Comprehensive Performance Evaluation of LID Practices for the Sponge City Construction: A Case Study in Guangxi, China

TL;DR

This study develops a comprehensive evaluation system using SWMM and AHP to assess the environmental, economic, and social benefits of LID practices in sponge city construction, demonstrated through a case in Guangxi, China.

Contribution

It introduces a quantitative evaluation method combining SWMM and AHP for assessing LID practices' benefits in sponge city projects, filling a gap in performance assessment.

Findings

Green scenario achieved 75% runoff reduction and high ecological benefits.

Optimal LID configuration was identified for the Guangxi sports center project.

Proposed evaluation system is applicable to other sponge city projects.

Abstract

Sponge city construction is a new concept of urban stormwater management, which can effectively relieve urban flooding, reduce non-point source pollution, and promote the usage of rainwater resources, often including the application of Low Impact Development (LID) techniques. Although 30 cities in China have been chosen to implement sponge city construction, there is a lack of a quantitative evaluation method to evaluate the environmental, economic, and social benefits of LID practices. This paper develops a comprehensive evaluation system to quantify the benefits of different combinations of LID units using the Storm Water Management Model (SWMM) and the Analytical Hierarchy Process (AHP) method. The performance of five LID design scenarios with different locations and sizes of the bio-retention facility, the grassed swale, the sunken green space, the permeable pavement, and the storage tank were analyzed for a sports center project in Guangxi, China. Results indicated that the green scenario that contains 34.5% of bio-retention facilities and 46.0% of sunken green spaces had the best comprehensive performance regarding meeting the requirements of 75% annual total runoff reduction and the attainment of good operation performance, rainwater utilization, landscape promotion, and ecological service functions, mainly because they are micro-scale and decentralized facilities that can manage stormwater at the source through the natural process. The optimal scenario was adopted to construct the project, and the proposed evaluation system can also be applied to optimal selection and performance effect evaluation of LID practices in other sponge city projects.