Links between ecological and human wealth in drainage ponds in a fast-expanding city, and proposals for design and management

Sustainable Drainage Systems (SuDS) are engineering solutions for managing storm water, and they can also provide blue spaces that equitably benefit the health and wellbeing of urban dwellers. The main objectives of this study were to test whether affluent neighbourhoods have SUDS with better ecological quality in one of Europe's fastest developing cities, and to investigate whether designable or manageable habitat characteristics of the SuDS, and the adjacent terrestrial area, are related to ecological quality. We estimated SuDS ecological quality by dimension reduction of five biotic and abiotic ecosystem components through performing a Principal Coordinate Analysis. Then we regressed SUDS ecological quality against socio-economic descriptors of the neighbourhood. We next applied non-parametric Kruskal Wallis tests and probabilistic co-occurrence analysis to assess associations between habitat characteristics and ecological quality of SuDS. Our data showed that more affluent neighbourhoods have SuDS of higher ecological quality. We identified thresholds for some easily designable and manageable habitat characteristics of SuDS clearly linked to their ecological quality. There was strong co-occurrence of habitat characteristics, with aggregation of features linked to poor and good ecological quality, in SuDS designed as detention basins/swales or ponds respectively. Our results can be applied to the design and management of SuDS to foster good ecological quality irrespective of the neighbourhood. This study will be valuable for building and managing SuDS in a nature-based way, thus providing more socially equitable access to high-quality urban blue space.