Project Background & Purpose

Fish and other aquatic species need to move around in streams to access habitats they need at different times in their life cycles (spawning, rearing, feeding, sheltering) and under different environmental conditions (water too cold or too warm, floods, droughts, predators). Human-made barriers to movement abound, and are increasingly being shown to damage fish and mussel populations. The Forest Service is committed to achieving goals stated in the Clean Water Act, the Endangered Species Act, and the National Forest Management Act, which call for (among other things) maintaining viable populations of endemic aquatic species. Doing this requires managing habitat to support native species, which very often means removing barriers.

The Forest Service estimates at least 25,000 crossings on National Forest System lands at least partially obstruct movement for some or all aquatic species. Work began in the 1970s to identify and correct passage problems for spawning salmon in the Northwest and the Northeast United States, but the Forest Service had no consistent policy or funded program until recently. Since 2004, annual funding for fish passage has permitted an aggressive crossing-barrier removal program throughout the country. Hundreds of crossings have been replaced or retrofitted at costs averaging on the order of $150,000 each (Heller, pers. comm., 3/2010). The HTAP (Highway Trust funds for aquatic passage) program alone has expended $10 million annually for fish passage improvement on NFS lands. With this large expenditure of public funds comes the responsibility to monitor and evaluate the program. Is it succeeding in achieving its goals? How can it be improved?

Goals for the Aquatic Organism Passage (AOP) program include replacing crossing structures that disrupt the necessary life cycle movements of endemic aquatic species and/or impair aquatic habitat quality and extent. The Forest Service's preferred type of crossing replacement is a bridge or culvert that accommodates a self-sustaining channel similar to the natural stream channel. If the channel inside the culvert (or under the bridge) mimics the natural channel, aquatic species are thought to pass through the crossing as freely as they move in the natural channel (FSSSWG, 2008). Such constructed channels simulate the size, slope, and structure of the natural channel and should therefore be dynamically stable in the changing stream environment, passing, and storing sediment much as the natural channel does. They should be less prone to plugging and other types of flood damage than traditional crossings, and lifecycle costs including maintenance and replacement are expected to be lower. This project will develop standard methods to evaluate how well some of these performance expectations are being met.

Project Goal: Develop a monitoring protocol that, implemented over time, answers the question "Is our aquatic organism passage restoration program effectively achieving its goals? Are we providing adequate and sustainable passage through crossings for all species and all lifestages of aquatic organisms? Are reconstructed crossings maintaining stream connectivity at both high and low flows? What changes are needed to improve the AOP program's effectiveness and efficiency?"

Project Objectives

  1. Identify specific monitoring questions that define effectiveness for AOP projects.
    See key questions that have been identified
  2. Identify approaches (site selection, study designs, considerations for field data collection and analysis) for answering those questions in a scientifically credible way. Ideally methods should be implementable by field personnel. [For related project activities, see the literature synthesis and Science Synthesis Workshop]
  3. Test study designs and data analysis in a variety of situations; identify implementation issues, possible confounding factors, factors affecting statistical power. Test results should be reported in peer-reviewed journals. [A number of pilot projects are underway. See activities and linked project descriptions.]
  4. Based on tests, recommend set of procedures for answering specific monitoring questions. They should be scientifically sound and well-documented enough that many agencies and groups adopt and use them. The goal is to have a broadly accepted set of methods that will yield consistent data sharable across land ownerships and jurisdictions so that conclusions can be drawn about restoration needs and priorities in large watersheds.
  5. Develop implementation monitoring procedure, along with table of contents for case monitoring files. This background information links effectiveness monitoring results to design standards and construction practices, and will enable us to learn from mistakes and improve standards and practices.
  6. Develop flood-damage monitoring elements/procedure. Accumulating consistent flood-effects monitoring results over time will help us evaluate how maintenance and replacement costs differ between different types of crossings (e.g., stream simulation, geomorphic design, culverts designed using hydraulic methods only, retrofits, etc.) and how their effects differ on channels subjected to flooding.
Forest Service Stream Simulation Working Group (FSSSWG). 2008. Stream Simulation: and ecological approach to providing passage for aquatic organisms at road-stream crossings. USDA-FS National Technology and Development Program, San Dimas CA.
Required under regulations implementing the National Forest Planning and Management Act, 36 CFR 219.19 and 219.27
Clean Water Act nationwide permit general condition 9 requires that projects "withstand expected high flows, and not impede passage of normal or high flows..."