Effects of Soil Amendments and Other Practices on the Success of the Virginia Department of Transportation's Non-tidal Wetland Mitigation Efforts

Report No: 05-CR25

Published in 2005

About the report:

Construction of created wetlands to mitigate for highway impacts requires more than $100,000 per ha of impacts. A detailed study of soil, hydrology, and vegetation at 10 recently constructed non-tidal mitigation sites indicates excessive soil compaction and a lack of organic matter continue to limit mitigation success. Detailed hydrologic studies at two mitigation sites (Charles City and Sandy Bottom) point out significant differences in their hydrologic regime vs. adjacent natural wetlands related to soil reconstruction procedures. Results from two compost amendment experiments at Charles City indicate that approximately 100 Mg/ha of organic amendment is optimal for reconstructing hydric soil conditions when natural organic enriched soil materials cannot be returned. Overall mitigation success would improve from (1) utilization of appropriate organic amendments, (2) tillage/ripping protocols at all sites to meet target density specifications, and (3) reconstruction of a soil-geologic profile that is similar in texture and permeability to natural wetland soils. These reconstruction guidelines will help ensure that VDOT complies with existing mitigation regulations in the most cost-effective manner.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


  • G. Michael Fitch, Ph.D.
  • W. Lee Daniels, Gabriela Fajardo, Cara R. Bergschneider, James E. Perry, Richard G. Whittecar, Aaron D. Despres

Last updated: November 29, 2023

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