| Since the large-scale development of China’s western region, the city construction innorthwest China has reached a new climax. City construction can better embody thepeople-oriented idea, and the good ecological environment can better embody the ecologicalphilosophy. The ecology in northwest China is vulnerable and water resources are short dueto the geographical location and climate, and according to the relevant statistics, the watershortage will reach to2.2×1011m3by the mid-21st century. In recent years, to alleviate theshortage of water resources in Lanzhou New Area, Gansu Provincial government haslaunched many large-scale water projects, such as Water Diversion Project from Datong Riverto Qinwangchuan District(WDP). Though these water projects alleviate the water-shortageproblem in Lanzhou New Area to a certain degree, many more problems inevitably emerge inthe course of water utilization. With the rapid development of Lanzhou New Area, waterconsumption will accordingly increase. Therefore, if Lanzhou New Area could not improvethe efficiency of water utilization and promptly deal with problems, such as water pollution,inefficiency of wastewater treatment etc, its further development could be hindered and policyprivileges cannot be fully enacted when the water supply can’t meet the need of waterconsumption.This research mainly focuses on the rainwater resources in the construction of LanzhouNew Area. Based on the field research, on-the-spot investigation and simulation experiments,firstly, we analyze the sampling rainwater quality in the district, and then carry out anexperiment on rainwater runoff in Lanzhou New Area with the technology of LID greenbeltsystem in order to provide technical support for the construction of the Lanzhou New Area.What’s more, we conduct research on the exploitation of rainwater resources in Lanzhou NewArea to provide technical support for the utilization of rainwater resources in the constructionof new towns in Northwest China.The analysis on the sampling rainwater quality in the District includes the quality analysisof collected rainwater and the quality-correlation analysis of collected rainwater. Through theanalysis, we reach the following conclusions:(1) the quality index of rainwater collected fromroofs and cement roads considerably exceeds the standard at the beginning of rainwater runoff.With the prolonged rainfall, the pollutant concentrations in rainwater runoff collected fromroof and surface of cement roads seem to decrease. The longer the rain falls, the more slowlythe pollutant concentrations decrease, eventually to a relatively stable numeric range, but stillexceed the standard by comparing with the National Drinking Water Standard;(2) Therainwater runoff turbidity on the roof and cement road surface has obvious correlations withammonia nitrogen, CODMn, UV254, which all will increase with the rainwater runoff turbidity; (3) With the increase of CODMnin rainwater runoff, UV254will increase obviously, that is tosay, CODMnin rainwater runoff on the roofs and cement road has obvious correlation withUV254.The experimental study on sampling rainwater runoff in Lanzhou New Area with thesupport of LID greenbelt system is to comparatively analyze the water quality indexes onammonia nitrogen, turbidity, CODMnUV254, etc., before and after using the system, and drawthe conclusion: the pollutant removal effects of the greenbelt system on rainwater runoffpollutants (turbidity, ammonia nitrogen, CODMn, UV254) are fairly good, with the highest of70%on the ammonia nitrogen, and the lowest of30%on CODMnand UV254.Bluegrass group has the highest removal rate of pollutants, followed by alfalfa group, theblank group has the lowest. The experiment proves the validity of the greenbelt system toremove the rainwater runoff pollutants in Lanzhou New Area, and provide a theoretic basisfor its construction.In general, according to the status quo of water utilization in Lanzhou New Area, somefeasible schemes can be summed up. However, the strong regional characteristics and greatvariety are the key features in the efficient utilization of water resources. The study of LIDgreenbelt system applied in water utilization in Lanzhou New Area is still in the preliminarystage, and many further researches are to be done in future. |
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