Hydrological and water quality simulation and future runoff prediction under CMIP6 scenario in the upstream basin of Miyun Reservoir

Abstract Water resources are a key factor restricting human survival and social economic development. The Miyun Reservoir, which is the only surface drinking water source in Beijing storage reservoir of South-to-North Diversion Project, plays decisive role ensuring water-use sustainability capital. This study focused on Baihe River Basin, one important inflows Reservoir. mathematical data climate hydrological changes Basin over past 30 years were obtained, evolution law runoff its influencing factors was analyzed. Our analysis used obtained via multi-source meteorology to establish Soil Assessment Tool (SWAT) model Basin. Sequential Uncertainty Fitting version 2 (SUFI-2) Generalized Likelihood Estimation (GLUE) simulate from 1990 2017 monthly scale, along with sediment, total nitrogen (TN), phosphorus (TP) contents 2010. Then, parameter uncertainty SWAT applicability determined. land-use transfer matrix showed that complex transformation forms diverse. simulation results patterns 2010 had slight impacts hydrologic quality basin. By identifying areas non-point pollution basin, three management measures basin simulated. reductions flow rates, sediment content, TN, TP (4.37, 31.93, 23.13, 35.30%, respectively) through terrace engineering significantly better than those acquired stubble mulch contour planting. Additionally, this uses Sixth International Coupling Mode Comparison Program (CMIP6) change scenario BCC-CSM2-MR coupled corrected predict future runoff, thereby providing references suggestions for managing