Why old clay land drainage systems are failing?

Why old clay land drainage systems are failing?

According to the Agriculture and Development Board, around 6.4 million hectares of agricultural land in England and Wales have been drained with piped systems. Unfortunately, more and more land drainage systems are being reported to fail.

Why are land drainage systems failing?

The installation of clay piping systems was popular over 30 years ago when government grants were available for land drainage. In the 1980s, these grants were retracted leading to fewer farmers choosing to invest in them.

More than 30 years on and, unsurprisingly, these systems are now causing problems. Here are the main problems you will find:

Clogged with silt

The older clay drainage pipes are often prone to becoming blocked with silt, which builds up over many years. Unfortunately, they are almost impossible to cleanout. High-pressure water jetting is an option, if you can locate the blockage, but due to the construction of the system, you can end up flushing as much sub-soil into the lines as you are removing it.

Fractured or broken pipe

Old clay drainage systems can also fracture and break. This can be due to a number of reasons. For example, water loss from defective joints, which leads to erosion of the sub-soil around the pipework and then movement and stress fractures from within the pipe walls. Also, damage can occur during the backfilling process or from vehicle movement above. These fractures can lead to pipes becoming completely sub-soiled and blocked.

Tree root ingress

A common blockage of clay drainage systems is tree root ingress. Tree roots can penetrate mortar joints or access the system through fractures and breaks in the pipe. Once inside the pipe, the roots can then pan out reducing the internal bore of the pipe and left long enough, well-established tree root ingress can completely fill the pipe. Debris can also get caught up in the roots and eventually fully block the pipe.

Picture: Taken by Rob Burtonshaw, Farm Services Ltd

How does modern land drainage pipe compare?

Today’s land drainage pipe is no longer made from clay. Instead, it is manufactured from high-density polyethylene (HDPE), which is designed to provide strength, flexibility and resistance to chemicals and impacts.

It can be constructed from solid wall or flexible perforated pipework. Perforated land drainage pipe has tiny holes cut into the dwells of the coil. These holes are designed to allow surface water to flow through them and be collected. In contrast, unperforated land drain coil is used to distribute collected surface water. When installed the pipes are surrounded in a granular fill. This is then wrapped in geotextile to prevent soil erosion, root ingress and silting to the system.

How can we help?

Our background is in farming so we understand your needs – our MD’s family have been farming for generations. We are also specialists in land drainage and supply a wide range of products at cost-competitive prices, including land drainage coil, twinwall pipe and large diameter structured pipe.

Our team of specialists can provide you with expert advice. Call us today on 0121 351 3230.

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