平原湖区下垫面变化条件下排涝流量的响应机理研究

With the increasing impacts of human activities, the underlying surface of the plain lake district has changed obviously, which has seriously affected the formation process and the severity of waterlogging disaster. Considering the fact that few studies explore quantitative effects of changes in the underlying surface on runoff yield and concentration of waterlogging, the plain lake district is taken as an example in this study to research on this issue. Through data collection and statistical survey, a statistical model of runoff yield and underlying surface factors is established to discriminate the main underlying surface factors that affect the process of runoff yield and concentration. Then the spatio-temporal variations of the main underlying surface factors is analyzed. On this basis, the field and drainage district drainage experiments are conducted. By combining theoretical analysis of runoff yield and concentration with numerical simulation, the response mechanism of runoff yield and concentration of the drainage district to the main underlying surface factors and control factors of concentration is studied. Then, a distributed drainage model based on the hydrology and hydrodynamics at drainage district scale is built, which reflects the temporal and spatial characteristics of the underlying surface. The quantitative effect of the spatio-temporal variations of the main underlying surface factors on drainage discharge is analyzed using that model. Finally a method for calculating drainage discharge under the change of the underlying surface is proposed. The research results provide a theoretical basis for determining the water logging control standard and the scale of projects reasonably.

随着人类活动影响的加剧，平原湖区下垫面条件发生了显著改变，严重影响了涝水的致灾过程和致灾程度。针对目前关于下垫面改变对涝水产汇流定量影响研究的不足，本研究以平原湖区为对象，通过建立产流量与下垫面因子关系的统计模型，辨识影响产汇流过程的主要下垫面因子，并分析主要下垫面因子的时空变化特征；在此基础上开展排水观测试验，通过产汇流理论分析和数值模拟相结合，分析排区产汇流对主要下垫面因子和汇流控制因子的响应机理，并建立排区尺度上反映下垫面空间分布、具有水文和水动力学基础的分布式排涝模型；分析主要下垫面因子时空变化对排涝流量的定量影响，并提出下垫面变化下排涝流量的计算方法。研究成果可为排涝标准和排涝工程规模的合理确定提供理论依据。

随着人类活动影响的加剧，平原湖区下垫面条件发生了显著改变，严重影响了涝水的致灾过程和致灾程度。针对目前关于下垫面改变对涝水产汇流定量影响研究的不足，本研究以湖北省四湖流域的螺山排区作为研究区，分析了影响产汇流过程和排涝流量的主要下垫面因子及其时空变化特征，构建了排区尺度上具有水文和水动力学基础的排涝模型，并利用构建的模型分析了主要下垫面因子时空变化对排涝流量的定量影响，提出下垫面变化条件下排涝流量的计算方法。得到的主要研究成果有：（1）种植结构（水旱比）、城市化（地面硬化率）、水面率、土地利用方式等下垫面因子对产汇流和排涝流量影响显著。排涝流量分别随着水旱比和水面率的增加而减小，而随着地面硬化率的增加而增大。水面率对排涝流量的影响大于水旱比和地面硬化率的影响。排区1994~2011年期间主要下垫面因子的变化趋势是建设用地的大幅增加和水域、其他用地的大幅减少。（2）通过耦合SCS和MIKE11 模型来建立排区尺度的涝水产汇流模型，并对水面产流和闸站进行改进，分别采用1980 年、1983 年和1991 年、1996 年螺山泵站站前的实测水位数据对模型进行率定和验证，结果表明：率定期的相对误差分别为-0.20%和-0.40%，相关系数分别为0.980 和0.952，效率系数分别为0.949和0.849；验证期的相对误差分别为-0.10%和1.70%，相关系数分别为0.919 和0.967，效率系数分别为0.782 和0.906，表明耦合模型模拟效果较好。（3）利用构建的耦合模型分析主要下垫面因子时空变化对排涝模数的影响。结果表明：同一重现期下，以2011年下垫面为基础求得的排涝模数比1994年下垫面求得的排涝模数大。研究成果可为排涝标准和排涝工程规模的合理确定提供理论依据。