Bank repair on the River Uck, East Sussex

20 Dec

River House is a private residence, located in an elevated position on the bank of the River Uck in the Wealden District of East Sussex.

Close to a long, straight section of the river, the banks that protect the property are often subject to high levels, coupled with a high-velocity flow — something the customer was keen for us to inhibit damage from along the 26m frontage.

Before and after

The works

Addressing the high rate of erosion, we proposed methods to stabilise the bank to prevent potential future damage to the property.

Our work at River House involved complete project management from initial surveying and risk assessment to planning and consent applications, through to full design and delivery.

We used a combination of a high strength Armour Matting, overlaid with seeded Grass Reinforcement Mesh. Armour Matting is a super-strong, three-dimensional matrix of UV stabilised, non-degradable synthetic fibres that are extruded onto a double twisted, steel, woven mesh.

The matting is held in place with steel pins which are driven into the ground. It is used on steep slopes vulnerable to erosion runoff; once installed it immediately increases the soil resistance and provides conditions that enhance the growth of vegetation.

Our design also included the fitting of a lovely larch revetment.

Using coir rolls to define the edge of the bank

At the toe of the bank, we used pre-vegetated coir rolls.

These were planted with native aquatic plants which matured in the rolls before installation.

The coir rolls increase the resistance of the bank to erosion without having an impact on the channel capacity.

The coir rolls and established vegetation also trap sediment from surface water runoff which would otherwise enter the river.

Using Grass/Turf Reinforcement Mat to help sure up the soil at a steep angle

The Grass Reinforcement Matting is made from coir (coconut fibre) and is seeded with a mixture of dwarf perennial ryegrass and fine fescues. It is placed on the surface of the soil and held in place with wooden eco-stakes.

The seeded matting will allow vegetation to establish on the soil which is protected from erosion – even at this steep gradient.

As the plants grow, the roots will increase the integrity of the soil and the foliage protects it from erosion. Over time the matting will biodegrade and the vegetation will remain which will prevent erosion.