dam

A regional analysis of the impact of dams on water temperature in medium-size rivers in eastern Canada

Source: 
Canadian Journal of Fisheries and Aquatic Sciences
Volume: 
73
Year: 
2016
Abstract: 
Various studies have helped gain a better understanding of the thermal impacts of dams on a site-specific basis, but very few studies have compared the thermal impacts of varying types of dams within the same region. In this study, we conducted a regional-scale assessment of the impacts of dams on the thermal regime of 13 medium-size rivers in eastern Canada. The objectives of this study were to identify features of the thermal regime of rivers that are predominantly impacted by dams and to compare the impacts associated with different types of regulation (run-of-river, storage, peaking). The thermal regime of regulated and unregulated rivers was characterized using 15 metrics that described the magnitude, frequency, duration, timing, and rate of change of water temperature. Results indicate that storage and peaking dams impounding at least 10% of the median annual runoff generally (i) reduced the magnitude of water temperature variation at seasonal, daily, and subdaily timescales and (ii) increased the monthly mean water temperature in September. This regional assessment offers important insight regarding a generalized pattern of thermal alteration by dams, and this information could be used to guide biological monitoring efforts in regulated rivers.
Author(s): 

Audrey Maheu, André St-Hilaire, Daniel Caissie, Nassir El-Jabi, Guillaume Bourque, and Daniel Boisclair

Category: 

Eliminating Sediment Problems Cheap, Easy and Permanently

Source: 
Waterpower XVI
Year: 
2009
Abstract: 

When talking about sediment issues at hydropower plants or other hydro facilities operators usually face millions of dollars removing or even reducing their problems. Only when economic and/or ecologic pressure starts to force action companies usually drag the sediment or try to flush it out by the dam’s main valve. A prominent example is the great rinse of the Colorado River in 2008 which is going to be repeated at least every two years, probably more frequently. Here each flush comes with the transport of some hundred thousand tons of sediment, but unfortunately also with the loss of some million cubic meters of water and therefore some million dollars in power generation revenues. Dragging the sediment comes with the shutdown of a concerned facility for several months causing the same or even bigger economical effect.A hydro storage power plant in Germany almost inoperable due to sedimentation turned out to be the start for a complete different approach. A combination of wet dredging, new equipment operation techniques and plant operation allows for low cost and no negative effect on plant performance. Once implemented, three years later the plant and combined reservoir is going to be free from sediment problems permanently. The new technical approach is transferable on almost any range of plants, small to large and run-of-river to pump storage. It also restores river morphology almost back to its natural situation improving often criticized ecological matters. Best of all: It fully suits European Water Framework Directive and U.S. sediment acts at no extra cost. 

Author(s): 

Joachim E. Hewicker, Michael Detering

Contact: 
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Category: 

Offering Public Access While Maintaining Security

Source: 
Hydro Review
Year: 
2005
Abstract: 

The events of September 11, 2001 caused a shift in thinking about public access at hydro facilities, but the need to provide recreation remains. A Federal Energy Regulatory Commission team works to help owners keep their projects secure while still providing essential public access. 

Author(s): 

Heather E. Campbell & Frank Calcagno, Jr.

Contact: 
Notes: 
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