China Sponge City database development and urban runoff source control facility configuration comparison between China and the US.

Urban runoff source control facilities (URSCFs) are important parts of Sponge City (SC) by controlling urban flooding, restoring eco-balance, and enhancing city resilience. To evaluate the performance of URSCF, one needs to summarize and analyze the past SC construction and operation data. Previous studies however are predominately engineering practice studies. There lacks localized reference datasets to quantitatively evaluate the performance and guide public policy development for SC. Therefore, it is imperative to develop a database, which would summarize data obtained through the already completed pilot sponge cities, and provide a reference for future URSCFs planning and construction. This study makes a zero to one breakthrough by establishing a SC database using New Orleans method. Then statistical results of facility type, size, and costs information for 30 pilot sponge cities have been summarized and analyzed. The URSCFs type distribution statistical results show that bioretention, permeable pavement, detention cell, grassed swale and constructed wetland are the top five most constructed facilities in China. The cost statistical results display that the range of facility cost collected is usually larger than the range given by the reference value, which may attribute to the variation in material cost, labor cost and design parameters in different cities. To check the similarities and differences of URSCFs parameters between China and the US. A configuration parameters comparison of URSCFs has been conducted. Bioretention is taken as an exampl. Comparison results show that factors such as climate type, geographical environment, and socio-economic conditions will affect the configuration parameters of URSCFs. The groundwater depth and designed rainfall intensity are mainly influenced by local climate and geographical conditions. Surface area is influenced by local socio-economic conditions. The thickness of the covering layer and drainage layer are not affected by geographic location. The service area ratio, water storage depth and planting soil layer thickness are significantly different between China and the US.

Marginal-cost-based greedy strategy (MCGS): Fast and reliable optimization of low impact development (LID) layout.

Cost effectiveness is a major concern when implementing low impact development (LID) practices for urban stormwater management (USWM). To optimize LID layout, an efficient and more reliable method, namely, the Marginal-Cost-based Greedy Strategy (MCGS) was developed based on the economic law of increasing marginal costs (MCs) and the stepwise minimization of MCs. To verify its broad applicability, MCGS was applied in three case studies in China with different system settings and environmental goals. Both Cases I and II were watershed-scale studies in Suzhou City urban districts, but in Case II, the impact of future uncertainties (i.e., climate change, urban expansion, and LID performance degradation) on USWM system performance was considered. Case III was a block-scale study of the Xixian New District (a pilot "Sponge City" in China), which involved a rainwater pipe network and a complicated environmental goal. Compared with the extensively used but complicated NSGA-II, the MCGS performed better in terms of yielding more converged performance trade-offs, providing more choices for city planners, and requiring much less computational resources in all three cases. Meanwhile, MCGS established an optimal pathway for multi-stage LID layout planning. The success of MCGS indicated that the MC of a LID practice determined its favorability in an USWM system.

[Effect of different nitrogen forms and concentrations on biomass and alkaloids of isatidis folium].

OBJECTIVE: In order to provide theoretical basis of improving nitrogen utilization efficiency in Isatis indigotica, the biomass and active components in Isatidis Folium under different nitrogen forms and concentrations were analyzed. METHOD: I. indigotica was cultivated by sand culture in greenhouse, and the experiment was designed with orthogonal test L25 (5(6)). As an index to the biomass and indigo, indirubin, the effects on the I. indigotica by three factors [NO3(-) -N, NH4(+) -N, CO(NH2)2] at five different levels were studied. RESULT: There were significant difference of the biomass and active components by different nitrogen forms and concentrations. The effect of amide nitrogen [CO(NH2)2] on biomass of Isatidis Folium was the most apparent, and the effect of ammonium nitrogen on indirubin was more obvious. Considering the biomass and active ingredient, one combination was optimized, which was (NH4)2SO(4)-7.5 mmol x L(-1), KNO(3)-2.5 mmol x L(-1), CO(NH2)(2)- 5 mmol x L(-1). CONCLUSION: It is important to promote the growth in pre-stage of I. indigotica, and cost-effective combination of balanced nitrogen fertilizer could reasonably promote the growth, and improve the contents of active components and individual biomass.