Watershed-Scale Impacts of Forest Buffers on Water Quality and Runoff in Urbanizing Environment

Abstract

Forestry practices that are applied to buffer regions can be used as a strategy to improve water quality and flow regime in urbanizing watersheds. This study evaluates watershed-wide impacts of buffering urban forestry practices. Watershed simulation modeling is used to study the effectiveness of best management practices (BMPs) scenarios representing riparian and street buffers on water quality, quantity, and open space in rural, suburban, and urbanized environments. Results indicate that the watershed health can be improved through location-specific application of urban forestry practices. The proportion of urban forest cover reduced sediment and nutrient loading, decreased stormwater runoff, and increased groundwater recharge in urbanizing watersheds. Reduction in variability of watershed processes indicate that forest BMPs make the watershed more adaptive to handling adverse conditions, such as large storms, nonpoint source pollution, flooding, and high winds. Watersheds that are starting to get urbanized responded well to the BMP scenarios compared to more urbanized subbasins. General strategies include a focus on increasing pervious cover of the watershed with a higher priority in riparian and street buffers. Specific tree species and practical issues in forest buffering are also discussed. Policies like financial incentives and encouraging voluntary participation can be used to improve urban watersheds.