Research On Engineering Project Of Sino-singapore Eco-city Landscape Water Replenishment And Hydrodynamic Circulation

To solve the serious water environmental problems faced by Sino-Singapore Tianjin Eco-City landscape water system,this study took the water yield guarantee and water quality maintenance of landscape water system as the goal,carrying out systematic research on engineering problems of water replenishment,hydrodynamic cycle and water conservation.The research results were as follows:(1)Based on the landscape water balance analysis,it was proposed that the water replenishment capacity reach to 40,000 m~3/d in the near future(now-2018)and80,000 m~3/d in the long term(after 2018).The water changing frequency in Sino-Singapore Tianjin Eco-City can be up to 2~3 times per year,and the water quality can be basically maintained to meet the standard of class IV water according to the Surface Water Environmental Quality Standard(GB3838-2002),and the total dissolved solids in water(TDS)concentration can be diluted to 1000mg/L or less.(2)The proposed water replenishment was divided into two ways:One is utilizing the water from YingCheng sewage treatment plant as the main daily filling water,forming clockwise water circulation system from north to south;Another is pumping water from Jiyun River with a pumping capacity of 1 m3/s(86,400m3/d)through three-in-one pumping station in the north section of GuDao River in the emergency need of water changes when TDS of the landscape water system in Sino-Singapore Tianjin Eco-City is high or there is a sudden water pollution accident after the water quality of Jiyun River meet to the standard of class IV water according to the Surface Water Environmental Quality Standard(GB3838-2002)in 2020.(3)Based on the study of the water circulation scheme,it was put forward to construct the internal circulation pump station of Jing Lake,and water from Jing Lake is extracted by united pipeline to overflow to the cecum section of GuDao River to achieve the circulation and the water cycle project among Jing Lake,Huifeng River and north section of GuDao River.It was proposed to build a circulating pump station to put water from GuDao River back into Jing Lake in order to improve the overall flow of rivers and lakes,to reduce the proportion of low velocity area of lakes;It was proposed that after the implementation of long-term water cycle project,taking the water from YingCheng sewage treatment plant as the main daily filling water,in cooperation with circulating pump station,to form a counterclockwise water cycle in Jing Lake,and it will greatly improve the current situation similar to the"stagnant water".After simulation calculation with the flow rate of"Stagnant water",the water self-purification capacity in Sino-Singapore Tianjin Eco-City water system can increase by about 10%to 30%.(4)The analysis of performance analysis shows that by the introduction of other sources water to complement the river to improve the ecological situation of water shortage of water can increase water mobility,dilute river nutrients concentration,reduce the water turbidity and pH value.And it can maintain to create a certain water environment and protect water ecology.But such project accounts for a large proportion of one-time investment,and the follow-up water curing is crucial,which mainly rely on the ecological maintenance and intelligent management technology support.