Reducing the Risk of In-Situ Urban Stormwater - Case Study From India (PAP014867)

Código

PAP014867

Autores

Dr.S.K.Sharma

Tema

Urban Floods

Resumo

The challenges for the sustainable urban storm-water management in developing countries are considerable because of rapid increase of their population due to immigration. Urbanization in India has entered the stage of rapid development. It has the 2nd largest urban system in the world and nearly 310 million people live in more than 5000 cities and town. Urbanization in the country has entered the stage of rapid development but the urbanization leads to increase in impervious areas which, in turn, significantly increases the rate of runoff, resulting in overwhelming of designed capacity of the stormwater drainage system. As a result of all these happenings, even small amounts of rainfall can cause urban flooding. Delhi is the capital of India with an area of 1483km2 and the population of Delhi (including New Delhi) is 13.8 million (2001census). It is located on the banks of the River Yamuna and the average annual rainfall is about 700mm, most of which falls during the monsoon in June to September. During the months of monsoon Delhi experiences major spells of flood till September, which inundates many areas of Delhi and this is unprecedented in recent times. Such flooding in Delhi is specific due to the fact that there is little open soil left that can be used for water storage due to rapid mindless urbanization, therefore, nearly all the precipitation is transport to surface water or the sewage system. The usual drainage systems have proved to be inefficient and excessively expensive. Alternative solutions, trying to compensate urbanization and imperviousness effects are being researched, trying to favor source control. This paper takes the city of Delhi in India, as a case study to analyze this situation. Delhi is blessed with an average annual rainfall of about 700mm and there are many houses and buildings for collecting the roof-top rain water to control the stormwater. In this context, the experimental house of Mr and Mrs S .P. Singh in East Delhi was equipped for two years with a system for collecting and reusing rain water. For stormwater storage, 'hard' structures such as modular block systems and concrete chambers have been found suitable because of space constraints. This technique of roof-top rain water harvesting reduces the risk of in-situ urban stormwater on roads to a minimum.