The White Cart Water Flood Prevention Scheme covers White Cart Water and its tributaries and involves the formation of three flood storage reservoirs upstream of Glasgow City. The five conical shaped Hydro-Brake Flow Controls, from Arc Energy Resources, allow water to flow through the reservoir dams normally up to a pre-determined height, after which the increasing velocity causes a vortex to form. The air pressure within the vortex ‘throttles’ the flow of water, slowing it down and allowing the reservoir to fill up. Water is then released to flow through the city in a controlled manner.

Each of the five units differs slightly in design, the largest (also the largest in the world) being 6 m in diameter and 8 m long with an outlet size of 1.8 m. The two largest Hydro-Brake Flow Control units were also too large to be transported by road and too heavy to lift by helicopter, so with input from Arc Energy, each was designed in sections to create a ‘former’. When installed, the 12 mm thick stainless steel formers will be encased in 600 mm thick reinforced concrete to provide the structural strength required to withstand a through-flow of water estimated at 8,800 tonnes per second.