Nendrum

In 1999 excavation on the shore in front of Nendrum Monastery uncovered a spectacular and unique early medieval tidal mill. The excavation revealed two phases of mill construction, the earlier dating to 619-21AD making it the earliest tidal mill known anywhere in the world. It operated by impounding water in a millpond. As the tide rose, water entered the tidal millpond through a sluice gate, which was closed at high water. At low tide the impounded water was released to power a waterwheel and milling could begin.

The first mill was replaced in 789AD by a largely stone-built monument which survived in excellent condition, notably the wheelhouse, dam and mill stones. In addition wooden components included the water wheel paddles, beams and wattle work. The discovery and excavation of the tide mills has provided information on the organisation of an early Irish monastery and on hydraulic engineering, mill technology and the social and ecological environment of the 7th and 8th centuries. They have particular relevance to modern concerns, with the increasing need to harness the power of the natural world for our energy requirements.

A small exhibition in the visitor centre explains how the mill was found, describes the excavations and some of the artefacts that have enabled us to produce this reconstruction drawing of a tide powered horizontal mill.