Design of Road Culverts for Fish Passage


This document is provided for archival purposes only. Archived documents do not reflect current WDFW regulations or policy and may contain factual inaccuracies.


Published: 2003

Pages: 112

NOTE: Works in Progress - These "works in progress" have been developed to show the progress being made with the Aquatic Habitat Guidelines program. Drafts of guidelines currently under development, as well as information pertaining to their development, are presented here. The "works in progress" documents posted on this site illustrate the thoughts of those individuals contributing to the program. The information provided is continually changing and being updated. The "works in progress" documents do not necessarily reflect current guidelines or the policies of state agencies. By entering the links below, you agree to use these documents as discussion drafts only.


Design of Road Culverts for Fish Passage is part of a series called the Aquatic Habitat Guidelines. The Aquatic Habitat Guidelines collection was created by a consortium of public agencies to assist property owners, planners, designers and regulators in protecting and restoring marine, freshwater and riparian fish and wildlife habitat. The agencies involved in developing this series include the Washington Department of Fish and Wildlife, the Washington State Department of Transportation, the Washington Department of Ecology, the U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service. The authors of the guidelines are widely recognized experts in their fields. The content and organization of information is based on a set of guiding principles developed by professional resource managers, engineers and other practitioners.

Each guideline is based on current best science and technical practice surveyed in topical state-of-the- knowledge white papers or a thorough literature search. Their content includes background science and literature; policy issues; site and vicinity environmental-assessment processes; project-design processes, standards and details; and case studies. Technical assistance materials produced under the Aquatic Habitat Guidelines program include documents in printed, compact-disc, and web-page format, as well as training and outreach workshops. You can obtain additional copies of this and other available guideline documents, downloadable versions of white papers, drafts of guidelines in development and other information about the Aquatic Habitat Guidelines on line by visiting the WDFW website.

The overwhelming majority of Washington's fish and wildlife species depend on aquatic and riparian ecosystems for all or part of their life cycle. This rich and diverse fauna, and the flora on which they depend are irreplaceable elements of Washington's natural resources and are the basis for much of the state's cultural heritage, economy and quality of life. Unfortunately, in our enthusiasm for enjoying and developing land surrounding these aquatic habitats, we have destroyed, degraded and fragmented many of our most precious marine, freshwater and riparian ecosystems. Over time, these adverse impacts have resulted in the federal listing of many marine, freshwater and riparian animal species as "endangered" or "threatened" under the federal Endangered Species Act, and the state of Washington's wildlife protection legislation. Of particular note is the listing of several salmon species under the ESA.

In 1999, Governor Gary Locke and several Washington State agencies adopted a statewide strategy to protect and restore salmon habitat in the state. At the heart of the strategy is the hands-on involvement of landowners and other individuals. Incentives and technical assistance in salmon protection/recovery initiatives are included in the strategy to encourage such participation. In the 1999-2001 biennium, Washington State distributed nearly $50 million to more than 300 salmon protection/recovery projects sponsored by local governments, watershed groups, County Conservation Districts, Regional Fisheries Enhancement Groups, volunteer groups and individuals. For such involvement to be effective, there is an urgent need for increased technical guidance to ensure that these local efforts are strategic in approach, address the source of a problem and not just the symptoms, make the best use of limited funds and are based on the best available science that can be consistently and effectively applied across the landscape. The Aquatic Habitat Guidelines program is designed to help provide this technical assistance.

Each guideline in the Aquatic Habitat Guidelines series is designed in part to provide technical guidance supporting regulatory streamlining; however, it is important to remember that the information in these guidelines is not a substitute for the law. Current local and state policies, rules and regulations supersede any and all recommendations made in these guidelines.

The Aquatic Habitat Guidelines Program was created to:

  • address habitat requirements and guide recovery projects for marine, freshwater and riparian animal species listed under the federal ESA;
  • facilitate consistent application of good science and technical practice for project designs, construction and operations affecting aquatic systems;
  • increase the success rate and enhance the worthwhile expenditure of public funds on protection and recovery projects;
  • streamline and reduce costs for environmental review and permitting for activities that affect marine, freshwater and riparian ecosystems; and
  • provide a single set of benchmarks for the evaluating and prioritizing projects affecting aquatic and riparian habitats.

To carry out such a mission, the program is designed to meet the following objectives:

  • make the expertise of professional resource managers available to a wide variety of organizations and citizens who are seeking assistance in habitat protection and restoration activities;
  • streamline local, state and federal regulatory review of activities involving aquatic environments by providing guidelines based on best available science;
  • provide a scientific basis for any future changes to current local policies or activities associated with aquatic resource in the state; and
  • maintain ongoing reviews and updates to the Aquatic Habitat Guidelines to reflect experience and emerging science and technical practice.

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