The New River

The towers of Docklands from Muswell Hill

This morning's run took me on a 9.7 mile loop via 4 north London parks: Clissold Park, Finsbury Park, Alexandra Park and Queen's Wood at Highgate. 

The last two thirds of the route is the most pleasurable as it is mainly downhill (!) and off-road as well.

On Parkland Walk towards Finsbury Park

But the first third of the route has interest too, because it broadly follows the line of the New River. The name "New River" is misleading as it's neither new nor a river. It's an aqueduct that was constructed over four hundred years ago, between 1609 and 1613, to bring fresh water into north London. 

London’s population was at that time growing quickly, and the existing water supply for the city was inadequate and increasingly polluted. Most of it was pumped up from the Thames.

Construction of the New River was the biggest engineering feat of its time. It involved designing and digging a channel from the River Lea at Ware in Hertfordshire to Islington, ending next to where Sadler’s Wells is now. That’s 20 miles as the crow flies, but the “river” is actually 40 miles long after the idiosyncrasies of the landscape were allowed for, as the design relied on gravity to bring the water in, and so the channel had to skirt any rising ground. The channel drops 5 inches per mile, which proved to be enough. Over 400 workmen were employed.

From the final reservoir at New River Head in Islington, the water was carried - again by gravity - via elm-wood pipes down into the City. Water connections into individual houses (belonging to the better-off - the poor had to collect their water from wells and pumps) were then made via lead pipes from these wooden distribution mains.

London from Islington Hill c1740. New River Head is centre left

Water continued to be distributed in London using wooden pipes for around two hundred years, until they began to be replaced after 1810 with caste iron pipes, to reduce leakage and contamination and to increase pipe capacity. In the final decades of the 20th century metal mains have in turn begun to be replaced with plastic pipes - again to reduce leakage.

Today, the New River continues to supply a good proportion of London’s water, though the water no longer travels as far as Sadler’s Wells: instead it feeds reservoirs just north of Clissold Park, from where it enters the London Ring Main system.