Bank Protection Work on River Itchen at Winchester

Contractor: Land & Water Services Ltd

The River Itchen is a river in Hampshire, England. It flows from mid-Hampshire to join with Southampton Water below the Itchen Bridge in the city of Southampton. The river is noted as one of the world’s premier chalk streams for fly fishing, especially using dry fly. It is designated as a Site of Special Scientific interest (SSSI) and is noted for its high quality habitats, supporting a range of protected species including the endangered water vole, otter, brook lamprey and white-clawed crayfish.

Terraqua Environmental Services supplied a range of high quality products to enable a soft-bioengineered erosion system to be installed at the water’s edge. A key objective was to collect a constant supply of fine sediment and to establish vegetation, the bioengineering design detail was critical within this SSSI site.

Lines of 300mmɸ brushwood faggots were installed along the bankside to establish an erosion protection system to trap fine sediments and to prevent future soil erosion during flood events. Two faggots were laid on-top of each other between two rows of cleft chestnut posts and secured into place with galv steel tying wire.

Repairs were made at a junction in the river by recreating the original bank line by installing several layers of brushwood faggots, the system will quickly fill with river sediments, vegetation will quickly re-establish and further stabilise the bank.

Several spaces were opened up in the line of faggots to allow water voles access to the bank.

In places preplanted coir rolls were installed at the front of a line of faggots, helping to regain up to 600mm of lost bank & habitat. The rolls provide immediate bank protection and a physical habitat structure; the rolls & faggots will quickly establish diverse marginal vegetation helping to protect the bank side and wildlife species.