基于SWAT模型的晋江流域土地利用变化对水文过程影响分析

Effects of Landuse Changes on Hydrological Processes: An Analysis Based on SWAT Model

为了进一步揭示晋江流域土地利用变化的水文效应,基于SWAT模型,分别模拟了1985年和2006年2种土地利用条件下,2002—2010年气象条件时的年、月水文过程,以定量分析土地利用变化对流域年、月的蒸散发、土壤剖面渗漏、地下径流和地表径流的影响。研究表明:与1985年土地利用相比,在2006年土地利用涵养水源能力较好的林草地减少了,而不透水面积的增加,降低了流域的降雨截留能力和土壤下渗能力,地表蒸散发量和地下水随之减少,而减小的水量则转为地表径流直接汇入河道,其中晋江全流域的蒸散发量、土壤渗漏量和地下径流量年平均减少11.86 mm、48.86 mm和25.62 mm,年平均减少幅度分别为2.23%、11.27%和16.69%,而地表径流量年平均增加76.06 mm,年平均增幅为26.12%;土地利用变化的水文过程效应与年内降水分布具有密切的关系,降雨量越小,蒸散发和地表径流的效应越显著,而土壤剖面下渗和地下径效应则相反。

The Soil and Water Assessment Tool （SWAT） was used to reveal the influences of landuse changes on hydrological processes in Jinjiang Watershed. The hydrological processes （yearly and monthly scales） were simulated from 2002 to 2010 under two different landuse scenarios （1985 and 2006） . The effects of landuse changes on evapotranspiration, percolation, groundwater and surface runoff were analyzed with the simulation output. The results show as follows ： 1 ） When the land use changed by increasing impervious area （urbanized, orchard） and decreasing in the good water conser- vation area （forest, grassland, farmland） from 1985 to 2006, which resulted in the reduction of thecapacity of rainfall interception, soil infiltration. Compared to landuse in 1985, the annual evapotrans- piration, percolation and groundwater from 2002 to 2010, which were simulated by SWAT model in landuse 2006, decreased by 11.86 ram, 48.86 mm and 25.62 ram, and tile range were 2.23%, 11.27% and 16.69% , respectively. On the contrary, the surface runoff increased by 76.06 mm and 26. 12%. 2） The change in hydrological processes was associated to precipitation, that is, when plv ：ipitation was smaller, change in evapotranspiration and surface runoff were larger, and change in per- colation and groundwater were snmller.