Variations of Soil Water Replenishment in Manasi River Basin over the Last 40 Years
近40年来玛纳斯河流域土壤水分补给量的变化分析

Based on the soil water balance principle,this paper uses GRID data structure in the Geographical Information System(GIS)and its spatial analysis to establish a distributed hydrolo-gical model by selecting Manasi River basin in Xinjiang as a study area.Four significant factors influencing soil water replenishment,specifically precipitation,runoff,irrigation and groundwater were introduced in the model according to geographical characteristics of the study area.With this model,the temporal and spatial distributions of soil water replenishment from 1961 to 2000 were analyzed.The results showed that:(1)soil water replenishment is the greatest in June to August and the least in February in a year;(2)it varies with the precipitation in the last 40 years and reached two apexes in the 1960s and 1980s;(3)it was the greatest in oasis and the least in desert which was a bit less than in the mountain areas;and(4)the contribution of precipitation to soil water replenishment is always around 50% regardless of in wet or dry seasons.The contribution of irrigation was 36% and 0 in the two scenarios,while that of runoff remains at a low level all the time.