| Dam safety
threshold. And most, if not all, are design landscaped features and play a significant part in the places the trust looks after. Looking into more detail, Roberts stated that 69 of the National Trust’s reservoirs are located in registered grade 1, 60 are in registered grade II* and 18 are in grade II landscapes. There are 11 reservoirs in World Heritage Sites, 141 in the setting of a mansion, with 39 in designated Sites of Special Scientific Interest. The above numbers, Roberts said, mean that you
automatically can create tension between nature and heritage. However, the National Trust has learnt key lessons when trying to successfully address any safety or maintenance issues associated with such dam structures. These include understanding the significance of the project and involving stakeholders early on, as well as communicating any importance of the dam/water element. For example are reflections in the lake important? Does the lake or dam affect the setting of the area or house? Could there even be the potential for archaeological finds? It’s also important to develop a project team as soon as possible with the appropriate specialists on board. Any loss or harm needs to be minimised and justified to the public, while gains should be designed in where possible. “Through design,” Roberts added, “heritage loss can be offset elsewhere.” Climate change is also set to have an impact on heritage sites. “We know climate change will impact reservoirs. Four in five sites in the National Heritage List for England will face high levels of risk by the second half of 21st century. There will be a requirement for more investment and a risk of more harm,” Roberts said. “Tough decisions are ahead which will result in the loss of some heritage features. And with changing hydrological records how do we also ensure we deal with risk but don’t overdesign?” Developing support mechanisms and communicating change will deliver benefits for all. And where change needs to happen, Roberts urged, let’s make most of it.
Welsh experiences Over in Wales, Cadw is the Welsh Government’s
historic environment service which is responsible for the sustainable management of heritage assets such as scheduled monuments, listed buildings, registered historic parks and gardens, and outstanding and historic landscapes. Wales has 400 large raised reservoirs, and located within 150m of these are: 50 scheduled monuments. 268 listed buildings. 34 registered historic parks and gardens. 33 registered landscapes. Dr Jonathan Berry, a senior inspector of ancient monuments and archaeology at Cadw, explained that Cadw would expect to be consulted on any proposals to change, decommission or demolish reservoirs that impact these heritage assets. Such assets do not necessarily have to be associated with the reservoirs and could, for example, be Second World War pillar boxes etc.
Highlighting that heritage assets are a finite, fragile and vulnerable resource, Berry said the highest levels of justification will be required to override
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national policy and demolish or alter a monument. Archaeological evidence cannot recover or regenerate, he adds. Once it’s lost, it is gone forever. Cadw’s policies state all historic reservoirs and associated structures have intrinsic and recognised heritage values, whether they are designated or not. The justification for altering or decommissioning a historic reservoir should be set out in a heritage impact assessment, where the impact of the proposed works is assessed against the reservoir’s evidential, historical, aesthetic and communal values. Indeed some historic reservoirs are legally designated as scheduled monuments and/or listed buildings. Heritage legislation is designed to protect the heritage asset for the future, irrespective of whether the asset is operational or not while the decision to designate does not take into account future maintenance costs. Prior consent is required before undertaking works and Berry urged dam owners to contact them or local conservation officers for advice as unauthorised work/ damage to designated heritage assets is a criminal offence.
Better understanding Various examples of projects were given throughout
the BDS presentation. They included several from Wales, such as the Beacons Reservoir Dam which was built in 1897 to supply water to Cardiff. Its listed buildings include the clay core of the dam, inner pitched masonry face, turfed outer face, spillway weir, cascade and overbridge and revetment walls. The structure was listed as it is seen as being an integral part of the historic water supply system for Cardiff, representing a major Welsh civic engineering scheme. Cwm Clydach Dam was operational from 1840 and was built to supply water to Neth Abbey Ironworks. Viewed as an integral part of the industrial water supply system, its scheduling includes the dam core, inner and outer pitched masonry faces, spillway, culverts, road machinery and overbridge, and revetment walls. Caerphilly Castle is operated and managed by Cadw
in Wales. Located in a bowl surrounded by hills, the castle made use of a gravel ridge in an acre of marshy ground. This scheduled monument is extensively and legally protected from alteration and damage due to archaeological values above and below ground.
Below: Prior Park in Bath, England has a reservoir in a registered grade 1 landscape
Above: The National Trust carried out work at Felbrigg Lake, part of Felbrigg Hall in Norfolk during 2023
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