Landsat Imagery in Runoff Volume Estimation

Remote sensing has been used in the field of hydrologic modeling as a source of data to address the spatial variability of hydrologic processes including storm runoff. Although remote sensing does not directly provide a means of runoff estimation, it can provide quantitative land cover information of suitable spatial resolution that is extremely valuable for model inputs. The USDA-NRCS runoff curve number method is employed in this study to assess the spatial and temporal variability of storm runoff in relation to historical land use changes. The study area was the S-65A sub-basin of the Kissimmee River basin in south Florida. Land use data were obtained from Landsat images for the years 1980, 1990 and 2000, which include a period of development and a period of wetland restoration. Unsupervised classification was performed to assess the changes in land cover, with augmentation from Landsat-derived surface temperatures (for 1990 and 2000 images) and derived vegetation indices. Using the runoff curve number techniques, runoff volumes were determined and comparisons were made. Results show that the temporal and spatial variability of runoff volume resulting from changes in land cover can be readily determined from Landsat images.