Case study:River Somer channel enhancement, Midsomer Norton

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Location: 51° 17' 8.66" N, 2° 28' 55.68" W

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Project overview

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Status	Complete
Project web site
Themes	Fisheries, Habitat and biodiversity, Social benefits
Country	England
Main contact forename	Luke
Main contact surname	Kozak
Main contact user ID	User:NickRRC
Contact organisation	Woodland, Water and Gardens
Contact organisation web site
Partner organisations
Parent multi-site project
This is a parent project encompassing the following projects	No

River Somer on the high street (post-restoration)

Project summary

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The reach of the River Somer flowing through Midsomer Morton had been a focus of concern for many years. A complete lack of vegetation, weir impoundment and large amounts of silt accumulation were severely effecting habitat and amenity potential of the channel. This was in stark contrast to the natural brook up and downstream of the town.

Local residents formed the River Somer Management Team (RSMT), with the aim of improving the channel based around the following project objectives: • Removal of three weirs • Build new channel based on the geomorphology of the “natural” stretches of the River Somer • To enhance the aesthetic value of the reach, including the development of vegetated margins, in channel flow regime and opportunities to engage with the public • Restore habitats and enhance ecological value • “bring trout to the town” • Use localised materials • Use construction techniques which are flood resistant • Community engagement for construction, long term maintenance and educational opportunities

The project was split into four stages: 1. Weir removal 2. Berm construction 3. Bed raising and fine adjustment 4. Planting aquatic margins

The RSMT commissioned Woodland, Water and Gardens (Luke Kozak) as project consultants, designers and construction managers. BANES were commissioned as the overall project managers. Construction started in May 2011 taking three weeks to complete. The planting phase was completed by volunteer Midsomer Norton residents. The berms were constructed from coarse interlocking local limestone which did not exceed 30cm high. This allowed flow to be released over the berms, increasing channel capacity when needed (2-stage channel design). Flow events shortly after construction demonstrated the effectiveness of this design. In June 2012 the first formal assessment took place post-project completion. This encompassed fish, invertebrate and vegetation assessment. The report concluded that: berms were intact and in good condition despite several high flow events, plant communities had matured well providing a diverse habitat, maintenance carried out by volunteers has helped to keep the channel litter free. Diversity of aquatic organisms has increased, and although some small silt deposits have form in low energy areas the channel in generally self-cleansing. The project has been given a civic “Pride of Place” award for environmental enhancement, and the establishment of the RSMT will ensure the success of the project into the future.

The River Restoration Centre would like to thank Luke Kozak (Woodland, Water and Gardens) as well as Dominic Longley for providing the information and photographs for this case study.

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Monitoring

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