Making Urban Trees Count: A Stormwater Crediting Framework for Urban Tree Planting

Track 2B: Quantifying Stormwater Treatment
Thursday, October 12, 2017, 2:00 pm – 3:10 pm

Karen Cappiella
Director of Research
Center for Watershed Protection

The use of trees for stormwater management is hampered by the uncertainty of how to “credit” trees for runoff and pollutant load reduction in order to compare with other BMPs. Quantifiable tree benefits are not generally accessible to the stormwater community, limiting the potential to apply the benefits for pollutant removal credits. The Center for Watershed Protection recently finalized a national crediting framework for urban tree planting with funding from the U.S. Forest Service’s National Urban and Community Forestry Advisory Council. The crediting system was based on a literature review, input from experts, and an integrated water balance model using i-Tree Forecast to project key urban tree growth metrics. The crediting system may be adapted by regional or local regulatory agencies to encourage greater use of trees to meet requirements such as stormwater management regulations, and total maximum daily loads.