You are here:
Stream hydrologic response to increased urbanization in Mid-Atlantic watersheds
Citation:
Mangiante, M. AND T. Jarnagin. Stream hydrologic response to increased urbanization in Mid-Atlantic watersheds. US IALE, Asheville, NC, April 03 - 07, 2016.
Impact/Purpose:
In this abstract we describe a comparison of stream hydrologic response to urbanization between 1984 and 2011. This information will be used to predict stream Richard-Baker flashiness index for the region and can be used to evaluate the effectiveness of storm water best management practices.
Description:
Urban development alters stream hydrology; resulting in increases in the Richard-Baker Flashiness index, peak flow, and the number of flood events for many watersheds throughout the U.S. To better understand and predict the relationship between stream flow patterns and watershed characteristics, we evaluated the influence of nationally available anthropogenic and watershed factors on streamflow metrics and determined a measurable threshold at which urbanization affects watershed hydrology. Average annual Richard-Baker Flashiness, Mean Flow, Peak-Flow, Low-Flow, and the 7Q2 were calculated using daily mean flow observations between 1970 and 2014 from 151 U.S. Geological Survey stream gages across the Mid-Atlantic States. Streamflow calculations were aggregated to five year windows around 1984, 1992, 2001, 2006, and 2011 and compared to watershed edaphic characteristics and urbanized land cover calculated from the North American Landscape Characterization program and the National Land Cover Dataset for those same time periods. Urbanization was highly correlated with stream flashiness and mean-flow for watersheds with greater than 30% urbanization. Additionally, watershed road area accurately predicted percent developed area and was highly correlated with streamflow metrics. A secondary trend was identified with lower than expected flashiness at high rates of urbanization which could be attributed to effective storm water runoff best management practices. The results of this research depict how hydrology responds to landscape change and provide a guide with which to evaluate the effectiveness of storm water management systems to reduce stream flashiness.
