SRA Annual Report 2018-19: Extra repairs, improvements and maintenance (W1)
A scheme to repair the river banks in Frome town centre, and reduce flood risks to about 300 properties, was carried out during the summer. Works focused on strengthening the River Frome’s revetment: the fortified layer designed to shield river banks from erosion, especially on bends hit hardest during storms and times of high flow. Stabilised banks mean the river can now safely carry more water away and so reduce flood risks. The improvements were delivered for the SRA by the Environment Agency, using contractors Land & Water. Repairs were last done here more than 10 years ago.
A popular sight with watching spectators was a big amphibious excavator. This was used for several jobs, such as shifting broken-off chunks of concrete from the river bed and putting rocks in place to protect the river banks. A tug boat and hopper were used to carry materials along the River Frome. Frome Canoe Club, Frome Town Council, Mendip District Council, Wessex Water and Network Rail were all involved in developing this project.
Just outside Dunster, repairs were made to the River Avill Flood Relief Channel. This runs from the edge of Dunster under the A39, and under a West Somerset Railway bridge, down to the sea. It consists of 300 eight-metre slabs of concrete. The joints between these were cleaned out and re-sealed. This strengthened the banks of the channel and so maintained its capacity to carry water away. This reduces the risk of flooding on the A39 and helps to protect local homes, businesses and land. The improvements were delivered for the SRA by the Environment Agency, using contractors Bridge Civil Engineering Ltd and specialist sub-contractors SW Concrete Repairs.
Following the works, the channel showed its worth when 127 mm of rain fell at West Dunkery from 27 November to 4 December 2018 and another 134 mm fell between 15 December and Christmas Eve.
Also near Dunster, works carried forward from 2017-18 were finished off near the ancient monument of Gallox Bridge. The aim here was to prevent the erosion of a 35-metre stretch of bank, by putting in a ‘rock roll’ system, and thereby in turn protect an access track and the main River Avill flood bank. This project was joint-funded by the SRA and the Environment Agency, and delivered by the Environment Agency using contractors Land & Water. The works were successfully tested not long after their completion when 20mm of rain fell on West Dunkery between 1.15pm and 2.15pm on 31 May 2018.
Both Dunster schemes complement earlier SRA-funded moves, such as buying equipment and a store for a new Dunster Flood Group and de-silting work at Ford Bridge upstream on the River Avill near Timberscombe.
Sedgemoor District Council used SRA funding for extra works to make local flood defence schemes and infrastructure in the Sedgemoor area more effective. A key aim is to deal with issues before they become problems. There were five activities:
- Clearance of an overgrown, congested ditch at Blackford near Wedmore, to help keep the local flood relief scheme working well.
- CCTV survey and inspection of surface water system in Bridgwater. The system was found to drain nowhere. Those responsible are now being pressed to complete the drainage works required.
- Structural inspection and assessment of sluice structure at Bays Pond in Cheddar. Proactive maintenance works identified and scheduled for 2019-20.
- CCTV survey and inspection of flood relief scheme in North Petherton. Culvert-checking found no preventative maintenance works required now.
- Structural inspection of damaged culvert in North Petherton. Minor repair works required because of tree growth.
West Sedgemoor and Aller Moor rhynes
On West Sedgemoor and Aller Moor, SRA funding enabled the Parrett IDB to carry out extra maintenance of viewed rhynes. Work on West Sedgemoor covered 20.171 kilometres (12.5 miles), on Aller Moor 9.658 km (6 miles).
‘Viewed rhynes’ are a big network of the more important ditches, that the IDB keeps an eye on and usually maintains every two years. Extra SRA funding has allowed work to be done every single year. This additional work ensures that water is carried away more effectively from flooded and flood-prone areas to outfalls into main rivers such as the Parrett, and to pumping stations. This helps to protect local homes, farms and businesses, and local roads, including 650 metres of the A378 at Wrantage. It reduces the likelihood of summer flooding, which can be particularly damaging to farmers and wildlife, as it was in 2012. It also enables seasonal water level management in accordance with Water Level Management Plans. West Sedgemoor is a Site of Special Scientific Interest and a Special Protection Area and its character depends on people’s ability to manage water levels.