The Horseshoe Falls
In 1804 it was agreed to build a feeder section of canal running between the Horseshoe Falls on the River Dee to Pontcysyllte, capable of supplying the Ellesmere Canal with around eight million gallons of water a day and ensuring that the canal would never suffer from a shortage of water. Completed in 1808, this is six miles in length and runs along the north side of the Vale of Llangollen. A J-shaped weir was built across the falls which extended out 460 ft/140m from the south bank, channelling water through a meter house at the start of the canal before continuing to the north bank. It is constructed of masonry capped with bull-nosed cast iron sections which maintain a perfect level across the river.
The Culverts
In places where a watercourse has to be carried under the canal, but the size or terrain did not warrant the construction of an aqueduct, a culvert was the most effective response. These allowed effective draining of the area around the canal via small watercourses, preventing erosion and damage of the earthen banks of the canal. All the original culverts of the canal are constructed of sturdy rubble masonry, sometimes with dressed stone portals set in retaining walls.
Sluices, Overflow Weirs and Outlets
The ability to control the water levels both in the canal and in the drainage sections is of absolute importance in the operation and maintenance of the canal, and hence there are eight sluices and overflow weirs in the nomination area. These vary from simple sluice gates in the tow path to high quality masonry overflow weirs. At Wenffrwd an outlet passes through a culvert before reaching a flagstoned cascade 46 ft/14 m down the side of the embankment, while the waste water channel from the Trefor Basin is carried in a stone lined channel all the way down the hill to the River Dee.
All the over bridges, tunnels and steeply sloping valley sides have slots constructed in the masonry on either side of the waterway allowing stop planks to be inserted to create temporary dams. This allows isolated sections of the canal have to be drained for maintenance or repair.