基于SCS-CN模型在山地海绵城市不同下垫面径流预测的优化及应用

Optimization and Application of SCS-CN Model for Runoff Prediction of Different Underlying Surfaces in Mountain Sponge Cities

山地区域因其独特的地形地貌,降雨产汇流过程较复杂,潜在水环境问题不可小觑。以针对此区域进行降雨产流预测模型的选取、建立,可以为以后海绵城市建设与改造提供水文方面的支持与借鉴。由美国农业部土壤保持局提出的SCS-CN模型,该模型区域适用性欠佳,因此需要对模型中参数进行优化以提高预测精度。以典型山地城市——重庆为例,选取巴南区未开发区域为研究对象,采用人工模拟降雨实验得到不同下垫面条件下的降雨径流系列数据,结合海绵城市建设措施,设置裸地、透水铺砖和草地3种土地利用方式,3种下垫面优化初损系数λ均为0.01,考虑前期土壤含水量情况下,裸地、透水铺装和草地的CN分别为97.76、94.64、89.60,在此基础上采用Huang坡度修正公式修正CN值,进一步提高模型预测精度。裸地、透水铺砖和草地优化参数模型后率定期与验证期相比标准模型NSE系数提高了9.41%、16.36%、5.62%与2.72%、5.37%、4.08%。

Due to its unique topography and landform,the process of rainfall production and confluence in mountainous areas is more complex,and the potential water environment problems should not be underestimated.The selection and establishment of the rainfall runoff prediction model in this area can provide hydrological support and reference for the construction and reconstruction of sponge cities in the future.The SCS-CN model proposed by the Soil Conservation Service of the United States Department of Agriculture is not very applicable regionally,so it is necessary to optimize the parameters in the model to improve prediction accuracy.This paper uses a typical mountain city named Chongqing as an example to select Banan District,an undeveloped area,as the research object.It uses the artificial rainfall simulation experiments for different underlying surface conditions of rainfall runoff series data.Based on sponge urban construction measures,the bare land,permeable shop is designed,and the grass of three methods for land use,three kinds of underlying surface optimization coefficient of the early damage ofλare 0.01,this paper considers the antecedent soil moisture conditions,bare land,permeable pavement.The NSE coefficients of the standard model increased by 9.41%,16.36%,5.62%and 2.72%,5.37%,4.08%in the optimized parameter models of bare land,permeable brick paving and grassland.