Research On Rural Drainage System Planning In Dry Areas Based On Sponge City Concept

Based on the concept of sponge city,this paper optimizes the planning and construction methods of rural drainage system in arid area,and mainly completes the following work:Firstly this paper introduces the research and practice of rural drainage system in sponge city at home and abroad,points out that the theoretical research of sponge city in arid region is inadequate,and the construction of rural drainage mode needs to follow the principle of adapting to local conditions.The experience and lessons of successful cases of rain and flood management at home and abroad are summarized and analyzed.It is determined that sponge city construction must be carried out according to the principle of adapting measures to local conditions.It provides a thinking method for the drainage system planning of Lanjiang Village in Minning under the concept of sponge city.Secondly,taking Lanjiang village in Minning as an example,this paper introduces its general situation.According to its natural environment and drainage status,a new type of drainage system combining local drainage pipe network with LID facilities is determined.The design objective of local drainage system was determined.Combining with local climate,soil,vegetation and hydrological conditions,the selection and application methods of facilities for sponge city construction in rural transportation in arid areas were put forward.According to the local topography and drainage,the drainage pipeline network was planned,and the transformation and construction scheme of rainwater retention and storage and utilization in farmyards in arid areas were further designed.Thirdly,the rainwater system model of Lanjiang village is established by using MIKE URBAN to simulate the state of drainage system under different facilities after rainfall.The results show that when the drainage pipe network is constructed solely,there are still more water accumulation under the condition of 2-year precipitation.The total area of water accumulation area is 22922 m2,which accounts for 8%of the total area of Lanjiang Village.With the addition of LID facilities,there are almost no deep water in the whole village area except scattered low and shallow water depressions,and the area of water accumulation is about 3891.28 m2,which accounts for about 0.4%of the total area of Lanjiang Village.By comparing with the new drainage system design of Lanjiang Village,it can be seen that the drainage system based on the concept of sponge city can effectively cope with strong rainfall,reduce the runoff after rainfall,reduce the area of flooded area and water depth of the village,and better meet the drainage requirements.Fourthly,the cost of building LID facilities in Lanjiang village is estimated,and then the benefit after building LID is estimated and analyzed according to the local water price in Lanjiang village.The results show that although the initial construction cost is high,the benefit after construction is still considerable.Among them,the annual water resources income obtained through LID is about 10,000 yuan,and the cost of pollution control is about 4,421 yuan,which can effectively reduce the cost of urban rainwater pipe system design and transformation.The indirect benefits to the local environment and ecology are more in line with the requirements of the new socialist countryside,beautiful countryside and Rural Revitalization construction.