SESSION D:

Title: Designing Land Management Road Crossings that are Passage Friendly for Aquatic Species

Authors: Christopher R. Martin
Maine Forest Service, 22 State House Station, Augusta, ME. 207/287.1073. chris.martin@maine.gov.

Abstract:

In forested watersheds, opportunity for stream habitat restoration occurs when failed closed bottom structures are replaced or upgraded with open bottom devices. Unlike closed bottom structures, open bottom devices, such as arched culverts, lack structural integrity, thus require proper installation techniques. Preconceived opinions about installation difficulties and associated cost concerns often preclude use of bottomless structures in favor of round culverts. Replacement of failing round culverts associated with land management roads is critical in reducing the number of problematic water quality sites in Maine.

The Maine Forest Service estimates that between 7,000 to 10,000 miles of land management roads lie within the Washington/Hancock Coastal and Penobscot River Watersheds.

Results of improperly installed round culverts include: 1) passage barriers for fish, amphibians and macro invertebrates, 2) bank instability from inadequate compaction and excessive slopes, 3) alteration of stream flow, 4) inadequate maintenance, and 5) premature failure often preceded by prolonged erosion.

Conversely, stream crossing structures which are properly sized and installed according to best management practices: 1) maintain natural stream substrate within the structure, eliminating most passage barriers, 2) provide embankment grade stabilization from reduced slopes, 3) maintain natural stream flow by extending bank to bank, 4) disperse road drainage into filter areas, and 5) reduce land management road costs by prolonging useful life of the crossing structure.

Chris Martin will summarize efforts to-date on Maine Forest Service’s promotion of stream connectivity utilizing bottomless crossing devices. The session will describe the importance of partnerships and pooling together existing resources, increasing capacity to achieve positive results. Maine Forest Service water quality BMP’s regarding stream crossings will also be reviewed.