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This paper applies Soft Systems Methodology (SSM) within the context of action research and Integrated Flood Management (IFM). A case study from the Adayar watershed, Chennai, is provided as an example of how SSM can be used to understand complex situations and as a problem-solving strategy for flood management. Flat topography, uncontrolled urban development, population growth, sand bar formation at the river mouth and low tidal action render complexity to flood management in Chennai. For effective flood management, a participatory and integrated approach, which includes stakeholders in the decision-making process and an enabling institutional set-up, is essential. As part of an integrated approach, the relationship between various organizations and the public is identified. SSM is an approach for addressing fuzzy problematic situations involving human activity. In this paper, SSM techniques like 'Rich Picture Diagrams' and 'CATWOE analysis' and participatory action research tools like 'pairwise ranking' and 'force field analysis' were investigated. Two workshops were conducted to define and explore the problematic situation, the role of various actors involved in the problem, to develop the conceptual model, to rank decision-making criteria, and to analyse the forces for and against to solve the problem. The flood management approach provided in this paper can be used by government agencies and policy makers to manage floods. bs_bs_banner Water and Environment Journal. Print

Managing storm water under climate uncertainty is a major concern in urban areas throughout the world. There were several floods events recorded in Chennai, a one of the major metropolitan coastal city in India. The flood incidences were repeatedly reported in recent decades. In this study, the existing state of storm water drains are evaluated under current and future climate scenarios in one of the most flood-prone areas of Chennai viz. Velachery zone. The mitigation measures are recommended to increase its resilience against floods. The Intergovernmental Panel on Climate Change (IPCC) CMIP5 models of Representative Concentration Pathways (RCP) 4.5 are used to develop possible future climate change scenarios of the city. The daily rainfall data for the period 1975–2015 obtained from India Meteorological Department are used to find the extremities and to generate Intensity-Duration-Frequency (IDF) curves. The IDF curves are generated for 2, 5, 10, 50, 100 year return period under current and future climate scenarios. The storm drainage network are delineated with Differential Geographic Positioning System (DGPS) survey. The integrated hydraulic and hydrological modelling is carried out to assess the flood carrying capacity of storm drainage under present and future climate scenarios. The vulnerable hotspots are identified and flood mitigation measures are suggested to reduce the flood risk at Velachery.

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