Research On The Comprehensive Utilization Pattern Of Sand Pit Detention Basin In Western Suburbs Of Beijing

As urban construction develops rapidly, recently extreme weather events occur frequently, runoff condition changes obviously, and flooding victims increase significantly. Therefore, the urban flood control is attracting much attention. Urban detention basin, as the cure composition of the flood control system, is an effective measure to guarantee flood safety and mitigate flood damage. It can not only control flood, increase the flood carrying capacity of urban flood-relief channels, but also supplement ground water and improve the urban environment. This dissertation takes the example of sand-pit urban detention basin in the western suburbs of Beijing to study the comprehensive utilization of urban detention basin and shows its applicability and demonstration.The main part of the sand-pit detention basin in the western suburbs of Beijing, the Fushilu sand pit with a capacity of 6,800,000 m3, can gather the flood of a surrounding river basin with an area of 27 km2. This dissertation uses PCSWMM(Storm Water Management Model) to build the hydrologic model of the river basin and calculate the runoff process of the flood season in 2012-2014, which provides the hydrologic basis of the comprehensive utilization analysis of the detention basin.In this dissertation, the inner structure of the detention basin is divided into the landscape region, recharge region, and recession region. We design the parameter program to describe the detention basin, and use the PCSWMM model to build the water balance model of the detention basin. On basis of different recurrence intervals, we analyze the water-level variation of the detention basin and get the water-level proportions used for landscape, recharge and recession. According to the simulated runoff process of the flood season in 2012-2014, we analyze the comprehensive utilization effects of the detention basins in the conditions of high, normal and low flow year. It shows that to maintain the lowest water level for landscape takes up a little flood control capacity, the operation rules influence its recharge function, and demand of water for landscape can be covered.This dissertation summarizes the key-point management of the comprehensive utilization of the detention basin. In the operation rules of the detention basin, the key points are the rules of starting, discharging and combined dispatching. In landscape planting and environment monitoring, the key point is to protect the greenery and water quality. In sediment accumulation, the key point is to evaluate and monitor the sediment accumulation and to formulate the desilting plan.This dissertation quantitatively evaluates the effect and qualitatively summarizes the management key-points of the comprehensive utilization of the urban detention basin. The future research can focus on the verification and optimization of the hydrologic model, the dispatching and distribution of the detention basin, and the simulation and forecast of the sediment accumulation.