Compile and Evaluate Alternate Strategies for Maintaining Ecosystems Crossed by Transportation Facilities

Focus Area

Wildlife & Ecosystems


Natural Resources






2-3 years

Research Idea Scope

TERI Database Administrator Notes:  Not recommended at present time by 2009 Natural Systems Subcommittee.

Highway crossings can have a negative impact on ecosystems by creating
barriers that inhibit the movement of fish, reptiles, and mammals, as well as fragmenting and
destroying habitat. This fragmentation can result in the loss of important spawning areas, low
water refuges, nesting areas, and travel corridors. Culverts are frequently seen as the most cost-effective structures for small stream crossings. However, in view of additional regulatory and resource management requirements, bridges may be more effective over the operational lifetime of the facility when project development times, costs, and construction schedules are considered.

Research should compare the effectiveness of crossing structures, including corrugated metal pipes, concrete box structures, and bridges, on a variety of projects to establish:

• Development time,
• Construction cost,
• Maintenance requirements, and
• Ecological characteristics such as passage of fish, other aquatic organisms, other riparian-based wildlife, mammals, and birds.

This comparison will be done by:

• Completing a synthesis of existing research and data;
• Surveying several representative states, which will provide a depiction of regional
considerations and a variety of indicator species; and
• Conducting interviews with resource and regulatory agencies to determine time frames
and restrictions effecting future installations and current maintenance requirements.

The two products are to provide a comparison of crossings on comparable streams in
terms of

• Project development schedule,
• Time for environmental reviews (NEPA, Section 404, ESE, etc.),
• Ecological effectiveness in fish passage and ecosystem integrity,
• Maintenance scheduling and costs, and
• Context-sensitive designs, which can be used nationally in a variety of habitats.

This research will provide a better understanding of how to successfully design crossing
structures to improve and enhance habitats.

Suggested By

Transportation Research Board 2002 Environmental Research Needs Conference Notes

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