SRA Annual Report 2019-20: Pioneer dredging of the River Parrett between Oath and Burrowbridge
In July 2017 the Board of the SRA approved the dredging of the River Parrett between Oath and Burrowbridge, as soon as a legally compliant and affordable scheme could be found. Planning began in late 2017 and continued throughout 2018-19. Two rounds of statutory public consultation took place in spring and summer 2019.
In mid-September 2019 two local archaeologists monitored site preparation activities on the northern bank of the River Parrett. Remains were uncovered from the lost 16th century hamlet of Tappingweir, mostly fragments of substandard pottery suggesting the inhabitants’ low economic status. A more detailed account of this Prospect Archaeology study and its findings can be read in the News section of the Somerset Rivers Authority website.
Pioneer dredging started in late September.
It focused on the 2.2km (1.4mile) stretch of the river between Beazley’s Spillway at Stathe and the confluence with the River Tone at Burrowbridge because that is where modelling showed the biggest benefits would be obtained. Ongoing work in 2020 includes final bank restoration and re-seeding and mitigation activities such as the planting of old varieties of apple tree.
The scheme is being led for Somerset Rivers Authority (SRA) by the Parrett Internal Drainage Board (IDB), working closely with the Environment Agency, Natural England, contractors WM Longreach and local specialist sub-contractors. The SRA is using Growth Deal funding from the Heart of the South West Local Enterprise Partnership.
This work is important because it supplements all other dredges of the Parrett and Tone since 2014. It also ties in with other projects, particularly existing and forthcoming enhancements of the River Sowy (a.k.a. the Parrett Flood Relief Channel) and King’s Sedgemoor Drain. It will help the SRA to reduce flood risks across a large part of the Somerset Levels and Moors that were badly affected in winter 2013-14 and summer 2012, particularly Aller Moor, King’s Sedgemoor, Moorlinch, Muchelney, Huish Level, Wet Moor, King’s Moor, and Witcombe Bottom. In total, it could potentially reduce flooding to around 65km2 and benefit around 200 homes.
Between Stathe and Burrowbridge, around 22,000m3 of sediment was removed using conventional methods with long-reach excavators on the banks. Sediment was used to widen banks and strengthen the Southlake reservoir dam wall.
In some areas, two-stage channels with marginal berms and areas of shallow water were created. These improvements could benefit water voles, otters, fish, birds and macroinvertebrates (aquatic bugs). Special attention has been paid throughout to the need to protect rare hairy click beetles.