Landsat-Based Impervious Surface Mapping And Storm Runoff Response Modeling

The hydrologic response of urbanized watersheds is greatly affected by the extent of fractional impervious surface (FIS) area. Impervious surfaces effect on ecohydrology of watersheds include reduction of infiltration, soil moisture storage, natural interception and depression storage, base flow and groundwater recharge, increase peak discharge, reduction in time to peak and time of concentration. These effects have important ecological and economic impact on the hydrology of watersheds. Thus accurate estimation of these surfaces is an important part of urban watershed management. For larger areas, it has been shown that remote sensing of these surfaces using standard procedures is practical and cost effective. Estimation of FIS areas using Landsat imagery for two watersheds of different settings (Simms Creek, Florida and Red River basin of the North @ Grand Forks, North Dakota) was conducted. The respective storm runoff response was studied using a spatially distributed storm runoff model based n the concept of travel time and temporal comparisons were made. For Simms Creek, the increase in urban built-up areas in the year 2000 compared to 1984 increased the peak flow by 16.2% and reduced the time required to attain the peak flow 18.1%. The results at the Red River basin of the North show that an increase in impervious areas (FIS >0.5) (by 79% from 1974 to 2001) attributed to the growing cities in the Red River Basin for the period of study. Hydrograph analysis of the flow at Grand Forks gauging station also indicated runoff response of the basin has increased between 1993 and 2002 with all years having percent runoff greater than 10% compared to only 35% of the years between 1974 and 1993. Keywords: Landsat; storm runoff, Land-cover; impervious surface area, Simms Creek; Red River