A Shift to Credit/Debit for Mitigation is Likely

By Emmett Pritchard

For wetland mitigation projects in Washington, the Washington Department of Ecology (WDOE) is recommending the use of the new Credit/Debit Method (Calculating Credits and Debits for Compensatory Mitigation in Western Washington, Ecology Publication #10-06-011) to analyze whether adequate mitigation is being provided to off-set wetland impacts. Although not required for projects by WDOE at this time, the Credit/Debit method is based on wetland assessment analysis that was incorporated into the new wetland rating systems recently issued by WDOE and required for use in Washington beginning January 1, 2015. Therefore, a shift to regulatory agency reliance on the Credit/Debit Method for development of wetland mitigation plans is likely to continue.

The Credit/Debit Method is a tool designed to estimate impacts to three wetland functions and to compare these to the functions that would be provided at a proposed mitigation site. Functions that are analyzed include: 1) improving water quality; 2) flood storage and flow reductions; and 3) habitat for plants and animals. The method is used to compare impacted wetlands to the proposed mitigation with regard to the potential to provide these functions, the potential of the landscape to maintain the function over the long-term, and the value that each function has for society. In addition to assessing specific wetland functions, the Credit/Debit method incorporates findings of current Washington Department of Ecology studies with regard to compensation for temporal loss of the impacted wetland and compensation for risk of mitigation site failure.

WDOE highly recommends that users of this method take the training provided by WDOE.