SRA End of Year Report 2016-17: Resilient Infrastructure – Workstream 4
Inspections and remedial works to culverts under roads in IDB areas
A programme that prioritises around 700 of the most vulnerable and strategically important culverts within Somerset Internal Drainage Board areas. Responsibilities are sometimes unclear, so SRA funding is being used to gain a better understanding of structures, and to make necessary improvements, irrespective of ownership. Through activities such as repairing, removing blockages, and replacing life-expired structures, this enhanced flood risk management will improve the conveyance of water and help to prevent disruption to residents and travellers. Being achieved: Preliminary inspections have been carried out of more than 500 culverts. Work continues in 2017-18.
Somerset County Council’s existing budgets only allow for the de-silting of structures such as bridges when there is a threat to the structure itself. But extra SRA funding enables de-silting where there is also a benefit to the watercourse and, therefore, a reduced risk of flooding to roads and nearby properties. Co-ordination with other de-silting activities increases the benefit to whole catchments. Achieved: Structures de-silted in: West Somerset – Holnicote, Horner; Taunton Deane – near Creech St Michael; Sedgemoor – Edithmead; Mendip – Huxham (A37), Leigh upon Mendip. Not yet achieved: West Somerset – Monksilver, awaiting Environment Agency consents.
Somerset has 152,000 gullies. They are emptied by Somerset County Council’s Highways Department on three types of rounds: annual rounds (in flood-susceptible areas), 2-year rounds (non flood-susceptible rural areas) and 4-year rounds (non flood-susceptible urban areas). The SRA funds an additional six-month round for the highest-risk gullies in flood-susceptible areas on SCC’s annual round. This work keeps roads open, makes them safer, preserves access for communities, and safeguards properties from flooding. Achieved: Various Somerset locations benefited from this extra work. West Somerset – Bridgetown, Carhampton, Dulverton, East Quantoxhead, Exford, Minehead, Monksilver, Porlock, Treborough, Wheddon Cross, Withycombe: South Somerset – Bruton, Cudworth, East Stoke/Stoke Sub Hamdon, Forton, Montacute, Mudford, Pitcombe, Somerton/Compton Dundon, Winsham, Yeovilton: Sedgemoor – Cannington, Compton Bishop, Greinton, Nether Stowey, Wedmore: Mendip – Ashwick, Croscombe, Holcombe, North Wootton, Nunney, Wanstrow.
Under existing budgets, Somerset County Council’s Highways Dept can only afford to jet drains when a bad blockage has occurred. SRA funding allows for earlier preventative maintenance at locations known to suffer problems with flooding. The programme is carefully integrated with other SRA-funded activities. So drain jetting sites also feature on annual gully rounds; but final selections are made using local knowledge and professional judgement. Achieved: Various Somerset locations benefited from this extra work. West Somerset – Clatworthy, Crowcombe: Taunton Deane – Kingston St Mary, Wiveliscombe: South Somerset – Ilchester, Martock: Sedgemoor – Axbridge, Catcott, Compton Bishop, Highbridge, Wedmore, Westonzoyland: Mendip – Ashwick, Croscombe, Holcombe, Wanstrow.
SRA-funded road sweeping is delivered by Somerset County Council’s Highways Dept and targeted primarily at flood-susceptible rural areas. SCC does no other sweeping, while district council provision varies (for example, West Somerset does none, while Sedgemoor tends to focus on towns). The aim of this extra SRA-funded work is to stop detritus entering and blocking drainage systems, thus reducing flood risks. Sweeping is done after trees have shed their leaves and is integrated with other preventative maintenance activities. Local knowledge and professional judgement are also used in choosing sites. Achieved: Just over 500 hours of sweeping removed 636 tonnes of detritus from just over 50km of roads, at places including: West Somerset – Nettlecombe, Old Cleeve: Taunton Deane – Kingston St Mary, North Curry/Fivehead, Wiveliscombe: South Somerset – Bruton, Cudworth, Montacute, Tatworth & Forton, Winsham, Yeovilton: Sedgemoor – Compton Bishop: Mendip – Ashwick, Binegar, Cranmore, Evercreech, Kilmersdon, Upton Noble.
Accurate information enables Somerset County Council’s flood risk team to ask riparian owners to remedy problems or to carry out enforcement. Achieved: As a result of extra SRA funding, blockages have been cleared, trash screens funded, flood alleviation schemes advanced, riparian owners made aware of problems they need to address and previously unknown issues revealed. It is expected that several neighbourhood disputes will also be resolved. Locations included: West Somerset – Brushford, Doverhay (Porlock), Dulverton, East Quantoxhead, Monksilver, Williton (x2); Taunton Deane – North Curry (x2); South Somerset – Barrington, Chard, Combe St Nicholas, Galhampton, Knowle St Giles, Martock (x2), Misterton, Somerton, Sparkford, Stoke sub Hamdon (x2); Sedgemoor – North Newton; Mendip – Frome, Wraxall.
Flood Alert Systems
Proposed trial of sophisticated new flood detection and warning systems that provide real-time information, to help generate and broadcast warnings and reduce the risk of people getting injured and vehicles damaged, particularly when it is dark. Not yet achieved: Three sites selected by Somerset County Council’s Highways Dept for the SRA – A38 Wellington Road, West Buckland; A378 Langport Road, Wrantage; Oake Road, Bradford-on-Tone – but there are concerns about initial costs and yearly maintenance costs.
Local flood risk management measures
For the SRA, Somerset County Council tackled extra cases of property and/or highway flooding from surface water and ordinary watercourses.
Achieved: Four schemes that were unavoidably delayed in 2015-16: Combe Florey (culvert upgrade / new trash screen), Phase 1 of Enmore (Frog Lane interception of surface water), Exton (Week Lane drainage improvements), Ilminster (Cad Rd; feasibility study).
Being achieved: Old Cleeve to Blue Anchor Road (drainage improvements). CCTV survey done; unavoidably delayed from 2015-16, now due 2017-18. Phase 2 of Enmore now due 2017-18.