Natural Resources Wales c6aa305d-9ffb-452e-9304-15683bb564e2 c6aa305d-9ffb-452e-9304-15683bb564e2 Large Raised Reservoir register (Locations and undertakers) 2026-06-11 2026-06-11 This dataset contains details of Large Raised Reservoirs in Wales. Natural Resources Wales (NRW) collects and maintains data on all reservoirs designed or capable of holding more than 10,000 cubic metres of water above the natural level of any part of the land adjoining them defined as 'large raised reservoirs' under the Reservoirs Act 1975. Two types of reservoir are maintained within the register: - Impounding; or - Non-Impounding. This dataset is an extract from NRW’s Cronfeydd/Reservoir Database. It contains information on the location, undertakers and engineers of the reservoirs. 'Undertaker' is the legal term used to identify who manages and controls the use of the reservoir and is responsible for maintaining compliance with the law. The undertaker is the person, people or company that uses a reservoir for a particular purpose. If there is no use, the owners or lessees are the undertakers. The undertaker may be different from the owner. If several people or organisations manage and control the reservoir, there can be more than one undertaker. This data is collected as part of the Reservoirs Act Public Register. Attribution statement: Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. 51.37973173445827 -5.281155808232745 53.41033723495585 -2.701744724718854