Issues of Urban Drainage—Present Status and the Way Forward

Abstract

The 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC) has indicated that the global surface temperature is likely to rise a further 1.1–6.4 °C during the twenty-first century, while studies by NASA indicate that the urban heat island effect over cities has resulted in an increase in rainfall over several urban areas. A major concern is the likely effects of changes in the frequency and intensity of extreme weather events, especially droughts and floods—“an increased risk of drought” while “precipitation is projected to be concentrated into more intense events, with longer periods of little precipitation in between.” Cities/towns located on the coast, on river banks, upstream/downstream of dams, inland cities, and in hilly areas can all be affected. There has been an increasing trend of urban flood disasters in India over the past several years whereby major cities in India have been severely affected. The most notable amongst them are Hyderabad in 2000, Ahmedabad in 2001, Delhi in 2002 and 2003, Chennai in 2004, Mumbai in 2005, Surat in 2006, Kolkata in 2007, Jamshedpur in 2008, Delhi 2009, and Guwahati and Delhi in 2010 and again in September 2011. There is therefore an urgent need for adaptation and mitigation options for tackling the impacts of climate change on water resources, especially flooding from extreme rainfall. This paper describes the measures being taken at the local, national, and international level to make our cities flood resilient.