A Planning-Support Tool for Spatial Suitability Assessment of Harvesting Sites for Stormwater Infrastructure

Abstract

Increasing water shortages and the effects of global climate change require us to adopt sustainable methods to protect our natural water sources. Of all the techniques that are used to conserve water, stormwater harvesting (SWH) is considered the most sustainable approach to ease the pressure on freshwater resources. It is difficult to use multicriteria methods to estimate the potential of stormwater and identify appropriate locations for SWH. Therefore, this study proposes a robust method for assessing the potential of SWH and finding appropriate sites, which consider the suitable criteria for site selection. A geographic information system (GIS)-based approach is used to screen and identify areas with high potential for SWH, followed by a detailed analysis. Subsequently, to evaluate and analyze SWH sites, multiple suitability criteria are established with input from water experts to aid in the decision-making. The first step involves shortlisting potential sites and identifying suitable locations within the subcatchments. Thematic layers are created at a consistent spatial scale and used as input data for the model. The GIS environment is utilized to conduct computations that use the distributed curve number (CN) method, which helps when estimating the spatial distribution of event-based runoffs. Following the establishment of the thematic layers, an analytical hierarchy process (AHP) is employed to allocate proportional importance to each layer. This culminates in the production of a suitability map for SWH within the designated study region. The study could benefit water planners, because it enables them to identify suitable locations and make informed decisions at a regional scale.