Ecological Protection Technologies And Effect Evaluations Of River Water Quality In Rapid Urbanization Area A Case Study On Shangxian River

Fast urbanization has made serious problems in water resources of cities’ rivers. Thisarticle using Shangxian River as experimental demonstration project, aiming at features ofwater environmental pollution in fast urbanization area, and requirements of new city on riverlandscape, based on the concept of river ecological restoration, we studied the protectiontechnology in ecological environment of city rivers, proposed the protection measures formicro-pollution river fitting with fast development of new urbanization area, providedprotection technology system for rivers environment in rapid urbanization area, significantlyimproved micro-polluted water environment in rapid urbanization areas, and provided thebasic research information and technical support for managing work on regional waterenvironment. The research including the study on the effect for purifying water quality byaquatic plant, pilot scale test of stereo ecological shore side zone-constructed wetlandspollution controlling system and its practical use in Shangxian River.We select fleurdelis, spiked loosestrife, foxtail algae, potamogeton crispus andwaterweed as research object to test the purifying effect, the results state that botanical systemformed by different combination caused different removing rate on total nitrogen, ammonianitrogen, permanganate index, total phosphorus during experimental period, its order is Irispseudacorus+Myriophyllum spicatum+Potamogeton crispus>Potamogeton crispus+Egeriadensa+Myriophyllum spicatum>Lythrumsalicaria> Iris pseudacorus>Potamogeton crispus> blank, the hightest removal rate is71.7%,38.5%,25.7%,43.3%. Therefore, in theimplement procedure of river water quality protection, the constructed wetlands should usediversification combination, using stability of ecological diversity to remove the pollutant.Using the purifying effect of aquatic plant as research basis, obeying the rule of adjustingmeasures to local conditions, we plant red leaves-berberis, radix ophiopogonis around thepond from outside to inside with the span of0.2m in Jiangnan University. We mixed foxtailalgae with water lily, cedar moss in the scale of20-30plants per square meter and plantedthem in water, building the pilot scale test-project of stereo ecological shore sidezone-constructed wetlands pollution controlling system. The system states that: The removalrate of total nitrogen, ammonia nitrogen, permanganate index in water can reach64.2%,75.6%,46.6%, its purifying ability is similar with chemistry methods, the aquatic plant persquare meter can remove total nitrogen, ammonia nitrogen, permanganate index:3.33g,0.46g,3.64g. Stereo ecological shore side zone-constructed wetlands pollution controlling systemcan purify the water very well and supply its practical use with the reliable basis.According to the research result of pilot scale test and the characteristic of ShangxianRiver, we plant shore side plant such as red leaves-berberis, radix ophiopogonis and aquaticplant such as fleurdelis, spiked loosestrife, foxtail algae, potamogeton crispus and waterweed,building stereo ecological shore side zone-constructed wetlands pollution controlling systemdemonstration system. The operation condition states: the nitrogen in water reduced34.8% than before, nitrate nitrogen reduced88.6%than before, the classification of surface waterincreased from class IV to class III; after we use gray clustering method did the comprehensiv-e evaluation on the water quality of Shangxian River, we found that; in the season of autumn,winter and spring the water quality can reach class III, and in summer it also can maintainclass IV, the purifying effect on water quality by stereo ecological shore side zone-constructedwetlands pollution controlling system is obvious, and it also caused beautiful urban riverscene, establishing good basis for its further application.