PREDICTING INFLUENCES OF URBAN DEVELOPMENT ON THERMAL HABITAT IN A WARM WATER STREAM¹

Abstract

Watershed and aquatic ecosystem management requires methods to predict and understand thermal impacts on stream habitat from urbanization. This study evaluates thermal effects of projected urbanization using a modeling framework and considers the biological implications to the fish community. The Stream Network Temperature Model (SNTEMP) was used in combination with the Hydrologic Simulation Program Fortran (HSPF) to assess changes in stream thermal habitat under altered stream‐ flow, shade, and channel width associated with low, medium, and high density urban developments in the Back Creek watershed (Roanoke County, Virginia). Flow alteration by the high density development scenario alone caused minimal heating of mean daily summer base flow (mean +0.1°C). However, when flow changes were modeled concurrently with reduced shade and increased channel width, mean daily temperature increased 1°C. Maximum daily temperatures exceeding the state standard (31°C) increased from 1.1 to 7.6 percent of the time using summer 2000 climatic conditions. Model results suggest that additional urban development will alter stream temperature, potentially limiting thermal habitat and shifting the fish community structure from intolerant to tolerant fish species in Back Creek. More research is needed on the sub‐lethal or chronic effects of increased stream temperature regimes on fish, particularly for those species already living in habitats near their upper limits.

Urbanization Effects on Watershed Hydrology and In-Stream Processes in the Southern United States

“…In the southern U.S., where lowland streams are generally warm water ecosystems, increased stream temperatures could lead to an increased frequency of hypoxic or anoxic conditions during summer months. Model simulations of urban development in a VA Piedmont watershed predict the frequency of maximum temperatures exceeding the state water quality standard to increase from 1.1% to 7.6% of summer days [93].…”

Investigation of correlation between remotely sensed impervious surfaces and chloride concentrations

“…Impervious surfaces prevent precipitation and melt water from infiltrating soils and are likely to generate more runoff during wet seasons and less groundwater discharges to streams during dry seasons (Bowen and Hinton, 1998;Barnes et al, 2001;Shuster et al, 2005). The reduced stream flow and more extreme stream temperatures will stress aquatic ecosystems, therefore disrupting and degrading aquatic habitats (Krause et al, 2004).…”

Atmospheric Conditions, Landscape Characteristics, and Anthropogenic Factors Affecting Stream Water Temperature

“…Landscape characteristics affect stream water temperature by changing the local climate, heat capacity and residence time of stream water, and heat exchange with the streambed and banks. In addition, because of accelerating urbanization, the effect of anthropogenic activities on stream water temperature has become of increasing concerns in recent years (Krause et al, 2004) .…”

“…Urban development alters stream water temperature and thermal habitat (Krause et al, 2004). Furthermore, the timing and magnitude of heat input and flow regimes are also affected by human activities (Poole and Berman, 2001).…”