Urbanizing Watersheds and Changing River Flood Dynamics: Implications for Urban Wetland Restoration
Abstract
Urbanization alters river hydrology, morphology, water quality, and habitat and
ecology. Most of these associated changes are due to an increase in impervious surface cover
(ISC) throughout the watershed. But the spatial location of urban areas within the watershed also
greatly influences river hydrology. As river hydrology changes, functions and structure of
riverine wetlands associated with the hydrology may be impacted. In order to increase the longterm
success of wetland restoration attempts within an urbanizing environment, it is necessary to
quantify potential impacts to the wetlands as hydrology continues to change. This study
investigated the effects of increased ISC on stream hydrology between 1972 and 1995 for a subwatershed
located north of Dallas, Texas. Moving window and FRAGSTATS analyses
calculated the degree and location of ISC throughout the basin, and U.S. Geologic Survey
stream-gauge data were analyzed to determine changes in steam hydrology between the 2 time
periods. Average ISC for the watershed increased from 2 to 11% between 1972 and 1995, but
highest cover (50–80%) occurred along the southern and eastern borders. Annual river flooding
frequency and duration doubled between 1972 and 1995, and flooding velocity increased from
31.4 to 35.4 m3/sec. Wetland restoration attempts within the watershed should address the
potential for future hydrologic changes as ISC continues to increase.
Collections
Citation
Simmons, Matthew (2003). Urbanizing Watersheds and Changing River Flood Dynamics: Implications for Urban Wetland Restoration. Texas Water Resources Institute. Available electronically from https : / /hdl .handle .net /1969 .1 /191459.