What's Wrong with Weirs

Environmental and recreational groups sometimes call for new weirs to be built on freeflowing rivers. Motorboating interests support such calls, since weirs (dams) improve navigation. However weirs remain a form of environmental pollution. They convert running water to still and by masking pollution permit increased water abstraction. In this paper a miguided campaign by "environmentalists" to build new weirs on the river severn in Wales is described, and free and impounded stretches of water on the Rivers Wear in Durham and the Derwent in Yorkshire are compared. People sometimes regard weirs as river improvements because the water flowing over them and their adjacent locks provide a welcome interlude from impounded still water. This is mistaken. The weirs caused the ugly still water. Those who care about the environment should oppose government subsidy to build weirs, and campaign for existing ones to be removed