Research On The Stormwater Management In Tianjin

Due to the more frequent occurrence of extreme climate, the deeper degree ofurbanization and the shortage of world water resource, the contradiction betweenrainwater runoff and city drainage systems become worsened. People began to realizethat all the drain water transports by pipes could not only increase the pressure ofdrainage system, but also ignore the value of rainwater, so people formed a series ofstormwater managements to solve these problems.In this thesis, Tianjin was chosen as the study object. In order to complete theexisting stormwater management in Tianjin, design procedures and successful caseswere used for reference. The main contents and conclusions include:(1) The feasibility of stormwater management in Tianjin was analysed from3respects which were technologies, economy and society environment. The resultsshowed that: in Tianjin the average rainfall reached the minimum value of stormwaterutilization, and the soil permeability in central urban area match the requirement.However, due to the saline-alkali soil, permeability facilities could not be used inTanggu、Hangu、Dagang, in these cities stormwater storage was suggested. Accordingto calculate, we can save2.18billion RMB on sewage treatment,3.2575million RMBon landscape engineering and residents’ payments for water and gain14.24RMBecological value per1m2green land per year.(2) Tianjin stormwater design project was designed by the large scale and smallscale planning. Large scale planning was based on riverway, and stipulated thehydrological location index must over0.4. Small scale planning was based on livingquarters, streets. In Tianjin Low carbon community, the comprehensive runoffcoefficient should be controlled between0.53and0.58, but sometimes it can float by2%.(3) Tianjin stormwater management information platform should be set up toguarantee residents’ rights to know everything about stormwater management.Stormwater rights should be defined clearly. Laws and regulations should be perfectedsuch as <Tianjin Coastal Protection Planning><Soil Erosion Planning>. Rain watercharging system was formulated on the basis of Multi-factor Pollution EquivalentMethod and the combination of Cost Allocation Method and Stormwater RunoffCoefficient Method. What’s more when making choice we must considerate the localconditions. Tianjin rainwater subsidy system should be made which can standardized the management of funds. In addition, more attention should be paid on the service ofstormwater management facilities.