An integrated approach to determine appropriate stormwater management strategies for urban areas with various land-uses: the case of Güneysu

Abstract

This study focuses on a multi-criteria decision-making (MCDM) analysis backed by EPA's SWMM (storm water management model) to investigate stormwater management (SM) strategies for urban areas consisting of different land-use types. Güneysu city center (Rize, Türkiye) is used to exemplify areas consisting of impermeable surfaces, blocks of buildings, and green areas. The rising irregularity in expected rainfall coupled with unplanned urban development causes material damage and casualties worldwide. Extreme rainfalls and topographical factors worsen the scenario in regions with a high amount of precipitation. Güneysu city center consists of different land-use types located in a small region, and the reports from the Turkish Disaster and Emergency Management Presidency (AFAD) state 127 recent casualties from flood-related events in Rize. In this study, an MCDM approach is used to determine appropriate SM strategies for different land-use types in Güneysu. Additional SWMM simulations are carried out to compare total and mean surface runoff values to highlight the consistency of the findings. Results show that permeable pavements are the most suitable SM alternative for impermeable surfaces with a similarity (to ideal solution) coefficient (Formula presented.) in TOPSIS and a total surface runoff reduction rate of (Formula presented.) in SWMM. Similarly, rain gardens (TOPSIS: (Formula presented.), SWMM: (Formula presented.)) and green roofs (TOPSIS: (Formula presented.), SWMM: (Formula presented.)) are the most suitable alternatives for green areas and blocks of buildings, respectively. In contrast to literature, where SM planning studies mostly focus on a single type of land-use or single/combined SM approaches for specific regions, this study presents a tailored approach where suitable alternatives are assessed for each different type of land-use in a densely populated urban area. The most appropriate SM strategy is selected for each land-use type with an integrated approach that considers MCDM results with sensitivity analysis and SWMM simulations to achieve the best surface runoff reduction. This methodology provides a comprehensive approach for strategizing effective SM where combined SM alternatives are selected according to the specific characteristics of the land-use.