Integrated Stormwater Management With The Existing Built Environment: Water Quality Based System Design And Application In A Low-lying Urban Watershed

The watershed-based approach for improving the surface water hydrological condition is the trend of the current stormwater management research. Up to now, compared to the enormous researches focusing on the methods using the optimal quantity and scale of mono-facility to simulate target peak flow, very few concern about the treatment objective in view of the spatial restriction on the urban watershed. Other than the exploration of the regulation frame, there is no further research upon the efficiency of the management program from a watershed scale perspective. None of the design principles for the appropriate facilities have been integrated with the environment layout. This paper describes a watershed model of the optimal integration of the facilities and environment, which contains:1) the general-planning model for the sub-watershed; 2)the definite-design model for the catchmen(titerative-design model); 3)the water quality management model suitable for any scale. The design strategy has been applied to 36.77km2 urban watershed system of Haihe River to optimize facility planning, the objective of which are maximizing the processing capability of concentration facilities and minimizing the land usage of the distributed facilities while utilizing the stormwater transmission feature of the scattered allocation ones. Moreover, taking a specific layout-unit-design as an example, this paper introduces the iterative-design module whose water-quality is valued by MUSIC4.0. The design result not only reflects the constraints on the stormwater facilities, which are enforced by the space of the constructed watershed, but also reveals the ratio of the occupation area to the contributing drainage area of the facilities under the goal of optimizing water quality along the watershed. Eventually, this paper proposes an integrated design guideline capable of directing construction and alteration of environment and stormwater facilities under different land usage type.