Sough

It can also drain sloping farmland: these are to be found (at least) around the Pennine areas of East Lancashire to carry water from higher up, down through the clay based fields to reduce flooding and soft ground.

By digging soughs, miners found they could lower the water table and allow mines to be worked deeper.

Soughs were typically dug from their open end near a stream or river back into the hillside beneath the mine to be drained.

According to the British Geological Survey, the Meerbrook sough, started in 1772, still provides 3.75 million litres (990,000 US gal) a day for the public water supply.

With the advent of the steam engine, which could pump out water, soughs became less necessary for de-watering mines.