Leat

An artificial watercourse dug to carry water from a river or stream to a mine, mill or waterwheel, sometimes running for miles to reach a site with no water power of its own.

Historical usage

Leats have been used to supply mining operations since Roman times, when aqueducts fed water for hushing — sluicing away soil to expose bedrock veins. From the 17th century onward, leats became essential infrastructure across the lead, tin and silver mining districts of Cornwall, Devon, Wales, the Pennines and the Leadhills-Wanlockhead area of southern Scotland.

How it worked

A leat was cut as a shallow, gently graded channel following the contour of the land, carrying water by gravity alone from an intake on a river or stream to the mine, sometimes over considerable distances — Cornwall's Fowey Consols mine drew on a four-mile leat delivering up to 25,000 gallons a minute in winter, enough to power thirteen separate waterwheels.

Why it was used

Many mines had no river or stream close enough to power their pumping and crushing machinery directly; a leat let them bring water from wherever it was available to drive waterwheels for pumping, ore crushing (see Stamps) and hushing, without which an inland mine could not use water power at all.

Risks & limitations

Building and maintaining a leat, especially a long one, was a substantial engineering undertaking in its own right, adding real cost before a mine could even begin exploiting water power — smaller or poorer operations often made do with much shorter leats and correspondingly less powerful waterwheels.

Regional variation

Leats appear across every British mining district that used water power, from short site leats a few hundred yards long to exceptional cases like Dartmoor's Devonport Leat, over 34km long and still partly in use today.

Images

Mines associated with this term

Included only where MineArchive's own research gives a reasonable evidential basis — not every mine where this might plausibly apply.

• Ystrad Einion Mine — Ceredigion (well documented example)
  A mile-and-a-half leat was built to supply the mine's waterwheels, including its surviving underground wheel.
• Cwmystwyth Mines — Ceredigion (historical documentary reference)
  Leats fed the site's water-powered ore-dressing plant.

Sources

1. (secondary) Cornish Mining WHS - Early Mining Methods — Cornish Mining World Heritage Site
2. (secondary) Leat — Wikipedia

Record created: 22 August 2026 · Last researched: 22 August 2026