The overall objective of the Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology is to ensure water security, which is a critical national priority, while adhering to the principles of comprehensiveness, systematicity, and foresight in meeting the scientific and technological requirements entailed in the construction of sponge city in Beijing City. In order to ensure the water security in Beijing City, factors pertaining to the overall urban hydrological cycle such as groundwater, the quantity and quality of water, and water environments and ecologies, will be investigated. The team will continue its efforts to achieve a breakthrough relating to simulation of urban hydrological cycle and sponge city technology, and the construction of the sponge city will provide the theoretical basis and technical support. As a result of coordinated efforts to foster cooperation among scientific research institutions, institutions of higher education, enterprises, and other related institutions, prominent experts in the field of science and technology will work together, and provide training for research professionals. Consequently, the urban hydrological scientific innovation group, which is the leading research group in Beijing City and is establishing benchmarks for the entire country, will be formed as an institutional center that is promoting a platform for independent innovation and providing training to advance scientific and technological innovation talent in the field of urban hydrology and sponge city technology.
Main research fields
Research field 1: Urban storm/flood simulation and forecasting technology
Urban storm and flood modeling system will be developed to simulate and forecast the flooding process. According to the characteristics of runoff generation and routing in Beijing City, the flow generation, surface runoff, and streamflow processes under different underlying surfaces will be simulated synthetically. Complex underlying surface characteristics will be investigated using an distributed urban hydrological model, and an in-depth analysis of the spatial variability of the underlying surfaces will be performed. Simulation accuracy of the model can be improved through the performance of parameter sensitivity analysis, a multi-objective parameter optimization method based on the characteristics of the urban hydrological model. Applying the hypothesis of a continuity existing between media interfaces, the coupling of flow models entailing different module, such as urban river network, urban land surface, and urban pipe network system, can be implemented. Moreover, a dynamic flow model encompassing pipeline network, pump station, street, and river channels can be developed with the combination of distributed hydrological model, and a flood routing model for low-lying urban area. A complete simulation of the entire process of storm flooding in the city will provide scientific and technical support for the planning and management of urban storm and flooding events as well as for flood control and disaster mitigation in Beijing City.
Research field 2: Application of sponge city technology for the storage of surface water and groundwater
A technical system for the storage and utilization of rain and flood resources will be developed. Models for estimating surface water and groundwater quantity conversion as well as pollutants transforming processes will be investigated. The integrated numerical simulation method will be applied, and a coupling model of surface water and groundwater will be developed. This model encompasses water regulation and storage based on the relationship of the urban water supply, groundwater, and surface water. The application of the above method for the coupling of surface water and groundwater along with a method of assimilating data and estimating parameter uncertainty for the groundwater model, and of gravity satellite data in the numerical simulation of groundwater, will improve its accuracy. Furthermore, the reliability of water supplies obtained from different water sources and modes of utilizing water resources according to different storage facilities are included in this model. A framework for stormwater regulation and storage system in Beijing City will be proposed. Moreover, the connections between regulation, storage system, and urban stormwater management facilities will be analyzed. This analysis can provide supports for the processes of adjusting and accumulating surface water and groundwater in Beijing City, and improving the reliability of water supply, leading to the provision of scientific and technical support that contributes to the reduction of urban flooding disasters.
Research field 3: Pollution control mechanism and simulation of sponge city construction
Optimal management measures, notably Low Impact Development (LID)-BMPs (Best Management Practices) in the construction of the sponge city will be explored. We will also investigate the mechanism of runoff pollution purification, and simulate and optimize quantity control and the effect of runoff pollution reduction in the area where the sponge city is constructed, and perform urban surface water quality simulations and cost-benefit analyses. A primary research focus will be on the mechanisms whereby runoff are intercepted, filtered, absorbed, and degraded. These include submerged green belts, biological retention facilities, osmotic ponds, oxidation ponds, rainwater wetlands, grass trenches, vegetation buffer zones, and artificial soil infiltration. The study suggests that this mechanism is applicable to the different climatic conditions and rainfall patterns that exist throughout China. Major objectives are to develop new methods and design parameters for LID-BMPs that match the characteristics of urban conditions, to conduct R&D on water-saving and pollution control and engineering pilot demonstrations, and to develop a comprehensive treatment protocol for improving the quality of urban strormwater. A simulation system will bee developed for conducting a comprehensive assessment of water environment in the construction of the sponge city, with the aim of simulating and optimizing the efficiency of urban runoff pollution reduction and improving surface water quality in the sponge city. These efforts will provide a scientific basis for the rational planning and construction of sponge city in Beijing City.
Research field 4: Development of technology integration platform for sponge city
The research field relating to the development of the sponge city is integrated into a systematic method of analysis entailing the fusion of multiple data sources and the forging of seamless connections among various subject models. The data and models associated with the above-mentioned three research fields at the laboratory are integrated within one platform to achieve a synergy of “monitoring, simulation, and evaluation”, and to support scientific decision making in the construction of the sponge city. At the same time, connections and coupling of the multiscale urban hydrological cycles, representative areas and watersheds, and the construction of multiple sponge city technology integration test bases at different scales will be considered. On the one hand, the integration of various measures for monitoring surface water and groundwater, water quality and quantity, along with comprehensive ecological and environmental monitoring, will provide a foundation for exploring the evolving mechanism of urban hydrological cycle and the application of sponge city technology. On the other hand, the integration of sponge city technology will be accomplished using a variety of technologies, including minimum intervention and green sponge technologies as well as technologies for ecological flood control, artificial wetland purification, ecosystem services bionic restoration, and other basic modes of technology. The optimal design for the sponge city, and solutions under various scenarios, will simultaneously be addressed.