00308483

Monograph

http://onlinepubs.trb.org...s/nchrp/nchrp_rpt_218A.pdf

The importance of wetlands in the life-cycle balance of earth ecology is becoming increasingly recognized. Consequently, transportation agencies are required to make assessments of possible environmental effects when transportation facilities are being proposed for location in the vicinity of wetlands. Determination of the impact of such facilities as bridges or earth fills on the ecology of a wetland is a very complex problem. There has been rather extensive study of the biological activity in wetlands, but little research has been directed toward highway-wetland interaction. The objectives of NCHRP Project 20-15 were to (1) determine the ecological effects of placing highway fills on wetlands primarily from available literature and experience and (2) prepare guidelines for ecological assessment of the location of fills, bridges, and related elements in wetlands. To accomplish the first project objective, the University of Massachusetts researchers conducted an extensive literature review with particular emphasis on biological information applicable to the wetland-transportation facility interaction and made a thorough evaluation of available information from eight individual sites, in various parts of the United States, that had been identified as having highways constructed in wetlands. The major product of the research is a manual, which is based on the findings of the literature review, the case studies, and the extensive knowledge and experience of the research team. The manual presents in detail the physical impacts and potential biological effects from construction activity in wetlands. A feature of the manual is the inclusion of a series of charts to assist in identifying potential biological effects associated with construction activity. A separate chart is included for each construction activity--such as consolidation, displacement, excavation and fill, and culvert placement. Each chart identifies the physical impacts associated with the particular construction activity and the resulting potential biological effects. For example, the placement of a culvert in a wetland can alter subsurface water flow, which could change the mean water level and cause mortality of certain aquatic species in the wetland.

Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.

34 p.

1979-12

NCHRP Report

Digital/other

Appendices; Figures; References

Case studies; Ecology; Fills; Guidelines; Reviews; Road construction; Wetlands

Design; Environment; Highways; Hydraulics and Hydrology

TRIS, TRB, USDOT

Apr 22 1980 12:00AM