Nature-based alternative-water landscapes for water security and green space health

This paper is concerned with highlighting and learning from Alternative-Water Urban Landscapes (AWULs) from around the world. Such systems contribute to issues such as water security and greenspace health. Nature-based methods for treating alternative-water can provide for secure water supplies in local landscapes and a wide range of social and environmental co-benefits. However, such treatment methods have raised concerns about efficacy, safety, public opinion, and cost, which have often led to a reliance on centralised, and high-energy and chemical treatment methods. To move forward, more understanding about AWULs is required. The aim of this research is to reveal principles for the design of nature-based AWULs. A framework for the analysis of AWULs was developed from relevant literature works. The framework comprised two sets of criteria based on conservative and innovative aspirations for the AWUL design. A search of AWUL and landscape literature revealed 26 precedents as suitable. These were then analysed using the two sets of criteria which revealed three key outcomes for nature-based AWUL applications. These included making use of free-water surface flow landscape-based treatment, large AWUL footprints and, partial decentralisation. These findings helped to fashion a set of design principles to guide and encourage adoption of nature-based AWUL by implementers.HIGHLIGHTSNature-based, alternative-water landscapes can be embraced by local communities. Centralised, piped recycled water schemes have limited 'deep green' sustainability outcomes. Nature-based alternative-water landscapes are most successful when they are partially decentralised, large scale and use free-water flow wetlands. Design principles created for the use of implementers of nature-based alternative-water infrastructure.