Portable Bridge Project for Temporary Water Crossings
Bayfield County, WI

Grantee: Bayfield County Forestry Department
Basin Program Funds: $4,897
Non-federal Funds: $1,809
Project Duration: 06/1996 - 06/1997
Status: complete

Problem Statement
The soils in approximately one third of Bayfield County are characterized as highly erodible calcareous red clay. Nearly all of those soils are located in the Lake Superior watershed, along with a range of soils from deep glacial outwash composed of sands to silt loams. Timber harvesting, a major part of the county's economy, has a significant impact on these soils. Poor forestry practices, including poor forest road construction and poorly designed or inadequate stream crossings, are a major source of silt eroding into area streams.

Before channel treatment

Slightly less than 800 square miles of Bayfield County drains into Lake Superior, with forested lands making up the majority of that land area. Timber harvesting is a major part of the county's economy. Currently, there are 159.7 miles of Outstanding Resource Waters (ORW), 91.6 miles of Exceptional Resource Waters (ERW), and 181 miles of other perennial streams in the county. Logging practices often impact these water resources, and poor practices have historically been a significant contributor to nonpoint source pollution problems and water quality degradation in the Lake Superior basin.

The goal of this project was to demonstrate the feasibility of using portable timber bridges for temporary stream crossings for timber harvesting equipment in order to reduce nonpoint source pollution in the Lake Superior watershed. Portable bridges have not been widely used in the region, therefore this is an opportunity to provide information about the cost and sources of portable bridges as well as to encourage their use. The advantages of this type of crossing are that it requires no in-stream construction or fill material placed in the channel, there is a low potential for introduction of sediment into the waterways, fish movement is not restricted, and there is minimal resistance to flood waters. Portable bridges may also assist logging contractors or other forest users that require temporary water crossings to access woodlands in an efficient, cost-effective, and less damaging manner.

The bridge was designed, ordered, and delivered. Project personnel applied for and received a navigable stream crossing permit. The bridge was then moved to a site, but could not be installed due to poor weather and road conditions. Another site was then selected and the bridge was installed. Demonstration materials and related information were gathered and prepared, and notices about the first demonstration day were sent to forestry staffs and other interested parties. The first demonstration day was held and information was disseminated to a large number of people in the forestry industry about the costs and benefits of temporary stream crossings.

After the first demonstration, a draft contract outlining bridge use by other organizations was produced and approved by the Bayfield County Corporation Council. The bridge was then made available for mechanical operations with stream crossings within the Lake Superior watershed. A suitable project with permits from the Department of Natural Resources was approved and the bridge was installed across a Class 1 trout stream. Once installed, the bridge was available for other agency personnel and loggers to view. When harvesting operations across the stream were completed, analysis of the bridge was conducted which concluded that it reduced the amount of nonpoint source pollution entering the stream. Customized designs for different types of harvesting operations and equipment have been developed.

After channel treatment

Overall, the project has been quite successful, and has stimulated considerable interest and discussion in the region about the use of portable bridges for temporary stream crossings.

Contact: Paul G. Stone, (715) 373-6114


Great Lakes Commission des Grands Lacs.  2805 S. Industrial Highway, Suite 100.  Ann Arbor, MI  48104-6791.  phone: 734/971.9135.  fax: 734/971-9150.  projects.glc.org. Join the Friends of the Great Lakes GLIN Partner