Can the Sponge City Project improve the stormwater drainage system in China? ——Empirical evidence from a quasi-natural experiment

Abstract

Rapidly-developing cities face serious surface water flooding risks in China. But the flood control infrastructure, especially the stormwater drainage system, is very outdated and inefficient. Due to the long cycle and high cost of such infrastructure, which cannot meet the political performance needs of local officials in china, drainage system is being consciously ignored by them in China. The goal of the article is to evaluate the effect of the Sponge City Project initiated by the central government of China on infrastructure. We view this Sponge City pilot as a quasi-natural experiment and use the difference-in-difference model to assess the policy impact. The result shows that the Sponge City Project have enabled the selected cities to increase the length of drainage pipelines, and promoted the diversion of stormwater and sewage. In a further analysis, we confirm the impact of the pilot policy on local government preference using different infrastructure expenditure data. This study assesses the impact of sponge city policy on drainage and stormwater infrastructure and explains how the government's preference for infrastructure shifts.