SPATIAL ANALYSIS OF STREAM TEMPERATURE RESPONSE TO PATTERNS OF LAND COVER AND STORMWATER INFRASTRUCTURE IN AN URBAN WATERSHED

Abstract

This study examined effects of summer storm runoff on stream temperature in the 47% impervious Dead Run watershed, Baltimore County, Maryland. Five-minute temperature data spanning 2.5 years from 204 sensors spaced 50-100 m apart were analyzed to identify spatial patterns of stream thermal response. Significant differences in temperature change between paired sensors occurred predominantly in headwater areas with drainage areas smaller than 1.5 km², revealing a clear spatial sensitivity threshold. Warming effects were associated with large drainage increments added between sensors near roadways and pipes, while cooling effects were associated with lower percent impervious cover. Differences in temperature impacts associated with inflow from stormwater management facilities were not significant, and differences in impervious cover were too small to cause significant temperature variation. Drainage area size proved to be the strongest predictor of thermal response. These findings highlight the utility of spatially targeted analyses to better understand stormwater thermal impacts.