汾河流域水土保持措施水文水资源效应初析

应用具有物理机制的分布式水文模拟模型(W EP-L),模拟了不同下垫面条件情景下的水循环过程,在此基础上,定量分析了汾河流域水土保持措施的水文水资源效应。通过对比分析2种不同情景下的水资源量,初步得出:汾河流域水土保持措施影响了局部水循环和水资源量及其构成,加强了水循环的垂向过程,引起地表截留量、土壤入渗量、土壤蒸发量以及补给地下水量增加;削弱了水循环的水平过程,引起地表径流量和河川基流量减少,壤中流微弱增加;地表水资源量衰减,而地下与地表水资源不重复量增加,狭义水资源量减少,但有效蒸散(发)量增加,广义水资源量有一定幅度增加。研究成果对于研究大尺度流域水土保持措施的水文水资源效应具有参考价值。

Preliminary Analysis of Hydrological and Water Resources Effects under the Impact of Water and Soil Conservation Engineering in Fenhe River Basin

According to the application of the distributed hydrological model(WEP-L model) with physical mechanism to the simulation of the hydrological cycle under different underlying surface data,this paper analyzes the quantitative influence of water and soil conservation engi-neering on hydrological cycle and water resources taking Fenhe River Basin as an exapmle.Two cases were described.Case I,the simulated underlying surface data in 2000 was used.Case II,the underlying surface data displacing the water and soil conservation engineering in 2000 with bare soil was used in the model.By contrast between Case I and Case II,the change and evolution of hydrological cycle and water resources have been investigated.The results showed that the local hydrological cycle as well as the quantity and compositions of water resources change distinctly under the impact of water and soil conservation engineering.Three main variations are as follows:(1)the vertical process of hydrological cycle was strengthened,each part of which including interception of surface,infiltration to soil,evaporation of soil and recharge of groundwater increased by 9.4%,1.8%,2.2% and 0.5%,respectively;(2)the horizontal process of hydrological cycle was weakened,each part of which such as direct surface runoff and base runoff decreased by 51.7% and 1.8% but interflow increased 4.9%;and(3) the surface water resources decreased 29.7% but groundwater resources nonoverlapped with surface water increased 5.1%,the special water resources reduced 23.2% but the general water resources increased 32.5% accompanied with 50.4% increase of the effective evaporation,namely,effective utilization of precipitation.The research achievement can be referenced to the studies on hydrological and water resources effects under impact of water and soil conservation engineering in other large watersheds.