The impact of watershed land use on maintaining acceptable quality influents for water treatment plants

Providing acceptable quality water in sufficient quantities is a challenge that local authorities have to face in various parts of the world, especially for bigger cities and megacities where there is a rapidly increasing population and difficulties in the control of new housing and provision of proper infrastructure. The quality of water distributed is strongly dependent on the quality of water coming in to the water treatment plant from the water resource, which in turn is dependent on the conditions of its watershed. Better quality influents are expected of water resources with well-controlled watersheds in terms of population, population density, residential, industrial and agricultural activities and pertinent infrastructure to account for those activities. The Turkish megacity of Istanbul, which has been experiencing this pressure with apparent impacts of watershed land use on the water quality of its water supply reservoirs, provides a case to be considered for water management in the new century.