| With the acceleration of urbanization, more and more ecological and environmental problems began to attract people’s attention, especially the problems of urban runoff water. On one hand, urban stormwater runoff water can cause disasters which makes people’s lives and property been threatened; on the other hand, secondary pollution may be caused by rainwater runoff draining away, which is a waste of fresh water resources. Micro Waterscape ecological technology as an important means to alleviate stormwater problems, not only to purify stormwater runoff be used, and can create a better ecological environment.This paper selects the mountain city of Chongqing as the study site, by study the characteristics of pollutants in the runoff migration of the typical area, provide reference data for the construction of the ecological Micro Waterscape in Chongqing Expo Garden; Investigated 45 Micro Waterscape in Chongqing in order to find the seasonal change of water quality, the coefficient of variationin in aquatic plant carbon (C), nitrogen (N), phosphorus (P) and their spatio-temporal difference; Meanwhile,10 elements factor was analyzed. On this basis, a new Micro Waterscape was proposed in Chongqing. Through this study found that:1) The concentrations of contaminants increased first due to the influence of human activity, and then decreased during the migration. Before entering into the lake, the concentration of chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH3-N) were 26.6～87.1,0.87～6.96,0.08～0.28, and 0.52～1.48 mg/L, respectively. Except for dissolved TN (DTN), the percentage(the dissolved concentration to the total concentration) of the other 3 dissolved pollutants were increased along with the level and intensity of rainfall. Although the concentrations of NH3-N, COD and TP in the runoff had the positive linear relationship with the concentrations of total suspended solids (TSS), there were no correlation between dissolved COD(DCOD), dissolved TN (DTN), dissolved TP(DTP) and TSS. There was good positive linear relationship between TSS and the maximum rainfall intensity.2) The concentration of COD, TN, TP was greatly influenced by runoff in seasonal changes in 45 Micro Waterscapes, show the performance of the summer> autumn> spring. At the same time, to analyse the variation of leaf C, N, P, and C:N, C:P, N:P mass ratios for five aquatic plants from water landscape pool in summer, Cyperus alternifolius L., Iris pseudacorus L., Myriophyllum aquaticum, Pontederia cordata L. and Thalia dealbata leaf’s P content showed more seasonal dynamics——it was 28.55 with the concern range changing between 1.01 and 6.24 mg/g. The coefficient of variationin (CV) of N:P was followed by,and then the N, C:P and C:N has the lower CV.The concent of C has the lowest CV with the values of 3.58%ranging from 418.43 to 495.00 mg/g, The concent of C,N,P in Cyperus alternifolius L., Iris pseudacorus L., Myriophyllum aquaticum, showed significant differences Due to different sampling date and different water landscape pool. Meanwhile, Thalia dealbata showed some differences, and the differences of Pontederia cordata L. are smaller. In addition, based on the comprehensive evaluation index of landscape pool by factor analysis can be found that Whether there is liquidity in the construction of waterscape pool, the construction in the bottom/all around of the pool and to maintain the water quality were main factors to influence the whole water landscape pool.3)The design and construction of Micro waterscape must be based on the physical features of a place, and local growth of aquatic plants, at the same time, precipitated of particles, increased oxygen by aeration, filtered through the matrix and activity of microorganism should be included in order to deep cleansing the runoff water. |
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