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Environmental Hydraulics

Program Lead: Brent Mefford, 303-445-2149

The environmental hydraulics program in the Hydraulic Investigations and Laboratory Services Group is focused on applied research to improve environmental compatibility of man's use of water. Reclamation is a provider of irrigation water, municipal and industrial water and power generation. Protecting the resource and managing increasing demands on the resource has created a strong environmental program within the laboratory that includes work in the areas of fish protection, fish passage, reservoir release water quality programs, river restoration projects, and wetlands design. These programs are undertaken by cooperative, interdisciplinary teams of engineers, biologists and resource managers.

Fish Protection/Screening

The use of positive barrier screens is common practice for protection of fish at all types of water intakes. Screen performance must meet stringent criteria developed by state and national resource agencies. The Hydraulic Investigations Group can perform laboratory and field evaluations of positive barrier screens using innovative techniques and sophisticated instrumentation. In addition, we perform research on new screening technologies aimed at developing new designs and improving existing designs to better meet evolving bioengineering requirements.

Online report: Model Tests Of Air Burst And Hydraulic Back-Flush Cleaning Efficiency For A Cook Cylindrical Screen
Abstract: A 2-ft-diameter by 2-ft-long cylindrical fish screen was loaned to Reclamation by Cook Screens for cleaning efficiency tests. The screen was constructed of wedgewire with 1.75 mm openings between the wires. The screen was installed in a recirculating flume located at Reclamation’s Water Resources Research Laboratory in Denver, Colorado. The following test sequence was conducted on the screen: clean screen velocity profile, clogged screen velocity profile, air burst cleaning tests, hydraulic back-flushing cleaning, and clean screen velocity profile with 45 degree upstream cone.

Fish Passage

The Hydraulic Investigations Group is working to develop improved fish passage technologies for native and sport fisheries. Passage for both warm and cold water species are being studied. Laboratory and field demonstration research is being conducted for design and evaluation of fish ladders and fish locks for small diversion dams and fish pumps for screen bypasses.

Online report: Physical Model Studies of the GCID Pumping Plant Fish Screen Structure Alternatives.
Abstract:The Bureau of Reclamation constructed a positive barrier fish screen (alternative D) physical model for GCID (Glenn-Colusa Irrigation District) to evaluate, improve, and document the viability of the concept as a means to protect the fishery resource. The information included in this report is provided to the GCID Technical Advisory Group to assist in the evaluation of proposed screen alternatives and to provide design data for the selected alternative. Results demonstrate the D alternative is a viable design. The study results show the long flat plate screen concept can be designed to meet the listed objectives. A series of modifications to the screen design was identified and instituted through the model study to improve performance. Prior to completion of model testing, a final test was conducted to verify repeatability of the data. The final configuration test results showed satisfactory agreement of data.

Reservoir Release Water Quality

Maintaining the water quality of reservoir releases is an important goal of Reclamation water storage projects. Reservoir curtain structures, louvered intake controls, and multi-level intake structures developed and tested by the Hydraulic Investigations Group have improved release water temperature, turbidity, dissolved oxygen content and gas supersaturation levels.

Online report: Modifying Reservoir Release Temperatures Using Temperature Control Curtains
Abstract:Reclamation (Bureau of Reclamation) has constructed four temperature control curtains to reduce release water temperature at structures in the Sacramento and Trinity River drainages in northern California. These curtains provide selective withdrawal at intake structures, control topography induced mixing, and control interfacial shear mixing associated with plunging density currents entering reservoirs. Comprehensive field monitoring has been conducted to measure curtain performance characteristics. Monitoring included continuous temperature profiling, and velocity profiling using an ADCP (acoustic Doppler current profiler). This paper presents and summarizes performance data collected near curtains in Lewiston and Whiskeytown Reservoirs.

River Restoration

River restoration is another important component of enhancing environmental compatibility of the many structures and activities that reside within or adjacent to our streams and rivers. Mining, flood protection, land use channelization and many other factors have altered to some degree most of America's rivers. In some cases, these activities have greatly degraded the natural riverine environment. The Hydraulic Investigations Group is working with other federal, state, and local organizations to revitalize rivers that have been severely impacted. Grade and planform stabilization of Muddy Creek (Sun River basin, Montana) and research on flushing of spawning gravels are two ongoing projects in this area.


Natural and constructed wetlands are diverse and complex microenvironments. Hydraulic Investigations Group researchers are working with other resource scientists to identify the importance of flow and cycling of water to a healthy wetland.

Last reviewed: 03/28/12