Scale-Dependency and Sensitivity of Hydrological Estimations to Land Use and Topography for a Coastal Watershed in Mississippi

This paper investigates the effect of land use and digital elevation models spatial resolution and scale on the simulation of stream flow in two coastal watersheds located in the Mississippi Gulf Coast (USA). Four elevation datasets were used: USGS DEM, NED, NASA’s SRTM and IFSAR (300, 30, 30, and 5 meter resolution, respectively). Three land use datasets were included in this study: USGS GIRAS, NLCD, and NASA MODIS MOD12Q1 (400, 30, and 1000 m resolution, correspondingly). The Hydrological Program Fortran (HSPF) was used for estimating stream flow in the two watersheds. Results showed that swapping datasets in a factorial design experiment produce equivalent statistical fit of measured and simulated stream flow data. The results also showed that HSPF-estimated stream flows are not sensitive to scale and spatial resolution of the datasets included in the study.