route yet again, this time raising the summit by 12m in order to reduce the length of the tunnel – known as the Bruce Tunnel – to 459 metres. This would substantially decrease the cost and time required to construct the canal, even though more locks and a steam-driven pump would be required to raise water to the new canal summit.
Finally, in October 1794, work started on the canal. The section from Newbury to Kintbury opened in 1797, followed by Hungerford in 1798 and Great Bedwyn in 1799. The section west of Great Bedwyn, including the Caen Hill Locks, took a further 10 years to build. In 1810, the Kennet and Avon Canal was finally opened, giving a direct trade route between London and Bristol.
A narrowboat negotiates Brimslade Lock (53), between Wootton Rivers and Burbage (Stage 3, Walk 9)
For 40 years the canal prospered, transporting a range of goods to and from wharves built along the canal, but the passing of the Great Western Railway Act in 1835 led to the building of Isambard Kingdom Brunel’s railway, which offered a faster and more efficient transport route between London and Bristol. In 1852, the Great Western Railway Company succeeded in buying the Kennet and Avon Canal, although on the proviso that it was kept open as a canal. However, they made little attempt to maintain the route over the next 100 years, leading to its gradual decline; they even offered traders preferential tolls to use the railway instead.
During World War II, with the threat of a German invasion, a series of General Headquarters Anti-Tank Lines (or GHQ Stop Lines) were devised. These utilised existing natural obstacles such as rivers and also man-made ones, including canals and railway embankments, supplemented by a vast number of pillboxes, anti-tank ditches and other obstacles. The primary purpose of these defences was to delay any invasion forces, although fortunately they were never used in combat. One of these lines, GHQ Stop Line Blue, utilised the near-derelict Kennet and Avon Canal and along the length of the canal there are many former pillboxes.
By 1955, the canal was in very poor condition, but plans to abandon it completely were thwarted by public opposition. The Kennet & Avon Canal Trust purchased Crofton Pumping Station and Beam Engines from British Waterways in 1968, with the objective of restoring them to full working order, and two years later the steam engines were working again. Although electric pumps have been installed to pump water into the canal, these magnificent steam-driven beam engines are still used on several occasions throughout the year. The 1812 Boulton and Watt is the oldest working beam engine in the world.
The full length of the canal, restored and cared for by the Kennet & Avon Canal Trust, was formally reopened by Queen Elizabeth II in 1990. Nowadays the canal forms a popular heritage tourism destination for boating, walking and cycling as well as being an important feature for wildlife conservation. A selection of books that provide interesting further reading on the Kennet and Avon Canal are given in Appendix E.
Looking east, shortly after Crofton Pumping Station (Stage 3)
Geology
The landscape through which the Kennet and Avon Canal travels tells the story of the seas that once covered southern England and the sediments that were laid down at that time. Due to movements within the earth’s crust some 50 million years ago that gave rise to the Alps, these layers of sedimentary rocks, which lie with the older deposits at the bottom and the more recent ones at the top, now gently slope down to the south-east. This, combined with subsequent erosion, has allowed the older layers to be revealed in the west.
Throughout the eastern section of the canal, from Reading through the North Wessex Downs Area of Outstanding Natural Beauty (AONB) to Devizes, the predominant feature is a thick layer of Upper Cretaceous chalk (99–65 million years ago), composed of incredible numbers of tiny fossil skeletons of algae, called coccoliths. Associated with the upper (white) layer of chalk are horizontal bands of irregular silica concretions, known as flints; these also occur in profusion in the jumbled deposits of weathered chalk, known as ‘clay-with-flints’. When struck, flint breaks with a shell-shaped fracture, leaving very sharp edges, and our Stone Age ancestors used flints to make arrowheads and hand axes. Being a very hard-wearing rock, flint has also been widely used as a building material.
Within the sandy beds that overlay the chalk, a natural process of patchy and irregular hardening produced blocks of tough sandstone, known as sarsens, that are more resistant to erosion. Sarsens can be seen on some of the walks to the west of Hungerford and above the Vale of Pewsey (especially Walk 12).
Underlying the porous chalk is a layer of greensand and impervious Gault clay, laid down during the latter part of the Lower Cretaceous period (140–99 million years ago). This layer of clay gives rise to a spring-line where water that has seeped through the chalk is forced to the surface to form springs, which become chalk rivers such as the River Kennet.
The River Kennet near Hamstead Lock (81) (Walk 5)
Further west in the southern reaches of the Cotswold Hills AONB, older layers of rock lie below the Gault clay. These layers include oolitic limestone (a buff-coloured rock that has been widely used as a building material throughout the Cotswolds), laid down during the Jurassic period (200–140 million years ago). Oolitic limestone is made up of ooids (small spherical grains composed of concentric layers) that form in shallow, warm sub-tropical seas where calcium carbonate is deposited from sea water due to evaporation. The tiny grains gradually grow in size as they are rolled around by wave action.
The area around Bath is home to a fine-grained oolitic limestone known locally as Bath stone. This was used extensively in the construction of many buildings in Bath as well as the Dundas and Avoncliff Aqueducts along the canal. Bath stone was first worked by the Romans and is still mined at Stoke Hill Mine, Limpley Stoke (Walk 17). Other areas where Bath stone was quarried include Monkton Farleigh and around Brown’s Folly (itself made of Bath stone), where there are a number of interesting rock outcrops (Walk 18).
Travelling further west to Bristol sees the appearance of the oldest rocks along the route, namely red sandstone from the Triassic period (250–200 million years ago). This fine-grained rock was mined in the Redcliffe area of Bristol between the 15th and 18th centuries for use in the glass industry. Pennant sandstone from the Upper Carboniferous (310–300 million years ago) has also been mined around Hanham and Troopers Hill.
Throughout the last 2.6 million years (the Quaternary period), Britain has been subject to periods of glaciation separated by warmer interglacial periods (the last glacial period ended about 12,000 years ago). There is no evidence to suggest that southern England was ever covered in ice, but the area did suffer periglacial conditions. In the chalk downs, this allowed the formation of dry valleys, which were eroded by water flowing over the surface during cold periods when the underlying ground was frozen, making the normally porous rock impermeable. During this geological period, rivers formed large gravel deposits, especially along the Kennet Valley, and these gave rise to the development of gravel extraction works. Many former gravel pits have been flooded to form wetland habitats and the canal passes a number of these between Reading and Newbury.
Looking west across the Avon Valley towards Monkton Combe (Stage 6, Walk 17)
Plants and wildlife
Following the canal takes you on a journey through a patchwork landscape with areas of open grassland, broadleaved woodland and farmland.
Throughout the walks you should have plenty of opportunities
