基于减沙效益和经济效益的流域退耕还林方案优化  

Optimization of Grain for Green Program based on sediment reduction and economic benefits

作　　者：喻丹[1,2] 董晓华 彭涛[1,2] 刘冀 刘超[3] 刘芳[4] YU Dan;DONG Xiaohua;PENG Tao;LIU Ji;LIU Chao;LIU Fang(College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443000,China;Engineering Research Center for the Ecological Environment of the Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang 443000,China;Yichang Yiling District Water Resources Utilization Service Center,Yichang 443000,China;Yichang Hydrology Bureau,Yichang 443000,China)

机构地区：[1]三峡大学水利与环境学院,宜昌443000 [2]三峡库区生态环境教育部工程研究中心,宜昌443000 [3]宜昌市夷陵区水资源利用服务中心,宜昌443000 [4]宜昌市水文局,宜昌443000

出　　处：《农业工程学报》2023年第13期260-270,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(52109058)。

摘　　要：实施退耕还林,是控制中国水土流失、改善生态环境的有效途径。如何制定最具成本-效益的退耕还林方案,以平衡生态、经济和粮食安全之间的矛盾,是保证退耕还林工程可持续发展的关键。该研究以淮河上游的息县流域为研究区,在土地利用现状的基础上,一方面通过建立分布式水文模型SWAT(soil and water assessment tool)依次模拟各子流域的退耕还林操作得到泥沙削减系数,另一方面通过GDP(gross domestic product)与土地利用现状的空间叠置分析得到各子流域进行退耕还林的GDP损失系数,据此分别构成退耕还林的减沙效益目标和经济效益目标,采用多目标遗传算法NSGA-II优化求解子流域尺度的退耕还林方案。研究结果表明:1)建立的SWAT模型对研究区径流和泥沙的模拟精度较高,Nash系数分别在0.90和0.70以上,决定系数均大于0.80,且百分比偏差均控制在-20%~20%以内,可认为SWAT模型能够用于评估退耕还林的泥沙削减效果;2)子流域泥沙削减系数范围为26.70~2675.85 t/km^(2),并表现出从上游到下游逐渐减小的趋势,说明在流域上游的河源区实施单位面积的退耕还林能够取得更好的泥沙控制效果;3)子流域GDP损失系数在空间上呈现出较大的差异性,既有子流域出现了GDP的增加也有子流域出现了GDP的减小,对比发现在行政市或县主要居民点所在的子流域进行退耕还林需要付出更大的经济代价;4)多目标优化求解得到的退耕还林方案集将人均耕地面积维持在1.04×10^(−3)~1.54×10^(−3) km^(2),明显高于粮食安全的警戒水平,同时该方案集能够在仅损失30.13%~37.67%经济产值的同时将泥沙产量削减53.54%~69.86%,并达到区域可持续发展的土壤侵蚀水平。该研究提出的基于生态减沙效益和经济效益的子流域尺度退耕还林优化方法可为流域水土保持、退耕还林工程的科学规划提供借鉴和指导。The Grain for Green Program(GGP)is an effective way to control soil erosion and improve the eco-environment in China.How to develop the most cost-effective GGP scheme,which can balance the contradiction among ecology,economy,and food security,is the key point for the sustainable development of the GGP.In this study,Xixian watershed located in the upper reaches of the Huaihe River is taken as the study area.Based on the current land use situation,the distributed hydrological model SWAT(Soil and Water Assessment Tool)was used to simulate the runoff and sediment processes.Then sediment reduction resultants per unit area of GGP,which defined as the sediment reduction coefficients,were obtained by simulating the successive GGP operations in each sub-basin based on the validated SWAT model.Meanwhile,considering the spatial correspondence between GDP(gross domestic product)and land use type,GDP loss coefficients at sub-basin scale were obtained by overlapping the GDP map and current land use map.On this basis,the ecological benefit and economic benefit of the GGP operation was expressed by sediment reduction coefficients and GDP loss coefficients respectively.Finally,the multi-objective genetic algorithm NSGA-II was used to optimize the GGP scheme at sub-basin scale.The results showed that 1)The SWAT model performed high simulation accuracy for runoff and sediment modeling.The Nash–Sutcliffe coefficients were above 0.90 and 0.70,the deterministic coefficients were both greater than 0.80,and the percentage deviation of the total amount is controlled within−20%to 20%,respectively.It can be conclude that the SWAT model can be used to evaluate the impact of the GGP on sediment reduction.2)The sediment reduction coefficients ranged from 26.70 to 2675.85 t/km^(2),decreasing gradually from the upper reaches to the lower reaches,which indicated that implementation of GGP per unit area can reduce sediment more effectively in the upstream river source area.3)The GDP loss coefficient presented spatial differences significantly

关 键 词：土地利用 泥沙 退耕还林 SWAT模型 空间叠置分析 多目标遗传算法 淮河息县流域 

分 类 号：S19[农业科学—农业基础科学]