土地利用变化对东江流域径流量的影响

Impact of land use change on the runoff in Dongjiang basin

依据东江流域1980年和2000年两期土地利用现状图,采用改进的SCS月水量平衡模型,以顺天、蓝塘、九州及岳城4个子流域逐月实测水文资料为输入,进行模型率定和验证,并对各子流域不同土地利用情景下的径流进行了模拟。结果表明:1980年以后,流域城镇化面积显著增加,林地大幅度减少,耕地有所增加,水域和未利用土地面积变化不大;改进的SCS月水量平衡模型在东江4个子流域模拟效果总体较好;由于土地利用的变化,东江4个子流域月均径流量、最大月径流量和汛期径流量都有不同程度的增加。

An improved monthly SCS model was calibrated and used to simulate the runoff of each sub-basin of Dongjiang under different land use scenarios, based on the status quo of the land figures for two periods （the years 1980 and 2000） and the inputs of monthly hydrological data in the sub-basins Shuntian, Lantang, Jiuzhou and Yuecheng. Simulations of the four sub-basins by this model are satisfactory. The results show that since 1980s the land use in the Dongjiang basin have been characterized with a prominent increase in built-up land and strong farmland, while little change in forest, water and unutilized land. Land use change in the subbasins have caused increases in monthly mean runoff, maximum runoff and runoff in the flood period to different extent.