1500s - London's water supply before the New River

At the end of the 16th century, London was a thriving, bustling centre of trade and commerce. The population had increased enormously, to about 180,000, since Norman times and now faced an acute shortage of clean drinking water. The River Thames and its tributaries which had made London such a suitable place for a port and city were badly polluted.

In Elizabeth I's time London had no sewerage system separate from its water supply. Since the 13th and 14th centuries various monarchs and Parliaments had tried to stop people throwing dung, garbage and entrails into ditches, rivers and streams but to little effect. Pollution and the general careless disposal of waste made London evil-smelling and unhealthy.

Many people got their water from open water courses. Some depended upon water-bearers to bring their supply from the river in barrel-like containers. Other people, often the more wealthy, obtained their water from shallow wells that tapped the ground water and in a few cases water was piped to different parts of the city. However, even these sources were soon contaminated.

1500s - the search for new water supplies

In Elizabeth I's reign, the Corporation of London sought ways of alleviating the problem of the shortage of clean water. They concentrated on bringing in more drinking water into the metropolis rather than trying to stop the pollution of their existing supply. By 1570 the City Corporation had obtained an Act of Parliament to cut a channel to bring water from Middlesex or Hertfordshire.

In 1580, a man named Russell suggested building a channel from the River Colne at Uxbridge to Holborn in north London. Nothing came of this proposal but at the turn of the century, Edward Colthurst, a former army captain, made plans to bring water from springs near Hertford in a channel to Islington. This was to become the New River.

Was it really necessary to go so far afield to find a supply of clean water? The answer probably lies in the quantity of water required and in the way in which the water could be brought into the capital and distributed. The Elizabethans' ability to pump water over long distances was not well developed.

1600s - surveyors map the course of the New River

There were, though, some very skilled engineers and surveyors who were capable of constructing channels with great precision. The principle behind proposals to bring water from the Colne or from Hertfordshire was that it could reach London entirely through gravity. Bringing it to Holborn or Islington, meant that the water could then be piped to large areas of the city also by gravity.

The map shows how by using the 100 foot (30.5m) contour the supply could be achieved. The proposed channel for the New River was nearly 40 miles (60k) almost twice the straight line distance from the Hertfordshire source. The drop in height from beginning to end was about 18 feet (5.5m) giving an average fall of about 5.5 inches (13.2cm) a mile.

That Colthurst and his contemporaries should be so confident in their ability to build to this precision indicates a high level of expertise. The New River was to become the longest channel carrying drinking water in Britain and even now it is one of the longest remaining stretches in Europe.

1600s - Hugh Myddelton takes charge of the project

Edmund Colthurst put forward his plans around 1600 and got the backing of the Corporation of London in 1602. However, Queen Elizabeth was concerned that, as water flowed from the springs to the nearby River Lee, the navigation there might suffer. A commission was set up to look into this, but the Queen died before Colthurst could be given a licence to start the work.

In 1604, Elizabeth's successor James I did give Colthurst permission, in Letters Patent, to go ahead provided that he made the river no more than 6 feet (1.8m) wide and finished it within seven years. The next year, Edmund Colthurst got three miles dug at a cost of 200 and then applied to the Corporation for funding.

The City Council declined to put up further finance and discussions on who should fund the New River project dragged on for another three years between 1605 and 1608. Finally in 1609, the Council accepted an offer from to complete the work in four years.

1600s - work on the New River commences

The Council's change of mind may have been because they felt that Myddelton, an MP, banker and merchant adventurer had greater resources than Colthurst. What the latter thought of it does not seem to be recorded, but there is no doubt that the two men worked together for several years, up to and after the New River's completion.

Myddelton started work on the New River at Chadwell Spring, where a monument gives the date of opening as 1608 (although permission for the New River was only apparently granted in 1609). Colthurst was the overseer. Edward Wright, a prominent mathematician from Norfolk, had the task of surveying and directing the course of the New River.

The New River hugged the 100 foot (30.48m) contour on the west side of the Lee valley. The bed, now ten feet (3m) wide was four feet (1.2m) deep. Much of the course was on a chalk or other porous substrate so that the bed was sealed with impervious London clay which had to be brought in. The clay was "puddled" or trampled into the ground to make a firm bond with the substrate.

1600s - construction techniques employed on the New River

Clay lining, to say nothing of the actual digging, required a large number of labourers. Skilled men were also needed. For example, every time the proposed course crossed a road or lane, a bridge had to be built, of wood or brick. (When completed, the New River was spanned by a total of 157 bridges.) Estimates of the number of men employed at busy times vary from 130 to 200.

Labourers received 10d a day (a little over 4p) and if they were working in water a little more. Those excavating the channel were usually on piecework, paid for each pole or rod (5.03m) from 1s. 2d (almost 6p) to 3s 6d (17.5p) according to the depth or width. Bricklayers earned about 1s 6d (7.5p) a day and carpenters, who built bridges or lined the banks, 1s 4d (7p) a day.

Frequently the New River's (especially those facing into the valley) needed to be raised and strengthened with clay and piles to prevent flooding. The only machine to be used appears to have been the "Ingen" (probably an "engine") that was a kind of plough pulled by as many as 13 horses. It may not have worked well since it was not used after the first year.

1600s - objections to the New River

The New River came to a standstill near Wormley in 1610. This may have been because several landowners resisted the acquisition of land for it. They complained to Parliament that the channel would turn their meadows into "bogs and quagmires". However, they failed to get the New River Acts repealed before Parliament was dissolved in 1611, and work resumed later in the same year.

There are likely to have been other reasons for the temporary stoppage. Myddelton's money was probably running out and he needed to seek further funds. His approach to the city was rebuffed, partly because they were not convinced that the New River would succeed and partly because the city water carriers threatened to take strike action against supporters of the New River.

Fortunately for Myddelton, the New River enterprise attracted the interest of King James I and he allowed the New River to cross the Royal Estate of without charge and cleared the way for Myddelton to proceed with the channel to London. In return, the king took a share of the profits of the New River Company.

1600s - overcoming geographical obstacles

An example of the detours needed to follow the 100 foot contour can be seen at Maidens Brook north of Enfield Chase. Here the New River made a three and a half mile diversion westwards through Whitewebbs Park to Crewe Hill. A large horseshoe loop was also built to carry the New River around .

The map shows that in following the 100 foot contour the New River had to cross several tributaries flowing eastwards to the River Lee. If impeded, their water would cause local flooding and reduce to some extent the amount reaching the Lee. Engineering solutions had to be found to prevent this.

At Crews Hill, a wooden trough was built to carry the Cuffley Brook over the New River. At Salmons Brook, , the New River was taken over the valley in a 666 foot (203m) lead trough on a timber frame. Further south other diversions and structures were made in Hornsey and Haringey until the New River reached Clerkenwell, Islington, in April 1613.

1600s - opening of the New River and extraction from the River Lee

The New River was ceremonially opened on 29 September, 1613, by the Lord Mayor of London, Sir John Swinnerton, in the presence of the Lord Mayor elect, Sir Thomas Myddelton, Hugh's brother. The ceremony took place at the New River's terminus - the Round Pond, at New River Head, Islington.

From the water was delivered to houses by pipes. There were 58 "mains" made out of elm trunks with a seven inch (18cm) bore that took water to the streets and suburbs. Lead pipes with a one inch (2.5cm) bore took the supply to the ground floors of the houses of those people who could afford to pay for the service.

Within 50 years, the supply of water was no longer sufficient and an Act of 1660 authorised the New River Company to extract water from the River Lee. This was achieved by laying pipes between the two rivers. However, there were complaints from mill owners and bargemen who feared a drop in water levels would affect their livelihood

1600s - monitoring extraction from the River Lee

An Act of Parliament in 1738 attempted to settle the disputes by limiting the amount of water extracted from the Lee to 22 and a half million gallons (102 megalitres) a day. A timber gauge was built in the Lee to measure the flow and this was replaced in 1770 by the which is still in place (though not in use).

Later, the flow was regulated by means of a wooden balance engine which spanned the channel. It consisted of a pivoted beam with a sluice gate at one end and a float at the other. As the level of the Lee changed, the float would rise or fall and cause the sluice gate to fall or rise by a corresponding amount - thus maintaining a constant and measured flow of water.

In the building (built in 1856) the intake from the Lee passes over a horizontal metal plate held at a constant distance beneath the surface. The flow can be further regulated by adding or removing vertical plates to adjust the width of the channel. The principle is similar to that of the which will be found on the New River itself.

1700s - improvements in water distribution

By 1709, it had become necessary to increase the supply and therefore the water pressure from the New River Head. An upper pond was built in Claremont Square some 200 yards further up the hill from the original round pond. Initially the water was pumped uphill to this pond by a , but this was replaced in 1720 by a horse mill. The remains in place.

Possibly the horses were more reliable than the wind, as they were worked for 16 hours a day and raised some 42 tons of water an hour. In the 1750s, plans were considered for increasing the number of working horses from four to six or even eight. However, advances in technology led to the use of a Newcomen steam engine instead.

In 1793, Robert Mylne the Surveyor to the New River Company, began laying cast iron pipes which he described as "wonderful and magnificent". The course of the New River did not alter significantly during the 18th century, although the wooden "frames" at Bush Hill and Highbury were replaced by clay embankments.

1800s - the course of the New River is straightened

Great changes to the course of the New River were made in the 19th century. The Chief Engineer, William Chadwell Mylne, who succeeded his father in the post, shortened the loop in Whitewebbs Park by building a cast iron aqueduct over Cuffley Brook in 1820. The loop was finally abandoned in 1859 with the building of the over Maidens Brook.

Other aqueducts eliminated loops near Broxbourne and Arnos Park. Tunnels in and Haringey further shortened the route in north London. Underground pipes made the Enfield loop redundant. Whereas most redundant stretches were abandoned, the had a small supply from Thames Water to retain it as an amenity.

As sections of the old course were abandoned, people seem to have appreciated the water's potential for ornamental and leisure purposes. In 1820, when the loop in Whitewebbs Park was shortened, the redundant part of the loop was purchased by Edward Harman who dammed the Cuffley Brook to form an ornamental lake which now forms part of Wildwoods Estate.

1800s - meeting the demand for more water of better purity

Concern about the purity of the water supply grew after the outbreak of cholera in 1846 and bathing in the New River was prohibited. Along with other companies supplying the metropolitan area, the New River Company had to meet new statutory demands. After the 1852 Metropolitan Water Act, the company built filtration plants at Stoke Newington, Hornsey and New River Head.

A series of wells, from Amwell to Whitewebbs, provided much of the water needed to meet the extra demand of the second half of the 19th century. Steam engines pumped water into the New River from depths as low as 500 feet. Electric pumps replaced steam power, mostly in the 1940s, but a few steam pumps still operated in the 1960s. Many Victorian pumphouses still exist alongside the New River - e.g. .

The took over the water supplying responsibilities of all the London Water Companies in 1904. Ten years later, the Board built its new headquarters on the site of the Round Pond in Islington. It was called . In 1946, all treatment stopped at New River Head and the course of the New River finished at Stoke Newington, as it does today.

1900s - Thames Water, the New River and the Thames Water Ring Main

The Thames Water Authority replaced the Metropolitan Water Board in 1974, and its responsibilities were taken over by Thames Water plc in 1989. Since then Thames Water has had to contend with routing the New River in a concrete over the M25. But the major impacts on the New River have come from the development of the Thames Water Ring Main and the Artificial Recharge Scheme.

The Thames Water Ring Main, inaugurated in 1994, is a fifty mile (80km) tunnel encircling London. Pumps, including one at Stoke Newington, raise water for local distribution. At first, it seemed that the ring main would make the New River redundant for economic reasons. However, the New River was saved by a combination of: the additional demand for water in the London Docklands; the development of the Artificial Recharge Scheme; and interest from local residents.

Today, water is extracted from the New River at Turkey Street, Enfield, and piped to the King George V Reservoirs. This water is cleaned at the Water Treatment Works at Walthamstow. The river terminates at Stoke Newington where the old and filter beds have been turned over to other uses including a watersports and and a nature reserve. Water from Stoke Newington is piped to the Coppermills Water Treatment Works and helps to supply north London.

1900s - The Artificial Recharge Scheme and other developments

Thames Water's Artificial Recharge Scheme involves new boreholes and at 20 sites from Maidens Brook to Stoke Newington, mainly along the New River. When water supply exceeds customer demand, pumps release treated water into the aquifer lying about 250 feet (76m) below London. At times of drought, water can be pumped up from the aquifer and into the New River and diverted to the Coppermills Water Treatment Works.

The stretch of New River from Stoke Newington to is no longer in use. However, two small loops can still be seen at Clissold Park and Canonbury. Large stretches of the remaining course of the New River have been opened to the public as a leisure facility.

The former water company office buildings which were built on the site of the Round Pond earlier this century have been converted to housing. The 17th century panelling from the New River Company's boardroom (the ) is preserved in the building and open to the public.