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In Channel Systems for Providing Endangered Species Habitat While Providing Continued Water Delivery and Use and Power Production

Project ID: 7621
Principal Investigator: Drew Baird
Research Topic: Sediment Management and River Restoration
Funded Fiscal Years: 2005, 2006 and 2007
Keywords: None

Research Question

Endangered aquatic species needs throughout the Western United States have the potential via court action to increase river flows, thereby potentially reducing water and power deliver to Reclamation customers.

* What are stable instream structures that will provide habitat to help recover endangered species thereby reducing adverse water delivery impacts?

* Can simple instream channel structures be developed that improve habitats and provide bank and bed stabilization and reduce sediment deposits near fish screen structures?

Need and Benefit

Effective use of limited water and power resources while meeting endangered species habitat requirements is becoming increasingly contentious and difficult to achieve in the Western United States. Water users desire to continue to use historic water supplies, power users desire to maximize power production, while Endangered Species Act (ESA) compliance causes increased water supplies for endangered species habitats.

River restoration structures can be used to meet requirements of threatened and endangered species while enabling continued water use and delivery, and power production by increasing the quality and diversity of the habitat. Native material habitat restoration structures have been constructed without knowledge of the engineering performance properties and, as a result, fail to perform as intended. Many restoration structures also provide bank and bed stabilization benefits. Restoration structures that provide bed stabilization are used as water diversion structures and roughened channels for fish passage and are constructed using boulders without the traditional structural features of sheetpile walls or geomembranes.

In addition, past methods of bank stabilization offered limited habitat value or diversity. Transverse structures used in habitat restoration also are used to reduce sediment deposits in front of fish screen and bypass structures. Currently, methods and standards based upon predictable engineering and hydraulic performance to implement the above listed structures with habitat value do not exist. Yet Reclamation personnel are tasked with implementing these types of structures on many rivers throughout the Western United States, including but not limited to the Rio Grande Basin, the Columbia River Basin, the Sacramento River basin and the Lower Colorado river. To address the lack of methods and standards, the Albuquerque Area Office began a physical hydraulic model study in fiscal year (FY) 2001 at Colorado State University. The purpose of the physical model study is to measure the engineering and hydraulic performance properties of these structures in both a fixed bed model with bends of the same shape as natural rivers, and a mobile bed flume. From FY 2001 to the present, the physical model has been used to develop engineering and hydraulic performance data for restoration and bank stabilization structures.

In addition, the U.S. Army Corps of Engineers (Corps) Engineer Research and Development Center recognized the lack of methods and standards and is conducting a field survey of these type of structures. The goal of the Corps' research is to compile a database that can be used to characterize long term performance. The Corps recognized the need to integrate the physical model and field performance data and offered their data set to Reclamation. Reclamation's laboratory data provides detailed information in a controlled setting that can be used for planning and performance that can not be measured accurately in the field. The Corps research provides long-term performance data and river system effects on the structures and the effects of the structures on the river system that can not be measured in the laboratory. In addition, the Corps research provides an assessment of whether or not the structures actually perform their intended purpose, and a comprehensive inventory of individual project performance.

Together, both will provide Reclamation personnel with the ability to select and design the most appropriate river restoration and bank/bed stabilization structures that meet project purposes in the most environmentally and cost effective manner consistent with river conditions. The laboratory data can be extended to river conditions not tested in the laboratory using the Corps field data. This research will render the results useful for rivers and projects throughout Reclamation.

Contributing Partners

None

Research Products

Independent Peer Review

The following documents were reviewed by qualified Bureau of Reclamation employees. The findings were determined to be achieved using valid means.

Alphabet Weirs Physical Modeling (interim, PDF, 5.0MB)
By Joseph J Mecure
Report completed on October 02, 2006

Physical model objectives were to quantify dimensions of scour pools downstream of cross channel weirs, measuring bed and water-surface elevations to develope water-surface profiles, and measuring 3-dimensional velocity to analyse velocity and shear stress distributions in the model. The project included constructing the physical model, testing, and measurments for three bed gradations (5mm, 9.8mm, and 15mm) and three discharges 1/3, 2/3, and bankfull discharge.
Keywords: in-stream rock structure, u and w weir scour, physical modeling

Stage-Discharge Relationships For U-A-, and W-Weirs in Un-Submerged Flow Conditions (interim, PDF, 446KB)
By Dr. Christopher Thornton, Anthony M Meneghetti, Mr. Kent Collins, Dr. Steven R. Abt and S. Michael Scurlock
Report completed on February 01, 2011

Instream rock weirs are placeed to provide grade control, reduce bank erosion, provide energy dissipation and allow fish passage. Stage-discharge relationships for subcritical-unsubmerged flow conditions were developed as a function fo the effective weir length, flow depth, mean weir height, rock size, and discharge coefficient. Discharge coefficients for weirs was proposed for determining upstream stage-discahrge rating.
Keywords: rock weirs, stage-discharge ratings, streamflow measurements, stream restoration structures

Numerical Analysis of River Spanning Rock U-Weirs: Evaluating Effects of Structure Geometry on Local Hydraulics (interim, PDF, 1.6MB)
By Chris Holmquist-Johnson
Report completed on July 01, 2011

3D numerical modeling simulations were used to examine the effects of variations of U-weir geometry on upstream water surface elevations and downstream velocity and bed shear stress. Geometry variations included arm angle, arm slope, drop height and throat width. Maximum velocity increase ranged from 1.24-4.04 times the reference velocity in the channel with no structure present. Similarly, maximum increase in bed shear stress was 1.57-7.59 times critical bed shear stress for bed mat'l size
Keywords: 3d numerical modeling of u-weir, cross channel structure hydraulics, shear stress, velocity

Equilbrium Scour Downstream of Three-Dimensional Grade-Control Structures (final, PDF, 1.0MB)
By Dr. Steven R. Abt, S. Michael Scurlock and Dr. Christopher Thornton
Report completed on July 25, 2011

A-, U-, and W-shaped rock weirs are commonly used in streams for grade-control, bank stability, and fish habitat enhancement, yet 3-dimensional scour hols develop downstream of the weir crest and often undermine the weir foundation. This paper summarizes laboratory experiments conducted and evaluated existing scour-prediction methodologies. New dimensionless expressions were developed for the prediction of scour depth accounting for weir geometry.
Keywords: scour downstream of 3-d cross channel structures, hydraulic structures, weirs, rivers, grade-control structrues

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Qualitative Evaluation of Rock Weir Field Performance and Failure Mechanisms (final, PDF, 4.5MB)
By David Mooney, Chris Holmquist-Johnson and Elaina R Holburn
Report completed on September 03, 2007

River spanning loose provide sufficient head for irrigation diversion, permit fish passage over barriers, protect banks, stabilize degrading channeles, activate side channels, reconnect floodplains, and create in-channel habitat. This document describes initial field observations and hypotheses developed through field reconnaissance as a first step in evaluating river spanning loose rock structures. The objective was to identify physical processes related to success or failure.
Keywords: river spanning loose rock structures, fish passage, rock weirs, rock ramps

Quantitative Investigation of the Field Performance of Rock Weirs (interim, PDF, 1.4MB)
By Ms. Elaina R Holburn, Mr. David Varyu and Ms. Kendra Russel
Report completed on December 29, 2009

This report covers field analyses of rock weir performance in support of a broader research effort on river spanning rock structures. Topographic surveys of 76 structures was completed, the most likely cause of rock dislodgement was identified to include throat width, scour depth, peak flows, head drop, depth of footer rocks, and structure spacing where multiple structures were constructed in series.
Keywords: river spanning loose rock structures, u, w, and a weirs, scour

Rock Ramp Design Guidelines (final, PDF, 1.0MB)
By David Mooney, Chris Holmquist-Johnson and Susan Broderick
Report completed on June 28, 2014

Rock ramps or roughned channels consist of steep reaches stabilized by large immobile material (riprap). The Primary objectives of rock ramps include:1) create adequate head for diversion, 2) maintain fish passage during low flow conditions, adn 3) maintain hydraulic conveyance during high-flow conditions. Secondary objectives include: 1) emulate natural systems, and 2) minimize cost. This design guide outlines the process for designing rock ramps.
Keywords: keywords: rock ramps, fish passage, diversion structures

This information was last updated on September 18, 2014
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