基于SWAT模型的格尔木河上游分布式水文模拟和径流预测

SWAT-based Distributed Hydrologic Simulation and Runoff Prediction in the Upper Golmud River Watershed

研究格尔木河流域水文循环过程并预测未来流域水资源的变化特征,对地区生态环境保护和下游盐湖矿产资源可持续开发利用具有重要意义。选取格尔木水文站以上区域构建SWAT(Soil and Water Assessment Tool)分布式水文模型。采用大气同化数据集为气象驱动,联合区域内纳赤台和格尔木水文站的实测月尺度径流数据进行参数的率定和验证。在率定期和验证期内,纳什效率系数、确定性系数和相对偏差系数均达到了良好的标准,表明SWAT模型在格尔木河高寒山区流域水文过程模拟中具有较好的适用性。研究表明流域降水量偏少,地表径流量、壤中流量与降水量的变化趋势具有较好的一致性,降水量年际变化中蒸散发量为主要消耗量,占40.26%。根据未来气候预测模型RegCM4.6,预测路径浓度RCP2.6、RCP4.5和RCP8.53种情景下格尔木河未来40年径流量呈增加趋势。3种情景下的年平均径流量较基准期(2006—2018年)分别增加了7.63%、11.01%、15.96%;随着温室气体排放浓度的增加,径流量呈现出增加趋势,特别是夏秋季增幅较大。短时间内径流量增大可能会引发格尔木市洪涝灾害,破坏盐湖企业生产设施;但若将洪水资源进行调控和利用,不仅防范了洪涝灾害,同时也利于解决盐湖企业日渐增大的用水需求难题。

It is of great significance for the sustainable development and utilization of mineral resources in the Qarhan Salt Lake to study the hydrological cycle of the Golmud River watershed and predict the change characteristics of water resources in the future.Based on the data set of watershed topography,soil type,land use and atmospheric assimilation database,we established a SWAT-based distributed hydrological model for the upper Golmud River watershed.The monthly runoff data of Nachitai and Golmud stations were simulated.The SUFI-2 algorithm was used to analyze the sensitivity and uncertainty of the model pa-rameters.The Nash-Sutcliffe efficiency,correlation coefficient and percentage deviation indexes during the calibration and verification periods of Nachitai and Golmud stations all reached the standard of“good”.Thus,the model can simulate monthly runoff well in the upper Golmud River watershed.The analysis of water balance showed that the precipitation in the basin was less,and the variation trends of surface runoff,soil discharge and precipitation were in good consistency.In the interannual variation of precipitation,evapotranspiration is the main consumption source(40.26%).The future climate prediction model RegCM4.6 was used to predict the runoff in the Golmud River basin under three scenarios of RCP2.6,RCP4.5 and RCP8.5 according to the SWAT model.Compared with the baseline period(2006-2018),the annual average runoff under the three scenarios increased by 7.63%,11.01%and 15.96%,respectively.With the increase of greenhouse gas concentrations,the runoff showed an increasing trend especially dur-ing summer season.Considering the large increase of annual runoff,the possibility of summer flood disas-ter increases correspondingly.As a result,Salt Lake industrial facilities could be damaged.The regulation and utilization of flood resources can not only prevent the flood disaster,but also solve the water supply problem caused by the increasing water demand of industrial facilities on the salt lake companies.