Model to determine how dams affect river geomorphology
Scientists with the U.S. Geological Survey are proposing a conceptual model of how interacting dams might affect river geomorphology, resulting in distinct and recognizable morphologic sequences that they term “inter-dam sequence” characteristics of major rivers in the U.S.
In the October 2013 issue of Anthropocene, the scientists detailed the history of anthropogenic modification on the Missouri River and its considerable impacts on river and riparian ecology, form and function. Several large dams were built in the basin during the 20th century to serve needs for irrigation, flood control, navigation and power generagion. Fifteen dams impound the main stem of the river, with hundreds more on tributaries.
Scientists say the effects of dams and reservoirs have been studied individually, with relatively little attention paid to their interaction along a river corridor. They examined the morphological and sedimentological changes in the Upper Missouri River between Garrison Dam in North Dakota and Oahe Dam in South Dakota. Garrison impounds water for a 517.8-MW powerhouse, while Oahe’s powerhouse has a capacity of 786 MW.
Using aerial photography, stream gage data and cross-sectional surveys, the researchers 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.
The scientists also conducted a geographic analysis of dams along 66 major rivers in the contiguous U.S. to determine how often dams occur in series. Of the rivers analyzed, 404 dams were located on the main stem of 56 of the rivers. Fifty of these rivers had more than one dam, creating a total of 373 possible interacting dam sequences. More than 80% of large rivers may have interactions between their dams.
“The unique contribution of this study is development of a conceptual model that establishes a framework for future studies of the many rivers affected by dams in series,” said Jerad Bales, acting associate director for water with USGS.
For more information, visit www.usgs.gov/newsroom/article.asp?ID=3777#.UvqTh4Wor3M.
Corps to perform sturgeon and lamprey studies
The U.S. Army Corps of Engineers is looking to hire companies to perform studies and hatchery work aimed at propagation of endangered pallid sturgeon on the Missouri River. Under the Missouri River Recovery Program, the Corps is required to monitor, propagate and conduct investigations in the Missouri River on pallid sturgeon to meet jeopardy avoidance requirements of the U.S. Fish and Wildlife Service’s 2003 amended biological opinion.
On the Missouri River below 185.3-MW Fort Peck Dam in Montana, a hatchery is to be established that has a Fish and Wildlife Service permit for raising pallid sturgeon. The company chosen also must obtain a FWS endangered species handling and collection permit for monitoring and focused investigations related to the sturgeon species. If the Corps determines there are no other qualified sources, it intends to issue the contract to the Montana Fish, Wildlife and Parks Commission.
The work discussed above is also to be conducted from the Missouri River below the Nemaha River in Nebraska to the Mississippi River and in the lower Kansas River below Bowersock Dam, site of the 6.5-MW Kansas River project in Kansas. In the absence of other qualified sources, the Corps will issue the contract to the Missouri Department of Conservation.
On the Missouri River below 132.3-MW Gavins Point Dam in Nebraska to the Nemaha River in Nebraska, the chosen company is to obtain a FWS endangered species handling and collection permit, a Nebraska Game and Parks Commission endangered species collection permit and provide other equipment necessary to the work. Lacking other qualified sources, the Corps will issue the contract to the Nebraska Game and Parks Commission.
Finally, on the Missouri River in South Dakota, the company must obtain an FWS endangered species handling and collection permit, a South Dakota Department of Game, Fish and Parks endangered species permit for pallid sturgeon and other equipment necessary to the work. Without other qualified sources, the Corps will issue the contract to the South Dakota Department of Game, Fish and Parks.
In other news, the Corps plans to hire a small business to perform a lamprey migration and passage study at four hydro projects on the lower Snake River.
Work would include radio tracking of adult lamprey through the lower Snake River dams to determine behavior, passage routes and success during upstream migration. Work would be performed at the 603-MW Ice Harbor, 810-MW Lower Monumental, 810-MW Little Goose and 810-MW Lower Granite dams.
CEATI offers four new guides for the hydro industry
CEATI International has recently published the results of four projects relevant to the hydropower industry:
– Hydro Generator – General Maintenance and Inspection Guide outlines the activities that constitute a good maintenance philosophy for hydro generators in order to maximize unit availability and reliability. It is concerned primarily with the generator and is restricted to those components on the generator side of the main shaft coupling. The guide primarily deals with vertical units, as they form the vast bulk of the fleet and capacity of hydro generators worldwide, CEATI says. The guide was released by the Hydraulic Plant Life Interest Group (www.ceati.com/publication-details?pid=0380).
– Technology Review: Brushgear Maintenance Guide provides definitions for terms commonly used in the design, operation and maintenance of slip ring and commutator type brush gear systems used on hydroelectric generator units. The defined terms are to be used in conjunction with other sections of the Brushgear Maintenance Guide, which provides key parameters, tolerances, testing and verification procedures for various types of hydro turbine-generator units. The guide was released by the HPLIG (www.ceati.com/publication-details?pid=0343B).
– Dam Safety Inspection Procedures, Guidance and Training for Plant Operators is intended to help hydro plant operators recognize, understand and respond to potential dam safety hazards. The guide serves as the participant’s manual for the associated Dam Safety: Training for Hydroelectric Plant Operators. It is intended to be a primer on dams and associated structures, as well as a reference for surveillance monitoring and emergency preparedness and response activities at dams that impound water for hydro generation. The guide was released by the Dam Safety Interest Group (www.ceati.com/publication-details?pid=0227).
– Comparison of Flood Hazard Estimation Methods for Dam Safety – Phase 1 provides a structured review of the available and evolving methods for estimating flood flows, where they are used and the assumptions and limitations they contain. The project outputs are provided in two task reports: Task 1 provides a review of the regulatory frameworks in place around the world and their impact on the estimation of flood flows, and Task 2 focuses on the estimation approaches themselves. The guide was released by the DSIG (www.ceati.com/publication-details?pid=0225).
CEATI’s electrical utility participants collaborate and act jointly to advance the industry through the sharing and developing of practical and applicable knowledge.