| Rainwater is an important imput and origin in water circulation system,and it is also a supporting force of the ecosysterm. Due to the great changes in underlying surface properties during the urbanization, the urban water cycle has been changed by the increasing of impervious area, and the pressure on the water logging and drainage of the urban also has increased. So the rainwater collection and utilization has been a world-wide concern. As the origin of the urban rainwater drainage system, the residential area makes up about 70% of the city’s area, and it plays an important role in the control and utilization of rainwater.Firstly, the paper analyzes the potential of rainwater utilization in Zhuzhou, on the trend of the torrential rain days, annual rainfall and evaporation data. The hourly rainfall data is provided by the meteorologic agency. Due to the differences of rainfall distribution for different region,Then it chooses the comprehensive runoff coefficient method to calculate the rainwater availability. and it can prove the water utilization potential of Zhuzhou by the comprehensive runoff coefficient. It finds that the monthly rainfall more than 50 mm is 75%, adove 100 mm is 40.9% in Zhuzhou. Also the amount of collected rainwater is obtained to be 9156.9 m3.In view of the low impact development technology has great ecological and environmental benefits, its application is analyzed emphatically. The results shows that:1) With the increase of return period, the decreasing trend for the system total flow and the rush-hour traffic is enhanced on the low impact development technology. Under the recurrence interval for 1a,2a and 3a, the cutting rate under low-impact technology to the system flow is 24.4%,24.81% and 25.50% respectively, and to the peak traffic of the runoff amount is 21.46%,23.03% and 26.62%. 2)Under the recurrence interval for 1a,2a and 3a, the cutting rate under low-impact technology to SS is 9.46%,11.46% and 9.89%, and to TN is 14.55%,9.88% and 10.01%, to COD are 7.84%,8.06% and 8.33%. The development of low-impact method has been different effect in the rinse of pollutants, but the concentration change of the pollutant appears to be similar. 3) the low-impact development method can also reduce the runoff coefficient of sub-catchment, and make an apparent increasing of the infiltration, which is 56.27%,67.88% and 71.13% respectively.Finally, Through the simulation of runoff amount and filtration of the resident, it determines that the filtration area is 4083.25 m2 based on the filtration amount. On the other hand, it analyzes the simulated water storage volume, through comparing with the calculated result by rainfall estimation method and the rainfall intensity curve calculation method, and the water storage volume is obtained to be 120 m3. Further it establishes the rainwater utilization systerm in the resident. Through the economic benefits of the community rainwater utilization, it finds that it can create 3.4 yuan/m3 for the direct economic benefits,also can reduce the environmental resources loss. |
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