SUMMIT LEVEL

The Grand Union Canal leaves it`s jct. with the River Thames and ascends 380` through 56 locks on its 36 mile journey to its summit level at Tring. Completed in 1797 the summit level is 2 1/2 miles long stretching from Cow Roast lock just south of Tring in Hertfordshire to Bulbourne lock at the jct. of the Wendover Arm.
The Wendover Arm, the arch to the left in the above picture, was built in 1797 for the purpose of feeding water to the summit level from local springs and as its name suggests went into the village of Wendover. Sadly little of the arm is in water but work has been going on since the late 80`s by the Wendover Trust WWW.WENDOVERARMTRUST.CO.UK to once again make it navigable for its entire length.
Eventually the arm began to leak and instead of it had the opposite effect. In the dry summer months working boats would queue for days to cross the summit level so in the early 1800`s the canal co. built tring reservoir to feed a pumping station on the Wendover Arm.

One of the reservoirs at Tring

Today there are 4 reservoirs at Tring feeding the Gd. Union. The reservoirs are lower than the canal so Tringford pumping stn. on the Wendover Arm was used to pump water from deep wells created below the pumping stn. into the W Arm and thence by gravity water entered the summit level. The water travelled from the reservoirs underground through brick lined tunnels into the wells.
At the height of summer 4 million galls are pumped into the canal. As a lock is used 50,000 galls will drain from the summit level.
So after that long climb up to the summit we start to descend 42` down the Marsworth flight of 7 locks using water from the summit level to lower us down. Anyone coming the other way would use water from the summit to fill the same lock to raise them up.

A festive cottage half way down Marsworth flight

Nice to satisfy your curiosity and not just accept that the locks take you up and down. How? Why? When? didn`t seem to important in my working life perhaps the rat race didn`t allow time to stop and think but just get on with it. Nice now to have that time and to pass on to you all what i have found so interesting.