Cardiff Bay barrage and managing the impounded water quality

Cardiff is the capital city of Wales, U.K., with the city having a population of approximately 300,000 and being located some 2 kmfrom itswaterfront. In the 1990s, and following an Act of Parliament, a tidal exclusion barrage was built across the mouth of Cardiff Bay, with the aim being to regenerate 1100 ha in the area to the south of Cardiff. The Cardiff Bay Barrage impounded the estuaries of the rivers Taff and Ely, creating a 200 ha freshwater lake and about 13 km of attractive waterfront. In the paper brief details are given of the barrage structure, the loch gates and the auxiliary structures, followed by details of a numerical hydro-environmental model study to predict the hydrodynamic and water quality characteristics within the Bay. Details are also given of a physical model study and a field monitoring programme.