D3.4 Public summary of the geographical information system (GIS) location tool for Nature Based Solutions (NBS) hybrid solutions at city scale

This deliverable (D3.4) is the last one of the Work Package 3 (WP3) of the D4RUNOFF project. WP3 is divided in four tasks of six months each, with four deliverables in total, being the two last ones (D3.3 and D3.4) dedicated to the D4RUNOFF location tool for Nature-Based Solutions (NBS). The D3.4 is the public summary of the work done for the development of the GIS location tool for NBS at city scale. This GIS tool has been developed supported by the D4RUNOFF Parametric Library (D3.1) and the multi-criteria decision analysis (MCDA) for the selection of NBS (D3.2), and its objective is to locate the best NBS in the best place of the city, according to the existing conditions, limitations, and requirements. Firstly, the D4RUNOFF researchers have collected the data needed in GIS format for the three case studies (Santander, Odense and Pontedera), mainly related with the restrictions and limitations identified in the D3.1 for the NBS related with urban drainage. After discussion, it was decided to select mainly open access sources of geographical information to make it easier the application of this methodology in any place in Europe, ensuring the future replicability. Once the input data was clearly defined, two models were developed for the initial data processing. The first for the general data preparation (e.g., slope, water table depth or land uses), and the second for the roads preparation (e.g., definition of sidewalks and pedestrian areas). Each NBS typology counts with a specific geoprocessing module or model, resulting in 11 because swale and filter drain share the same module. These models allow the location of the best potential areas for the application of each NBS, considering the specific restrictions pointed out in the D3.1. Then, one extra geoprocessing module is in charge of taking into account the final ranking of alternatives obtained in the D3.2 with the application of the Analytic Hierarchy Process (AHP) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). This ranking list could be changed if needed, considering any other MCDA agreed. Considering this prioritization, the best NBS is the first one in occupying the available suitable area in the city, leaving the rest to the next NBS in the ranking. Finally, an integration module was created to run all the previous models at once. With all, it is recommended to proceed step by step to ensure the detailed control of the results. This GIS tool is applied initially to Santander, Odense, and Pontedera. As conclusion, this GIS tool allows the prioritized location of NBS according to different criteria, offering as result a city map with the potential NBS that could be implemented to improve the urban drainage making it hybrid thanks to the combination of NBS with the conventional sanitation network.