The Application Research of Sunken Green Space on the Sponge City Designation (An Ecological Perspective)

In response to the water crisis caused by the rapid development of urbanization in China, the idea of the sponge city was put forward. In the study on the runoff control capacity of the sunken green spaces with different parameters, the first project of regulating reservoir in Yizhuang was chosen as the study area, and the storm water management model (SWMM) was constructed for simulating and calculating. The results are summarized as follows: The sunken green land with a depth of 150mm and an area ratio of 1/2 can reduce the rainfall-runoff effectively by up to 11.85%-24.59% in the return period below 10 years. When the depth is 200mm and the area ratio is 1/2, the sunken green land can reduce the peak runoff effectively by up to 41.9%-48.68% in the return period below 20 years. In other words, the optimal area ratio of green land is 1/2, and the depth can be selected between 150mm and 200mm according to the standards of flood control and costs in actual projects. Moreover, sunken green space should be in conjunction with various LID facilities so as to avoid the uniformity and eventually achieve the best effect.