Path Exploration and Practice of Sponge City Construction in the Pearl River Delta:A Case Study of Dalang Town,Dongguan City

In order to deal with global climate warming and practice the construction of national ecological civilization,a sponge city has become an important national plan for regional comprehensive management and development because it can systematically solve the issues of regional water resources,water security,water environment and water ecology,and provide a comprehensive plan of sustainable development for regional water control,storage and use.Sponge city construction has been carried out across the country.In this paper,taking Dalang Town as an example,and combining its local climate,geological geomorphology,hydrological conditions,current situation and future planning of urban space,management system and other characteristics,the connotation,construction strategy and objectives,index decomposition and other key contents of sponge city were discussed,and the methods of sponge city construction in the builtup area with high rainfall,abundant groundwater and high density were studied to provide reference for formulating solutions and schemes for Dalang Town and developing sponge city construction in the Pearl River Delta.

Regional ecosystem services relationships and their potential driving factors in the Yellow River Basin,China

The Yellow River Basin(YRB)occupies an important position in China’s socioeconomic development and ecological conservation efforts.Understanding the spatiotemporal characteristics of the relationships among multiple ecosystem services(ESs)and their drivers is crucial for regional sustainable development and human-earth system coordination.This study simulated food production(FP),water yield(WY),net primary production(NPP),soil conservation(SC),and habitat quality(HQ)in the YRB from 2000 to 2020,and evaluated the spatial evolution and the relationship of ESs at the raster scale.Redundancy analysis was used to identify the impact of natural,socioeconomic,and landscape patterns on the relationship between ESs.The results demonstrated that the average HQ per unit area decreased by 18.10%,while SC,NPP,WY,and FP increased by 42.68%,47.63%,30.82%,and 67.10%,respectively,from 2000 to 2020.The relationship between ESs in the YRB was dominated by weak trade-offs and weak synergies at a temporal scale,with the trade-offs strengthened in the Upper Yellow River Basin(UYRB)and the Middle Yellow River Basin(MYRB),and synergies strengthened in the Lower Yellow River Basin(LYRB).At the spatial scale,the relationships between HQ and WY,HQ and SC,HQ and NPP,FP and SC,and FP and HQ were all dominated by trade-offs,while other ES pairs were mostly based on synergistic relationships.In the YRB,the relationships among ESs were mainly influenced by human disturbance,precipitation,and land-use and exploitation intensity.Specifically,the trade-offs among ESs in the UYRB were primarily affected by precipitation,and those in the MYRB and LYRB by human disturbance.The heterogeneity of the landscape could also effectively promote synergies among ESs.This study could provide insights into trade-offs and synergies among ESs and their driving forces and lay a foundation for ecological restoration and sustainable development of ESs in the YRB.

Voltage-dependent P-Q Reserve Capacity Evaluation for TSO-DSO Interface Considering Uncertainties of DGs and FLs

Increasing distributed generators(DGs)and flexible loads(FLs)enable distribution systems to provide both active and reactive power reserves(P-Q reserves)in supporting the frequency and voltage regulations of transmission systems.However,such requirements at the interface between the transmission system operator(TSO)and distribution system operator(DSO)affect the distribution system operation security,considering the uncertainties of DGs and FLs.To exploit the reserve potential of distribution systems,this paper investigates the voltagedependent P-Q reserve capacity(V-PQRC)of such types of distribution systems.V-PQRC reflects the feasible space of PQ reserves that the DSO can provide to the TSO taking the voltage deviation limit at TSO-DSO interface into consideration,while ensuring the distribution system operation security under uncertainties of DGs and FLs.An evaluation method for VPQRC at the TSO-DSO interface is proposed.To improve the robust performance of the evaluation method,the DG uncertainty is captured by a generalized ambiguity set and the FL uncertainty is addressed by designing a constrained sliding mode controller(CSMC).Three objectives are considered in the evaluation,i.e.,P reserve capacity,Q reserve capacity,and the voltage deviation limit at the TSO-DSO interface.Then,a multiobjective optimization model integrating the generalized robust chance-constrained optimization and CSMC(GRCC-CSMC)is established for V-PQRC evaluation to obtain the Pareto optimal reserve schemes.Finally,a non-approximated selecting(NAS)method is proposed to build up a simplified V-PQRC linear model,which can be convenient to apply in the transmissiondistribution system coordination.Simulation results reveal that the V-PQRC evaluation method can achieve a good performance of accuracy and robustness against uncertainties.