Urban Stream Corridors and Forest Patches—The Connections: A Case Study of Bloomington, IN

Abstract

Streams and forests are ecosystems connected through hydrology, but few studies have looked at the connectivity between streams and forests in the context of urban development. City-made decisions affect connections between streams and forests by isolating both ecosystems. Streams are often channelized or buried to increase potential development areas. Forests often become fragmented and may be removed unless protected. Historical choices in land usage affect the sites and sizes of current urban streams, forests, and development. This affects the distribution of impervious surfaces, which separates streams from forests. Despite these barriers to stream/forest interactions, cities can experience stream/forest connectivity. Seven Bloomington watersheds are ranked on their proportions of buried streams, channelized streams, forested hydrology, forested streams, urban forest patch cover, and impervious surface cover, along with the historical presence of urbanization. Watersheds demonstrate stream/forest connectivity, with five watersheds containing 50% or greater forested stream segments. Bloomington canopy cover reduces stormwater runoff by approximately 127 kiloliters per year. These forested areas reduce flooding, reduce nutrient loading, and reduce stream conditions associated with urban stream syndrome. Understanding urban stream/forest connectivity can improve green infrastructure design and green space design, which improve urban resilience and better connect residents to the environment.