FiveRivers have recently completed a design and build river restoration project on the River Welland in Market Harborough for Anglian Water. The project consisted of the construction of brushwood and earth berms, the excavation of a backwater, and the installation of woody deflectors to help create variation in form and flow throughout the project reach.
Project requirements
The problem
Anglian Water identified a stretch of the River Welland as at high risk of flooding. The River alongside the Market Harborough Water Recycling Centre (WRC) is classified as a main river and has a high probability of flooding, representing a 1 in 100 or greater annual probability of inundation.
Anecdotally, the flows in the River Welland within the study reach are very low in the summer. This combined with the engineered dimensions and gradient of the channel, result in sluggish and stagnant river flow conditions that encourage deposition of silt through the reach. The River Welland also responds rapidly to rainfall events and can experience flashy peak flows and extended periods of high-water levels during the winter months.
The channel was identified as having heavily modified geomorphology, exhibiting an over-wide and over-deep character throughout the entire reach with trapezoidal cross-sectional shape.
Our approach
The solution
FiveRivers provided outline design options report to Anglian Water to assist in conversations with the Environment Agency, adjacent landowner and other catchment stakeholders.
Once a preferred option from the three presented was selected, FiveRivers proceeded the option to detailed design and undertake the necessary actions to submit for a Flood Risk Activity Permit (FRAP).
The FiveRivers construction team then carried out the build in August 2022, delivering the preferred option which included…
• The excavation of backwater
• The creation of localised two-stage channel with brushwood and earth berms
• Installation Woody flow deflectors and rootwads
• Hinged and pinned riparian trees and installation gravel riffles
Project outcomes
The results
The scheme outcome has provided a morphologically improved channel for approximately 1 km, which provides for greater aquatic and riparian biodiversity, in this currently uniform, straightened channel. An additional benefit is improved water quality.
The second outcome is an understanding of ground conditions to inform the potential wetland construction for consideration in AMP8, notwithstanding any need to use the site for future expansion of the WRC.
Contact us today.
Our services
Services implemented.
Contact us
Looking to talk to an expert?
Luke Roberts
Design & Construction General Manager
Get in touch by either phone or email to speak with Luke and discuss your needs.
Telephone: 01722 783 041
sales@five-rivers.com
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