基于SWAT模型的典型区域高标准农田综合管理方案模拟与优化

Simulation and Optimization of Well-facilitated Farmland Comprehensive Management Scheme in Typical Regions Based on SWAT Model

为研究不同高标准农田管理措施对流域排水影响,以芳溪湖流域为研究对象,以2019-2020年连续2年的径流和水质(总氮、总磷和产沙)监测数据为基础,率定并验证了SWAT模型的适用性,并基于率定后SWAT模型对典型区域高标准农田综合管理方案进行了模拟和优化。结果表明:(1)率定的SWAT模型模拟效果总体较好,构建的灌区分布式水文及面源污染模型适用于芳溪湖流域;(2)高标准农田建设可以实现流域节水减排,最大径流排放减少可达6.93%,最大总氮、总磷、泥沙排放减小均可达7.81%以上,适当提高塘堰汇流面积比例,增加生态沟的建设密度和长度,能有效减少地表径流及总氮、总磷负荷,最大径流排放减小可达18.92%,最大总氮、总磷、泥沙排放减小均可达20.37%以上;(3)不同轮作模式中,水作模式与现状条件相比能有效减少流域径流、总氮、总磷和泥沙的排放;(4)高标准农田建设综合管理优化方案下,流域排水总量减少可达24.59%,总氮、总磷和泥沙减少均可达36.36%以上。合理的沟塘系统设计和种植结构调整能有效减少流域面源污染排放。

In order to study the impact of different high-standard farmland management measures on the drainage of the basin,this paper took the Fangxi Lake basin as the research object.Based on the monitoring data of runoff and water quality(total nitrogen,total phosphorus and sediment production) for two consecutive years from 2019 to 2020,the applicability of the SWAT model was calibrated and verified,and based on the calibrated SWAT model,the high-standard farmland comprehensive management scheme in typical regions was simulated and optimized.The results show that:(1)The simulation effect of the calibrated SWAT model is generally good,and the constructed distributed hydrology and non-point source pollution model is suitable for the Fangxi Lake basin;(2)The construction of high-standard farmland can realize water saving and emission reduction in the basin,and the maximum runoff can be achieved.The emission reduction can reach 6.93%,and the maximum total nitrogen,total phosphorus,and sediment discharge can be reduced by more than 7.81%.Properly increasing the proportion of pond and weir confluence area and increasing the construction density and length of ecological ditches can effectively reduce surface runoff and total nitrogen,total phosphorus load.The maximum runoff discharge can be reduced by 18.92%,and the maximum total nitrogen,total phosphorus and sediment discharge can be reduced by more than 20.37%;(3)In different crop rotation modes,compared with the current conditions,the water cropping mode can effectively reduce the discharge of watershed runoff,total nitrogen,total phosphorus and sediment;(4) Under the comprehensive management optimization plan of high-standard farmland construction,the total drainage of the watershed can be reduced by 24.59%,and the reduction of total nitrogen,total phosphorus and sediment can reach 24.59%,36.36% or more.Reasonable ditch and pond system design and planting structure adjustment can effectively reduce non-point source pollution discharge in the basin.