of Check Dams in Streams

    Directory of Open Access Journals (Sweden)

    Szu-Hsien Peng

    2015-12-01

    Full Text Available With Taiwan’s steep terrain and fracture geology, natural disasters are likely to occur after heavy rainfall. To reduce the effects of upstream sediment on human surroundings, check dams are an essential transverse structure for streams in watersheds. However, there is likely to be a detrimental visual impact on the landscape without consideration of the integration of dams with the environment. Based on previous studies of landscape assessment, this paper considers the factors of texture, color, and form, often used as part of expert paradigms, as the major aesthetic aspects of check dams. These factors are used to construct an expert questionnaire using the Delphi Method and Analytic Hierarchy Process (AHP. The preliminary criteria and weights for Scenic Beauty Assessment of check dams are determined based on the results of AHP. A Fuzzy Logical System is further applied to solve the linguistic fuzziness of landscape assessment so as to establish a complete expert scenic beauty assessment model. Five cases are further tested for comparison with 224 public samples with Scenic Beauty Estimation (SBE. Results demonstrate that the model presents the validity of expert paradigm and the reliability of the psychophysical paradigm. These results can provide a reference for engineering designers seeking to integrate check dams with the natural landscape. The results indicate that the present method can efficiently assess the scenic beauty of check dams as established by a scientific method.

  13. 7 CFR 1724.55 - Dam safety.

    Science.gov (United States)

    2010-01-01

    ... result from encountering unanticipated or unusual conditions during construction. (5) The independent review of construction shall include: (i) Foundation preparation and treatment. When the foundation has... construction. The reviewer must have demonstrated experience in the design and construction of dams of...

  14. Aquifer performance under the Mactaquac Dam

    Energy Technology Data Exchange (ETDEWEB)

    Tawil, A.H. [Acres International, Niagara Falls, ON (Canada); Harriman, F.B. [New Brunswick Power, Fredericton, NB (Canada)

    2001-10-01

    The highest dam in the whole of the Maritimes and New Brunswick in particular is the Mactaquac Dam, with a height of 58 m above the foundation. It forms an integral part of the Mactaquac Hydroelectric Development and the construction of the dam was completed in 1967. Composed of a central core of clay till and external shells of rockfill, it is a zoned embankment. The high artesian pressure rising 6 m above the Saint John River dominates, and the foundation under the dam is composed of a stratum of stiff glacial till underlain with a thick, water bearing aquifer. The aquifer needed to be depressurized during the construction phase and in the long term, and special measures were required to accomplish this. Measurements obtained over a period exceeding 30 years were used to describe the performance of the aquifer, which is discussed in this presentation. A continuous reduction in the yield from the six permanent relief wells in the aquifer was indicated by the instrumentation data. The outflow from the wells diminished by two-thirds over the thirty-four years since first filling the reservoir. The piezometric pressure in the aquifer remained constant over the same period. The sparse results of a two-hour pump test had formed the basis for the design decision not to install a costly foundation seepage cut-off to bedrock, as the conclusions drawn from the pump test were that the aquifer was hydrogeologically confined. 3 refs., 4 tabs., 9 figs.

  15. Increasing dam safety with multi beam sonar

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, M. [SwedPower AB, Stockholm (Sweden); Cederstrom, M.O. [Vattenfall AB, Stockholm (Sweden); Deborg, J. [SwedPower AB, Alvkarleby (Sweden)

    2004-09-01

    Multi-beam sonar technology has been introduced to Vattenfall's dam safety program. Vattenfall is the major energy producer in Sweden and the third largest utility in Europe. Embankment dams are subject to processes such as erosion, settlement and sinkholes. The new portable multi-beam echo sounder system is an important tool to detect minor damages and to intervene before they evolve into expensive or hazardous situations. A first survey of the upstream slope of a rockfill dam with this method provides a topographic map indicating the location of anomalies such as internal erosion or piping. Multi-beam sonar works by combining GPS-RTK positioning, gyro motion sensing, a multi-beam sonar and 3-dimensional digital terrain programs. Vattenfall is using the system to verify and monitor all high hazard rockfill dams in Sweden to ensure long-term stability. The data will be stored as a fingerprint for comparison with future surveys in 15 to 20 years as part of routine safety evaluation. This new technology can also be used to survey breakwaters, erosion of rivers and to locate submerged debris in harbours. 6 figs.

  16. A Final Test for the Big Dam

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ The water level at the Three Gorges Dam,the world's largest water control and utilization project,reached its designed highest mark on October 26,which will enable the project to fulfill its functions of flood control,power generation,navigation and water diversion.

  17. Will We. . .? Thai Dam Resource Book.

    Science.gov (United States)

    Murphy, Richard, Ed.; And Others

    This resource book is intended as an aid to persons working with Thai Dam refugees. To help the language teacher, some differences between Lao and English are discussed, specifically tonal inflections, positioning, declension of pronouns, conjugation of verbs, interrogatives, classifiers and predicate adjectives. An outline of cultural differences…

  18. Fish reproductive guilds downstream of dams.

    Science.gov (United States)

    Vasconcelos, L P; Alves, D C; Gomes, L C

    2014-11-01

    Fish reproductive guilds were used to evaluate the responses of species with different reproductive strategies during two different periods of post-dam construction. The data used for the comparisons were collected in the upper Paraná River floodplain (Brazil), downstream of the Porto Primavera dam, 2 and 10 years after impoundment. The abundance (catch per unit effort, CPUE), species richness, evenness and structure of communities, all within reproductive guilds, were used to test the hypothesis that these metrics vary spatially and temporally. The influence of damming on species structure and the diversity of fish reproductive guilds varied spatiotemporally, and species with opportunistic reproductive strategies tended to be less affected. Conversely, long-distance migratory species responded more markedly to spatiotemporal variations, indicating that the ecosystem dynamics exert greater effects on populations of these species. Thus, the effects of a dam, even if attenuated, may extend over several years, especially downstream. This finding emphasizes the importance of maintaining large undammed tributaries downstream of reservoirs.

  19. Modelling approach for gravity dam break analysis

    Directory of Open Access Journals (Sweden)

    Boussekine Mourad

    2016-09-01

    Full Text Available The construction of dams in rivers can provide considerable benefits such as the supply of drinking and irrigation water; however the consequences which would result in the event of their failure could be catastrophic. They vary dramatically depending on the extent of the inundation area, the size of the population at risk.

  20. Socioeconomic and Institutional Dimensions of Dam Removals: The Wisconsin Experience

    Science.gov (United States)

    Born; Genskow; Filbert; Hernandez-Mora; Keefer; White

    1998-05-01

    / There are tens of thousands of small dams in the United States; many of these aging structures are deteriorating. Governments and dam owners face decisions regarding repair or removal of these structures. Along with the many benefits society derives from dams and their impoundments, numerous recent ecological studies are revealing the extensive alteration and degradation of river ecosystems by dams. Dam removal-a principal restoration strategy-is an infrequent event. The major reasons for removal have been public safety and the high costs associated with repair; the goal of river ecosystem restoration now warrants greater attention. Substantial study is being given to the environmental aspects of dams and dam removals, but very little attention has been given to the socioeconomic and institutional dimensions associated with the removal of dams, although these factors play a significant role in the removal decision-making process. Based on a case study of dam removals in Wisconsin-where more than 30 of the state's 3600 small dams have been removed in the past few decades-legal, financial, and socioeconomic issues associated with dam removal are documented and assessed. Dam removal has been complex and contentious, with limited community-based support for removal and loss of the impounded waters. In cases examined here, the estimated costs of repairing a dam averaged more than three times the cost of removal. The availability of governmental financing has been a key determinant in removal decisions. Watershed-scale ecological considerations are not major factors for most local interests. As watershed management and restoration increasingly include dam removal options as part of an integrated strategy, more attention will need to be focused on socioeconomic factors and stakeholder perspectives-variables that strongly influence the viability of this management alternative.KEY WORDS: Dam removal; River restoration; Institutions; Stakeholders

  1. River restoration by dam removal: Enhancing connectivity at watershed scales

    Directory of Open Access Journals (Sweden)

    F.J. Magilligan

    2016-05-01

    Full Text Available Abstract The prolonged history of industrialization, flood control, and hydropower production has led to the construction of 80,000 dams across the U.S. generating significant hydrologic, ecological, and social adjustments. With the increased ecological attention on re-establishing riverine connectivity, dam removal is becoming an important part of large-scale river restoration nationally, especially in New England, due to its early European settlement and history of waterpower-based industry. To capture the broader dimensions of dam removal, we constructed a GIS database of all inventoried dams in New England irrespective of size and reservoir volume to document the magnitude of fragmentation. We compared the characteristics of these existing dams to the attributes of all removed dams over the last ∼25 years. Our results reveal that the National Inventory of Dams significantly underestimates the actual number of dams (4,000 compared to >14,000. To combat the effects of these ecological barriers, dam removal in New England has been robust with 127 dams having been removed between ca. 1990–2013. These removed dams range in size, with the largest number (30% ranging between 2–4 m high, but 22% of the removed dams were between 4–6 m. They are not isolated to small drainage basins: most drained watersheds between 100–1,000 km2. Regionally, dam removal has re-connected ∼3% (3,770 river km of the regional river network although primarily through a few select dams where abundant barrier-free river lengths occur, suggesting that a more strategic removal approach has the opportunity to enhance the magnitude and rate of river re-connection. Given the regional-scale restoration of forest cover and water quality over the past century, dam removal offers a significant opportunity to capitalize on these efforts, providing watershed scale restoration and enhancing watershed resilience in the face of significant regional and global anthropogenic

  2. Stream Temperature Spatial and Temporal Response to Large Dam Removal and Groundwater Pumping under Varying Climate Conditions

    Science.gov (United States)

    Risley, J. C.; Constantz, J. E.; Essaid, H.; Rounds, S. A.

    2016-12-01

    We simulated the effects of large upstream dam removal and in-reach groundwater pumping on stream temperature spatial and temporal patterns in a hypothetical river basin under varying climate conditions. A MODFLOW-2000 model, with options for stream-aquifer interaction and grid-block rewetting, was constructed to simulate monthly streamflows for 12 watershed scenarios described below. For each scenario, streamflow output became input into a stream temperature simulation model. Stream temperatures were simulated using the CE-QUAL-W2 water quality model over a 110 km model grid, with the presence and removal of a dam at the top of the reach and pumping in the lower 60 km of the reach. Measured meteorological data from three locations in Oregon and California representing the three meteorological conditions were used as model input to simulate the impact of varying climate conditions on streamflows and stream temperature. For each climate condition, four hypothetical watershed scenarios were modeled: (1) natural (no dam or pumping), (2) large upstream dam present, (3) dam with in-reach pumping, and (4) no dam with pumping continued, resulting in 12 cases. If a transition from a humid to more arid environment occurs under future climate change, the simulations showed that decreased streamflow, increased solar radiation, and increased air temperatures would result in overall increased stream temperatures as expected. From March to August, the presence of a dam caused monthly mean stream temperatures to decrease on average by approximately 3.0°C, 2.5°C, and 2.0°C for the humid, semiarid, and arid conditions, respectively; however, stream temperatures generally increased from September to February. Pumping caused stream temperatures to warm in summer and cool in winter by generally less than 0.5°C. Though dam removal led to greater changes in stream temperature than pumping, ephemeral conditions were increased both temporally and spatially by pumping.

  3. RESEARCH ON SEEPAGE MONITORING MODEL OF EARTH-ROCK DAM

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the characteristics of seepage flow in earth-rock dams, a seepage monitoring model was established based on the finite element method for 3-D seepage flow together with observed data and was used to analyze and monitor the seepage of dams. In order to find out and monitor the seepage status of the whole dam, the separation of seepage amount for dam body, dam foundation and side banks was made theoretically by using the model. Practical example shows that the accuracy of computed results is satisfactory and the separation results are more objective.

  4. Mining dams safety regulations : where does Canada stand?

    Energy Technology Data Exchange (ETDEWEB)

    Priscu, C. [AMEC, Winnipeg, MB (Canada); Small, A. [AMEC Earth and Environmental Ltd., Fredericton, NB (Canada); Lupo, J. [AMEC, Englewood, CO (United States); Diaz, M. [AMEC, Ashford, Kent (United Kingdom); Davies, M. [AMEC, Vancouver, BC (Canada); Musse, M. [AMEC, Santiago (Chile)

    2009-07-01

    While many jurisdictions in Canada use the Canadian Dam Association (CDA) dam safety guidelines, their applicability to the safety of mining dams is limited. Mining dams are some of the largest containment structures in the world, and impound millions of cubic meters of mine process residues in both solid and liquid form. This study presented a review of dam safety regulatory frameworks for mining dams located in various countries. The aim of the study was to compare the Canadian framework with various dam safety legislations in order to evaluate Canada's current status and recommend best practices in dam safety regulations. The study reviewed incremental consequence classifications; best practices in operation, surveillance and maintenance manuals and procedures; emergency preparedness plans; and dam safety inspections. The study showed that Canada has limited documentation regulating the safe management of tailings facilities, and does not have an all-encompassing national guideline for mining dams. It was concluded that an incremental consequence classification (ICC) system should be developed specifically for mining dams. 12 refs.

  5. Seismic failure modes and seismic safety of Hardfill dam

    Directory of Open Access Journals (Sweden)

    Kun XIONG

    2013-04-01

    Full Text Available Based on microscopic damage theory and the finite element method, and using the Weibull distribution to characterize the random distribution of the mechanical properties of materials, the seismic response of a typical Hardfill dam was analyzed through numerical simulation during the earthquakes with intensities of 8 degrees and even greater. The seismic failure modes and failure mechanism of the dam were explored as well. Numerical results show that the Hardfill dam remains at a low stress level and undamaged or slightly damaged during an earthquake with an intensity of 8 degrees. During overload earthquakes, tensile cracks occur at the dam surfaces and extend to inside the dam body, and the upstream dam body experiences more serious damage than the downstream dam body. Therefore, under the seismic conditions, the failure pattern of the Hardfill dam is the tensile fracture of the upstream regions and the dam toe. Compared with traditional gravity dams, Hardfill dams have better seismic performance and greater seismic safety.

  6. Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

    Science.gov (United States)

    Gómez-Fragoso, Julieta; Heriberto Torres-Sierra,

    2016-08-09

    The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers.The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model.Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are

  7. An index-based framework for assessing patterns and trends in river fragmentation and flow regulation by global dams at multiple scales

    Science.gov (United States)

    Grill, Günther; Lehner, Bernhard; Lumsdon, Alexander E.; MacDonald, Graham K.; Zarfl, Christiane; Reidy Liermann, Catherine

    2015-01-01

    The global number of dam constructions has increased dramatically over the past six decades and is forecast to continue to rise, particularly in less industrialized regions. Identifying development pathways that can deliver the benefits of new infrastructure while also maintaining healthy and productive river systems is a great challenge that requires understanding the multifaceted impacts of dams at a range of scales. New approaches and advanced methodologies are needed to improve predictions of how future dam construction will affect biodiversity, ecosystem functioning, and fluvial geomorphology worldwide, helping to frame a global strategy to achieve sustainable dam development. Here, we respond to this need by applying a graph-based river routing model to simultaneously assess flow regulation and fragmentation by dams at multiple scales using data at high spatial resolution. We calculated the cumulative impact of a set of 6374 large existing dams and 3377 planned or proposed dams on river connectivity and river flow at basin and subbasin scales by fusing two novel indicators to create a holistic dam impact matrix for the period 1930-2030. Static network descriptors such as basin area or channel length are of limited use in hierarchically nested and dynamic river systems, so we developed the river fragmentation index and the river regulation index, which are based on river volume. These indicators are less sensitive to the effects of network configuration, offering increased comparability among studies with disparate hydrographies as well as across scales. Our results indicate that, on a global basis, 48% of river volume is moderately to severely impacted by either flow regulation, fragmentation, or both. Assuming completion of all dams planned and under construction in our future scenario, this number would nearly double to 93%, largely due to major dam construction in the Amazon Basin. We provide evidence for the importance of considering small to medium sized

  8. Fast changes in seasonal forest communities due to soil moisture increase after damming

    Directory of Open Access Journals (Sweden)

    Vagner Santiago do Vale

    2013-12-01

    Full Text Available Local changes caused by dams can have drastic consequences for ecosystems, not only because they change the water regime but also the modification on lakeshore areas. Thus, this work aimed to determine the changes in soil moisture after damming, to understand the consequences of this modification on the arboreal community of dry forests, some of the most endangered systems on the planet. We studied these changes in soil moisture and the arboreal community in three dry forests in the Araguari River Basin, after two dams construction in 2005 and 2006, and the potential effects on these forests. For this, plots of 20m x10m were distributed close to the impoundment margin and perpendicular to the dam margin in two deciduous dry forests and one semi-deciduous dry forest located in Southeastern Brazil, totaling 3.6ha sampled. Besides, soil analysis were undertaken before and after impoundment at three different depths 0-10, 20-30 and 40-50cm. A tree minimum DBH of 4.77cm community inventory was made before T0 and at two T2 and four T4 years after damming. Annual dynamic rates of all communities were calculated, and statistical tests were used to determine changes in soil moisture and tree communities. The analyses confirmed soil moisture increases in all forests, especially during the dry season and at sites closer to the reservoir; besides, an increase in basal area due to the fast growth of many trees was observed. The highest turnover occurred in the first two years after impoundment, mainly due to the higher tree mortality especially of those closer to the dam margin. All forests showed reductions in dynamic rates for subsequent years T2-T4, indicating that these forests tended to stabilize after a strong initial impact. The modifications were more extensive in the deciduous forests, probably because the dry period resulted more rigorous in these forests when compared to semideciduous forest. The new shorelines created by damming increased soil

  9. Gabcikovo dam and Liptovska Mara dam - statistical analysis of measurement data

    Science.gov (United States)

    Hakac, J.; Sabo, M.

    2012-04-01

    Introduction: Water level in the observation wells is measured regularly and one of the reasons is evaluation of the safety of the water constructions. In this paper we are exploring the reliability of the measuring devices that are responsible for evaluation of the safety of the two largest and the most important dams in Slovakia. We test ability of selected statistical methods to detect early inaccuracies of measuring devices and thus improve the evaluation of the safety of the water constructions. As a follow-up study, we used the time series model (Neural network) to predict water levels in the observation wells that were considered to be without defects. Neural Network is also able to show dynamics of the filtration stability of the observational well. Methods: On the Liptovska Mara dam weekly data was used as a monitoring tool. On the Gabcikovo dam five minute time series of the measurements of the water level in observation wells around the right lock chamber were used. Data from the measuring devices of the dams were explored with boxplots, correlations, neural network, etc. The mentioned statistical tools analyze time series and detect the errors that measuring devices make when generating data and can be used to predict errors even in real time. In the second step, agreement between predicted data from neural network and measured data in the real time was evaluated. We used grid search for finding the optimal number of neurons and then predicted errors by using this model. The ability of the neural network in evaluation of the sealing of the dilatation joints on the filtration stability in the years 2009 - 2011 is presented. Results: From the 18 selected measuring devices on the Liptovska Mara dam there are only 3 devices which can be considered as reliable. On the Gabcikovo dam, 8 of 9 measuring devices (observation wells around right lock chamber) were considered as a reliable. There was very good agreement between the predicted and measured data at the

  10. Ice-dammed lake drainage in west Greenland: Drainage pattern and implications on ice flow and bedrock motion

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Bjørk, Anders

    2017-01-01

    Ice-dammed lakes drain frequently in Greenland, but the impacts of these events differ between sites. Here we study the quasi-cyclic behavior of the ~40 km2 Lake Tininnilik in west Greenland and its impact on ice flow and crustal deformation. Data reveal rapid drainage of 1.83 ± 0.17 km3 of water...... in less than 7 days in 2010, leading to a speedup of the damming glacier, and an instantaneous modeled elastic bedrock uplift of 18.6 ± 0.1 mm confirmed by an independent lakeside GPS record. Since ice-dammed lakes are common on Greenland, our results highlight the importance of including other sources...... of surface loading in addition to ice mass change, when assessing glacial isostatic adjustment or elastic rebound using geodetic data. Moreover, the results illustrates a linkage between subglacial discharge and ice surface velocity, important for assessing ice flux, and thus mass balance, in a future...

  11. First-Year Downstream Sediment Budget Following the Marmot Dam Removal from the Sandy River, Oregon

    Science.gov (United States)

    Podolak, C. J.; Wilcock, P. R.; Pittman, A.

    2008-12-01

    The October 2007 removal of the Marmot Dam, from the Sandy River, OR, provides an opportunity to assess the impact of increased sediment flux on a river channel. The Sandy River drains the west flank of Mt Hood and typically carries a large load of sand and gravel. The 14-meter-tall dam impounded over 750,000 m3 of sediment, only a small amount of which was removed during the decommissioning. Using a one- dimensional modeling approach, it was assessed that the river could transport the accumulated sediment without large adverse impacts downstream of the dam (Cui et al, 2008 - abstract submitted). In order to observe the actual changes to the river due to the dam removal and to test the modeled predictions, a significant monitoring effort has be in place on the Sandy River including bedload and suspended load measurements, discharge measurements, high-fidelity topographic surveys, repeat photography, multiple airborne LIDAR flights, long profile surveys, as well as mapping and characterizing the grain sizes throughout several reaches downstream of the dam. A key step in the quest to describe and predict the spatial distribution of the sediment throughout the downstream reach is to first account for all the sediment (both stored in the reservoir and supplied from upstream). Here, we examine the transport and deposition downstream of the dam through a 2-fraction sediment budget approach using the former dam as the upstream limit of the reach and choosing a the mouth of a bedrock gorge 7 km below the dam site as the downstream limit. Suspended sediment and bedload measurements taken by the USGS just below the dam site (Major et al, 2008 - abstract submitted) are combined with suspended sediment and bedload measurements collected just below the mouth of the gorge and the annual hydrograph to define the sediment fluxes into and out of the reach. Repeat surveys in the reach below the dam (Wallick et al, 2008 - abstract submitted) provide the measure of change in storage

  12. Assessment of hydrological changes in the Nile River due to the construction of Renaissance Dam in Ethiopia

    Directory of Open Access Journals (Sweden)

    Mohammed El Bastawesy

    2015-06-01

    Full Text Available This paper assesses impact of the Renaissance Dam on Ethiopia; on the Nile discharge ultimately reaches Egypt downstream. The Landsat-8 satellite images of 2013 were obtained and interpreted to identify locations for the construction sites for the Renaissance Dam. Then the Shuttle Radar Topography Mission (SRTM data were obtained and processed to create a digital elevation model (DEM for the Blue Nile upstream areas that will be submerged. Different scenarios for the dams’ heights and resulting storages were simulated to estimate the resulting abstraction of the Blue Nile flows until completion of the project and the annual losses due to evaporation thereafter. The current site (506 m asl for the Renaissance Dam allows the creation of a 100 m deep reservoir with a total storage of 17.5 km3; overflows will occur at that lake’s level (606 m asl from the north western part of the developed lake into Rosaires downstream. Construction of the spillway dam to control the overflow area can allow the creation of a 180 m deep lake that store up to 173 km3 in a lake that will cover 3130 km2. The analysis of Tropical Rainfall Monitoring Mission (TRMM suggests that the variation of total annual rainfall could reach 20%, thus the resulting hydrological fluctuations could affect the estimated filling time, the operational functions and discharge downstream. The negative hydrological impacts of the Renaissance Dam will increase by increasing the height of its spillway dam, as increasing the storage capacity could affect the strategic storage for the reservoirs in Egypt and Sudan. It is strongly recommended that an agreement should be reached to compromise the storage capacities and water supplies for all dams on the Nile to thoroughly satisfy the necessary needs.

  13. Incorporating Climate Change Projections into a Hydrologic Hazard Analysis for Friant Dam

    Science.gov (United States)

    Holman, K. D.; Novembre, N.; Sankovich-Bahls, V.; England, J. F.

    2015-12-01

    The Bureau of Reclamation's Dam Safety Office has initiated a series of pilot studies focused on exploring potential impacts of climate change on hydrologic hazards at specific dam locations across the Western US. Friant Dam, located in Fresno, California, was chosen for study because the site had recently undergone a high-level hydrologic hazard analysis using the Stochastic Event Flood Model (SEFM). SEFM is a deterministic flood-event model that treats input parameters as variables, rather than fixed values. Monte Carlo sampling allows the hydrometeorological input parameters to vary according to observed relationships. In this study, we explore the potential impacts of climate change on the hydrologic hazard at Friant Dam using historical and climate-adjusted hydrometeorological inputs to the SEFM. Historical magnitude-frequency relationships of peak inflow and reservoir elevation were developed at Friant Dam for the baseline study using observed temperature and precipitation data between 1966 and 2011. Historical air temperatures, antecedent precipitation, mean annual precipitation, and the precipitation-frequency curve were adjusted for the climate change study using the delta method to create climate-adjusted hydrometeorological inputs. Historical and future climate projections are based on the Bias-Corrected Spatially-Disaggregated CMIP5 dataset (BCSD-CMIP5). The SEFM model was run thousands of times to produce magnitude-frequency relationships of peak reservoir inflow, inflow volume, and reservoir elevation, based on historical and climate-adjusted inputs. Results suggest that peak reservoir inflow and peak reservoir elevation increase (decrease) for all return periods under mean increases (decreases) in precipitation, independently of changes in surface air temperature.

  14. Damned If You Do, Dammed If You Don't: Debates on Dam Removal in the Swedish Media

    Directory of Open Access Journals (Sweden)

    Dolly Jørgensen

    2013-03-01

    Full Text Available Dam removal is an increasingly common practice. Dams are removed for various reasons, with safety, economics, and ecosystem restoration being the most common. However, dam removals often cause controversy. Riparian land owners and local communities often have a negative view of removal, and their reasons vary. It may be the loss of recreational benefits such as swimming and boating, loss of cultural and historical context tied to the dam, or fear that removal may have a negative effect on aesthetic values. Because controversies are often picked up by local media, and media in itself is an important channel to build support around a cause, the way in which dam removals are reported and discussed in the media is likely to influence the debate. Here, we examine the ways in which proponents and opponents of dam removal frame the services provided by two contrasting ecosystems, i.e., an existing dam and the potential stream without a dam, by performing a media discourse analysis of the reasons given for removal and the reasons presented for the dam to remain in place. Our source material includes Internet-based newspaper articles and their associated public comments in four dam removal controversies in Sweden. Our analysis indicates that public opposition is not based on knowledge deficiency, where more information will lead to better ecological decision-making, as is sometimes argued in dam removal science; it is instead a case of different understandings and valuation of the environment and the functions it provides.

  15. Lower Granite Dam Smolt Monitoring Program, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Verhey, Peter; Morrill, Charles; Mensik, Fred

    1999-01-01

    The 1999 fish collection season at Lower Granite was characterized by high spring flows and spill, low levels of debris, cool water temperatures, increased hatchery chinook numbers, and an overall decrease in numbers of smolts collected and transported. A total of 5,882,872 juvenile salmonids were collected at Lower Granite. Of these, 5,466,057 were transported to release sites below Bonneville Dam, 5,232,105 by barge and 233,952 by truck. An additional 339,398 fish were bypassed back to the river. A total of 117,609 salmonids were examined in daily samples. Nine research projects conducted by four agencies impacted a total of 440,810 smolts (7.5% of the total collected) of which 247,268 were PIT tagged and 572 were recorded as incidental mortalities.

  16. Dam-breach analysis and flood-inundation mapping for selected dams in Oklahoma City, Oklahoma, and near Atoka, Oklahoma

    Science.gov (United States)

    Shivers, Molly J.; Smith, S. Jerrod; Grout, Trevor S.; Lewis, Jason M.

    2015-01-01

    Dams provide beneficial functions such as flood control, recreation, and storage of water supplies, but they also entail risk; dam breaches and resultant floods can cause substantial property damage and loss of life. The State of Oklahoma requires each owner of a high-hazard dam, which the Federal Emergency Management Agency defines as dams for which failure or improper operation probably will cause loss of human life, to develop an emergency action plan specific to that dam. Components of an emergency action plan are to simulate a flood resulting from a possible dam breach and map the resulting downstream flood-inundation areas. The resulting flood-inundation maps can provide valuable information to city officials, emergency managers, and local residents for planning an emergency response if a dam breach occurs.

  17. GIS inundation mapping and dam breach analysis of Woolwich Dam using HEC-geoRAS

    Energy Technology Data Exchange (ETDEWEB)

    Mocan, N. [Crozier and Associates Inc., Collingwood, ON (Canada); Joy, D.M. [Guelph Univ., ON (Canada); Rungis, G. [Grand River Conservation Authority, Cambridge, ON (Canada)

    2006-07-01

    A study was conducted to determine the extent of flood inundation given a hypothetical dam breach scenario of the Woolwich Dam located in the Grand River Watershed, 2.5 km north of the Town of Elmira, Ontario. The dam is operated by the Grand River Conservation Authority and was constructed to provide low-flow augmentation to Canagagigue Creek. Advances in the computational capabilities of numerical models along with the availability of fine resolution geospatial data has lead to significant advances in the evaluation of catastrophic consequences due to the ensuing flood waters when dams fail. The hydraulic models HEC-RAS and HEC-GeoRAS were used in this study along with GIS to produce high resolution spatial and temporal flood inundation mapping. Given the proximity to the Town of Elmira, the dam is classified as having a high hazard potential. The large size and high hazard potential of the dam suggests that the Inflow Design Flood (IDF) is the Probable Maximum Flood (PMF) event. The outlet structure of the spillway consists of 4 ogee-type concrete spillways equipped with radial gates. A low-level concrete pipe located within the spillway structure provides spillage for maintenance purposes. The full flow capacity of the spillway structure is 297 cubic metres per second at the full supply level of 364.8 metres. In addition to GIS flood inundation maps, this paper included the results of flood hydrographs, water surface profiles and peak flow data. It was concluded that techniques used in this analysis should be considered for use in the development of emergency management planning and dam safety assessments across Canada. 6 refs., 3 tabs., 4 figs.

  18. National Dam Inspection Program. Lake Housatonic Dam and Dike (CT 00026 and CT 01714). Connecticut Coastal Basin, Housatonic River, Derby-Shelton, Connecticut. Phase I Inspection Report.

    Science.gov (United States)

    1981-08-01

    8217;’,.-+-.-. ""’"" . .•• "•;. - NATIONAL DAM INSPECTION PROGRAM PHASE I INSPECTION REPORT Identification No.: CT 00026, CT 01714 N *~ Name of Dam: Lake Housatonic Dam and Dike " Town...approach was used between 1868 and 1870 to strengthen the Holyoke dam. The dam that existed there at the time was a timber crib dam, 1,017 feet long and 30

  19. Compiling an Open Database of Dam Inundation Areas on the Irrawaddy, Salween, Mekong, and Red River Basins

    Science.gov (United States)

    Cutter, P. G.; Walcutt, A.; O'Neil-Dunne, J.; Geheb, K.; Troy, A.; Saah, D. S.; Ganz, D.

    2016-12-01

    Dam construction in mainland Southeast Asia has increased substantially in recent years with extensive regional impacts including alterations to water regimes, the loss and degradation of natural forests and biodiversity, and reductions in soil and water quality. The CGIAR Water Land Ecosystem program (WLE) and partners maintain a comprehensive database of locations and other data relating to existing, planned, and proposed dams in the region's major transboundary rivers spanning areas in Thailand, Cambodia, Laos, Vietnam, Myanmar, and China. A recent regional needs assessment and specific stakeholder requests revealed the need for a dataset reflecting the inundation areas of these dams for use in measuring impacts to river ecology, analyzing disaster risk, monitoring land cover and land use change, evaluating carbon emissions, and assessing the actual and potential impacts to communities. In conjunction with WLE and other partners, SERVIR-Mekong, a regional hub of the USAID and NASA-supported SERVIR program, formulated an explicit procedure to produce this dataset. The procedure includes leveraging data from OpenStreetMap and other sources, creating polygons based on surface water classification procedures achieved via Google Earth Engine, manual digitizing, and modeling of planned/proposed dams based on a DEM and the location and planned height of dams. A quality assurance step ensures that all polygons conform to spatial data quality standards agreed upon by a wide range of production partners. When complete, the dataset will be made publicly available to encourage greater understanding and more informed decisions related to the actual and potential impacts of dams in the region.

  20. Ecological Aspect of Dam Design for Flood Regulation and Sustainable Urban Development

    Directory of Open Access Journals (Sweden)

    Badenko Vladimir

    2016-01-01

    Full Text Available Many floodplains are excluded from urban development because the floods cause considerable damage to people’s lives and properties. This requires the development of new approaches to flood management and mitigation for support sustainable urban development. In present study as the measures for mitigation of flash floods, the regulation of river flow by the system of detention reservoirs for flood diversion with dams, which do not need any operation management, are analyzed concerning of Far East region of Russia. The main objective of this paper is to develop a method for analysis how the dam site selection meets the environmental criterion. The method to justify a selection of self-regulated flood dam parameters, primarily a height of a dam and its location on a water stream, providing minimization of impact on the environment have been developed. The result for Selemdzha river basin in Far East monsoon region of Russian Federation is analyzed. The result shows the robustness of the method.

  1. Critical Quality Source Diagnosis for Dam Concrete Construction Based on Quality Gain-loss Function

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2014-06-01

    Full Text Available In dam concrete construction process, it not only has quality loss arising from quality fluctuation, but also gains quality compensation effect due to the mutual cooperation and adaptation coupling between working procedures (WPs. The calculation and transmission complexity of the quality loss and quality compensation affect the quality management of dam concrete construction. As the quality compensation effect existing in the production practice cannot be described by Taguchi quality loss function, the concept of quality gain-loss function was presented in this paper, which was based on endowing the constant term in the expansion of Taylor series with physical meaning—quality compensation. Based on quality gain-loss function theory, a new quality gain-loss transmission model of dam concrete construction based on GERT network was constructed and its effective algorithm was designed. WP quality gain-loss and its impact on the final product were reasonably measured, and the critical quality routes and critical quality WPs were detected and diagnosed in dam concrete construction network. Summer temperature-controlled concrete construction in the third phase of Three Gorges Project (TGP was taken as an example to carry out the study, and the calculation results showed the validity and practicability of the presented model and algorithm.

  2. Optimizing multiple dam removals under multiple objectives: Linking tributary habitat and the Lake Erie ecosystem

    Science.gov (United States)

    Zheng, Pearl Q.; Hobbs, Benjamin F.; Koonce, Joseph F.

    2009-12-01

    A model is proposed for optimizing the net benefits of removing multiple dams in U.S. watersheds of Lake Erie by quantifying impacts upon social, ecological, and economic objectives of importance to managers and stakeholders. Explicit consideration is given to the linkages between newly accessible tributary habitat and the lake's ecosystem. The model is a mixed integer linear program (MILP) that selects a portfolio of potential dam removals that could achieve the best possible value of a weighted sum of the objective(s), while still satisfying the constraints. Using response functions extracted from the Lake Erie Ecological Model and an empirical cost model, the MILP accounts for ecological and economic effects of habitat changes for both desirable native walleye and undesirable sea lamprey. The solutions show the effect on removal decisions of alternative prioritizations among cost and environmental objectives and the resulting trade-offs among those objectives. The MILP can be used as a screening model to identify portfolios of dam removals that are potentially cost-effective enhancements of habitat and the Lake Erie ecosystem; subsequent site-specific studies would be needed prior to actually removing dams.

  3. Assessing the physical vulnerability of check dams through an empirical damage index

    Directory of Open Access Journals (Sweden)

    Andrea Dell'Agnese

    2013-06-01

    Full Text Available A comprehensive analysis of flood risk in mountain streams has to include an assessment of the vulnerability of the protection systems, in addition to an assessment of the vulnerability of the constructed environment on alluvial fans and floodplains. Structures forming the protection systems are of a dual nature, i.e. they are designed to mitigate natural process-related hazards and, on the other hand, are prone to be damaged during their lifecycle by the same processes they should mitigate. Therefore, their effectiveness declines over time. Hence, the knowledge of how effectively control structures perform is essential for risk management. A procedure was developed to assess the physical vulnerability of check dams based on empirical evidence collected in South Tyrol, Northern Italy. A damage index defined on pre- and postevent comparisons of check dam conditions was evaluated for 362 structures in 18 mountain streams along with the relevant processes and the structural characteristics affecting it. Although the available dataset did not allow conclusive functional relationships between damage index and impact variables to be established, it was possible to assess the average expected residual functionality of check dams according to structure characteristics, and event type and intensity. These results may help plan appropriate check dam maintenance.

  4. The Cotingo Dam as a test of Brazil's system for evaluating proposed developments in Amazonia

    Science.gov (United States)

    Fearnside, Philip M.; Barbosa, Reinaldo Imbrozio

    1996-09-01

    The proposed Cotingo Dam in Brazil's far northern state of Roraima is examined with the objective of drawing lessons for Brazil's system of evaluating environmental, social, and financial consequences of development decisions. The Cotingo Dam illustrates the difficulty of translating into practice the principles of economic and environmental assessment. Examination of the financial arguments for the Cotingo Dam indicates that justifications in this sphere are insufficient to explain why the project is favored over other alternatives and points to political factors as the best explanation of the project's high priority. Strong pressure from political and entrepreneurial interest groups almost invariably dominates decision making in Amazonia. The analysis indicates the inherent tendency of the present system to produce decisions in favor of large construction projects at the expense of the environment and local peoples. The requirements intended to assure proper weight for these concerns, such as the report on environmental impacts (RIMA) and the public hearing, fail to serve this role. Cotingo also provides a test case for constitutional protections restricting construction of dams in indigenous lands.

  5. Relationship of the Ben Franklin Dam Alternative to Water and Land Uses, Plans, Policies, and Controls for the Hanford Reach of the Columbia River.

    Science.gov (United States)

    1980-07-01

    at Hanford ? c) Would the dam introduce hydraulic or seismic problems relevant to underground waste repository siting? An analysis for DOE by C.H...FINAL controls for the Hanford Reach of the Columbia 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(a) S. CONTRACT OR GRANT NUMBER(e) 9. PERFORMING...Identify by block number) A HANFORD REACH LAND USE COLUNBIA RIVER ENVIRONNENTAL IMPACT WASHINGTON (STATE) BEN FRANKLIN DAM SIL AWTNAnW (Oinemu iM Mem

  6. A population growth trend analysis for Neotricula aperta, the snail intermediate host of Schistosoma mekongi, after construction of the Pak-Mun dam.

    Directory of Open Access Journals (Sweden)

    Stephen W Attwood

    2013-11-01

    Full Text Available BACKGROUND: The Pak-Mun dam is a controversial hydro-power project on the Mun River in Northeast Thailand. The dam is sited in a habitat of the freshwater snail Neotricula aperta, which is the intermediate host for the parasitic blood-fluke Schistosoma mekongi causing Mekong schistosomiasis in humans in Cambodia and Laos. Few data are available which can be used to assess the effects of water resource development on N. aperta. The aim of this study was to obtain data and to analyze the possible impact of the dam on N. aperta population growth. METHODOLOGY/PRINCIPAL FINDINGS: Estimated population densities were recorded for an N. aperta population in the Mun River 27 km upstream of Pak-Mun, from 1990 to 2011. The Pak-Mul dam began to operate in 1994. Population growth was modeled using a linear mixed model expression of a modified Gompertz stochastic state-space exponential growth model. The N. aperta population was found to be quite stable, with the estimated growth parameter not significantly different from zero. Nevertheless, some marked changes in snail population density were observed which were coincident with changes in dam operation policy. CONCLUSIONS/SIGNIFICANCE: The study found that there has been no marked increase in N. aperta population growth following operation of the Pak-Mun dam. The analysis did indicate a large and statistically significant increase in population density immediately after the dam came into operation; however, this increase was not persistent. The study has provided the first vital baseline data on N. aperta population behavior near to the Pak-Mun dam and suggests that the operation policy of the dam may have an impact on snail population density. Nevertheless, additional studies are required for other N. aperta populations in the Mun River and for an extended time series, to confirm or refine the findings of this work.

  7. Landfill liners from dam reservoir sediments

    Directory of Open Access Journals (Sweden)

    Koś Karolina

    2016-03-01

    Full Text Available Landfill liners from dam reservoir sediments. Every municipal solid waste landfill has to be properly secured to protect the natural environment from possible leachate. Most often an artificial sealing is used, which is based on a soil liner from cohesive soils (clays, silts. Usability evaluation of bottom sediments from Rzeszowski Reservoir for building these liners was presented in the paper. Sediments from dam reservoirs, gathered as a result of the siltation process, can be a valuable material for earthworks purposes. Determination of their possible ways of usage is important, especially before the planned dredging, because thanks to that this material will not be put on a heap. Based on the analysis of the geotechnical parameters of these sediments it was stated that this material can be preliminary allowed for using in liners.

  8. Augmented Reality to Access Dam Cracks Information

    Directory of Open Access Journals (Sweden)

    Fabiana Frata Furlan Peres

    2016-03-01

    Full Text Available Augmented reality technology is a tool with great potential for application in several areas, including engineering. During the early phases of the enterprise life cycle, as design and construction, augmented reality has been widely used. Concrete dams, during operation and maintenance phase, require regular inspections as part of the necessary activities to keep their structural safety. Cracks are common pathology in these structures that must be detected, mapped and measured as their evolution may evidence structure compromising, need for maintenance or intervention. In this context this paper aims to present a prototype to access in situ the dam cracks information through the use of augmented reality, thus giving a contribution to the effectiveness and efficiency of inspections

  9. Temporal and spatial distribution of dam failure events in China

    Institute of Scientific and Technical Information of China (English)

    X.Y.HE; Z.Y.WANG; J.C.HUANG

    2008-01-01

    Reservoirs play a vital role in economic development and flood control.Nevertheless,both human and natural factors may lead to dam failures with catastrophic consequences.Analyzing the data of dam failure events from 1954 to 2003 and using the method of energy spectrum analysis,this paper studies the periodicity of dam failures.The rate of failure of different dam ages is analyzed.The climate is the main factor affecting the rate of dam failure.Climate diagrams are used to analyze the spatial distribution of dam failure events in China.High rate of dam failure occurs with 25-year and 12.5-year periods.The distribution of the percentage of dam failure shows an L-shape as a function of service age.The first 5 years of operation is known as the "infant period",during which,the probability of dam failure is much higher than during any other periods.The failure rate in areas near or north to the 400 mm annual isopluvial line is notably higher than other areas.In areas with high temperature difference among seasons have a high annual average dam failure rate.

  10. Crack status analysis for concrete dams based on measured entropy

    Institute of Scientific and Technical Information of China (English)

    WU BangBin; WU ZhongRu; CHEN Bo; SU HuaiZhi; BAO TengFei; WANG ShaoWei

    2016-01-01

    The integrity and safety of concrete dams are seriously affected by the existing cracks in dam bodies,and some serious cracks may cause dam failure or disaster.The propagation of cracks in concrete dams is accompanied by changes in energy distribution,which can be represented by changes in the structure's system entropy.Therefore,the entropy theory can be used in analyzing the behavior of dam cracks.Due to the randomness and locality of crack propagation,it is difficult to predict the location of cracks by traditional monitoring methods.To solve this problem,the influence of spatial positions of monitoring points on inspection zones is represented by a weight index,and the weight index is determined by the distance measure method proposed in this paper.Through the weighted linear fusion method,the entropy of multiple monitoring points is obtained for analyzing the behavior of dam cracks in the selected zones.Meanwhile,the catastrophe theory is used as the variation criterion of an entropy sequence in order to predict the instability time of dam cracks.Case studies are put forward on a high arch dam,and the fusion entropy is calculated according to the monitoring data from strain gauges.Results show that the proposed method can effectively predict the occurrence time and location of dam cracks regardless of the layout of monitoring instruments,and it is a new way to analyze the occurrence and propagation of dam cracks.

  11. Dam removal increases American eel abundance in distant headwater streams

    Science.gov (United States)

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  12. Will Dam Removal Increase Nitrogen Flux to Estuaries?

    Directory of Open Access Journals (Sweden)

    Arthur J. Gold

    2016-11-01

    Full Text Available To advance the science of dam removal, analyses of functions and benefits need to be linked to individual dam attributes and effects on downstream receiving waters. We examined 7550 dams in the New England (USA region for possible tradeoffs associated with dam removal. Dam removal often generates improvements for safety or migratory fish passage but might increase nitrogen (N flux and eutrophication in coastal watersheds. We estimated N loading and removal with algorithms using geospatial data on land use, stream flow and hydrography. We focused on dams with reservoirs that increase retention time at specific points of river reaches, creating localized hotspots of elevated N removal. Approximately 2200 dams with reservoirs had potential benefits for N removal based on N loading, retention time and depth. Across stream orders, safety concerns on these N removal dams ranged between 28% and 44%. First order streams constituted the majority of N removal dams (70%, but only 3% of those were classified as high value for fish passage. In cases where dam removal might eliminate N removal function from a particular reservoir, site-specific analyses are warranted to improve N delivery estimates and examine alternatives that retain the reservoir while enhancing fish passage and safety.

  13. Seismic performance evaluation of concrete gravity dams

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Y.; Sasaki, T.; Kanenawa, K. [Public Works Research Institute, Tsukuba City (Japan); Hall, R.; Yule, D. [United States Army Engineer Research and Development Center, Vicksburg, MS (United States); Matheu, E. [Louisiana State Univ., Baton Rouge, LA (United States); Chudgar, A. [United States Army Corps of Engineers, Washington, DC (United States)

    2004-07-01

    This paper addresses technical issues related to seismic design practices and current evaluation methods in Japan and the United States. Nonlinear analysis procedures can identify the ultimate capacity of existing concrete dams, taking into account the most critical nonlinear phenomena controlling the response. A numerical model of a non-overflow monolith of Koyna Dam, subject to earthquake motion, is used as a case study to compare the different approaches for seismic evaluation of concrete gravity dams currently employed in the two countries. The complexity of nonlinear analysis procedures and the scarcity of appropriate calibration strategies force analysts to frequently interpret results using their own judgment. It was concluded that the influence of the input parameters and ground excitation on the nonlinear dynamic response should be investigated in order to identify the most critical conditions. It was also suggested that methodologies for qualitative damage estimation based on results from linear analyses could be used to develop a systematic assessment tool and reference framework for the adequate interpretation of results. 14 refs., 2 tabs., 13 figs.

  14. Malaria and water resource development: the case of Gilgel-Gibe hydroelectric dam in Ethiopia

    Directory of Open Access Journals (Sweden)

    Kloos Helmut

    2009-01-01

    significant (OR = 2.40, 95% CI = 0.84, 6.88. A classification tree revealed insights in the importance of the dam as a risk factor for malaria. Assuming that the relationship between the dam and malaria is causal, 43% of the malaria occurring in children was due to living in close proximity to the dam. Conclusion This study indicates that children living in close proximity to a man-made reservoir in Ethiopia are at higher risk of malaria compared to those living farther away. It is recommended that sound prevention and control programme be designed and implemented around the reservoir to reduce the prevalence of malaria. In this respect, in localities near large dams, health impact assessment through periodic survey of potential vectors and periodic medical screening is warranted. Moreover, strategies to mitigate predicted negative health outcomes should be integral parts in the preparation, construction and operational phases of future water resource development and management projects.

  15. Book Review: Dams, displacement, and the delusion of development: Cahora Bassa and its legacies in Mozambique, 1965–2007

    CSIR Research Space (South Africa)

    Meissner, Richard

    2015-10-01

    Full Text Available Allen and Barbara Isaacman give a sobering account of the consequences of large dams on people living in such a project's immediate vicinity and further afield. The authors focus not only on the impacts on people, but also the social...

  16. Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake

    Directory of Open Access Journals (Sweden)

    X. Fan

    2012-10-01

    Full Text Available Floods from failures of landslide dams can pose a hazard to people and property downstream, which have to be rapidly assessed and mitigated in order to reduce the potential risk. The Tangjiashan landslide dam induced by the Mw = 7.9 2008 Wenchuan earthquake had impounded the largest lake in the earthquake affected area with an estimated volume of 3 × 108 m3, and the potential catastrophic dam breach posed a serious threat to more than 2.5 million people in downstream towns and Mianyang city, located 85 km downstream. Chinese authorities had to evacuate parts of the city until the Tangjiashan landslide dam was artificially breached by a spillway, and the lake was drained. We propose an integrated approach to simulate the dam-breach floods for a number of possible scenarios, to evaluate the severity of the threat to Mianyang city. Firstly, the physically-based BREACH model was applied to predict the flood hydrographs at the dam location, which were calibrated with observational data of the flood resulting from the artificial breaching. The output hydrographs from this model were inputted into the 1-D–2-D SOBEK hydrodynamic model to simulate the spatial variations in flood parameters. The simulated flood hydrograph, peak discharge and peak arrival time at the downstream towns fit the observations. Thus this approach is capable of providing reliable predictions for the decision makers to determine the mitigation plans. The sensitivity analysis of the BREACH model input parameters reveals that the average grain size, the unit weight and porosity of the dam materials are the most sensitive parameters. The variability of the dam material properties causes a large uncertainty in the estimation of the peak flood discharge and peak arrival time, but has little influence on the flood inundation area and flood depth downstream. The effect of cascading breaches of smaller dams downstream of the Tangjiashan dam was

  17. Do Hydroelectric Dams Mitigate Global Warming? The Case of Brazil's Curuna Dam

    Energy Technology Data Exchange (ETDEWEB)

    Fearnside, P.M. [National Institute for Research in the Amazon (INPA), C.P. 478, 69011-970 Manaus, Amazonas (Brazil)

    2005-10-15

    Hydroelectric dams in tropical forest areas emit greenhouse gases, as illustrated by the Curuna dam in the Amazonian portion of Brazil. Emissions include carbon dioxide from decay of the above-water portions of trees that are left standing in the reservoir and methane from soft vegetation that decays under anaerobic conditions on the bottom of the reservoir, especially macrophytes (water weeds) and vegetation that grows in the drawdown zone and is flooded when the reservoir water level rises. Some methane is released from the reservoir surface through bubbling and diffusion, but larger amounts are released from water passing through the turbines and spillway. Methane concentration in the water increases with depth, and the turbines and spillway draw water from sufficient depth to have substantial methane content. In 1990 (13 years after filling), the Curuna Dam emitted 3.6 times more greenhouse gases than would have been emitted by generating the same amount of electricity from oil.

  18. Assessment model of dam operation risk based on monitoring data

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Although the dams produce remarkable social and economic benefits,the threat made by unsafe dams to the life and property of people who live in the lower river area is un-negligible.Based on the monitoring data which reflect the safety condition of dams,the risk degree concept is proposed and the analysis system and model for evaluating risk degree (rate) are established in this paper by combining the reliability theory and field monitoring data.The analysis method for risk degree is presented based on Bayesian approach.A five-grade risk degree system for dam operation risk and corresponding risk degree is put forward according to the safety condition of dams.The operation risks of four cascade dams on some river are analyzed by the model and approach presented here and the result is adopted by the owner.

  19. Geomorphic and Salmon Habitat Response to Dam Removal with Minimal Constraints to Channel Evolution, Wa'atch Creek, Western Washington, U.S.A

    Science.gov (United States)

    Ritchie, A. C.; Shellberg, J. G.

    2010-12-01

    Dam removal has become an important component of aquatic ecosystem restoration, but studies documenting the physical and ecological response to dam removal across a range of human modified hydroclimatic and physiographic settings are still lacking. This research documents channel geomorphic response and fine sediment storage in salmon spawning gravels after removing two derelict dams (largest 6m) from Wa’atch Creek, located in the temperate coastal-marine zone of the Pacific Northwest, USA. After removing dam sheet pile and earthen fill, natural river processes including sediment flushing were allowed occur. Technical engineering solutions were avoided, unlike comparably sized dam removals in western Washington that over-engineered channel stability. However, two-hundred large-logs (LWD) were placed unanchored below the dam sites and throughout the reservoir before drawdown to sort and store sediment and provide future habitat complexity. Initial sedimentation impacts were severe following dam removal, temporarily smothering the bed of the creek with a fine sediment slurry (fluid mud) from dam to delta, killing aquatic biota, and covering spawning gravels with inhospitable levels of fine sediment. Subsequently, several large floods within the first year (max 10-yr recurrence interval) flushed the channel sediment slurry and over half (11,000 m^3) of the fine sediment stored in the reservoir out to sea. Coarse sediment aggraded immediately below the dam where wood was placed in the channel, while channel incision occurred through the reservoir and into tributaries, both diminishing away from the disturbance center. Channel changes were greatest immediately following removal due to high stream power, steep energy slope and saturated unconsolidated alluvium. The rate of change in sediment volume diminished over time (2003 to 2008) due to sediment consolidation, vegetation colonization, and a reduction in energy slope. After reservoir and channel flushing, fine

  20. Passage and survival probabilities of juvenile Chinook salmon at Cougar Dam, Oregon, 2012

    Science.gov (United States)

    Beeman, John W.; Evans, Scott D.; Haner, Philip V.; Hansel, Hal C.; Hansen, Amy C.; Smith, Collin D.; Sprando, Jamie M.

    2014-01-01

    This report describes studies of juvenile-salmon dam passage and apparent survival at Cougar Dam, Oregon, during two operating conditions in 2012. Cougar Dam is a 158-meter tall rock-fill dam used primarily for flood control, and passes water through a temperature control tower to either a powerhouse penstock or to a regulating outlet (RO). The temperature control tower has moveable weir gates to enable water of different elevations and temperatures to be drawn through the dam to control water temperatures downstream. A series of studies of downstream dam passage of juvenile salmonids were begun after the National Oceanic and Atmospheric Administration determined that Cougar Dam was impacting the viability of anadromous fish stocks. The primary objectives of the studies described in this report were to estimate the route-specific fish passage probabilities at the dam and to estimate the survival probabilities of fish passing through the RO. The first set of dam operating conditions, studied in November, consisted of (1) a mean reservoir elevation of 1,589 feet, (2) water entering the temperature control tower through the weir gates, (3) most water routed through the turbines during the day and through the RO during the night, and (4) mean RO gate openings of 1.2 feet during the day and 3.2 feet during the night. The second set of dam operating conditions, studied in December, consisted of (1) a mean reservoir elevation of 1,507 ft, (2) water entering the temperature control tower through the RO bypass, (3) all water passing through the RO, and (4) mean RO gate openings of 7.3 feet during the day and 7.5 feet during the night. The studies were based on juvenile Chinook salmon (Oncorhynchus tshawytscha) surgically implanted with radio transmitters and passive integrated transponder (PIT) tags. Inferences about general dam passage percentage and timing of volitional migrants were based on surface-acclimated fish released in the reservoir. Dam passage and apparent

  1. Contaminated Sediment Management in Dam Removals and River Restoration Efforts: Critical Need for Research and Policy Development

    Science.gov (United States)

    Evans, J. E.

    2015-12-01

    Over 1,000 U.S. dams have been removed (1975-2015) for reasons including obsolescence, liability concerns, water quality upgrades, fisheries, or ecosystem enhancements. Contaminated sediment can significantly complicate the approval process, cost, and timeline of a dam removal, or stop it entirely. In a dam removal, reservoir sediment changes from a sink to a source of contaminants. Recently, the Sierra Club sued to stop the removal of a large dam in Ohio because of the potential impact of phosphate releases on toxic algal blooms in Lake Erie. Heavy metals, PCBs, PAHs, pesticides, and petroleum hydrocarbons can be present in reservoir sediments. In a non-dam removal scenario, reservoir management tools range from "no action" to dredging, dewatering and removal, or sediment capping. But it is not clear how these reservoir management techniques apply to dam removals. Case studies show typically >80% of the reservoir sediment is eventually eroded, precluding sediment capping as a containment option. However, the released contaminants are diluted by mixing with "clean" sediment and are transported to different physio-chemical environments which may immobilize or biodegrade the contaminants. Poorly understood options include phased drawdown/reseeding the former reservoir to contain sediments, diking contaminant "hot spots," and addressing contaminant stratigraphy (where historical use created "hot layers" in the reservoir sediment). Research and policy development needs include: (1) assessment methods based on synergistic effects of multiple contaminants being present; (2) ways to translate the pre-removal contaminant concentrations to post-removal health risks downstream; (3) evaluation of management practices for contaminant "hot spots" and "hot layers;" (4) tools to forecast the presence of contaminated sediment using easily accessible information; and (5) ways to limit liability risk for organizations participating in dam removals involving contaminated sediment.

  2. Predicting surfacing internal erosion in moraine core dams

    OpenAIRE

    2010-01-01

    Dams that comprise broadly and widely graded glacial materials, such as moraines, have been found to be susceptible to internal erosion, perhaps more than dams of other soil types. Internal erosion washes out fine-grained particles from the filling material; the erosion occurs within the material itself or at an interface to another dam zone, depending on the mode of initiation. Whether or not internal erosion proceeds depend on the adequacy of the filter material. If internal erosion is allo...

  3. Annual glacier dammed lake drainage in Zackenberg, Northeast Greenland

    Science.gov (United States)

    Lane, Timothy; Adamson, Kathryn; Matthews, Tom

    2016-04-01

    A.P. Olsen is a 295 km2 ice cap in the Zackenberg region of Northeast Greenland (74.6° N, 21.5° W), 35 km from the ZERO Zackenberg Research Station. The ice cap lies on a gneissic plateau, covering an elevation of 200 to 1450 m a.s.l. A.P. Olsen mass balance has been monitored since 2008 and reconstructed for the period 1995-2007. Meltwater from this ice cap drains into the Zackenberg River, and into Young Sund via the Zackenberg Delta. One outlet dams a c. 0.8 km2 lake fed by the northern part of the ice cap. Observational data suggests this lake drains annually, flooding subglacially into the Zackenberg River. But the impacts of these flood events on the hydrology, sediment transfer, and geomorphology of the proglacial zone downstream have not been examined in detail. Understanding the impacts of glacial lake outburst flood events is important in the sensitive Arctic environment, where glacial change is rapid. We use Landsat scenes to reconstruct lake extent from 1999-2015. This is compared to Zackenberg River discharge measurements, available from the ZERO Zackenberg monitoring programme. These datasets are used to examine the nature and timing of flood events, and assess the impacts on the Zackenberg river downstream.

  4. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    Science.gov (United States)

    Benchimol, Maíra; Peres, Carlos A

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

  5. Stochastic Boundary Element Analysis of Concrete Gravity Dam

    Institute of Scientific and Technical Information of China (English)

    张明; 吴清高

    2002-01-01

    Stochastic boundary integral equations for analyzing large structures are obtained from the partial derivatives of basic random variables. A stochastic boundary element method based on the equations is developed to solve engineering problems of gravity dams using random factors including material parameters of the dam body and the foundation, the water level in the upper reaches, the anti-slide friction coefficient of the dam base, etc. A numerical example shows that the stochastic boundary element method presented in this paper to calculate the reliability index of large construction projects such as a large concrete gravity dam has the advantages of less input data and more precise computational results.

  6. Comment on ‘An index-based framework for assessing patterns and trends in river fragmentation and flow regulation by global dams at multiple scales’

    Science.gov (United States)

    Hennig, Thomas; Magee, Darrin

    2017-03-01

    In their article ‘An index-based framework for assessing patterns and trends in river fragmentation and flow regulation by global dams at multiple scales’ (2015 Environ. Res. Lett. 10 015001), Grill et al utilized a graph-based river routing model to simultaneously assess flow regulation and fragmentation by dams at multiple scales. Using global dam data they developed the river fragmentation index and the river regulation index, both based on river volume. Their results indicate that, on a global basis, 48% of river volume is moderately to severely impacted by either flow regulation, fragmentation, or both. Assuming completion of all dams planned and under construction in their future scenario, Grill et al find this number would rise to 93%, an effect they attribute largely to dam construction in the Amazon Basin. They also provide evidence for the importance of considering small- to medium-sized dams. We find this approach interesting and the analysis straightforward, but in this response note some limitations to the Asia-specific data on which the analysis is based. China and India are not only the two most populous countries, but are home to the vast majority of the world’s largest dams and reservoirs, numbers which will rapidly increase in the future. Grill et al however, limit their modeling and subsequent basin assessment (flow regulation and river fragmentation) to less than ten percent of existing and forthcoming dams in those two countries. While we suspect this is due to data limitations, it results in what we feel are significant misinterpretations of the future of dams and rivers across much of Asia.

  7. Application of the contingent valuation method in a developing country: a case study of the Yusufeli dam in northeast Turkey.

    Science.gov (United States)

    Alp, Emre; Yetiş, Ulkü

    2010-01-01

    Hydroelectric power plants and dams often play an important role in developing countries in terms of their contribution to economy. In accordance with the energy policies of Turkish Republic, Yusufeli Dam and Hydroelectric Power Plant in Northeastern Turkey have been initiated. In this study, the Contingent Valuation Method (CVM) was conducted in Yusufeli Village to determine the environmental costs of the Yusufeli Project. The purpose is to assess the willingness to pay (WTP) of Yusufeli Village residents for restoration of the environmental impacts of the dam project and also to investigate the underlying economic, psychological, and social motivations for WTP. WTP was calculated as US$761 per person which can further be used in the cost-benefit analysis. The results from the study suggest that application of the CVM in rural and urban areas located in the same region can show differences.

  8. Signatures of self-assembly in size distributions of wood members in dam structures of Castor canadensis

    Directory of Open Access Journals (Sweden)

    David M. Blersch

    2014-12-01

    Full Text Available Beavers (Castor canadensis construct dams on rivers throughout most of their historical range in North America, and their impact on water patterns in the landscape is considerable. Dam formation by beavers involves two processes: (1 intentional construction through the selection and placement of wood and sediment, which facilitates (2 the passive capture and accretion of suspended wood and sediment. The second process is a self-assembly mechanism that the beavers leverage by utilizing energy subsidies of watershed transport processes. The relative proportion of beaver activity to self-assembly processes in dam construction, however, is unknown. Here we show that lotic self-assembly processes account for a substantial portion of the work expended in beaver dam construction. We found through comprehensive measurement of the stick dimensions that the distributions for diameter, length, and volume are log-normal. By noting evidence of teeth markings, we determined that size distributions skewed significantly larger for wood handled by beavers compared to those that were not. Subsequent mass calculations suggest that beavers perform 50%–70% of the work of wood member placement for dam assembly, with riparian self-assembly processes contributing the remainder. Additionally, our results establish a benchmark for assessing the proportion of self-assembly work in similar riparian structures.

  9. Dam operations affect route-specific passage and survival of juvenile Chinook salmon at a main-stem diversion dam

    Science.gov (United States)

    Perry, Russell W.; Kock, Tobias J.; Couter, Ian I; Garrison, Thomas M; Hubble, Joel D; Child, David B

    2016-01-01

    Diversion dams can negatively affect emigrating juvenile salmon populations because fish must pass through the impounded river created by the dam, negotiate a passage route at the dam and then emigrate through a riverine reach that has been affected by reduced river discharge. To quantify the effects of a main-stem diversion dam on juvenile Chinook salmon in the Yakima River, Washington, USA, we used radio telemetry to understand how dam operations and river discharge in the 18-km reach downstream of the dam affected route-specific passage and survival. We found evidence of direct mortality associated with dam passage and indirect mortality associated with migration through the reach below the dam. Survival of fish passing over a surface spill gate (the west gate) was positively related to river discharge, and survival was similar for fish released below the dam, suggesting that passage via this route caused little additional mortality. However, survival of fish that passed under a sub-surface spill gate (the east gate) was considerably lower than survival of fish released downstream of the dam, with the difference in survival decreasing as river discharge increased. The probability of fish passing the dam via three available routes was strongly influenced by dam operations, with passage through the juvenile fish bypass and the east gate increasing with discharge through those routes. By simulating daily passage and route-specific survival, we show that variation in total survival is driven by river discharge and moderated by the proportion of fish passing through low-survival or high-survival passage routes.

  10. 1000 years of valley bottom damming on low order streams in Central Europe and the record of landscape change

    Science.gov (United States)

    Larsen, A.; Bork, H.; Larsen, J.

    2013-12-01

    Historic dams of mostly unknown ages are a widespread feature within low (1st to 3rd) order streams in central Germany. Within many of these catchments, floodplain compilation studies have found increases in aggradation rates during medieval times, suggesting this was due to deforestation and agricultural land use causing widespread slope instability. However, this process only explains the delivery of sediment to these rivers, and we suggest that the construction of valley bottom dams was also critical to this process through the effective trapping of the increased sediment. Dams were built for multiple purposes from the beginning of human occupation in central Europe, culminating in very high dam densities of many ages and levels of operation. Dam construction probably peaked first during medieval times and again around 1830 AD, when new methods of river engineering were introduced. Preliminary results show an increased floodplain sedimentation rate at ~ 900 AD, which coincides with the earliest written sources from the area and represents the onset of human impact on riverscapes. As a result of these impacts on the flow regime and sediment load, some rivers experienced morphological changes and shifted from multithread to meandering. This is most pronounced where rapid floodplain sedimentation buried wetland soils, therefore altering both river morphology and ecosystem function. In order to test what role dams have played in morphological change and floodplain aggradation, we compiled historic maps and high resolution Lidar data for backwater modelling. In addition, extensive field and lab data are used to check the stratigraphy and age of the alluvial sequences.

  11. Balancing Energy, Food Security, and Critical Ecosystems: Dam Siting, Design and Operations in the Mekong River Basin

    Science.gov (United States)

    Wild, T. B.; Reed, P. M.; Loucks, D.

    2016-12-01

    The Mekong River basin in Southeast Asia is one of several river basins with exceptionally high biodiversity value where intensive hydropower dam development is anticipated. In the Mekong basin, over 100 dams are planned to be constructed in the next 20-30 years. As planned, these dams will alter the river's natural water, sediment and nutrient flows, and will fragment fish migration pathways. In doing so, they will degrade one of the world's most productive freshwater fish habitats, upon which some 60 million people depend for food and income security. For those dams that have not yet been constructed, there still exist opportunities to modify their siting, design and operation (SDO) to achieve a more balanced set of tradeoffs among hydropower production, sediment/nutrient passage and adult fish/larvae passage. We present a successful case study wherein we explored such alternative SDO opportunities in partnership with the Government of Cambodia for Sambor Dam, planned to be built on the main stem of the Mekong. Sambor would be one of the world's longest dams, spanning 18 km across the river just upstream of (1) Tonle Sap Lake, which supplies 70% of Cambodians' protein, and (2) the Mekong Delta in Vietnam, responsible for 50% of Vietnam's rice production. We will describe key dam siting and design modifications required to mitigate ecological impacts. We will then focus on the most promising alternative dam siting/design concept, exploring the reservoir operations space to demonstrate that a complex set of tradeoffs exist among a diverse set of energy and ecosystem objectives. Results indicate that even for a hydrologically small reservoir, a wide array of potential reservoir operating policies exist that have vastly different food-energy implications. While some policies would significantly mitigate ecological impacts, many policies exist that would pose a severe threat to the sustainability of the fishery. Failure to sample the reservoir operations space at

  12. Monitoring health in African dams : the Kamburu dam (Kenya) as a test case

    NARCIS (Netherlands)

    J.M.V. Oomen

    1981-01-01

    textabstractDams are among the obvious efforts to improve the economic situation in a developing country. They aim at using locally available natural resources. At present they are among the most popular means for promoting socio-economic development. A significant number of these programmes have be

  13. Advanced numerical simulation of collapsible earth dams

    Energy Technology Data Exchange (ETDEWEB)

    De Farias, M.M.; Cordao Neto, M.P. [Brasilia Univ., Federal District (Brazil). Dept. of Civil and Environmental Engineering

    2010-12-15

    This paper discussed a systematic methodology for the hydromechanical coupled numerical analysis of earth dams constructed with unsaturated collapsible soil. Every design stage was considered, including construction, reservoir filling, and advance of saturation front until the steady-state flow condition is attained. A transient analysis of safety factors applicable to 3-dimensional conditions was presented, giving consideration to unsaturated materials and the interrelation between hydraulic and mechanical phenomena by solving equilibrium and continuity conditions at the same time. The finite element method was used to formulate equilibrium and continuity conditions for both soil skeleton and pore water, which necessitated a realistic mechanical model for the stress-strain-suction relation in unsaturated porous material and adequate constitutive models related to water flow and storage, giving special consideration to imposing appropriate boundary conditions for each simulation stage. The methodology was applied to the analysis of earth dams composed of soils at optimum, dry of optimum, and mixed compaction conditions. The dry section simulated dams constructed using poorly compacted, dry material, which are prone to collapse. By strategically placing the optimum materials in the areas of the earth fill that are most stressed, the mixed section could be designed less expensively with the same or better performance as the homogenous section at optimum conditions. The coupled analysis provides a higher safety factor than uncoupled analysis and a realistic picture of end-of-construction pore pressure distribution. The simulation of reservoir filling and saturation front advance permitted clear identification of the initialization, development, and evolution of internal failure mechanisms. 21 refs., 6 tabs., 19 figs.

  14. Examining global electricity supply vulnerability to climate change using a high-fidelity hydropower dam model.

    Science.gov (United States)

    Turner, Sean W D; Ng, Jia Yi; Galelli, Stefano

    2017-07-15

    An important and plausible impact of a changing global climate is altered power generation from hydroelectric dams. Here we project 21st century global hydropower production by forcing a coupled, global hydrological and dam model with three General Circulation Model (GCM) projections run under two emissions scenarios. Dams are simulated using a detailed model that accounts for plant specifications, storage dynamics, reservoir bathymetry and realistic, optimized operations. We show that the inclusion of these features can have a non-trivial effect on the simulated response of hydropower production to changes in climate. Simulation results highlight substantial uncertainty in the direction of change in globally aggregated hydropower production (~-5 to +5% change in mean global production by the 2080s under a high emissions scenario, depending on GCM). Several clearly impacted hotspots are identified, the most prominent of which encompasses the Mediterranean countries in southern Europe, northern Africa and the Middle East. In this region, hydropower production is projected to be reduced by approximately 40% on average by the end of the century under a high emissions scenario. After accounting for each country's dependence on hydropower for meeting its current electricity demands, the Balkans countries emerge as the most vulnerable (~5-20% loss in total national electricity generation depending on country). On the flipside, a handful of countries in Scandinavia and central Asia are projected to reap a significant increase in total electrical production (~5-15%) without investing in new power generation facilities. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Quasi-stable Slope-Failure Dams in High Asia

    Science.gov (United States)

    Shroder, J. F.

    2010-12-01

    Collapses of steep mountain slopes in the Himalaya, Karakoram, Pamir, Hindu Kush, and Tibetan Plateau are well known as a result of:(1) generally high seismicity in active tectonic areas; (2) prior deglaciation leaving undercut, unstable cliffs; (3) present-day debuttressing of rock cliffs by glacial down-wasting in conditions of global warming; and (4) degradation of permafrost cohesion and water-ice cementation in high mountain slopes. Landslide dams across mountain rivers are also well known worldwide and generally do not endure for long because of the common landslide-lake outburst floods (LLOF) whose discharge is commonly sufficiently large to remove much of the dam in a short time. A number of massive slope-failure dams in south High Asia, however, have endured for centuries and require explanations for the length of duration, whereas recent examples require robust assessment for better predictive hazard analysis. Three main factors contribute to longevity of slope-failure dams: (1) mega-rocks >15-30 m that inhibit dam failure in overflow breaches; (2) mega-porosity wherein incoming discharge to the landslide lake is balanced by subterranean water through-flow within the landslide dam; (3) impermeable clay fills caused by remobilization of prior lacustrine-dammed sediment that impart dam strength to allow lasting integrity for a time, and (4) climate-change induced lake-level lowering. Several examples of long-lived or unusually stable, slope-failure dams associated with pronounced structural/tectonic associations include: (1) Pangong Tso, Ladakh and Tibet; (2) Lake Shewa, Afghanistan; (3) Sarez Lake, Tajikistan; and (4) Lake Hunza, Pakistan. Pangong Tso and Lake Shewa were emplaced thousands of years ago and only Lake Shewa shows some instability of the dam front where percolating water maintains lake level but may be causing new slumping. Sarez Lake behind the Usoi landslide dam was emplaced by an earthquake in 1911 and maintains its level by seepage. Lake

  16. Earthquake safety assessment of concrete arch and gravity dams

    Institute of Scientific and Technical Information of China (English)

    Lin Gao; Hu Zhiqiang

    2005-01-01

    Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

  17. Minimum Reservoir Water Level in Hydropower Dams

    Science.gov (United States)

    Sarkardeh, Hamed

    2017-07-01

    Vortex formation over the intakes is an undesirable phenomenon within the water withdrawal process from a dam reservoir. Calculating the minimum operating water level in power intakes by empirical equations is not a safe way and sometimes contains some errors. Therefore, current method to calculate the critical submergence of a power intake is construction of a scaled physical model in parallel with numerical model. In this research some proposed empirical relations for prediction of submergence depth in power intakes were validated with experimental data of different physical and numerical models of power intakes. Results showed that, equations which involved the geometry of intake have better correspondence with the experimental and numerical data.

  18. Hovercraft drill probes Saraji tailings dam

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    In early operations at BHP-Utah's Saraji Mine in central Queensland, quantities of coking coal were pumped into the tailings dam because the preparation plant's flotation circuit was unable to handle ultra-fines. A reverse circulating drilling rig mounted on a hovercraft was used to recover 22 samples (representing 9 metres of tailings from 11 x 8 x 0.09 metre cores) in an investigation into whether the tailings can now be treated economically. 1 fig.

  19. Large-scale projects in the amazon and human exposure to mercury: The case-study of the Tucuruí Dam.

    Science.gov (United States)

    Arrifano, Gabriela P F; Martín-Doimeadios, Rosa C Rodríguez; Jiménez-Moreno, María; Ramírez-Mateos, Vanesa; da Silva, Núbia F S; Souza-Monteiro, José Rogério; Augusto-Oliveira, Marcus; Paraense, Ricardo S O; Macchi, Barbarella M; do Nascimento, José Luiz M; Crespo-Lopez, Maria Elena

    2017-08-28

    The Tucuruí Dam is one of the largest dams ever built in the Amazon. The area is not highly influenced by gold mining as a source of mercury contamination. Still, we recently noted that one of the most consumed fishes (Cichla sp.) is possibly contaminated with methylmercury. Therefore, this work evaluated the mercury content in the human population living near the Tucuruí Dam. Strict exclusion/inclusion criteria were applied for the selection of participants avoiding those with altered hepatic and/or renal functions. Methylmercury and total mercury contents were analyzed in hair samples. The median level of total mercury in hair was above the safe limit (10µg/g) recommended by the World Health Organization, with values up to 75µg/g (about 90% as methylmercury). A large percentage of the participants (57% and 30%) showed high concentrations of total mercury (≥ 10µg/g and ≥ 20µg/g, respectively), with a median value of 12.0µg/g. These are among the highest concentrations ever detected in populations living near Amazonian dams. Interestingly, the concentrations are relatively higher than those currently shown for human populations highly influenced by gold mining areas. Although additional studies are needed to confirm the possible biomagnification and bioaccumulation of mercury by the dams in the Amazon, our data already support the importance of adequate impact studies and continuous monitoring. More than 400 hydropower dams are operational or under construction in the Amazon, and an additional 334 dams are presently planned/proposed. Continuous monitoring of the populations will assist in the development of prevention strategies and government actions to face the problem of the impacts caused by the dams. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Simulating the effects of a beaver dam on regional groundwater flow through a wetland

    Directory of Open Access Journals (Sweden)

    Kathleen Feiner

    2015-09-01

    New hydrological insights for the region: The construction of a beaver dam resulted in minimal changes to regional groundwater flow paths at this site, which is attributed to a clay unit underlying the peat, disconnecting this wetland from regional groundwater flow. However, groundwater discharge from the wetland pond increased by 90%. Simulating a scenario with the numerical model in which the wetland is connected to regional groundwater flow results in a much larger impact on flow paths. In the absence of the clay layer, the simulated construction of a beaver dam causes a 70% increase in groundwater discharge from the wetland pond and increases the surface area of both the capture zone and the discharge zone by 30% and 80%, respectively.

  1. mpacts of Agricultural Non-point Pollution on Water-source Area in Songhua Dam

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    [Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source region. [Method] Water in Muyang River, lengshui River and Zizania aquatica region were sampled to measure content of pollutants in water and conclude relation between water contamination and agri- cultural non-point pollution to find the major cause of pollution. [Result] Organic pollu- tant in Muyang River was higher; N and P contents in Lengshui River were higher; the measured indices in Zizania aquatica region excessively exceeded related stan- dard. [Conclusion] The chemical fertilizers and pesticides are the toxic materials lead- ing to water contamination and constitute a major cause of pollution in Songhua Dam water-source region. Agricultural non-point pollution should be controlled in a scientific way.

  2. A New Approach for Structural Monitoring of Large Dams with a Three-Dimensional Laser Scanner

    Directory of Open Access Journals (Sweden)

    José Sánchez

    2008-09-01

    Full Text Available Driven by progress in sensor technology, computer methods and data processing capabilities, 3D laser scanning has found a wide range of new application fields in recent years. Particularly, monitoring the static and dynamic behaviour of large dams has always been a topic of great importance, due to the impact these structures have on the whole landscape where they are built. The main goal of this paper is to show the relevance and novelty of the laserscanning methodology developed, which incorporates different statistical and modelling approaches not considered until now. As a result, the methods proposed in this paper have provided the measurement and monitoring of the large “Las Cogotas” dam (Avila, Spain.

  3. Thermal effects of dams in the Willamette River basin, Oregon

    Science.gov (United States)

    Rounds, Stewart A.

    2010-01-01

    Methods were developed to assess the effects of dams on streamflow and water temperature in the Willamette River and its major tributaries. These methods were used to estimate the flows and temperatures that would occur at 14 dam sites in the absence of upstream dams, and river models were applied to simulate downstream flows and temperatures under a no-dams scenario. The dams selected for this study include 13 dams built and operated by the U.S. Army Corps of Engineers (USACE) as part of the Willamette Project, and 1 dam on the Clackamas River owned and operated by Portland General Electric (PGE). Streamflows in the absence of upstream dams for 2001-02 were estimated for USACE sites on the basis of measured releases, changes in reservoir storage, a correction for evaporative losses, and an accounting of flow effects from upstream dams. For the PGE dam, no-project streamflows were derived from a previous modeling effort that was part of a dam-relicensing process. Without-dam streamflows were characterized by higher peak flows in winter and spring and much lower flows in late summer, as compared to with-dam measured flows. Without-dam water temperatures were estimated from measured temperatures upstream of the reservoirs (the USACE sites) or derived from no-project model results (the PGE site). When using upstream data to estimate without-dam temperatures at dam sites, a typical downstream warming rate based on historical data and downstream river models was applied over the distance from the measurement point to the dam site, but only for conditions when the temperature data indicated that warming might be expected. Regressions with measured temperatures from nearby or similar sites were used to extend the without-dam temperature estimates to the entire 2001-02 time period. Without-dam temperature estimates were characterized by a more natural seasonal pattern, with a maximum in July or August, in contrast to the measured patterns at many of the tall dam sites

  4. 阿魏酸对兔受损窦房结细胞骨架F-actin、Vinculin的影响%Impacts of Ferulic Acid in F-actin and Vinculin of Cytoskeleton in Dam-aged Atrionector of Rabbits

    Institute of Scientific and Technical Information of China (English)

    刘如秀; 彭杰; 刘宇; 刘金凤; 汪艳丽

    2015-01-01

    目的:观察阿魏酸对模拟缺血再灌注损伤兔窦房结细胞骨架蛋白F-actin和Vinculin的影响,探讨其保护窦房结细胞的机制。方法取新生乳兔窦房结细胞,以缺氧缺糖模拟缺血,以恢复氧和糖的供应模拟再灌注造成窦房结细胞损伤模型。正常对照组与模型组给予等体积培养基,阿魏酸高、中、低剂量组分别给予相应浓度药物(终浓度分别为100μmol/ml、20μmol/ml、10μmol/ml),运用酶标仪、激光共聚焦显微镜观察各组窦房结细胞活性、细胞骨架蛋白F-actin和Vinculin形态的变化。结果模型组活细胞量较正常对照组明显减少(P<0.01);细胞骨架蛋白F-actin和Vinculin裂解明显。阿魏酸高、中、低剂量组活细胞量明显高于模型组(P<0.01),F-actin和Vinculin结构较模型组明显完整,平均荧光强度明显高于模型组( P<0.01)。结论阿魏酸可抑制模拟缺血再灌注引起的窦房结细胞损伤;阿魏酸保护窦房结细胞的机制可能与保护细胞骨架蛋白F-actin和Vinculin从而维持细胞电生理稳定有关。%Objective To observe the impact of ferulic acid in F-actin and Vinculin of cytoskele-ton in the rabbits with damaged atrionector of ischemic reperfusion and explore its protective mechanism on atrionector cells. Methods The atrionector cells of newly born rabbits were collected. The ischemia was sim-ulated with deprivation of oxygen and glucose. The reperfusion was simulated with recovery of oxygen and glu-cose. The same volume medium was used in the normal control group and the model group. The medicine of corresponding concentrations was used in ferulic acid high dose group,middle dose group and low dose group ( the final concentration was 100 μmol/ml,20 μmol/ml or 10 μmol/ml). ELIASA and laser scanning confo-cal microscope were used to observe the changes of atrionector cell activity and F-actin and Vinculin of cy-toskeleton. Results The

  5. Dynamic decision making for dam-break emergency management – Part 2: Application to Tangjiashan landslide dam failure

    Directory of Open Access Journals (Sweden)

    M. Peng

    2013-02-01

    Full Text Available Tangjiashan landslide dam, which was triggered by the Ms = 8.0 Wenchuan earthquake in 2008 in China, threatened 1.2 million people downstream of the dam. All people in Beichuan Town 3.5 km downstream of the dam and 197 thousand people in Mianyang City 85 km downstream of the dam were evacuated 10 days before the breaching of the dam. Making such an important decision under uncertainty was difficult. This paper applied a dynamic decision-making framework for dam-break emergency management (DYDEM to help rational decision in the emergency management of the Tangjiashan landslide dam. Three stages are identified with different levels of hydrological, geological and social-economic information along the timeline of the landslide dam failure event. The probability of dam failure is taken as a time series. The dam breaching parameters are predicted with a set of empirical models in stage 1 when no soil property information is known, and a physical model in stages 2 and 3 when knowledge of soil properties has been obtained. The flood routing downstream of the dam in these three stages is analyzed to evaluate the population at risk (PAR. The flood consequences, including evacuation costs, flood damage and monetized loss of life, are evaluated as functions of warning time using a human risk analysis model based on Bayesian networks. Finally, dynamic decision analysis is conducted to find the optimal time to evacuate the population at risk with minimum total loss in each of these three stages.

  6. Major Dams of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands. The map layer was created by extracting dams 50 feet or...

  7. Numerical Modeling of Sliding Stability of RCC dam

    Science.gov (United States)

    Mughieda, O.; Hazirbaba, K.; Bani-Hani, K.; Daoud, W.

    2017-06-01

    Stability and stress analyses are the most important elements that require rigorous consideration in design of a dam structure. Stability of dams against sliding is crucial due to the substantial horizontal load that requires sufficient and safe resistance to develop by mobilization of adequate shearing forces along the base of the dam foundation. In the current research, the static sliding stability of a roller-compacted-concrete (RCC) dam was modelled using finite element method to investigate the stability against sliding. A commercially available finite element software (SAP 2000) was used to analyze stresses in the body of the dam and foundation. A linear finite element static analysis was performed in which a linear plane strain isoperimetric four node elements was used for modelling the dam-foundation system. The analysis was carried out assuming that no slip will occur at the interface between the dam and the foundation. Usual static loading condition was applied for the static analysis. The greatest tension was found to develop in the rock adjacent to the toe of the upstream slope. The factor of safety against sliding along the entire base of the dam was found to be greater than 1 (FS>1), for static loading conditions.

  8. Safety of Italian dams in the face of flood hazard

    Science.gov (United States)

    Bocchiola, Daniele; Rosso, Renzo

    2014-09-01

    Most rivers in Italy are segmented by dams that need rehabilitation because of (1) safety requirements by increasingly risk-averse societies, (2) changes in the downstream river and riparian system after dams building, (3) poor initial design at the time of completion and (4) modified priorities of watershed management. Safe design of flood spillways is a major concern, and requires to cope with low frequency flood hazard. One must estimate flood figures with high return periods (R ⩾ 1000-10,000 years) but statistical methods involve large uncertainties because of the short length of the available records. This paper investigates the return period of the design flood of existing spillways RS of large dams in Italy. We used re-normalized flood frequency approach and regionalization using the Generalized Extreme Value distribution. The estimation of the site specific index flood is carried out by simple scaling with basin area at the regional level. The result show that 55% (245) of the 448 examined dams are equipped by spillway with RS > 10,000; and 71% (315) of the dams have RS > 1000. Conversely, 29% (130) of the dams display RS routing may dampen the outflow hydrograph, but one should carefully account for the need of achieving accurate dam safety assessment of these dams based on site specific investigations, also accounting for global change forcing.

  9. Research advance in safety analysis methods for high concrete dam

    Institute of Scientific and Technical Information of China (English)

    REN; QingWen; XU; LanYu; WAN; YunHui

    2007-01-01

    High tensile stresses occurred in high concrete dams and in their foundation lead to the growing importance of their safety with the increase of concrete dam height.Without any exiting specification or successful experiences of concrete dams up to 300 m at home and abroad for reference,experts feel obliged to figure out how to perform safety analysis on high concrete dam.This paper involves the main contents and mechanical features of the safety analysis on high concrete dam and shows the current state and progress of the analysis methods.For the insufficiency and problems existing in normative methods,study on modern numerical method such as finite element method must be strengthened to find out the stress control criterion which is in accordance with the methods.Two aspects of the safety analysis of high dam--local damage from material level and integral destruction from structure level--should be considered.For the local damage,we should consider the non-homogeneity of material and strengthen the research of meso-damage mechanics.While for integral destruction of the system of high dam and its foundation,a study on non-strength theory should receive enough concerns.Further,attention should be paid to the research on the failure modes and criterions of high concrete dam failure analysis and safety evaluation,and the effect of uncertainty and classification of safety should be considered too.

  10. Measures of struggle against appearance of cracks in earth dams

    Directory of Open Access Journals (Sweden)

    Ibraeva Yulia

    2016-01-01

    Full Text Available The article describes a method calculation of the basic parameters of the transverse rows of pile of simple printed or precast dam. As well, in this article have been shown all the necessary formulas for this calculation and have been proposed solutions to prevent cracking in the dams.

  11. 33 CFR 117.705 - Beaver Dam Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Beaver Dam Creek. 117.705 Section 117.705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.705 Beaver Dam Creek. The draw of...

  12. 78 FR 7810 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-02-04

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group.... L. 102-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work...

  13. 75 FR 34476 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2010-06-17

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation... Interior (Secretary) is renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group is to advise and to provide recommendations to the...

  14. 78 FR 21415 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-04-10

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group..., the AMWG, a technical work group, a Grand Canyon Monitoring and Research Center, and...

  15. 77 FR 43117 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-07-23

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  16. 77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-02-16

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  17. How to manage the cumulative flood safety of catchment dams

    African Journals Online (AJOL)

    2008-09-15

    Sep 15, 2008 ... Sustainable Law and Engineering Group, Centre for Accounting, Governance and Sustainability, ... associated with small-dam safety and practical feedback from ... catchment dams nor the supervision over the management of .... same time in an extreme design flood event of only 1-in-200 ..... These guide-.

  18. Will the Three Gorges Dam Stand The Test of Time?

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Netizens have collected several ar-ticles about the flood-control capacity of the Three Gorges Dam. In these articles, its capacity was differently described as tackling flooding "once-in-10,000-years" "once-in- l,O00-years" or "once-in-a-century" Can you give the specifics of the flood control capacity of the dam?

  19. INTRODUCTION All earth dams in their natural state experience ...

    African Journals Online (AJOL)

    Earth Dam constructed within the Precambrian Basement Complex terrain of Southwestern Nigeria. The study was aimed at ... The 2-D resistivity structure revealed that the core of the dam embankment is .... within the rain forest region of Nigeria. The ..... (citrus Sinensis Osbeck) Stored at Ambient Tropical Condition. 251.

  20. Seepage problem in Papan dam and the treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sharghi, A. [JTMA Co., Tehran (Iran, Islamic Republic of); Palassi, M. [Tehran Univ. (Iran, Islamic Republic of). Dept. of Civil Engineering

    2003-07-01

    The Papan dam in the Krygyz Republic is 97 metres high. It is located in the Osh Oblast, within a narrow and steep sided gorge on the Ak-Bura River, approximately 20 kilometres south of the City of Osh. The impoundment of the dam revealed large inflows of water to the downstream dam through the upper half of the dam and through the joints in the right abutment. A number of options were considered before a treatment method was selected. The causes of the leakage were poor grouting, and joints and fissures in the abutment. The remedial process involved the use of a plastic concrete cutoff wall extended from the crest of the dam to a depth of approximately 70 metres, in addition to the use of a grouting curtain in the right abutment. 2 figs.

  1. Management of dam safety at BC Hydro: the database tool

    Energy Technology Data Exchange (ETDEWEB)

    Oswell, Terry [BC Hydrom Burnaby, (Canada)

    2010-07-01

    BC Hydro has a wide range of dams, which raises a wide range of issues at many unique sites. A dam safety database was developed in 2000 to deal with the complexity and volume of information provided by deficiency investigations and surveillances. The database contains all documented deficiencies and non-conformances identified in the past 10 years. It records the risk ratings assigned to each issue. This paper described the implementation of the database tool, from the characterization of a dam safety issue to the use of the database itself. The dam safety database is now a key tool in managing the dam safety program at BC Hydro and has been useful for the last 10 years or so in prioritizing the program of deficiency investigations and capital projects. The development of a process to rate non-conformances is currently under study and will be implemented soon to aid in more efficient prioritization of maintenance activities.

  2. Modeling Experiment of Break of Debris-Flow Dam

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; GENG Xueyong; DANG Chao; LIU Jingjing

    2007-01-01

    Glaciers are extensively developed in the southwest of Tibet and the moraines are widely distributed with large depth. Large-scale debris flows are often reported which blocked rivers and formed dams. In this paper, seven large debris flows in four valleys are discussed, among which five dams developed. 13 sets of experiments have been conducted in laboratory to simulate the formation and failure of the dam. Finally, a model of dam failure is proposed and a formula is established to calculate the flood discharge:Q = kbhhk/T (B)/LG0.41, where bk is the outlet width of the dam atthe original water level, ht the erosive depth, T the time fromoverflow to final state of failure, the average width of lake; L thelength of the lake, and G the total potential energy of the water inthe lake.

  3. Dam Inventory - DAMS_1996_EPA_IN: Inventory of Dams in Indiana, Derived from EPA BASINS (United States Environmental Protection Agency, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — DAMS_1996_EPA_IN is a point shapefile developed by the USEPA BASINS 3.0 program and clipped by Bernardin, Lochmueller and Associates. Clips were performed using the...

  4. Hydrological Effects of Chashm Dam on the Downstream of Talar River Watershed

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Khaleghi

    2017-02-01

    Full Text Available Introduction: In the last century, dams have constructed with the objective of water supplies for agriculture, drinking water and industry. However, the results from the performance review of dams show adverse effects on the downstream environment and the availability of water resources. The purpose of the Chashm dam construction on the TalarRiver's tributaries is the water supply for Semnan city. Materials and Methods: This study was conducted in TalarRiver watershed. TalarRiveroriginatesfrom AlborzMountains in Mazandaran province, in the southern Caspian Sea basin, in north of Iran and flows parallel with the Firouzkooh-Ghaemshahr road and it arrives to the Caspian beach area in the Malek Kala village. In order to supply the water requirements of Semnan city, the construction of Chashm dam on the TalarRiver's tributaries placed on the agenda of the Ministry of Energy. However, because of the uncontrolled exploitation of agricultural streams and invasion of privacy riverbed, the TalarRiver has acute and critical conditions from the point of hydrologic and environmental. To study the hydrological impacts of Chashm dam, Talar watershed was considered with an area of approximately 1057 square kilometers of the Pole Sefid gauging station using a rainfall-runoff model. Results and Discussion: Simulation of the study area hydrological behavior shows that the Chashm Dam average water discharge is near to 8.6 million m3. This figure will be significant changes during wet and droughtperiods. The minimum and maximum monthly discharge of the Chashm Dam watershed in August and February is equal to 0.31 and 0.55 m3/s respectively. The minimum and maximum monthly water demand in turn in October and August is equal to 0.015 and 0.4 m3/s respectively and this shows that the river discharge in June is lower than the downstream water demand. Based on confirmed studies of the Kamandab Consulting Engineers, drinking water requirement of Semnan province, water

  5. Channel evolution on the dammed Elwha River, Washington, USA

    Science.gov (United States)

    Draut, A.E.; Logan, J.B.; Mastin, M.C.

    2011-01-01

    Like many rivers in the western U.S., the Elwha River, Washington, has changed substantially over the past century in response to natural and human forcing. The lower river is affected by two upstream dams that are slated for removal as part of a major river restoration effort. In preparation for studying the effects of dam removal, we present a comprehensive field and aerial photographic analysis of dam influence on an anabranching, gravel-bed river. Over the past century with the dams in place, loss of the upstream sediment supply has caused spatial variations in the sedimentary and geomorphic character of the lower Elwha River channel. Bed sediment is armored and better sorted than on the naturally evolving bed upstream of the dams. On time scales of flood seasons, the channel immediately below the lower dam is fairly stable, but progresses toward greater mobility downstream such that the lowermost portion of the river responded to a recent 40-year flood with bank erosion and bed-elevation changes on a scale approaching that of the natural channel above the dams. In general, channel mobility in the lowest 4 km of the Elwha River has not decreased substantially with time. Enough fine sediment remains in the floodplain that – given sufficient flood forcing – the channel position, sinuosity, and braiding index change substantially. The processes by which this river accesses new fine sediment below the dams (rapid migration into noncohesive banks and avulsion of new channels) allow it to compensate for loss of upstream sediment supply more readily than would a dammed river with cohesive banks or a more limited supply of alluvium. The planned dam removal will provide a valuable opportunity to evaluate channel response to the future restoration of natural upstream sediment supply.

  6. Check dam and polyacrylamide performance under simulated stormwater runoff.

    Science.gov (United States)

    Kang, Jihoon; McCaleb, Melanie M; McLaughlin, Richard A

    2013-11-15

    High levels of turbidity and fine suspended sediments are often found in stormwater discharges from construction sites even when best management practices (BMPs) for sediment control are in place. This study evaluated turbidity reduction by three check dam types: 1) rock check dam representing a standard BMP, 2) excelsior wattle representing a fiber check dam (FCD), and 3) rock check dam wrapped with excelsior erosion control blanket (rock + excelsior ECB) representing an alternative FCD. Three check dams (all same type) were installed in a lined, 24-m ditch on a 5-7% slope and three consecutive simulated stormwater flows were run in the ditch. Additional tests were performed by adding granular polyacrylamide (PAM) on the check dams in the same manner using two sediment sources differing in clay content. Without PAM treatment, significantly higher effluent turbidity (>900 nephelometric turbidity units (NTU)) exited the ditch with rock check dams than with excelsior wattles or rock + excelsior ECBs (dam types was in the order of excelsior wattle > rock + excelsior ECB > rock check dam, indicating better water pooling behind the wattle. The PAM treatment reduced turbidity substantially (>75% relative to no PAM treatment) for all check dam types and it was very effective in excelsior wattles (<57 NTU) and rock + excelsior ECBs (<90 NTU) even during the third storm event. This study demonstrates that the passive treatment of runoff with PAM on FCDs (or rock + excelsior ECB) in construction site ditches can be very effective for sediment retention and turbidity reduction.

  7. Geophysical Investigations at Hidden Dam, Raymond, California Flow Simulations

    Science.gov (United States)

    Minsley, Burke J.; Ikard, Scott

    2010-01-01

    Numerical flow modeling and analysis of observation-well data at Hidden Dam are carried out to supplement recent geophysical field investigations at the site (Minsley and others, 2010). This work also is complementary to earlier seepage-related studies at Hidden Dam documented by Cedergren (1980a, b). Known seepage areas on the northwest right abutment area of the downstream side of the dam was documented by Cedergren (1980a, b). Subsequent to the 1980 seepage study, a drainage blanket with a sub-drain system was installed to mitigate downstream seepage. Flow net analysis provided by Cedergren (1980a, b) suggests that the primary seepage mechanism involves flow through the dam foundation due to normal reservoir pool elevations, which results in upflow that intersects the ground surface in several areas on the downstream side of the dam. In addition to the reservoir pool elevations and downstream surface topography, flow is also controlled by the existing foundation geology as well as the presence or absence of a horizontal drain in the downstream portion of the dam. The current modeling study is aimed at quantifying how variability in dam and foundation hydrologic properties influences seepage as a function of reservoir stage. Flow modeling is implemented using the COMSOL Multiphysics software package, which solves the partially saturated flow equations in a two-dimensional (2D) cross-section of Hidden Dam that also incorporates true downstream topography. Use of the COMSOL software package provides a more quantitative approach than the flow net analysis by Cedergren (1980a, b), and allows for rapid evaluation of the influence of various parameters such as reservoir level, dam structure and geometry, and hydrogeologic properties of the dam and foundation materials. Historical observation-well data are used to help validate the flow simulations by comparing observed and predicted water levels for a range of reservoir elevations. The flow models are guided by, and

  8. Evaluations on the safety design standards for dams with extra height or cascade impacts. Part I:fundamentals and criteria%特高坝及其梯级水库群设计安全标准研究Ⅰ:理论基础和等级标准

    Institute of Scientific and Technical Information of China (English)

    周建平; 王浩; 陈祖煜; 周兴波; 李斌

    2015-01-01

    水电工程中高度200 m及以上的特高坝的设计已经超出现行规范的适用范围;考虑流域梯级效应的水库群的安全标准,迄今尚属空白。本文从公共安全风险防范和梯级连溃系统风险分析的角度,在现行水利水电枢纽工程等级划分及其设计安全标准的基础上,针对特高坝及其对下游梯级具有溃坝影响的大坝,提出了设立特等工程、特级建筑物及其相应安全标准的建议。经初步论证,建议特2级土石坝年计失效概率为5×10-8,目标可靠指标为4.45,坝坡抗滑稳定安全系数为1.6;特1级土石坝年计失效概率为1×10-8,目标可靠指标为4.7,坝坡抗滑稳定安全系数为1.7。基于我国某流域实际情况的一个虚拟大坝连溃案例,验证了确定上述工程等级和安全标准的可行性,对我国现有水电工程设计规范的修正和完善具有一定的参考意义。%The rapid development of China’s hydropower projects has resulted in a number of large dams whose heights exceed 200 m, an applicability limit of various design codes. Another concern comes from the cascade hydropower devolvement on a river, in which break of one dam may cause serious downstream secondary disasterds. Based on a comprehensive review on the social and professional safety control stan⁃dards the authors propose in these paper two extra classes as well as their related design criteria to the ex⁃isting Chinese dam classification systems. Class E2 refers to a dam with a height ranged between 200-250 m, or a dam whose breaching would cause a secondary break of a downstream Class 1 dam if early warn⁃ing is not available. The allowableannual probability of failure, reliability index and slope safety factor are specified as 5 × 10-8, 4.45, and 1.6 respectively. Class E2 refers to a dam with a height ranged between 250-300 m, or a dam whose breaching would cause a secondary break of a downstream Class 1 dam even with

  9. Safety and coping strategy for high dam under complex natural conditions

    Institute of Scientific and Technical Information of China (English)

    Niu Xinqiang

    2012-01-01

    In respect to current situation and new challenges for high dam construction in China, safety problems are an- alyzed for high dam construction under complex natural conditions such as high elevation, cold area, high seismic inten- sity, large-seale landslide and high dam and huge reservoirs with dam types such as concrete surface rock-fill, asphalt concrete core, roller compacted concrete (RCC) arch dam and so on. From several aspects, including risk response measures for high dam, strengthening safety awareness for high dam design and construction, improving high dam con- struetion technique, intelligent dam safety management system based on IT, developing dam rehabilitation and mainte- nance technologies, useful dam safety and coping strategy is proposed.

  10. Impact

    NARCIS (Netherlands)

    Lohse, Detlef; Bergmann, Raymond; Mikkelsen, Rene; Zeilstra, Christiaan; Meer, van der Devaraj; Versluis, Michel

    2004-01-01

    A lot of information on impacts of solid bodies on planets has been extracted from remote observations of impact craters on planetary surfaces; experiments however with large enough impact energies as compared to the energy stored in the ground are difficult. We approach this problem by downscaled e

  11. Chief Joseph Dam, Columbia River, Washington, Community Impact Reports,

    Science.gov (United States)

    1980-05-01

    eIlip t. o ’ W iI wil p I rob~ib IV b icc ai b’/ i,_ h r fam1i Ii es . P rO jc L1 ohl o! totl I p)OPUIoIt ion ink ’ I Mii’ , Oils5 Ii J ri i [11 01...IPRT LM:E L"G’Li "-;CU COUNTY ~ ~ i -T SOPLKC C U N,’._PH.4TA COL’""- COUN0 P~ij1~ RTYIAI<{ *H.*.\\(- U( rN 1LI Ti H ... -.... _ tlc ~t,JA’Y’ A:::) Re

  12. Riverbed-Sediment Mapping in the Edwards Dam Impoundment on the Kennebec River, Maine By Use of Geophysical Techniques

    Science.gov (United States)

    Dudley, Robert W.

    1999-01-01

    INTRODUCTION In July 1997, the Federal Energy Regulatory Commission (FERC) issued a Final Environmental Impact Statement recommending that the 162-year-old Edwards Dam on the Kennebec River in Augusta, Maine, be removed. The impoundment formed by Edwards Dam extends about 15 mi to the city of Waterville, near the confluence of the Sebasticook River with the Kennebec River. The impoundment has a surface area of 1,143 acres, a gross storage of approximately 740 million ft3, and a usable storage of about 184 million ft3 (Stone and Webster, 1995a). According to FERC, removal of the 917-ft-long, 24-ft-high timber crib and concrete structure would restore 15 mi of riverine habitat, improve passage of ocean-migrating fish species native to the Kennebec River, and result in substantial recreational enhancements (Federal Energy Regulatory Commission, 1997). Because the removal of Edwards Dam would change the hydraulic characteristics of the river in the present-day impoundment, the potential transport of erodible, fine-grained sediment currently in the impoundment is a concern. Of particular concern is the erosion and transport of this sediment to areas downstream from the dam, a process that could introduce possible bacterial and chemical contamination and could impede river navigation as a result of sediment deposition. In an effort to build upon available information on the composition of the riverbed, the U.S. Geological Survey (USGS), in cooperation with the Maine State Planning Office, classified riverbed sediment types and mapped their areal extents in the lower (southern) half of the Edwards Dam impoundment. This report describes the methods used to collect and analyze the data used to create a map of sediment types in the Edwards Dam impoundment. The map is included with this report. Data used to map riverbed sediment types were also used to estimate the volume of observed mud and mud-containing sediment in the study area.

  13. Stability of earth dam with a vertical core

    Directory of Open Access Journals (Sweden)

    Orekhov Vyacheslav Valentinovich

    2016-01-01

    Full Text Available Earth dam with impervious element in the form of asphaltic concrete core is currently the most promising type of earth dams (due to simple construction technology and universal service properties of asphaltic concrete and is widely used in the world. However, experience in the construction and operation of high dams (above 160 m is not available, and their work is scarcely explored. In this regard, the paper discusses the results of computational prediction of the stress-strain state and stability of a high earth dam (256 m high with the core. The authors considered asphaltic concrete containing 7 % of bitumen as the material of the core. Gravel was considered as the material of resistant prisms. Design characteristics of the rolled asphaltic concrete and gravel were obtained from the processing of the results of triaxial tests. The calculations were performed using finite element method in elastoplastic formulation and basing on the phased construction of the dam and reservoir filling. The research shows, that the work of embankment dam with vertical core during filling of the reservoir is characterized by horizontal displacement of the lower resistant prism in the tailrace and the formation of a hard wedge prism descending along the core in the upper resistant prism. The key issue of the safety assessment is to determine the safety factor of the overall stability of the dam, for calculation of which the destruction of the earth dam is necessary, which can be done by reducing the strength properties of the dam materials. As a results of the calculations, the destruction of the dam occurs with a decrease in the strength characteristics of the materials of the dam by 2.5 times. The dam stability depends on the stability of the lower resistant prism. The destruction of its slope occurs on the classical circular-cylindrical surface. The presence of a potential collapse surface in the upper resistant prism (on the edges of the descending wedge does

  14. Estimating Snow Budget of Karaj Dam Reservoir

    Directory of Open Access Journals (Sweden)

    Manijeh G. Tali

    2009-01-01

    Full Text Available Problem statement: Most of the cold period precipitation of Karaj Basin falls in the form of snow. This snow and its run off are important to the dam and the local needs such as agriculture and the drinking water of Tehran. But due to the scarcity and in some elevations the lack of weather stations, measuring this snow cover and its run off is difficult. We have decided to estimate the amount of this snow cover by using surrogate methods such as satellite images of MODIS and temperature thresholds. Approach: To estimate the snow water budget of the Karaj Dam Reservoir Basin, first a temperature threshold of 3° Celsius was defined according to the analysis of daily temperature and precipitation values of Nesa station during 1960-2000. The elevation of this temperature was as low as 1590 m in February and 5734 m in August. During each month the melting snow was computed over the area between 3 and zero degrees Celsius and precipitation below zero degrees was considered as permanent snow cover. The precipitation of areas above 3° was computed as rain. Using this temperature threshold and the DEM map of the basin we estimated the snow cover and snow melt water of the basin. The snow cover area on the MODIS images was estimated and compared with that computed from temperature threshold. Both methods gave relatively similar results. At the end the snow melt water of the whole cold period was calculated and added up to estimate the total snow water budget. Results: The results showed that during the study months most (67.7% of the precipitation comes in the form of snow. And most of this snow (97.5% melts during months March and onward. Its monthly distributions are 3.8% in March, 22.7% in April and 71% in May. The total snow water entering the dam was about 181.73 million cubic meters. Conclusion: The comparison of the results from temperature thresholds with the MODIS images snow cover showed very little and negligible discrepancy. Therefore, this

  15. Fosfortab fra det dyrkede areal til Stevning Dam, Hindemaj og Haderslev Dam

    DEFF Research Database (Denmark)

    Andersen, Hans Estrup; Heckrath, Goswin; Thodsen, Hans;

    Størrelsen af dyrkningsbidraget til søerne i Haderslev Dam-systemet er vurderet med to forskellige metoder til at udgøre ca. 42 % af den samlede tilførsel. En risikokortlægning med det nye, danske P-indeks viser, at i alt 15 % af det dyrkede areal er i højrisiko mht. fosfortab. P-indeks-kortlægni......Størrelsen af dyrkningsbidraget til søerne i Haderslev Dam-systemet er vurderet med to forskellige metoder til at udgøre ca. 42 % af den samlede tilførsel. En risikokortlægning med det nye, danske P-indeks viser, at i alt 15 % af det dyrkede areal er i højrisiko mht. fosfortab. P...

  16. Assessment of metallic pollution status of surface water and aquatic macrophytes of earthen dams in Ilorin, north-central of Nigeria as indicators of environmental health

    Directory of Open Access Journals (Sweden)

    Clement O. Ogunkunle

    2016-10-01

    Full Text Available The functional quality of an aquatic ecosystem is a reflection of the health of the environment. Therefore, the present study evaluates the trace metal contamination (Pb, Cd, Ni and Mn of water and aquatic macrophytes in Asa, Agba, Unilorin and Sobi (Moro earthen dams, north-central Nigeria to evaluate the level of anthropogenic impact on the immediate environment. The concentrations of trace metals in samples of water and available macrophytes from the earthen dams were determined by Atomic Absorption Spectrophotometry. Trace metal contamination of surface water in the earthen dams was assessed using metal index (MPI and metal pollution index (HPI. The biological accumulation factor of trace metals in the aquatic macrophytes was extrapolated from trace metal concentrations in the water and macrophyte samples. The results of the MPI revealed gross metal contamination of the surface water by Pb and Cd (>6.0 for both metals in the four earthen dams; while Agba and Sobi dams were slightly contaminated by Ni (MPIs = 1.43 and 1.14 respectively. All the earthen dams were considered safe from Mn contamination (MPI  100, but Asa dam (HPI = 2682.4 was the most contaminated. The biological accumulation factor of Mn in the macrophytes indicated Ceratophyllum demersum, Pycreus lanceolatus and Pistia stratiotes as moderate accumulators of Mn, and can be used as bioindicators in monitoring Mn pollution of aquatic ecosystem. The obtained results in this study showed that the earthen dams are polluted by Pb, Cd and Ni which pose human health risks to the inhabitants through drinking water.

  17. Geologic Hazards Associated With a Proposed Dam on the Yarlung-Tsangpo River in SE Tibet

    Science.gov (United States)

    Zeitler, P. K.; Meltzer, A. S.; Hallet, B.; Kidd, W. S.; Koons, P. O.

    2007-12-01

    For a decade anecdotes and media reports have been circulating about a proposed dam on the Yarlung- Tsangpo River in SE Tibet. The proposed site is in the deep canyon of the Yarlung-Tsangpo where the river leaves the Tibetan Plateau across an immense knickpoint, falling ~2000 m along an irregular U-shaped reach ~100 km in length. The fundamental purpose of the dam is generation of ~40,000 MW of hydropower, to be used in diverting a portion of the impounded river to water-starved regions of northern China. Offsetting benefits that would accrue from improved water supply in the north, debate has centered on the water-flow and sediment-flux impacts that would be felt downstream in the Brahmaputra system in northeastern India and Bangladesh, as well as the impact of a dam and large lake on the pristine, ecologically and ethnographically diverse area around the Yarlung-Tsangpo canyon, an area of great significance to Tibetan Buddhists. We have been examining the geodynamic evolution of eastern Tibet, and have gathered considerable geophysical and geological data on the knickpoint region. The knickpoint traverses the Namche Barwa-Gyala Peri massif, one of the most geologically active regions on Earth. In this region, very rapid bedrock exhumation at rates of 7 mm/yr or more has exposed granites as young as 1 Ma, and these rates have been ongoing for at least the past 3 m.y. Detrital-dating evidence shows that these high rates continue at present and that erosion within the massif contributes fully 50% of the suspended-sediment load in the Yarlung-Tsangpo at the point where it enters the Brahmaputra (this would be about 100 Mt/yr derived from the massif). The steep slopes in the massif fail by pervasive landsliding and suggest a steady-state topography where the high erosion rates are balanced by equivalent rates of rock uplift accommodated by numerous active structures. At a more regional scale, GPS results show that steep three-dimensional velocity gradients exist

  18. Seismology-based early identification of dam-formation landquake events

    Science.gov (United States)

    Chao, Wei-An; Zhao, Li; Chen, Su-Chin; Wu, Yih-Min; Chen, Chi-Hsuan; Huang, Hsin-Hua

    2016-01-01

    Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1–3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents. PMID:26753931

  19. China’s Policy on Dams at the Crossroads: Removal or Further Construction?

    Directory of Open Access Journals (Sweden)

    Chiyuan Miao

    2015-05-01

    Full Text Available During the past century, the number and scale of reservoirs worldwide has grown substantially to meet the demand for water and hydropower arising from increased population, industrialization, and urbanization. This is particularly the case in China, where reservoir construction increased rapidly after the Chinese economic reform and the introduction of open-door policies. On average, 4.4 large reservoirs with a capacity greater than 0.1 km3 were constructed per annum during the 1970s–1990s. This average reached 11.8 such reservoirs per annum in the 2000s. Considering the adverse impact of dams on rivers and riparian communities, various environmentalists and non-governmental organizations in China have begun to protest against the construction of dams. Now China’s policy on dams is at a crossroads: Removal or further construction? In this paper, we systematically assess the construction of reservoirs in China and discuss the benefits and drawbacks of large-scale reservoir projects on several major rivers in China: The Yangtze River, the Yellow River and the Mekong River. Lastly, we provide a perspective on the future of reservoir development in China, taking into account natural conditions, renewable hydropower resources, and greenhouse gas emissions.

  20. Bank erosion along the dam-regulated lower Roanoke River, North Carolina

    Science.gov (United States)

    Hupp, C.R.; Schenk, E.R.; Richter, J.M.; Peet, Robert K.; Townsend, Phil A.

    2009-01-01

    Dam construction and its impact on downstream fluvial processes may substantially alter ambient bank stability and erosion. Three high dams (completed between 1953 and 1963) were built along the Piedmont portion of the Roanoke River, North Carolina; just downstream the lower part of the river flows across largely unconsolidated Coastal Plain deposits. To document bank erosion rates along the lower Roanoke River, >700 bank-erosion pins were installed along 66 bank transects. Additionally, discrete measurements of channel bathymetry, turbidity, and presence or absence of mass wasting were documented along the entire study reach (153 km). A bank-erosion- floodplain-deposition sediment budget was estimated for the lower river. Bank toe erosion related to consistently high low-flow stages may play a large role in increased mid- and upper-bank erosion. Present bank-erosion rates are relatively high and are greatest along the middle reaches (mean 63 mm/yr) and on lower parts of the bank on all reaches. Erosion rates were likely higher along upstream reaches than present erosion rates, such that erosion-rate maxima have since migrated downstream. Mass wasting and turbidity also peak along the middle reaches; floodplain sedimentation systematically increases downstream in the study reach. The lower Roanoke River isnet depositional (on floodplain) with a surplus of ??2,800,000 m3yr. Results suggest that unmeasured erosion, particularly mass wasting, may partly explain this surplus and should be part of sediment budgets downstream of dams. ?? 2009 The Geological Society of America.

  1. Seismology-based early identification of dam-formation landquake events

    Science.gov (United States)

    Chao, Wei-An; Zhao, Li; Chen, Su-Chin; Wu, Yih-Min; Chen, Chi-Hsuan; Huang, Hsin-Hua

    2016-01-01

    Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1-3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.

  2. Mutually beneficial and sustainable management of Ethiopian and Egyptian dams in the Nile Basin

    Science.gov (United States)

    Habteyes, Befekadu G.; Hasseen El-bardisy, Harb A. E.; Amer, Saud A.; Schneider, Verne R.; Ward, Frank A.

    2015-10-01

    Ongoing pressures from population growth, recurrent drought, climate, urbanization and industrialization in the Nile Basin raise the importance of finding viable measures to adapt to these stresses. Four tributaries of the Eastern Nile Basin contribute to supplies: the Blue Nile (56%), White Nile-Albert (14%), Atbara (15%) and Sobat (15%). Despite much peer reviewed work addressing conflicts on the Nile, none to date has quantitatively examined opportunities for discovering benefit sharing measures that could protect negative impacts on downstream water users resulting from new upstream water storage developments. The contribution of this paper is to examine the potential for mutually beneficial and sustainable benefit sharing measures from the development and operation of the Grand Ethiopian Renaissance Dam while protecting baseline flows to the downstream countries including flows into the Egyptian High Aswan Dam. An integrated approach is formulated to bring the hydrology, economics and institutions of the region into a unified framework for policy analysis. A dynamic optimization model is developed and applied to identify the opportunities for Pareto Improving measures to operate these two dams for the four Eastern Nile Basin countries: Ethiopia, South Sudan, Sudan, and Egypt. Results indicate a possibility for one country to be better off (Ethiopia) and no country to be worse off from a managed operation of these two storage facilities. Still, despite the optimism of our results, considerable diplomatic negotiation among the four riparians will be required to turn potential gains into actual welfare improvements.

  3. Seismology-based early identification of dam-formation landquake events

    Science.gov (United States)

    Wu, Y. M.; Chao, W. A.

    2015-12-01

    Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥ 20 sec) waveforms for different source mechanisms. Results show that single-force (SF) mechanism better explains the observed seismograms generated by landquake events. We then perform inversions for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1-3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.

  4. Evaluating temporal changes in hydraulic conductivities near karst-terrain dams: Dokan Dam (Kurdistan-Iraq)

    Science.gov (United States)

    Dafny, Elad; Tawfeeq, Kochar Jamal; Ghabraie, Kazem

    2015-10-01

    Dam sites provide an outstanding opportunity to explore dynamic changes in the groundwater flow regime because of the high hydraulic gradient rapidly induced in their surroundings. This paper investigates the temporal changes of the hydraulic conductivities of the rocks and engineered structures via a thorough analysis of hydrological data collected at the Dokam Dam, Iraq, and a numerical model that simulates the Darcian component of the seepage. Analysis of the data indicates increased seepage with time and suggests that the hydraulic conductivity of the rocks increased as the conductivity of the grout curtain decreased. Conductivity changes on the order of 10-8 m/s, in a 20-yr period were quantified using the numerical analysis. It is postulated that the changes in hydraulic properties in the vicinity of Dokan Dam are due to suspension of fine materials, interbedded in small fissures in the rocks, and re-settlement of these materials along the curtain. Consequently, the importance of the grout curtain to minimize the downstream seepage, not only as a result of the conductivity contrast with the rocks, but also as a barrier to suspended clay sediments, is demonstrated. The numerical analysis also helped us to estimate the proportion of the disconnected karstic conduit flow to the overall flow.

  5. Environmental and dam effects on cannibalism in Wistar rat litters

    Directory of Open Access Journals (Sweden)

    Graziela Tarôco

    2015-08-01

    Full Text Available The factors related to cannibalistic behavior of dams in a Wistar rat colony are identified and analyzed. The maternal genetic effects were tested as a random effect by the method of generalized linear models. The season at parturition, the dam´s age at parturition and the density of the room at parturition were tested as fixed effects, whereas the litter size at birth was tested as a co-variable. The genetic effect of the dam was significant for the number of cannibalized pups. Although the season at parturition, the dam´s age and room density on the day of parturition were not individually significant (p > 0.05, most of the interactions between the variation sources were significant (p < 0.05. Cannibalism occurred mostly in dams aged over 241 days, with parturition during spring. So that occurrences of cannibalism could be avoided, dams with the smallest number of cannibalized pups should be selected, coupled to dams younger than 241 days, breeding during spring. The above strategies may reduce the number of couples in the vivarium and increase their production efficiency.

  6. Responses of riparian reptile communities to damming and urbanization

    Science.gov (United States)

    Hunt, Stephanie D.; Guzy, Jacquelyn C.; Price, Steven J.; Halstead, Brian J.; Eskew, Evan A.; Dorcas, Michael E.

    2013-01-01

    Various anthropogenic pressures, including habitat loss, threaten reptile populations worldwide. Riparian zones are critical habitat for many reptile species, but these habitats are also frequently modified by anthropogenic activities. Our study investigated the effects of two riparian habitat modifications-damming and urbanization-on overall and species-specific reptile occupancy patterns. We used time-constrained search techniques to compile encounter histories for 28 reptile species at 21 different sites along the Broad and Pacolet Rivers of South Carolina. Using a hierarchical Bayesian analysis, we modeled reptile occupancy responses to a site's distance upstream from dam, distance downstream from dam, and percent urban land use. The mean occupancy response by the reptile community indicated that reptile occupancy and species richness were maximized when sites were farther upstream from dams. Species-specific occupancy estimates showed a similar trend of lower occupancy immediately upstream from dams. Although the mean occupancy response of the reptile community was positively related to distance downstream from dams, the occupancy response to distance downstream varied among species. Percent urban land use had little effect on the occupancy response of the reptile community or individual species. Our results indicate that the conditions of impoundments and subsequent degradation of the riparian zones upstream from dams may not provide suitable habitat for a number of reptile species.

  7. The collapse of the Sella Zerbino gravity dam.

    Science.gov (United States)

    Petaccia, G; Lai, C G; Milazzo, C; Natale, L

    2016-08-23

    When a severe flood wave completely filled the Ortiglieto reservoir on August 13, 1935, the 14 m high "Sella Zerbino" secondary dam failed catastrophically causing > 100 casualties. Both of the dams, Sella Zerbino-Zerbino Saddle and Bric Zerbino-Zerbino Peak (Fig. 1) were overtopped but only the Sella Zerbino failed whereas the main barrage did not suffer any damage. The lawsuit that followed this tragic event ended with a full acquittal of the dam's designers since the plaintiff experts succeeded in demonstrating that the collapse was due to an extreme rainfall storm of unpredictable intensity. The case was then officially closed and still today the failure of the Sella Zerbino dam is attributed to the unpredictable hydrological event. Recently, Natale and Petaccia (2013) re-examined the case assessing the capacity of the flood spillways which equipped the Bric Zerbino dam. This paper thoroughly reviews the mechanics of the collapse of the Sella Zerbino dam focusing on the stability of the structure. The water pressure underneath the dam and the poor quality of the foundation rock is believed to have played a major role in the sequence of events that ended in the collapse of the barrage.

  8. Characterization of colostrum from dams of BLV endemic dairy herds.

    Science.gov (United States)

    Gutiérrez, Gerónimo; Lomonaco, Marina; Alvarez, Irene; Fernandez, Fernando; Trono, Karina

    2015-06-12

    Bovine Leukemia Virus (BLV) is endemic in Argentina, where the individual prevalence is higher than 80% in dairy farms. The aim of this work was to find preliminary evidence to know if the high level of infection of the dam would implicate a higher challenge to her own offspring. We collected 65 sets of samples consisting of dam's blood and colostrum from two heavily infected dairy farms, and investigated the correlation between the dam's blood proviral load and the presence of provirus in colostrum. We also described the dual antibody/provirus profile in the colostrum. Provirus was detected in 69.23% of the colostrum samples, mostly from dams with a high proviral load, 36/45 (80%). Colostrum proviral load was significantly higher in dams with high blood proviral load (pcolostrum samples all along the antibody distribution, even in those with a low amount of antibodies. These results show that even when high blood proviral load dams offer higher levels of infected cells to their offspring through colostrum they also offer higher levels of protection of antibodies. On the contrary, low blood proviral load dams also offer infected cells but a poor content of antibodies, suggesting that these animals could play an important role in the epidemiological cycle of transmission.

  9. Safety of small and medium dams in permafrost regions

    Institute of Scientific and Technical Information of China (English)

    Rudolf V.Zhang; Sergey A.Velikin

    2014-01-01

    Safe operation and performance of dams is one of the key issues in permafrost regions. At present, the existing dams are 40 45 years old and they are reaching their design life limit. Intensive geocryological processes (thermokarst, thermal erosion, frost heaving, suffosion, concentrated seepage along the voids left by melt ice and others) begin to develop at the early stages of construction. These processes are even more intensive under severe climatic conditions of the permafrost zone due to the large thermal and moisture gradients and the resulting complex thermal stress strain state in the structures. Determining safety criteria is a critical and difficult task in dam safety management. The existing procedures need to be continuously refined and improved depending on dam importance class. Some researchers recommend introducing process development criteria (stability, destabilization, and extremality) for more objective assessment of dam safety, in addition to the existing two condition criteria. In other words, they call for a multi factor dam environment interaction system. A case study of safety declaration for an existing dam is presented.

  10. Deformation reinforcement theory and its application to high arch dams

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the deformation reinforcement theory(DRT) proposed by the authors is elaborated with a new definition of instability that an elasto-pla