Reconstruction of the River Rea

Using natural resources can be a cost-effective and sustainable way to enhance river channels, whilst also creating habitat for wildlife.

We have been supporting work on one of the largest and most significant regeneration schemes in the UK, a long-term £1 billion initiative to breathe new life into Longbridge, the former heart of British car manufacturing.

To secure the long-term sustainable future for Longbridge and to protect the surrounding natural environment, the development is embracing holistic engineering methods in developing the local landscape.

Working with partners including ACS Construction Group, the Environment Agency, St Modwen’s design team JPA and Birmingham City Council, Idom Merebrook was appointed as geotechnical advisor and river reinstatement reviewer to carry out environmental monitoring for the construction phase of the project.

The project goal was to create a natural and ecological enhancing strategy to support the reconstruction of the River Rea. The consultancy provided specialist support to ensure that the earthworks specifications were met and that the soft landscaping techniques envisaged by the Environment Agency had been implemented.

Previously, the River Rea flowed through a brick lined, concrete and steel walled canal.  The naturalisation plan included removing the hard elements to create a natural channel. The channel design included widening the river bed and lining with lose stone.

Gentle graded batters were constructed and reinforced with larger stones, reclaimed tree trunks were pinned in place and the flood plain was lined with a seeded matting and a series of pools and riffles were created.

Although naturalisation of industrialised water courses is not a new concept, it is not without challenges.  There are often no design protocols for natural river bank reinforcement techniques and no guarantees that all concepts will work – in fact the first couple of attempts at installation resulted in localised revetments formed from tree trunks being dislodged and transported downstream, so a much more robust ‘fixing’ technique had to be developed by the contractor.

Other potential risks with soft landscaping on this site included; protecting existing mature trees, care need to be taken not to damage them in the development process, also the need for the contractor’s team to work in ‘live’ water courses with a risk of high flows which was mitigated by keeping a careful eye on weather forecasts.”

This development is testament to the fact that using natural resources can be a cost-effective and sustainable way to enhance river channels, while also creating habitat for wildlife.