淮河流域历史覆被变化及其对水文过程的影响

以淮河流域蚌埠集水区为研究区域,利用淮河流域1700、1800和2000年3种历史覆被情景,结合陆面水文耦合模型(CLHM)定量评价了流域土地利用/覆被变化的水文效应,并分析了流域径流与主要覆被类型变化方式的定量关系。结果表明:CLHM模型可以较好地模拟淮河流域的流量过程,在研究区具有较好地适用性;三期覆被情景下主要覆被类型变化为林地转变为耕地或草地以及草地转变为耕地,此种变化导致流域总蒸发量减少了6.5%,流域出口研究期平均径流量增加了6.1%;极端覆被情况下,年均蒸发量由多到少依次为林地、草地和耕地;林地对流域径流过程的影响主要体现在洪峰上,相对于耕地,林地具有削减洪峰的作用;通过分析覆被类型变化与流域多年平均径流的相关关系,林地转变为草地以及林地转变为耕地是近400年来影响淮河流域水文过程及水资源分配的主要覆被变化因子。因此,合理规划土地利用格局对流域水资源高效利用具有重要意义。

Historical vegetation change and its impact on hydrological process in Huaihe river basin

Taking Bengbu watershed of Huaihe basin as study area, the paper quantitatively assessed hydrological effects of land use and land cover change,and the quantitative relation between basin runoff and main types of vegetation change by use of three historical cover scenarios including 1700, 1800 and 2000.The results show that CLHM model can be used to simulate the flow process of the Huaihe basin and has good applicability in the area;the main type of vegetation change in the three cover scenarios are forest to farmland or grassland and grassland to farmland.The change result in the reduction of 6.5% of total evaporation and the increase of 6.1% of average outlet flow; under the condition of extreme vegetation, the value of annual average evaporation from more to less is forest, grassland and farmland;the effect of forest on runoff process is mainly reflected on flood peak,and forest has the effect of reducing peak; by analyzing the relationship between the type of vegetation change and mean annual runoff of the Bengbu watershed, forest converting to grassland and farmland are the main factors of effecting the hydrologic process and water resource distribution in Huaihe basin in near 400 years. Therefore, it is important and significant for efficient utilization of water resources to reasonably plan land use pattern.