Title : The Impacts of Suburban Development on Surface Runoff in Cypress , Texas

Urbanization has been known to alter the hydrologic characteristics of a watershed. This study empirically assesses this notion by investigating the relationship of developed land use/land cover (LULC) changes and surface runoff generation. We examine the Cypress Creek watershed, where its recent development pressure is significantly high due to the rapid growth of Houston, Texas. The watershed is located within Harris County, with the distance of 37 km from Houston. A hydrological model, the Soil and Water Assessment Tool (SWAT), is employed to estimate the generated runoff for two land use scenarios from 2002 to 2010. The findings show that the mean annual runoff change was high for most sub-basins that experienced significant suburbanization. The correlation coefficients between runoff changes and three developed LULC classes (low, medium, and high developed lands) ranged from 0.5 to 0.8, while its correlation with green spaces was about -0.6. The importance of development densities in managing stormwater runoff is highlighted throughout the research and the results suggest local planmakers and engineers on where and how to regulate the future residential developments and install low impact development practices in suburbanizing communities.