A Comprehensive Assessment of Fish Passage Barriers in the Scappoose Bay Watershed

Identification Information

Citation

Originator: Scappoose Bay Watershed Council and David Evans and Associates, Inc.

Publish Date: May 2001

Online Link: http://www.scappoosebay-wc.org/contents/fishbarrier.pdf

BPA Project #:

Contact Information

Agency: Watershed Councils

Name: Janelle St. Pierre

Job Position: Scappoose Bay Watershed Council Coordinator

Telephone: (503) 397-7904

E-Mail Address: janelle@scappoosebay-wc.org

Description

Abstract: The fish passage barrier assessment project began in June 2000. The Scappoose Bay Watershed Council (Council) contracted the project to David Evans and Associates, Inc.(DEA). The project consisted of two stages: Stage I, field surveys, and Stage II, analysis and prioritization. Field crew surveyed 293 road crossings, dams, and other human caused obstructions of known fish-bearing streams. Of these crossings, 131 potential barriers were identified that did not meet ODFW fish passage design criteria for passage of juvenile and adult salmonids. Most of the culverts and dams were found to be barriers. None of the bridges surveyed were identified as barriers. Of these potential barriers, the top 107 were surveyed in more detail, including surveys of fish and upstream and downstream channel conditions. For Stage II of the project, the detailed data for 107 potential barriers was used in hydrologic and hydraulic analyses to determine the severity of the barriers for various sizes and species of fish, existing flood capacity, and design options. If hydraulic analysis using the design flows indicated that the barrier did not meet fish passage criteria for the full range of salmonid species and life stages tested due to either high velocity or leap height, it was considered a complete barrier. Seventy-seven percent (77%) of the barriers were found to be complete barriers and the remainder were identified as partial barriers. Conceptual designs were developed and preliminary cost estimates were prepared for each of the 107 barriers. Barriers were then prioritized by sub-watershed and for the watershed as a whole. Prioritization was based on whether the barrier was partial or complete, and based upon a Habitat Index score. The Habitat Index summarized upstream habitat quantity and quality as measured by habitat length and access to refugia identified previously in the Scappoose Bay Watershed Assessment. The highest priority projects in this ranking system were those that were located in key subwatersheds, were complete barriers, provided access to refugia, and opened up the greatest length of upstream fish habitat. This prioritization is a provisional guideline. Additional factors, such as ownership and condition of the barrier, were also provided for use by various organizations in selecting correction projects.

Purpose: The goal of this project was to obtain the information most useful for expediting the correction of numerous barriers in the 85,000-acre Scappoose Bay Watershed, located along the Lower Columbia River. The Scappoose Bay Watershed Assessment recommended that a comprehensive assessment be conducted to identify and prioritize artificial fish passage barriers that occur in the watershed and to develop preliminary designs and cost estimates for correction of each barrier. This precedent-setting project, which was funded by most of the stakeholders in the watershed, was intended to provide the information needed to most effectively plan for barrier corrections and obtain the funding to conduct restoration projects in the near future.

Time Period of Content:

Geographic Extent: Scappoose Bay Watershed

Status: Final

Use Constraints:

Format: PDF file

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Is a physical copy maintained for reference at Headquarters? Unknown