Urban Stormwater To Improve The Urban Water Environment

The fast development of cities caused a series of water problems. On the one hand, with the centralization of the people and the economic activities, extension of the urban buildings and increase of the area of impervious stratum, the flood caused by urban storm flow cannot be neglected. On the other hand, new water-supply source is urgently demanded for the scarcity of urban fresh water. As a kind of slightly polluted water source, rainwater has less contaminations and it can be used as domestic water and industrial water by simply treatment. So the exploitation of the urban rainwater and making best use of the urban rainwater will be the effective measures of the water-saving city.The primary purpose of this paper is to research the utilization of urban rainwater and the improvement of urban water environmental system. Based on the investigation of the present research of the utilization of urban rainwater, it analyze the influence of urbanization on water source, water environmental system and water circulation, the relationship of the urbanization, water environmental system and the utilization of urban rainwater, and research the necessity and feasibility of the utilization of urban rainwater; The utilization ways are classified and the utilization modes are discussed; On the ground of the theoretical basis of the utilization of urban rainwater, the basic mode and procedure of the utilization of urban rainwater are established and discussed; After the discussion of the landscape and its contribution to the improvement of urban water environmental system and the analysis of the theory and facilities of rainfall penetration, the effect of rainfall penetration on the improvement of urban water environmental system is presented.On the specific application study, the paper makes a systematic analysis of the utilization of rainwater on the campus of DLUT in Dalian. The findings of the paper are as follows: ㏕he analysis of rainfall gives the relationships of distribution of rain, rainfall and the utilization of rainwater as basic data for the utilization of rainwater. ㏕he campus of DLUT is divided into two drainage areas according to the contour line, and then the two drainage areas are dividedAbstractinto smaller areas according to ground types. (3)Rainfall that can be collected in each smaller area and the water amount used on lawn are calculated. The amounts of two kinds of water are compared and then we can see that water amounts used on lawn are 73% and 73.8% of rainwater that can be collected in two drainage areas respectively. (4)Design flow of rainwater on the campus of DLUT is calculated, retention basins in two drainage areas are designed, the relationship between retention basin and rainfall reappearing period is analyzed and transfer scheme of rainfall is attained. (5)Rainwater samples got from representative places are analyzed three times. The qualities of rainwater fallen on old and new roofs and diverse roads are compared. Change of the rainwater qualities is also analyzed. Then sources of contaminations in rainwater are investigated. (6)Based on the calculation of total pollutants in the rainwater fallen on roofs, we get the gross COD taken into the environment. Then process of the utilization of rainwater is put forward.