Maintenance of low impact development facilities: A case study of pilot sponge cities in China

The concept low impact development (LID) has been provided for over five decades for achieving sustainable stormwater management. However, once installed, LID facilities often suffer from a lack of maintenance, resulting in impaired functionality and substantial wastage of financial resource. Since 2014, many LID facilities have been constructed in Chinese pilot sponge cities. However, to date, there is little knowledge about the post-construction status of these LID facilities. In response, we investigated the current status quo, common problems needing maintenance, and residents' attitudes towards maintenance of LID facilities. The results showed that, among 467 bio-retention facilities in three surveyed pilot sponge cities, approximately one third of the bio-retention facilities were in a good state; However, more than one thirds are facing issues of decreasing vegetation coverage rate, a deteriorating vegetation growth situation, and the slight silting or blocking of water inlets or overflow ports. Thus, regular maintenance is necessary, but the starting maintenance time can go through in the fifth year after construction. Unfortunately, public participation on the maintenance would be difficult. Even those respondents who willing to pay for the maintenance fee or possessing previous knowledge exhibit reluctance to engage in maintenance practices. The paper provides decision makers with a comprehensive overview of the status quo and common maintenance problems associated with LID facilities in the Chinese pilot sponge cities. It can also equip governments with insights to effectively address maintenance and management issues related to LID facilities.