Author(s): Yuyang Wu

Linked Author(s): Yuyang Wu

Keywords: Hydrological processes; Soil erosion; Watershed management; SWAT; Yangtze River;

Abstract: The upper reaches of Yangtze River, which spans a variety of natural geographic environments, are affected by different meteorological zones. Therefore, runoff generation and sediment yield in watershed are rather complex, exerting a huge influence on sustained management of water resources of Yangtze River system. In this study, a distributed hydrological model (Soil and Water Assessment Tool, SWAT) was employed to simulate the hydrological process and sediment yield over the watershed of upper reaches of Yangtze River over the past 48 years (1970–2017). Methods of Sen's estimator of slope and Mann-Kendall test were conducted to assess the variation characteristics and to test the significances of precipitation and temperature variation trends based on historical data, respectively. Significant increases in temperature were observed but not enough evidence were found in precipitation in TTH, BT and HL. The evaporation ranking form the highest to the lowest was forest (HL), dryland (HL), forest (BT), pasture (BT) and pasture (TTH). Surface runoff volume in TTH increased faster with the growing precipitation than the volume in BT did in general. The linear fit results of surface runoff and soil erosion showed that very strong correlations existed between them, with R2 all higher than 0.90. Forests and pasture lands tended to reduce runoff and sediment production, while agricultural lands exacerbate sediment yield greatly. Land use and climate variations were key factors influencing watershed hydrological processes and sediment yield dynamics both for freeze-thaw areas in high altitude region and for hot wet areas in subtropical region.

DOI: https://doi.org/10.3850/38WC092019-0516

Year: 2019