Understanding the linear and nonlinear responses of runoff to environmental change is crucial to optimally manage water resources in river basins. This study proposes a generic framework-based hydrological model (Soil and Water Assessment Tool (SWAT)) and two approaches, to comprehensively assess the impacts of anthropogenic activities and climate variability on runoff over the representative Hutuo River Basin (HRB), China. Results showed that SWAT performed well in capturing the runoff trend in HRB; however, it exhibited better performance for the calibration period than for the validation. During 1961–2000, about 26.06% of the catchment area was changed, mainly from forest to farmland and urban, and climate changed to warmer and drier. The integrated effects of the anthropogenic activities and climate variability decreased annual runoff in HRB by 96.6 mm. Direct human activities were responsible for 52.16% of runoff reduction. Climate (land use) decreased runoff by 45.30% (2.06%), whereas the combined (land use + climate) impact resulted in a more runoff decrease by 47.84%. Land use–climate interactive effect is inherent in HRB and decreased runoff by 1.02%. The proposed framework can be applied to improve the current understanding of runoff variation in river basins, for supporting sustainable water resources management strategies.
- environmental change
- integrated assessment
- interactive effect
- First received 16 November 2015.
- Accepted in revised form 11 March 2016.
- © IWA Publishing 2016