Analysis Of The Rainwater Quality Characteristics Of Different Underlying Surface In Xi’an High Tech Zone And Study On LID Utilization Technology

With the accelerating pace of development in Xi’an, the ground hardening rate is more and more high, leading to frequent water logging in the city. Recently years, construction of "sponge city" has become a hot spot. The research of urban current situation of rainwater utilization, analysis of urban runoff potential, analysis of urban runoff quality characteristics will be an important support better of the rainwater resources utilization.Through the investigation of Xi’an high tech Zone rainwater utilization, we analyzed the problems of the current urban rainwater utilization and give some suggestions, analyzed the water shortage status in Xi’an and the potential of utilization of rainwater resources, pointed out that we should use low impact development technology to better use the rainwater. We also monitored the runoff pollutants of different underlying surface in high tech Zone and analyzed the pollutant concentration characteristics and rules. According to the current situation of Xi’an hi tech Zone, we chose two sites and use LID rainwater utilization technology to design. The main conclusions are as follows:(1) Xi’an City rainfall runoff water pollution is serious: road runoff water quality pollution is the most grievous, parking lot runoff water quality is better than the road runoff. Roof runoff rainwater has the advantages of collection and utilization. Embedded brick grass plants has certain adsorption removal effect on pollutants in runoff.(2) We found that the road green belt is the main measures of rainwater collection, accounting for 52.44% of all measures, waterscape and low elevation greenbelt accounted for 12.76%, traditional pits accounted for 33.64%, new type filter pits only accounted for 0.46% and mostly located in the new zone. At present, High tech Zone has a weak awareness of the rainwater collection, and the traditional type facilities can only play the role of beauty, has no function of runoff collection, infiltration and transfer which leading to a waste of rainwater resource.(3)Xi’an city per capita water resources occupies the entire province about 24.4%,about 13.4% nationwide, about 3.1% of all over the world, has been in a very serious shortage of water. Through the rain can collect estimates, the average annual rainfall resources in Xi’an high tech Zone is 20.95 million cubic metres. This is a huge sum of wealth. Xi’an has the utilization potential of rainwater resources.(4) Xi’an City rainfall runoff water pollution is really serious. We should use the lid low impact development technology, take a use of the vegetation layer, packing layer filtering of bio-retention measures to absorbing pollutants, and then collect and use the rainwater. We do two LID design of road greening belt and pits.