 In 1956, an upsurge in the chemical industry on Teesside led ICI to negotiate increased water supply from the Tees Valley Water Board.The first site considered, Cow Green, was above Cauldron Snout and was in a sensitive habitat area, so Balderhead was built instead.The site was initially built as a direct supply route of water to Teesside, but later became a river-regulating reservoir, ensuring that water was available for the River Tees.