Caban-Coch Reservoir is the most southerly of the Elan Valley Reservoirs, located in the region of Powys, Wales. The Elan Valley Reservoirs are Troutmaster Waters and they have hosted the Welsh National Bank Fly Fishing Championships on many times. Along Garreg Ddu provide 35.530 megalitre capacity. It is the simplest and most functional in appearance of all 6 dams of Elan Valley, built on the Elan River. It resembles a natural waterfall when the reservoir is full. The Caban-Coch contributes to the supply water to Birmingham when water levels are normal.