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Welcome to this issue of Dams and Reservoirs, our fourth and last issue of 2021.

We rarely feature service reservoirs in this journal, so you will find the paper about a new United Utilities service reservoir, located in a National Park, of interest. It covers the earthworks that were necessary, and the construction of the reservoir using a semi-precast concrete system. Key innovations in the method of construction are described, which may be of value to other designers.

We stay with service reservoirs in a paper describing how a system to monitor leaks using temperature and strain measurements has been installed at a Severn Trent service reservoir. The paper describes how this system is also being used in earth embankments. In both cases a real-time warning system is provided, should leakage or movement be detected.

In the Republic of Ireland three open service reservoirs in Dublin were to be replaced by a single covered reservoir, but two of the open reservoirs had to remain operational while the new reservoir was built on the site of the third. The paper describes how this required careful monitoring of the earth embankments of the operational reservoirs during the excavation for, and construction of, the new service reservoir.

In the UK amenity reservoirs are often to be found in landscaped parks, which means that any necessary works have to be sensitively designed and carefully carried out. Such was the case for the increase in spillway capacity needed for a lake in Kent, but the paper explains how additional works to improve the drawdown capacity were then found to be necessary, and were included in the works.

Earthquakes in the UK that are of sufficient magnitude to damage dams or their appurtenant structures are rare, but nevertheless must be considered by engineers, as the consequences of a failure are potentially high. A paper from the British Geological Survey describes two different, but complementary, methods of remote monitoring of the effect of earthquakes on dams and other structures.

This issue also contains a Technical Note regarding the definition of Zero Wave Overtopping from EurOtop 2018, and how this could be applied in Floods and Reservoir Safety, 4^th Edition.

As always, we welcome discussion on any papers published in Dams and Reservoirs – whether you would like clarification on points raised or can contribute additional information. Please send your contribution to editor@britishdams.org.