小流域综合治理的水土保持效益评价不仅对推动小流域的综合治理具有指导意义,更是对推动我国生态文明建设中绿色GDP考核具有重要参考价值。为了提高对小流域水土保持效益进行全面评价的效率,实现评价的程序化,本研究以小流域地形图、土地利用分布图、土壤质地图及野外调查数据为基础,利用关系数据库技术、空间数据库技术和ArcGIS Engine二次开发技术,结合分布式水文模型和修正通用土壤流失方程(Revised Universal Soil Loss Equation,RUSLE)开发了小流域水土保持效益评价系统。系统包括数据管理、水文效应评价、保持土壤功能评价、生态服务功能评价、主沟道评价和经济效益评价6个功能,本研究将对保持土壤功能评价和主沟道评价2个主要功能进行阐述。基于构建的系统,对北京市房山区最早开展生态清洁小流域建设的蒲洼小流域进行评价,结果表明:小流域治理前后相比,土壤侵蚀强度大幅度减小,土地利用变化以及植被恢复是土壤侵蚀保护的主要影响因素;主沟道水文地貌等级总体情况较好,评价较差的沟道主要分布在中下游人类活动频繁地区,人类活动是影响沟道环境的主要因素。

The evaluation of soil and water conservation benefit of comprehensive management of small watershed is not only of guiding significance for promoting the comprehensive management of small watersheds,but also has important reference value for the assessment of green GDP in promoting the construction of ecological civilization in our country.In order to improve the efficiency of evaluating the benefits of soil and water conservation in small watersheds and to standardize the evaluation process.In this study,the basic data are small watershed topographic maps,land use distribution map,soil texture map and field survey data.The author uses relational database technology,spatial database technology and ArcGIS Engine secondary development technology,and together with the distributed hydrological model and revised universal soil loss equation, has developed a benefit evaluation system of soil and water conservation in small watersheds.The system can realize the six functions of data management,hydrological benefits evaluation,soil maintaining function evaluation,ecological service function evaluation,main channel evaluation and economic benefit evaluation.This study will elaborate on two main functions of soil maintaining function evaluation and main channel evaluation.The system is used for evaluating Puwa small watershed,which is the earliest one in carrying out the construction of ecological clean watershed in Fangshan District,Beijing.The results showed that the soil erosion intensity decreased significantly before and after the comprehensive management of small watershed.Land use change and vegetation restoration were the main influencing factors of soil erosion protection.The main channel hydro-geomorphology is generally good,poorly assessed channels are mainly distributed in the middle and lower reaches where human activities are frequent,and human activities are the main factor affecting the channel environment.