The objective of road-stream crossing assessments– also called inventories or field surveys – is primarily to identify problematic stream crossings, in order to understand the extent of habitat connectivity problems in a watershed and begin to identify candidate crossings for retrofit or replacement. Most assessments will include collection of information about stream characteristics such as the channel width, depth, and velocity, as well as information about the existing structure.
Field assessments are not decision-making tools. A field assessment is a means of collecting initial information about conditions at road-stream crossing sites. They do not themselves answer the questions of which crossings are the best candidates for retrofit or replacement or how to design a replacement crossing.
Before beginning field assessment work, it is important to think about what level of detail is needed, who will perform the assessments, and how you will manage and use the data that you collect. The tasks of training technicians or volunteers to conduct field inventories as well as managing data require a substantial investment of time and resources.
Various protocols have been developed for field assessment of road-stream crossings in many regions. These protocols have been updated and revised by experts over the years and should be used whenever possible. There are many advantages of using existing protocols for your region:
- This will enable you to integrate your data into regional databases, which will aid in larger scale prioritization.
- If using a regional database, you will not need to create or maintain the database over time.
- This will save you time and resources; experts have already devoted significant time and resources to develop, refine, and ensure the accuracy of these protocols and associated data sheets.
If the forms and questions do not fit your needs exactly, we recommend that you add a separate data sheet to answer additional questions of importance. This will allow for your data to fit into one of the existing regional databases.
Recommended regional assessment tools
Northeastern U.S.
The River and Stream Continuity Partnership, a consortium including the University of Massachusetts Amherst, The Nature Conservancy, Massachusetts Division of Ecological Restoration and American Rivers, has developed, field-tested and refined a protocol for field inventory of road-stream crossings (culverts and bridges). This is a rapid assessment tool designed for use at a small watershed scale to help identify sites with barriers to continuity. This information can then be used to understand where improvements may be necessary. This tool is fairly straightforward and quick to complete; an organization wishing to broadly understand issues of connectivity in a watershed can collect information about many structures in a fairly short time. Surveys take approximately 15-20 minutes per site and can be completed with only a survey measuring tape. Use of these protocols enables integration of the data into the River and Stream Continuity Road-Stream Crossing Database. Once data are entered, the database will rate the extent of the barrier as insignificant, moderate or significant. The database holds data from Connecticut, Massachusetts, Maine, New Hampshire, New Jersey, Rhode Island, and Vermont.
Great Lakes Region
Multiple agencies and organizations in Wisconsin and Michigan, including the U.S. Forest Service, U.S. Fish and Wildlife Service, Wisconsin Department of Natural Resources, Michigan Department of Natural Resources, and several conservation organizations, developed a road-stream crossing survey protocol for the Great Lakes region. The purpose of this protocol is to collect enough information on each crossing to estimate its passability by fish, and for problem crossings, to estimate the cost of replacing the existing structure with a fully passable structure. The protocol is a screening level assessment, and is not detailed enough to design a new crossing. The protocol takes 30-60 minutes to complete at each crossing, and requires just a few pieces of specialized equipment.
Additional field assessment tools and associated databases
California Department of Fish and Wildlife:
Maine:
New Hampshire:
Oregon Department of Fish and Wildlife:
U.S. Forest Service:
Vermont Agency of Natural Resources:
Washington Department of Fish and Wildlife: