Optimization method for sponge city construction based on capacity trading and multi-scale mesh division

Abstract

[Objective] To address the issues of high construction costs and low resource allocation efficiency in the application of Low Impact Development(LID) facilities in sponge city construction, [Methods] an optimization strategy based on capacity trading and multi-scale mesh division is proposed. The study area was divided into meshes at scales of 100 m, 200 m, 500 m, and 1 000 m. The Sequential Least Squares Quadratic Programming(SLSQP) optimization algorithm and capacity trading mechanism were integrated to simulate the runoff “transfer” potential between different units and allocate LID facilities as required. [Results] The result showed that as the trading scale increased, the runoff reduction effect gradually strengthened. Compared to the 100 m trading scale, when the runoff coefficient control target was met, the required LID facility construction areas for the 200 m, 500 m, and 1 000 m trading scales were reduced by 28.48 hm², 87.33 hm², and 138.16 hm², respectively. When the runoff control rate was set as a constraint, the required LID facility construction areas for the 200 m, 500 m, and 1 000 m trading scales were reduced by 24.74 hm², 117.32 hm², and 192.18 hm², respectively. [Conclusion] Comprehensive analysis shows that as the trading scale increases, the required construction area for LID facilities gradually decreases. However, when the trading scale becomes excessively large, the rate of benefit improvement begins to level off. The 500 m trading scale is considered the optimal scale for the study area, as it effectively integrates runoff reduction potential across regions, reduces construction costs, and avoids the diminishing returns associated with excessive large scales. In practical applications, the trading scales should be flexibly selected based on the topography, climate, and functional needs of the specific area to achieve optimal resource allocation and runoff reduction effects. The proposed approach provides a refined and highly coordinated pathway for sponge city construction.

Keywords

mesh division / sponge capacity trading / spatial scale / sponge city / green infrastructure / runoff reduction