Accounting for Trees in Stormwater Models is a resource to share with stormwater engineers. The paper is intended to help the stormwater engineering community more easily account for trees in runoff and pollutant load calculations and incorporate them into stormwater management strategies. It summarizes existing hydrologic and hydraulic models that can be applied at the site and small watershed scales to account for the stormwater benefits of conserving existing trees and/or planting new trees. The paper also includes examples of specific techniques to modify stormwater models to account for urban tree benefits, as well as associated resources and tools for estimating the hydrologic benefits of trees in the urban landscape.

The resource, funded by the USDA Forest Service, was developed with input from experts in stormwater engineering and urban forestry. This adds to a robust collection of resources the Center for Watershed Protection completed in 2017 on “Making Urban Trees Count,” which includes a comprehensive literature review and research-based tools for crediting trees in stormwater and water quality management programs.

For questions about this resource, contact Karen Cappiella, Director of Research for the Center for Watershed Protection at kc@cwp.org.