Ww. Doe et al., LAND-USE IMPACT ON WATERSHED RESPONSE - THE INTEGRATION OF 2-DIMENSIONAL HYDROLOGICAL MODELING AND GEOGRAPHICAL INFORMATION-SYSTEMS, Hydrological processes, 10(11), 1996, pp. 1503-1511
The integration of a two-dimensional, raster-based rainfall-runoff mod
el, CASC2D, with a raster geographical information system (GIS), GRASS
, offers enhanced capabilities for analysing the hydrological impact u
nder a variety of land management scenarios. The spatially varied comp
onents of the watershed, such as slope, soil texture, surface roughnes
s and land-use disturbance, were characterized in GRASS at a user-spec
ified grid cell resolution for input into the CASC2D model. CASC2D is
a raster-based, single-event rainfall-runoff model that divides the wa
tershed into grid cell elements and simulates the hydrological process
es of infiltration, overland how and channel flow in response to distr
ibuted rainfall precipitation. The five-step integration of CASC2D and
GRASS demonstrates the potential for analysing spatially and temporal
ly varied hydrological processes within a 50 square mile semiarid wate
rshed. By defining possible land-use disturbance scenarios for the wat
ershed, a variety of rainfall-runoff events were simulated to determin
e the changes in watershed response under varying disturbance and rain
fall conditions. Additionally, spatially distributed infiltration outp
uts derived from the simulations were analysed in GRASS to determine t
he variability of hydrological change within the watershed. Grid cell
computational capabilities in GRASS allow the user to combine the scen
ario simulation outputs with other distributed watershed parameters to
develop complex maps depicting potential areas of hydrological sensit
ivity. This GIS-hydrological model integration provides valuable spati
al information to researchers and managers concerned with the study an
d effects of land-use on hydrological response.