Many low-income communities in developing countries consider stormwater dra inage to be their most urgent need as far as urban infrastructure is concerned. This is partly because their houses are often built on unsuitable land. In areas sufficiently close to the city centre for the journey to work to be affordable, land prices tend to be beyond their means. The only land they can afford, or on which the owners will allow them to stay as squatters, is land that is unsuitable for other purposes. This is often on steep hillsides subject to erosion and landslides, or it is low-lying, marshy land often subject to flooding.
WHO (1991). Surface water drainage for low income communities the World Health Organization In collaboration with the United Nations Environment Programme
Urban informal settlements (slums)English