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Water transfer projects are important for realizing reasonable allocation of water resources, but once a water pollution accident occurs during such a project, the water environment is exposed to enormous risks. Therefore, it is critical to determine an appropriate emergency control system (ECS) for sudden water pollution accidents that occur in water transfer projects. In this study, the analytical hierarchy process (AHP) integrated with the coordinated development degree model (CDDM) was used to develop the ECS. This ECS was developed into two parts, including the emergency risk assessment and the emergency control. Feasible emergency control targets and control technology were also proposed for different sudden water pollution accidents. A demonstrative project was conducted in the Fangshui to Puyang channel, which is part of the Beijing-Shijiazhuang Emergency Water Supply Project (BSP) in the Middle Route of the South-to-North Water Transfer Project (MR-SNWTP) in China. However, we could not use an actual toxic soluble pollutant to validate our ECS, so we performed the experiment with sucrose to test the ECS based on its concentration variation. The relative error of peak sucrose concentration was less than 20 %.

Trees play important roles in urban stormwater management; through the loosening of soils by root growth, they increase infiltration and reduce runoff, helping to mitigate flooding and recharge groundwater. Malus baccata with fibrous roots and Sophora japonica with tap roots were studied experimentally to assess their enhancement of soil infiltration. A blank test without a tree was conducted for comparison. Steady-state soil infiltration rates at the bottom of test tanks were measured as 0.28 m/d, 0.33 m/d, and 0.61 m/d for the blank test, M. baccata, and S. japonica, respectively. This represents a 19% increase in the infiltration rate by planting M. baccata and a 118% increase by planting S. japonica. A larger increase in the infiltration rate by S. japonica is consistent with the effects of deeper and more vertical roots that help loosen deeper soils. Spatial variations in soil infiltration rates were also measured. Infiltration rates for M. baccata (1.06 m/d and 0.62 m/d) were larger than those for S. japonica (0.91 m/d and 0.51 m/d) at the same depths (0.35 m and 0.70 m); this is consistent with the expected effects of the shallower and more lateral roots of M. baccata. This study furthers our understanding of the roles of trees in watersheds and urban environments.