Land suitability analysis for blue-green infrastructure implementation in an urban stormwater management system in Surabaya, Indonesia

In low-lying areas, pluvial, fluvial, and coastal flooding can combine to form complex flood events. In this context, integrated blue-green infrastructure (BGI) has emerged as a viable approach to environmentally friendly stormwater management. This study concentrated on two primary objectives: i) the development of a geospatial technology-based land suitability map for BGI implementation and ii) the identification of optimal BGI nodes and corridors. Surabaya City in the Delta Brantas region of Indonesia was selected as the location for a pilot study. The land suitability analysis considered five criteria (slope, potential drainage density, land use/land cover, soil types, and proximity to roads), and the analytic hierarchy process (AHP) was employed to assign weights to these criteria before calculating a BGI index using the raster calculator tool in GIS. A BGI index map was then employed to identify potential BGI nodes on public land and priority corridors. The eastern and western regions of Surabaya, which are characterized by agriculture, fishponds, salt ponds, and mangrove forests, were identified as prime candidates for BGI implementation. Areas of public land under the jurisdiction of the city government, such as government offices, police stations, and educational zones, also offered the opportunity for BGI initiatives.