Watermills in Great Britain

Water has been used to power machinery for thousands of years. There were watermills in ancient Greece and it was the Romans who brought the technology to Britain. However, it was not until the Anglo-Saxon period that they were developed and used on a large scale. Domesday Book, which was the record that the Normans made of their new possessions in the 1080s, counted more than 5000 watermills in England.

Overshot and undershot watermills

The simplest arrangement for a watermill is for a wheel, fitted with paddles, to be placed in a stream such that the flow of the water turns the wheel and the wheel’s axle acts as a shaft to power machinery, such as stones for grinding corn. This sort of watermill is termed an undershot mill, and was the earliest type of watermill.

However, a more efficient arrangement (by about four times) is for the water to hit the top of the wheel and be caught in buckets, the weight of which then forces the wheel to turn. The extra efficiency comes from the fact that the water can be used for longer, because, on each turn of the wheel, several buckets will contain water and their weight will be considerably greater than that of the empty buckets on the other side. By contrast, with an undershot wheel the force comes from hits on one paddle at a time.

The larger the wheel, the more buckets can drive it. The “Lady Isabella” wheel at Laxey on the Isle of Man was built in 1854 and is the largest overshot wheel in the world, at 72 feet in diameter and 6 feet wide. It has 168 buckets around the rim, a quarter of which will contain water at any one time. When the wheel was operating for its original purpose of draining the local mines, this weight of water was sufficient to raise 250 gallons of water a minute from 1,000 feet below ground. Although the mines have long since closed, the wheel still turns as a tourist attraction.

The other main advantage of an overshot wheel is that the flow of water can be regulated more easily, as it has to be directed along a channel from a millpond or other reservoir, which is often provided by means of a weir that partially dams the stream or river. The more control that can be had over the flow of water, the more regular can be the supply of power to the machinery being driven.

Tidal mills

Another source of water power is provided by tides in coastal estuaries. The usual arrangement is that a mill pond is filled by the incoming tide that flows through a sluice gate which is closed when the tide turns. The water in the pond is released to flow over the wheel as the tide runs out. The disadvantage of such a mill is that it can only run at certain times of the day.

There are two such mills in England that have been restored to working order and now operate for visitors. Woodbridge Tide Mill in Suffolk originally had a 7-acre reservoir. A mill has stood on this site since 1170. Eling Tide Mill in Hampshire takes advantage of the double tides that flow in the Solent, thus allowing it to run for up to seven hours a day. There was a mill recorded on this site in Domesday Book but the current mill is probably around 200 years old.

Uses of watermills

As mentioned above, watermills have long been used to power pumps. However, in southern England, from the mid-16^th century up to the introduction of steam power in the late 18^th century, the iron industry used water power to drive a variety of machinery. Massive hammers were used to crush the ore, while other machines pushed air into the bellows that kept the furnaces hot. The ponds that supplied the water are still known as “hammer ponds” to this day.

Gayle Mill in North Yorkshire (see picture) is an example of a mill that has had several uses throughout its history. It was originally built in 1776 as a cotton-spinning mill but was later used for processing flax and then wool. The original waterwheel was replaced in 1878 by a set of water turbines, which at one time provided electrical power for the local community and was at other times a sawmill. However, the mill has now been restored as a woodworking workshop, with the water power driving a number of lathes and other machines.

These uses are of course on top of the use to which most watermills were originally put, namely to grind corn into flour. However, over the centuries windmills came increasingly to take over the function of flour milling in many areas, partly because of the greater certainty of wind over water. This was especially the case in the drier, eastern parts of the country where wheat was grown in greater quantities and the flatter terrain provided fewer opportunities for fast-flowing streams to drive millwheels.  

Like windmills, most watermills have fallen into disrepair over the centuries and have been demolished. However, many former watermills, to a greater extent than the more awkward-shaped windmills, have found other uses as waterside houses, restaurants and the like.

© John Welford