Friars Island, once a distinct piece of land in County Tipperary, was permanently submerged in 1929 as part of the Shannon Hydroelectric scheme, the large-scale infrastructure project that created Ardnacrusha power station and dramatically altered the river's flow and landscape. The island went under along with everything on it, including a holy well at its northern end and a church to the south. Holy wells in Ireland were typically sites of local veneration, associated with healing, patron saints, and seasonal patterns of prayer known as rounds or stations; this one simply ceased to be accessible almost overnight, not through neglect or the slow drift of religious practice, but by deliberate industrial inundation.

The scale of what the hydroelectric scheme erased is easy to underestimate. Friars Island was not unique in being lost; the Shannon works flooded significant stretches of low-lying land along the river corridor, and Friars Island, with its ecclesiastical remains suggesting a long history of monastic or devotional use, was among the casualties. The pairing of a holy well at the northern tip and a church further south suggests a site of some organisation and continuity, the kind of place that would have drawn people across water to pray or seek cures, and which likely had a named patron saint, though that name is no longer recoverable from what survives. By 1929, the scheme was complete, and whatever patterns of use or memory had attached themselves to the island were effectively severed.