基于InVEST模型的伊洛河流域水源涵养能力评估

Assessment of Water Conservation Capacity of Yiluo River Basin Based on the InVEST Model

水源涵养是生态系统最重要的服务功能之一,黄河流域生态保护和高质量发展规划纲要强调聚焦重点区域,恢复重要生态系统,对强化水源涵养能力提出了新的要求。收集并分析伊洛河流域1975-2019年的气象及下垫面资料,采用InVEST模型产水模块计算1975-2019年伊洛河流域每5年1期共9个时段的产水量,采用流速系数、土壤饱和导水率等对产水量进行修正,估算流域的水源涵养量,具体分析伊洛河流域降水、产水与水源涵养的特征及其相关关系。结果表明:1975-2019年,伊洛河流域多年平均水源涵养量为11.3 mm,多年平均产水量为143.2 mm,产水量及水源涵养量整体呈现先增后减的变化趋势,在1980-1984年达到峰值;流域水源涵养能力空间分布特征为上游植被丰富、土石山区水源涵养能力强,中下游相对较弱;对流域气象要素单相关及复相关分析,水源涵养能力与降水显著正相关,与参考作物蒸散发相关性不显著;流域内土地利用变化在一定程度上影响水源涵养能力空间分布,上游水源涵养高值区及退耕还林还草区受影响显著。研究结果可为相似流域水源涵养能力的评估提供参考。

Water conservation is one of the most important service functions of the ecosystem,and the outline of the Yellow River Basin Ecological Protection and High-quality Development Plan emphasizes focusing on key areas and restoring important ecosystems,which puts forward new requirements for strengthening water conservation capacity.We collected and analyzed meteorological and subsurface data of the Yiluo River basin from 1975 to 2019,calculated the water yield of the basin for a total of nine time periods in every five-year period during 1975 to 2019 using the water yield module of the InVEST model,and the water conservation was obtained by using the flow rate coefficient and soil saturation conductivity to correct the water yield.This study specifically analyzed the characteristics and correlations between precipitation,water yield and water conservation in the Yiluo River Basin.The results show that from 1975 to 2019,the annual average water conservation in the Yiluo River Basin is 11.3 mm,and the annual average water yield is 143.2 mm,and the overall water yield and water conservation show a trend of first increasing and then decreasing,reaching a peak from 1980 to 1984.The spatial distribution of water conservation capacity in the river basin is characterized by abundant vegetation in the upstream and strong water conservation capacity in mountainous areas of earth and rock,while the middle and lower reaches are relatively weak.The results of single-correlation and complex correlation analysis of meteorological elements in the basin show that the water conservation capacity is significantly positively correlated with precipitation,but not with evapotranspiration of reference crops.To a certain extent,the change of land use in the river basin affects the spatial distribution of water conservation capacity,and the areas with high value of water conservation in the upper reaches and the areas where farmland is returned to forest and grassland are significantly affected.The results can provide a reference for the assessment of water conservation capacity in similar river basins.