基于景观尺度的流域土地覆被变化及其水文响应

水资源短缺已成为限制华北地区社会经济发展的主要因子之一，其中山区来水减少问题已成为该区域水资源研究亟待解决的关键问题。采用景观格局分析法及统计学方法对华北土石山区典型流域--红门川流域土地/覆被变化及其水文动态响应进行分析。结果表明：(1)1990～2005年流域景观呈破碎化趋势，其中，优势景观林地在研究时段内面积变化不大；耕地、建设用地面积增加趋势显著，增幅分别为431%和444%；水域减少趋势最为明显，减幅达208%。(2)土地利用/覆被变化对流域径流有显著调节作用：随着土地结构不断优化，森林、耕地面积的增加，1998～2005年流域平均年径流系数较1990～1998年下降77%；丰、平和枯水年径流系数则分别减少64%、31%和85%；当剔除降水因素后，土地利用景观结构优化使得月径流系数减少16%～100%。(3)土地利用/覆被变化对流域径流的调节作用呈现季节性,植物生长季径流调节尤为显著

LAND USE /FOREST VEGETATION CHANGE AND ITS HYDROLOGICAL EFFECTS AT THE LANDSCAPE SCALE

The shortage of water has become one of the main factors limiting the social economic development in North China.And the reduce of water in mountain areas has been the key problems to be solved.The purpose of this paper is to analyze the land use/cover change and its hydrological dynamic response of Hongmenchuan watershed,which is the typical watershed in rocky mountain area of North China.The landscape pattern analysis method and statistical methods were used in this paper.The major results are as follows.(1) Watershed landscape showed obvious fragmentation in the past 16 years from 1990 to 2005,during which the change of the areas of forest was not so obvious,farmland and construction land increased rapidly by 431%and 444%,water area dropped sharply by 208%.(2) The land use/cover change could regulate the runoff significantly.As the optimization of land use structure and the increase of the forest vegetation cover and farmland from 1998 to 2005,the average runoff coefficient of years was dropped by 77% compared to the years from 1990 to 1998,while the runoff coefficient dropped by 64%,31% and 85% in high flow year,average flow year and low flow year.Moreover,under the premise of removing the precipitation factors,the average runoff coefficient of months was decreased by 16% to 100%.(3) The effects of land use on runoff production had been found to be seasonal,as a particularly significant influence in the plant growing period