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Assessing Impacts of Landuse Changes on Hydrology for the Upper San Pedro Watershed
Citation:
Nie, W., Y. YUAN, W. G. KEPNER, M. S. NASH, M. JACKSON, AND C. L. ERICKSON. Assessing Impacts of Landuse Changes on Hydrology for the Upper San Pedro Watershed. JOURNAL OF HYDROLOGY. Elsevier Science Ltd, New York, NY, 1(4):105-114, (2011).
Impact/Purpose:
Assessing impacts of landuse changes on hydrology is essential for watershed management and ecological restoration. The assessment usually includes evaluation of spatial patterns of hydrological consequences to different landuse scenarios, comparison of basinal values of simulated hydrological processes to landuse changes at the basinal scale, and examination of temporal responses in channel discharge with changes in landuse scenarios (e.g. Miller et al., 2002; Ghaffari et al., 2009; Franczyk and Chang, 2009). However, studies do not quantify contributions of change for individual land uses to different hydrological responses. Without accurate quantification, the impacts of changes for some landuse classes on hydrologic processes may be exaggerated or understated, or even misinterpreted. In this study, an integration approach of hydrological modeling and multiple regression analysis was applied in the upper San Pedro watershed to quantify contribution of changes for individual land uses on hydrological processes.
Description:
The assessment of landuse changes on hydrology is essential for the development of sustainable water resource strategies. Specifically, understanding how each land use influences hydrological processes will greatly improve predictability of hydrological consequences to landuse changes and thus can help stakeholders make better decisions. However, given the limited landuse data and simultaneous changes of multiple landuse classes, it is difficult to quantify impacts of individual land uses on hydrology. In this study, an integrated approach of hydrological modeling and multiple regression analysis was applied to quantify contributions of changes for individual land uses on hydrological processes. As a case study, hydrological modeling was conducted for four landuse scenarios (1973, 1986, 1992, and 1997) in the upper San Pedro watershed using the Soil and Water Assessment Tool (SWAT). Simulation results were used in a multiple regression analysis to quantify contributions for individual land uses to five major hydrological responses at the subbasinal scale. Results indicated that urbanization was the strongest contributor to the increased surface runoff and water yield from 1973 to 1997 and replacement of desertscrub/grassland by mesquite was the strongest predictor of decreased baseflow/percolation and of the increased ET. Increased runoff, declined percolation, and increased ET have a negative impact on the upper San Pedro River Basin, thus urbanization and mesquite invasion were characterized as two major environmental stressors affecting local watershed conditions. Approaches applied in this study successfully determined contributions of changes for individual land uses to hydrological processes, providing quantitative information for stakeholders to make better decisions for future landuse and/or water resource planning and management, thus it can be widely applied to a variety of watersheds to assess impacts of landuse changes on hydrology.
URLs/Downloads:
YUAN 10-070 FINAL JOURNAL ARTICLE..PDF (PDF, NA pp, 686 KB, about PDF)Assessing Impacts of Landuse Changes on Hydrology for the Upper San Pedro Watershed
