截流缓释生态工程对流域径流影响

The Impact of the Closure and Slow-release Ecological System on the Watershed Runoff

截流缓释生态坝是结合生物措施和工程措施对小型淤地坝改良后的水土保持措施。为了揭示改良后的水土保持措施对小流域径流的影响,为淤地坝新的发展提供借鉴,以骆驼林流域为研究对象,构建流域CASC2D-SED模型,以实测降雨径流资料进行参数率定及验证,通过实地勘察、试验确定工程建设后下垫面情况的变化,将工程与模型进行耦合,比较工程建设前后流域径流实测模拟对比分析,并结合流域径流量与径流系数的计算分析,确定工程对流域径流的影响。率定期模型确定性系数均在0.7以上,洪峰相对误差绝对值在20%以内,拟合度良好;工程建设后,流域径流量和径流系数均明显增加,径流系数增加3.5%左右;工程能够有效削减洪峰,减少洪峰流量30%左右。截流缓释生态工程能够显著地增加流域径流系数,并可以起消减洪峰的作用。

Construction standard of water and soil conservation project in the mountainous area of South Ningxia is low,the aging of the project is serious,and the utilization efficiency of local water resources is low.In order to solve this problem,a closure and slow-release ecological system has been built locally.The closure and slow-release ecological system is composed of a series of closure and slow-release ecological dams arranged reasonably in space.The closure and slow-release ecological dam is a water and soil conservation measure for improving small silt dams.Its main biological and engineering measures have synergistic effects on watershed hydrology.In order to reveal the impact of closure and slow-release ecological system on the runoff of small watersheds and provide a reference for the new development of the silt dam in the future,CASC2D-SED model of the watershed is constructed by taking camel forest watershed as the research object,the parameters are calibrated and verified based on measured rainfall-runoff data,the changes of underlying surface conditions after the project is completed are determined by field investigation and test,and these conditions are substituted into the model to couple the project with the model.By comparing the measured and simulated comparison and analysis of runoff before and after the project construction,and combining the calculation and analysis of runoff with runoff coefficient of the river basin,the influence of the project on the river basin runoff is determined.After the model is built,the deterministic coefficient of the rate periodicity and verification period are above 0.7,the absolute value of relative error of flood peak is within 20%,and the fitting degree is good.According to the calculation and analysis of runoff and runoff coefficient of the river basin,after the construction of the project,the runoff and runoff coefficient of the river basin have increased significantly,and the runoff coefficient has increased by about 3.5%.The basin model is used to simulate the basin flood process before project construction,and the coupling model is used to simulate the basin flood process after project construction.The results show that the project can effectively reduce the peak flow and reduce the peak flow by about 30%.The closure and slow-release ecological project can significantly increase the runoff coefficient of the watershed and reduce the flood peak.So,the closure and slow release ecological system can increase the water utilization efficiency and tap the potential of water resources.Moreover,due to the convenient construction and low cost of the project,it can be popularized to a certain extent.