基于SWAT分布式流域水文模型的下垫面变化和水利工程对径流影响分析

近年来随着人类活动的加剧,兴建了许多中、小型水利和水土保持工程,迅速改变着流域的自然面貌,因而改变了径流的原有规律。选取1960以前水利工程较少的时期作为人类活动不明显期来率定SWAT模型参数,对于1990以后人类活动稳定期的径流分别设置3个情景:应用原SWAT模型、应用只考虑下垫面变化的SWAT模型和应用考虑下垫面变化和水利工程影响的SWAT模型分别进行模拟。对于五道沟以上流域和流域内东丰、磐石、样子哨3个子流域模拟结果显示:考虑下垫面变化和水利工程影响后的径流模拟相关系数R2和纳什效率系数NSE分别从0.82、0.56提高到0.91、0.79,分别提高了11.0%和41.1%。其中模拟精度的提高量中91.3%是由于考虑水利工程作用所引起的,剩余部分是由考虑下垫面变化引起的。相比下垫面变化,水利工程运行对该流域径流变化占据主导作用。

Impacts of land cover change and hydraulic project on runoff based on SWAT distributed watershed hydrological model

With the intensification of human activities,a lot of hydraulic projects such as reservoirs, dams, levees, flood storage and detention areas have been built,which have completely changed the natural water flow. The soil and water assessment tool (SWAT) was calibrated and verified in the baseline period before 1960s. It simulated the runoff after 1990s with stability human activity.It set up the three circumstances such as natural SWAT, SWAT with just concerning land cover change and SWAT with concerning hydraulic projects activities as well as land cover change. The simulated results of Wudaogou, Yangzishao, Dongfeng and Panshi hydrological station show that the correlation coefficient R² and Nash coefficient NSE increases from 0.82, 0.56 to 0.91, 0.79. The 91.3% precision of the increase value is due to the role of hydraulic project,and the remainder is caused by the change of underlying surface.The operation of hydraulic project plays a leading role in the runoff change of the basin.