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Local and Regional Projects

Idaho agriculture is the second largest user of water for irrigation in the US and diverts more water for aquaculture than the rest of the US combined. Idaho has more than 93,000 miles of streams, with over 3,000 miles of world-class whitewater. These streams contain 19 species that are endangered, threatened, or species of concern. Over 900 rivers or river segments have been designated as impaired for water quality with the primary concerns being fine sediments and temperature. There are also concerns regarding geomorphic and ecological integrity of streams in the face of these stressors.

The Center for Ecohydraulics Research conducts research relevant to water challenges in Idaho and the West, and receives advice and direction from state and federal agencies to ensure research relevance. Recent local and regional projects have been performed in collaboration with the U.S. Forest Service, the U.S. Bureau of Reclamation, the Columbia River Inter-Tribal Fish Commission, the Kootenai Tribe, Idaho Power, the city of Boise, Boise Flood Control District, and the Idaho Department of Water Resources.

Globally, anthropogenic impacts have altered hydrology, morphology water quality, and thermal regime of streams. As a result, critical habitats of many cold water aquatic species have been negatively impacted, which may be exacerbated by climatic variability and lead to localized species extirpation. For recovery programs to meet their long-term goals for cold-water aquatic species, they must consider mitigating the impacts of warming waters with “thermal restoration” and creation of thermal refugia. This study seeks to understand the impact of various restoration strategies on altering localized stream temperatures and quantify the available thermal refugia provided by a recent river restoration project.

Study Site:

Grande Ronde River, Oregon


Thermal mapping of surface and groundwater.
Numerical simulations of coupled surface and groundwater models.

Funding Agency:

U.S. Bureau of Reclamation

Riparian forests and floodplains are some of the most productive and diverse ecosystems in the world and are under threat from hydropower development, agriculture, and urbanization. This project identifies riparian forest recruitment processes that occurred after a riparian wildfire and develops a spatially-distributed riparian vegetation recruitment model to predict areas of successful natural recovery and restoration forest planting. Further, numerical modeling of sediment transport is related to successful recruitment areas to explore the importance of depositional and erosional processes for successful native riparian forest regeneration.

Study Site:

South Fork Boise River, Idaho


Field mapping of floodplain groundwater and riparian seedling recruitment.
Numerical simulations of coupled 2D surface water and riparian vegetation models.

Funding Agency:

U.S. Bureau of Reclamation

Computer animations showing simulations of future scenarios and flood risks for the Boise River were presented at the Treasure Valley Water Summit (January 2002). This collaborative research undertaken with the USGS, city of Boise and the U.S. Army Corps of Engineers and was funded by FEMA, Idaho Bureau of Disaster Services, USGS and the city of Boise.

Reduction of x-sectional flow area: 20 percent

Physical Modeling Of Wave Generation For The Boise River Recreation Park

The Boise River Recreation Park, to be located just 2 km from the center of downtown Boise is currently in the design and planning phase.

The park design features a 0.6 km reach of the Boise River with enhanced recreational and ecological value — including whitewater features that are operational year around, low-hazard river access and passage, and improvements of the river riparian zone and fishery habitat. Planned whitewater features include a pool and drop standing wave feature.

One design goal is to produce a large and low-hazard standing wave at low to moderate river flow rates (7 to 70 cms).

A quarter-scale physical model of a novel wave generating structure is being investigated in the recently completed Center for Ecohydraulics Stream Laboratory (CERSL) flume.

The objective of the present project is to demonstrate an abrupt drop structure that will produce a standing wave with features that are desired by whitewater boaters and that will operate over a wide range of flow rates.

Research publication:

Budwig, R., McLaughlin, R.E., Clayton, S., Sweet, S., and Goodwin, P. Physical modeling of wave generation for the Boise River Recreation Park in the Center for Ecohydraulics Stream Laboratory. In review for the Proceedings of the International Conference of Science and Information Technologies for Sustainable Management of Aquatic Ecosystems, Concepción, Chile, January 12 -16, 2009.


  • Richard E. McLaughlin, McLaughlin Whitewater Design Group, Denver, CO
  • Steve Clayton, CH2M Hill, Boise, ID
  • Steve Sweet, Quadrant Consulting, Inc., Boise, ID
  • Peter Goodwin, Center for Ecohydraulics Research, Boise, ID

See the Waveshaper™ preliminary testing in the CER Stream Laboratory for the Boise River Recreation Park

Contact for further information:

Ralph Budwig
Professor and Director of the Center for Ecohydraulics Stream Laboratory 
Center for Ecohydraulics Research

University of Idaho
322 East Front Street, Suite 340
Boise, ID 83702

Phone: 208-364-4996
Fax: 208-332-4425 

Our research focuses on estimating post-fire sediment inputs to several tributaries of the South Fork Salmon River. After severe forest fires in the summer of 2007, heightened landslide, overland flow and debris flow occurrences may have contributed to increase erosion rates. Higher post-fire erosion rates have implications for forest vegetation recovery and aquatic habitat quality; such effects may be indicative of the future impacts of the more frequent and severe forest fires promoted by current climate change.

Research Questions:

  • What is the relative sediment input of landslides, debris flows and overland flow to the channel?
  • How does slope aspect, angle and burn severity affect overland flow erosion rates?
  • How much of the input sediment has been stored in the floodplain? How much has left the basin
  • How do these input rates compare to long-term (decadal to millennial) erosion rates?


  • Several tributaries to the South Fork Salmon River, Payette National Forest, Idaho.


  • Ground mapping of landslide and debris flow deposits and volume eroded.
  • 137Cs and 210Pb profiles of hillslope samples to determine overland flow erosion rates.

National Science Foundation


Rolf Aalto, Department of Geography, University of Exeter

Our research project focuses on effects of climate change and fire on sediment transport and aquatic habitat on South Fork of Salmon River basin. Climate change will alter the temperature and precipitation patterns in Idaho’s forested watersheds. This project analyzes a range of climate change scenarios within Idaho. Specially, increasing temperature in summer months can result in increased fire severity. After a wildfire, erosion and mass wasting processes often increase and alter the sediment supply to the streams. Intense rainfall and extreme floods may also be expected. This project aims to understand the effects of climate change and forest fire on sediment transport. We will use a one dimensional sediment routing model combined with different climate change and fire scenarios in mountainous streams. The model will be used to determine the impact of climate change and fire on sediment transport rates, water quality and aquatic habitat. The research results could be used for forest watershed management and by stream ecologists to assess the impact of climate change on aquatic ecosystems.


  • Develop climate change driven 1D sediment transport model
  • Measure hydrology (Flow velocity/ flow depth) and bed properties (width/slope/grain size/step size/boulder size)
  • Monitor suspended and bedload sediment transport
  • Calculate hillslope contributions to the channel

Study site:

Tributaries of South Fork of Salmon River

Funding Agency:

NSF Idaho EPSCoR Program

U of I Engineers Work to Aid Pacific Lamprey Migration Along the Columbia River

University of Idaho engineers, working with the College of Engineering’s Center for Ecohydraulics Research (CER), the Army Corps of Engineers, National Oceanic and Atmospheric Administration (NOAA) Fisheries, and Pacific Northwest tribal representatives have installed two Pacific lamprey (Entosphenus tridentatus) passage structures (LPS) at the Bonneville and John Day dams along the Columbia River.  The LPS have been constructed to assist with lamprey migration and improve declining populations.

University of Idaho, Center for Ecohydraulics Research Director, Ralph Budwig, civil and environmental engineering professor, Danielle Tonina, civil and environmental engineering graduate research assistant, Hattie Zobott, and fish and wildlife sciences professor, Christopher Caudill designed the LPS at the north shore of Bonneville Dam in consultation with NOAA Fisheries and tribal representatives and installed it with a grant secured by Caudill from the Army Corp of Engineers.  A smaller team composed of Tonina, civil and environmental engineering student, J. Channing Syms, and lab engineer Bob Basham installed a second LPS at John Day Dam also on the Columbia River.

The Pacific lamprey is an ecologically important fish species throughout the Pacific Rim as well as a being culturally significant to Pacific Northwest Native American tribes. The Columbia River Inter-Tribal Fish Commission has tracked Pacific lamprey populations over the past decade and noted a significant decline. Once lamprey returned to the Columbia in the millions, but in 2010 lamprey returns at Bonneville dam were recorded at an all-time low of 23,000.

According to Budwig the first issue recognized by fish biologists contributing to lamprey decline was that existing Salmon passageways at Bonneville and John Day dams were designed to aid Salmon migration. These passageways do not accommodate the Pacific lamprey’s natural anguilliform mode of swimming and in particular the lamprey’s unique use of their disk mouth to climb through suction.

Secondly according to Budwig the engineering challenge in designing lamprey passageways was to figure out not only the best design to facilitate the lamprey’s natural inclination to climb but to solve the problem of integrating LPS into the complex design of Bonneville and John Day dams without effecting how they operate.  This component of the project was very important to the Army Corps of Engineers who run both dams.

The resulting work is a unique series of aluminum ducts much like you’d find in any home or business heating and air condition system but much more complex and flowing with water. According to Zobbot, there are three components to the University of Idaho LPS, the climbing, traversing and resting sections. The climbing portions of the LPS are made up of ductwork 20 inches wide by 6 inches tall. The traversing sections are generally 9 inches wide by 6 inches tall and the rest boxes are approximately 30x30x30 inches. From the lamprey perspective they migrate along the bottom and edges of the river.  They then naturally congregate at specific areas below the dam which is where a Lamprey Flume Structure installed by the Army Corp of Engineers collects lamprey and then interfaces with the multiple component University of Idaho LPS system that facilitates climbing.

The work on lamprey passage at migration barriers on the Columbia River has earned U of I researchers the American Society of Civil Engineers, Environmental & Water Resource Institute and American Fisheries Society Bioengineering Section Fisheries Engineering Committee Distinguished Project in Fisheries Engineering and Ecohydrology Honorable Mention Award.

Watch Video Here

Center for Ecohydraulics (CER)

Center for Ecohydraulics Research

Mailing Address:

322 E. Front St., Suite 442
Boise, ID 83702

Phone: 208-364-6164