Water Sensitive Urban Design for Indian Cities - Synergising key principles and grey infrastructure elements in New Delhi, India

Abstract

Water Sensitive Urban Design (WSUD) recognises the urgent need for water as the critical component towards efforts to mitigate urban flooding and manage high runoff volumes generated from urban catchments. WSUD is essentially the efficient management of the urban water cycle. The current thinking around the urban water cycle and its management has emerged from research and discourse developed in Australia and Europe. These are appropriate in the context of Western cities, however, similar principles are dominating the conversations around Water Sensitive Cities in the Global South as well. Indian cities much like the cities of the Global South are witnessing rapid urbanisation, predominant with informality in the built environment. There is an urgent need to develop a new Water Sensitive Cities framework in the Indian urban context. This new framework must introduce the term “Planning” as an integral part of its solution to tackle the issue of urban flooding. Indian cities must shift to Water Sensitive Urban Design and Planning (WSUDP) guidelines and principles instead of merely applying normative WSUD principles. Urban water systems in Indian cities are confronted with significantly changing conditions and are fundamentally different from developed Western Cities. The escalating challenges of unplanned growth, intensified water cycle and outdated grey infrastructure are aggravating current water issues, including flooding, water scarcity, and escalating rehabilitation costs, reaching a scale that could overwhelm the capacities of Indian cities. By analysing the dense unplanned settlement in Sangam Vihar, New Delhi, this research acknowledges the inequity in Indian cities. It envisions a Water Sensitive Planning (WSP) framework for Indian cities rooted in inclusive planning, that aims to mitigate urban flooding by integrating adequate grey infrastructure with decentralised solutions for sustainable urban drainage. The key principles of the WSP framework in the Indian context are initially suggested, followed by the identification of essential principles tailored to Sangam Vihar. Subsequently, an in-depth analysis of the existing grey infrastructure (stormwater and sewage management) is conducted in the study area. The implementation of WSP principles is then translated into a concept design, yielding fitting recommendations to mitigate flooding risk in the settlement. Key principles involve prioritising the enhancement of suitable grey infrastructure in dense unplanned settlements as per the site hydrogeography. Implementing decentralised solutions for urban flood mitigation involves harnessing existing green spaces as potential retention ponds and incorporating nature- based approaches for effective greywater treatment. This not only significantly contributes to groundwater recharge but also aids in the revitalization of arid water bodies.