CANAL SOFT-BANK MAINTENANCE
The 2,000-mile network of canals are an important national asset, and although the traffic has decreased significantly since they were first built 200 years ago, the waterways are still enjoyed by many people, so it is essential that a careful maintenance plan is followed. There are many aspects to consider to ensure canals are preserved and protected for many years to come, with bank maintenance being an essential factor in the smooth running of the UK’s waterway network.
Why is canal bank maintenance needed?
Historically, canals were lined with clay and the banks were planted with reeds which helped to improved stability. However, as traffic along canals increased, the clay eroded quickly, and it was essential that new methods were used to strengthen banks. Today, the gradual degradation of canal banks is still inevitable, and maintenance is needed to ensure the integrity of banks is maintained.
All canal banks are subjected to natural seepage and internal erosion, with rain, wind, water levels, vegetation, animals, and fish within the canal all impacting the speed of water losses. In addition, conditions within a single stretch of canal can vary greatly, with the surrounding terrain, its construction and natural drainage all impacting levels of seepage and erosion. The following are just some examples of issues which are likely to need regular maintenance and repair:
Flaws created by burring animals
Cracks resulting from tree root systems
Construction issues due to poor compaction or material choice
Cracked utility crossings
Failed canal linings
Modifications to the canal bank such as deep excavations
Above average water flow levels
Why is canal bank maintenance important?
The above flaws can occur at any time, so regular inspection is needed to ensure the canal remains fully operational. If issues such as tree roots or cracked utility pipes are left unresolved, the water availability could be severely impacted, and as erosion of the bank increases the excess water within the bank will eventually lead to the collapse of the banks and the release of the canal water.
Bank maintenance is essentially used to protect the bank from erosion, with various materials used to reduce the effect of water washing along the canal bank, such as concrete filled bags, vegetation, stone, rubble, metal sheet piling and masonry walling. However, many of the canals were built without our current knowledge of foundations, slope stability and material compaction, which creates vulnerabilities during bank repairs. Although there are many options available, it is important that any modifications to the canal are completed with care and attention to avoid potentially disastrous consequences.
Canal banks are designed to stop water within the channel from spreading outside of its boundaries, by acting as a lateral boundary along the stretch of water. If a canal flows within the ground the boundary is known as a canal bank, whereas if a canal is built above ground, it is an embankment which acts as both a boundary and support to the structure.
How are canal banks built?
The canals themselves are generally lined with puddle clay, with modern compaction machinery used to compact the material to a thickness of at least 1000mm. However, materials such as concrete, steel, gabions, coir matting and geotextile membranes are often used to provide additional protection. For example, interlocking sheet steel pilling can be installed to provide additional bank protection, with reinforced concrete then installed as a capping beam. This prevents the need for dewatering the canal, so tends to be a more popular option than building concrete or masonry banks.
Although natural vegetation can be planted along the canal bank edge to provide support, it does need to be maintained regularly. Common examples of techniques include reeds that are planted within coir matting, hazel wattles and rolls of brush wood, which are often paired with stone filled gabions.
How to report canal bank issues?
If you spot an issue with a canal bank, please report the problem to The Canal & River Trust. The trust manages the historic waterways throughout England and Wales, so if you ever spot an issue with a towpath, dock, bridge, aqueduct, reservoir or bank, this organisation should be called as soon as possible. The head office can be contacted during normal office hours using the number: 0303 040 4040, although if the situation is an emergency, the following 24-hour contact number should be used: 0800 47 999 47.
Here at The Rothen Group, our experienced team of canal engineers have the skills, knowledge and equipment needed to complete all types of canal bank repairs. From repairs along a stretch of bank which houses electricity or gas services through to the installation of sheet pilling, gabions, and concrete along a large canal stretch, we are the team you need. To find out more about how we can repair and maintain canals and waterways throughout the UK, contact our experienced team today.