Agricultural and fisheries activities around the watershed of an African tropical reservoir (Oyun reservoir, Offa, Nigeria) were found to contribute significantly to water quality deterioration of the dam axis of the reservoir, leading to eutrophication of that part of the reservoir. This is evident from the high amount of nitrate (6.4 mg/l), phosphate (2.2 mg/l) and sulphate (16.9 mg/l) in the...

Dam construction causes the accumulation of phosphorus in the sediments of reservoirs and increases the release rate of internal phosphorus (P) loading. This study investigated the longitudinal variability of phosphorus fractions in sediments and the relationship between the contents of phosphorus fractions and its influencing factors of the Manwan Reservoir, Lancang River, Yunnan Province, Chi...

Human-made ecologic transformations have occurred at an unprecedented rate over the past 50 years. Prominent among them are water resource development projects. An estimated 40,000 large dams and 800,000 small dams have been built, and 272 million hectares of land are currently under irrigation worldwide. The establishment and operation of water projects has had a history of facilitating a chan...

Operational policy for hydropower dams must balance energy generation goals with environmental impacts under federal regulation, such as the Endangered Species and the Clean Water Acts. Multiple impoundments, reservoirs, outlet structures, and stochastic weather patterns complicate decision making to minimize impacts on downstream ecosystems. Currently, hydropower management to meet water quali...

Time-series observations were conducted in the Dowleiswaram dam reservoir that was constructed on the largest monsoonal river in India to understand the source of inorganic carbon, and fluxes to the atmosphere. The reservoir stores water during dry period of six months and water increases during the period when Indian subcontinent receives significant rainfall. Significant modification of organ...

Dam safety is a significant issue being taken seriously worldwide. However, in Australia, although much attention is being devoted to the mediumto large-scale dams, minimal attention is being paid to the serious potential problems associated with smaller dams, particularly the potential cumulative safety threats they pose in catchments. This paper establishes the significance of this problem an...

Ecological consequences of large dams, particularly regarding the Three Gorges Dam (TGD) on the Yangtze River in China, have been controversially and internationally discussed. Water quality within the Three Gorges Reservoir (TGR) has been deteriorated by highly underestimated eutrophication and algal blooms. Globally, the TGR is delineated from other comparable reservoirs by its low mean water...

Thermal layering in reservoirs upstream from hydroelectric dams can create temperature gradients in fishways used by upstream migrating adults. In the Snake River, Washington, federally-protected adult salmonids (Oncorhynchus spp.) often encounter relatively cool water in dam tailraces and lower ladder sections and warmer water in the upstream portions of ladders. Using radiotelemetry, we exami...

Cyanobacterial blooms are potential health hazards in water supply reservoirs. This paper reports analyses of a cyanobacterial bloom by use of PCR-based methods for direct detection and identification of strains present and determination of their toxigenicity. Serial samples from Malpas Dam, in the New England region of Australia, were analyzed during a prolonged, mixed cyanobacterial bloom in ...

In January 2006 the French Committee on Dams and Reservoirs – FrCOLD issued provisional guidelines for structural safety of gravity dams. It was the first attempt to produce a semi-probabilistic limit-state method for the design of hydraulic works, in a format similar to the Eurocodes. After 5 years of a progressive implementation of those guidelines, FrCOLD decided to produce an upgraded and e...