The Calder and Hebble Navigation
The Calder and Hebble Navigation completed in 1770 consisted of artificial improvements to the River Calder and River Hebble to allow canal boats use what used to be un-navigable rivers.
It ran for 21 miles from the Aire and Calder Navigation at Wakefield to Sowerby Bridge, was one of the first navigable waterways into the Pennines. It was an extension westwards of the Aire and Calder Navigation.
Work began in 1758 to make the River Calder navigable above Wakefield. The navigation to Sowerby Bridge was completed in 1770, including a short branch to Dewsbury.
In 1828 a branch to Halifax was opened, rising 110 feet to a terminus at Bailey Hall, behind Halifax Railway Station. There were 14 locks on the branch which closely followed the route of the River Hebble. Most of the branch was abandoned in 1942 apart from the short section from Salterhebble to Exley.
About half of the navigation is along the course of the River Calder, with short man-made cuts with locks to by-pass weirs. There are two lengthy man-made sections, from Calder Grove to Ravensthorpe and from Brighouse to Sowerby Bridge.
Most commercial traffic on the Calder and Hebble had ceased by 1955, although coal was still carried to Thornhill power station until 1981. However, the whole of the Calder and Hebble remained open for leisure use. The re-opening of the Rochdale Canal between Sowerby Bridge and Littleborough summit in 1996 and Manchester in 2002 has increased the traffic along the Calder and Hebble and it now forms part of the South Pennine Ring.
Ledgard Flood Lock
This lock is at the upstream end of one of the short artificial navigation cuts that bypass the main course of the river Calder.
A flood lock is used to prevent a river from flooding a connected waterway. It is typically installed where a canal leaves a river. At normal river levels, the lock gates are left open, and the height of the canal is allowed to rise and fall with the height of the river.
However, if the river floods beyond a safe limit for the canal, then the gates are closed (and an extra lock created) until the river drops again. Since this is a true lock it is possible for boats to leave the canal for the flooded river despite the difference in water levels (though this is not likely to be wise) or (more sensibly) to allow boats caught out on the flood to gain refuge in the canal.
Because of the dual nature of this lock the area of water between the lock gates is much large than a normal lock and can act as a refuge for a number of boats when the river is in flood.
At the junction with the river a coloured indicator board acts as a visual guide as to whether it is safe to use the lock gates. Green indicates it is safe to use, orange means take care and red indicates it is too dangerous to use the lock.
When the canal was first built and used commercially boats were more likely to use the lock in times of high river water. These days the lock gates are usually locked shut when the water level rises to prevent accidents.
Because the gates are left open when the river level is safe, it is rare these days that the lock is actually used as a lock.
Each end of the lock has a double pair of gates. On this canal all the lock gates have paddles built into them to let water in or out of the lock and in some cases there are also paddles on the canal side.
Each set of gates has wooden platforms to stand on when operating the gate paddles. In the case of the top gates the platforms stretch the full length of the gate to give access to both sides of the canal.
All the locks on this canal have a beam of 14 feet and are wide enough to take 2 narrow boats side by side. In addition although the locks are only 57 and ½ feet long they can accommodate narrow boats of up to 60 feet if they enter the lock diagonally and with extreme care. Although they are wide most of the locks on this canal are quite shallow and at only 2 metres the rise is not very high.
There is a bridge that crosses the tail of the lock that carries Newgate Road over the canal. The operators of the canal, The Canal and River Trust called the bridge Ledgard Bridge and the lock Ledgard Flood Lock. However the lock is an English Heritage Grade II listed Building and they refer to it as Newgate Bridge after the name of the road.
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