Change of the environment, namely climate change and human activities, is influencing hydrological cycles globally. Nonstationary changes have been widely detected in precipitation series, which has significantly increased the flood risk in various areas. Taking Taihu Basin as the typical study area, the nonstationary characteristics of precipitation are analyzed through the Mann-Kendall trend test, Pettitt abrupt change test, Sen’s slope estimator and Seasonality Index in this study. Spatial distributed daily precipitation data during 1979–2017 is used. An 1D-2D coupling hydrodynamic model is built by MIKE Zero to simulate the change of flood risk under the nonstationarity of precipitation. According to the results of statistical analysis, the precipitation of Taihu Basin shows increasing trends in various temporal and spatial scales. Especially, the torrential rain and extreme precipitation, which are the main cause of flood disasters of the basin, are increasing significantly especially in highly urbanized areas such as Shanghai city. According to simulation results, the increase of flood risk shows high correlation with the nonstationary change of precipitation. The results indicate a great impact of climate change and urbanization on the regional flood risk, which must be well solved during social and economic sustainable development.

Jiangyin is a typical plain river network city in the Yangtze River Delta. The water ecological environment in urban area faces a range of environmental challenges, including poor water quality, black and odorous water bodies, serious isolation of river network, degradation of water ecological environment and low efficiency in urban wastewater treatment. This study proposed a systematic treatment plan which includes source sewage control, river regulation, water cycle enhancement, water environment restoration and waterscape improvement. Such an approach was informed by four principles, which is prioritizing pollutant control, introducing flowing water, co-management of river and bank, and combination of construction and management. By implementing such measures, the water environment carrying capacity and water ecological restoration capacity of the urban area have been greatly improved, and the overall water ecological environment quality has been significantly improved. The urban water system has realized a new picture of smooth river, clear water, green bank and beautiful scenery.