Journal of Environmental Hydrology
Electronic Journal of the International Association for Environmental Hydrology
JEH Volume 19 (2011), Paper 18 Posted July 29, 2011
EFFECTS OF SPATIAL HETEROGENEITY ON HYDROLOGIC RESPONSES AT WATERSHED SCALE
Prem B. Parajuli
Spatial heterogeneity of the watershed characteristics such as soils, land use, and topography can have an important influence on the hydrologic response of large watersheds. Understanding the effects of spatial heterogeneity on hydrologic parameters is essential to develop water quality improvement programs. Hydrologic models have been used to investigate the interaction between various watershed characteristics. This study was conducted in the Upper Pearl River watershed (UPRW) in east central Mississippi to evaluate the spatial heterogeneity effect on hydrologic responses using the Soil and Water Assessment Tool (SWAT). The SWAT model was calibrated from January 1981 to December 1994 and validated from January 1995 to September 2008 using five USGS gage stations monthly measured stream flow data. The calibrated and validated SWAT model was used to evaluate spatial heterogeneity effects at the UPRW. Five sub-basins of the UPRW were selected based on their size, soils, topography, and precipitation inputs to investigate their interactions on water yield, groundwater yield, potential evapotranspiration (PET), sediment yield, and total phosphorus yield. Model results determined that the spatial heterogeneity effects were the greatest for the groundwater yield (100%) followed by sediment yield (44%), water yield (40%), total phosphorus yield (33%), and potential evapotranspiration (7%) from the selected five sub-basins. Overall, the results indicate that the UPRW hydrology is very sensitive to spatial heterogeneity of the watershed.
Reference: P. Parajuli. 2011. Effects of spatial heterogeneity on hydrologic responses at watershed scale. Journal of Environmental Hydrology, Vol. 19, Paper 18.
Prem B. Parajuli
Department of Agricultural and Biological Engineering
Mississippi State University
Starkville, MS 39762
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