History of the Tring Reservoirs

Some 200 years ago, when the canals were Britain’s motorways, the newly-built Grand Junction Canal (as it was then called) created enormous new trading possibilities between London and the Midlands. Suddenly, coal, grain, livestock and mass-produced goods could be moved around the country in a fraction of the time — and cost.

This new network depended on locks, which were used to carry canal traffic over high ground. In all, it takes no less than 57 locks to raise the Grand Union Canal some 400 feet from the River Thames at Brentford to the highest point on the canal, Tring Summit between Cowroast and Bulbourne.

So for the canal to function, a reliable source of top-up water was essential. Originally the Wendover Arm Canal, constructed to bring water from Wendover Springs to the main canal, was intended to fulfil this function. But as it was prone to leakage and some of the water was lost, a storage reservoir was constructed at Wilstone in 1802. Between 1806 and 1818, three more reservoirs were excavated to meet the ever-growing demands of canal traffic, after which Wilstone Reservoir was itself twice extended, in 1836 and 1839.

In 1818, Tringford pumping station opened. Originally driven by steam (the pumps are now powered by diesel and electricity), the station was connected to the reservoirs by a series of deep underground channels. Even today, up to four million gallons of water are pumped into the canal every day.

In the 1830s, canal traffic had grown to such an extent that to ease congestion, new locks were dug alongside the existing ones. At the bridge at Startop’s End and the dry dock at the Wendover Arm Junction, you can still make out where these locks were located.

As activity on the canal gathered pace, so associated businesses grew up to serve the passing trade. In 1875, a new flour mill on the Wendover Arm Canal arrived to meet the demand from London’s bakeries — and flour milling continues on the same site to this day.

For a short time in the 1850s, the narrowboats carrying grain to the mill were built and repaired next door in Bushell Bros Boatyard.

For over 100 years — and as recently as 2004 — lock gates for canals throughout the southern region were built at Bulbourne Workshops. The gates were made-to-measure, and fashioned from unseasoned oak. Each took around ten days to make, and was expected to last at least 25 years.

Nowadays, the nation’s commercial cargos thunder up and down the M1, and the canals have become a refuge of peace and quiet for holidaymakers looking to slow down and unwind. But whatever else has changed, it still takes 57 locks to raise the Grand Union up and over Tring Summit. And with something like 6000 boat crossings still being made every year, the reservoirs are as vital today as they were 200 years ago.

Timeline
1793: Work begins on the Grand Junction Canal

1802: Wilstone Reservoir Built

1806: Marsworth Reservoir built

1814-18: Startop’s End Reservoir and Tringford Reservoir built

1815: Aylesbury Arm opens

1818: Tringford Pumping Station opens

1830s: Parallel locks dug at Startop’s End and Wendover Arm Junction to ease congestion.

1836 & 1839: Wilstone Reservoir twice extended

1875: ‘New Mill’ built alongside the Wendover Arm.

1904: Wendover Arm Canal closed beyond Tringford Pumping Station due to leakage.

1955: Reservoirs declared a National Nature Reserve

1960s: Canals cease to carry commercial traffic

1987: Reservoirs redesignated a Site of Special Scientific Interest