Case Studies

Harnham Riverbank Restoration

A stone wall situated on the riverbank of a private garden was damaged, resulting in the loss of the client’s back yard. Therefore, Five Rivers were employed to remove the existing dilapidated wall and install a hardwood edge protection to enable the creation of an inclined garden. Stabilisation of the front edge was achieved by reprofiling the riverbank and through the plantation of native plant species. Furthermore, a hardwood decking was installed over the new bank with posts placed at the line of the marginal area to ensure that the main channel was not encroached upon.

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FlexMSE Bank Protection – Waterside.

Five Rivers were engaged as principal contractor to design and proceed with the installation of a FlexMSE® bank protection system to replace an impaired wood and post-revetment in-channel on the Fovant Brook at Waterside. The installation covered the 37m of the existing riverbank and was set at 6 bags high (0.75m) to prevent further bank erosion.

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Riverbank enhancement with FlexMSE – Beaminster

Five Rivers was hired by a residential riparian landowner to repair an eroded riverbank located at the back of their garden. The old wooden revetment and drainage pipe were heavily suffering from erosion and needed to be replaced. FlexMSE geo-modular blocks appeared as the best solution to replace them. Furthermore, the new bank was hydroseeded with a mix of marginal species to create a diverse habitat.

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Low Cost Baffle installation – Isle of Wight

The Environment Agency contracted Five Rivers to install two low cost fish baffles onto the Caulbourne based on the Isle of Wight. The first site is located at Woodbrook, this project aimed to increase longitudinal connectivity by installing recycled plastic baffles. Secondly, a rock pre-barrage was installed at Yew Tree Cottage to re-establish fish migration on this watercourse.

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River Habitat Survey (RHS)

Our in-house accredited RHS surveyor carried out a River Habitat Survey (RHS) as part of an assessment of a river enhancement scheme undertaken by Five Rivers in 2018. The enhancement works were intended to increase the diversity of flow and habitat types and create suitable spawning grounds for salmonid and rheophilic cyprinid species. Features were established through the addition of large wood in various forms as well as gravel. This in turn diverted and deflected flow to create riffles, glides, pools, and backwaters where appropriate.

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Reservoir Fish Removal

A two-phase fish removal and translocation, undertaken on a large reservoir in 2019. The reservoir was to be discontinued, so fish were successfully captured and transported to a suitable water body nearby.

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Larinier fish pass installations on the river Dun

Construction of two Larinier fish passes and by-pass channels on the River Dunn, Hampshire.  The EA and the Wessex Chalk Stream & Rivers Trust since 2015 have been working in partnership to deliver a design to improve fish passage at Holbury and Lockerley Mills on the River Dun in Hampshire. The project involved river modelling and engineering design work which was contracted to the civil engineering company Black & Veatch Limited. Hydraulic modelling was undertaken as part of the initial project design to help ascertain the best means to enhance fish passage at both mills which had various artificial flow regulation measures in place. Five Rivers mission was to build a new off-take on the right bank of the River Dun which will provide a passage through a Larinier bypass channel. The existing mill bypass stream was widened and narrowed downstream through gravel placement. In addition, an eel passage was incorporated within the fish pass and inert stones were placed to reduce the toe erosion process at the confluence between mill bypass and the main channel.

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Digswell Chalk Stream Restoration

 

Five Rivers were contracted by the Environment Agency to design and construct a restoration scheme on the River Mimram. The site at Digswell contains deciduous woodland contributing to the local wildlife. However, the River Mimram is failing to meet Good Ecological Status under the Water Framework Directive. Adjacent to Digswell Lake, the river suffers from over widening, over shading and siltation. For the reasons above, Five Rivers was contracted to undertake habitat improvements over a 300m impounded stretch of the watercourse.
Brash berms and large woody habitat features were incorporated into the stream, as a result, the channel was selectively narrowed. This physical alteration of the habitat allowed to increase flow conditions and fishery conditions. Selective tree thinning was also required to increase light to the channel and provide large woods and brushes for the habitat features.

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Avon Turn Erosion Protection

Five Rivers were contracted by a private riparian owner to carry out bank protection works along the banks of the River Avon. In 2015 the location experienced flooding and a bank collapse due to high flows. In 2018 Five Rivers were tasked with creating a marginal zone and a lower level bank that can be allowed to flood in times of high flows. This included the installation of large woody debris (LWD) to stabilise the bank, coarse woody debris (CWD) to provide fish refuge, and the planting of native aquatic plant species to provide habitat for wildlife and aquatic invertebrates.

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Tank Crossing A River Restoration

Five Rivers were contracted to deliver a multi-benefits project including the reinstatement of a palaeochannel. The project incorporated the lowering of the floodplain and the installation of a variety of wetland features. The overarching goal was to enhance the water quality of the River Avon and enhance habitats. Given a wide design brief, we tailored the works to achieve the best possible environmental improvements.

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