Agenda Item No. 6


The Vale of Glamorgan Council


Environment and Regeneration Scrutiny Committee: 19th July, 2016


Report of the Director of Environment and Housing


Flood Alleviation Schemes


Purpose of the Report

  1. To inform Committee of the progress in delivering three significant flood alleviation schemes; Coldbrook Catchment Flood Alleviation Scheme, Boverton Flood Alleviation Scheme and Llanmaes Flood Alleviation Scheme.


That Committee note the contents of this report.

Reason for the Recommendation

To keep Members apprised of the current progress delivering three critical flood alleviation schemes; Coldbrook Catchment Flood Alleviation Scheme, Boverton Flood Alleviation Scheme and Llanmaes Flood Alleviation Scheme.


  1. The Local Flood Risk Management Strategy, adopted as Council policy in April 2014 (Minute No C2313), sets a local objective to "Identify and prioritise local risk mitigation works for feeding into the National Investment Programme". The measures adopted to meet this objective include the identification and prioritisation of flood risk areas and subsequent preparation and submission of feasibility studies for Flood Defence Grant in Aid funding to mitigate the risk in high risk areas.
  • Coldbrook Catchment Flood Alleviation Scheme
  1. There was a localised flooding incident within the Coldbrook Catchment on 20 July, 2007 following a prolonged period of localised heavy rain. The source of the flooding being a combination of overland flow and the watercourse.
  2. A report was taken to Cabinet on 20 July 2011 (Minute No C1390) to provide Members with an update on the progress of the scheme.
  3. A further report was taken to Cabinet on 23 July 2012 (Minute No C1771) to update Members on scheme progress, obtain approval to allocate match funding and authorisation to enter into contract for the delivery of the Coldbrook Catchment Flood Risk Management Scheme.
  4. The latest report was taken to Cabinet on 14 July 2014 (Minute No C2399) to update members on scheme progress, obtain approval to revise the allocated match funding and authorisation to enter into a contract for the delivery of the Coldbrook Catchment Flood Risk Management Scheme.
  5. The proposed scheme will provide flood risk protection up to a 1 in 100 year storm plus 20% allowance for climate change in accordance with the Welsh Government flood risk management strategy.
  • Llanmaes Flood Alleviation Scheme
  1. There is a history of flooding in the village of Llanmaes both from local watercourses and surface water flows shedding off the surrounding fields. The most recent incident affecting both properties and highways occurred in November 2007 when Gadlys Road and two properties were affected. Prior to this, flooding had occurred on average every 5 years often with properties affected.
  2. A report was taken to Cabinet on 15 October 2012 (Minute No C1868) to inform Members of progress delivering the flood alleviation scheme.
  • Boverton Flood Alleviation Scheme
  1. Since the late 1990s a number of flooding events have seriously affected the village of Boverton. The cause of the flooding has been attributed to an under-capacity highway culvert under Boverton Road. The most recent incident affecting both properties and highway occurring in December 2012 when 11 properties were affected.
  2. Natural Resources Wales (NRW) provided individual property protection to a number of affected properties in February 2013.
  3. Development of the scheme is being led by the Council working in conjunction with Natural Resources Wales.

Relevant Issues and Options

  • Coldbrook Catchment Flood Alleviation Scheme
  1. The final scheme detailed design was completed in May 2014, and the various scheme elements remain as reported to Cabinet on 14 July 2014 (Minute No C2399).
  2. An objection to elements of the proposed scheme was received on 27 July 2014 following publication of an EIA notice, pursuant to the Environmental Impact Assessment (Land Drainage Improvement Works) Regulations 1999 and subsequent amendments, delaying development of the scheme. A ministerial determination, allowing the scheme to proceed to construction, was received on 14 May 2015 deeming that there would be no significant environmental detriment resulting from the proposals.
  3. Grant funding approval for the construction phase of the scheme was subsequently obtained from Welsh Government on 20 July 2015.
  4. Construction procurement commenced in July 2014 and a pre-award meeting was held with Dyer & Butler Ltd in August 2015.
  5. The construction contract was awarded to Dyer & Butler in October 2015 following renegotiation of scheme costs due to the delays commencing construction.
  6. Construction commenced on site in January 2016. Ward members and affected residents were advised in December that works would shortly be commencing. The main site compound was established at Little Hill, the public open space adjacent to Brock Street, early in January 2016.
  7. Contract management and site supervision is being undertaken by Peter Brett Associates on behalf of the Council. There are 2 full-time site staff and a part-time project manager managing the construction contract.
  8. The Contractor is issuing regular newsletters updating the general public (Appendix A), and all residents directly affected are contacted in person by the Contractor and Site Supervision team, with support from Council project team as required. From April the newsletter will be circulated to ward members directly to ensure they are kept informed of forthcoming works. The Contractor has appointed a Community Liaison Officer for scheme, and is registered with the Considerate Contractors scheme. The scheme was inspected in March 2016 and scored very good and excellent in all areas. A further inspection will be undertaken later in the year. The scheme website ( will continue to be updated as scheme progresses. Usage of the scheme specific social media accounts established during the design and development phase was very low. Both the Twitter and Facebook accounts have now been closed and future updates will be issued via the corporate social media accounts.
  9. Progress to date:
  • Solva Close - Installation of improved highway drainage connecting into culverted watercourse completed;
  • Solent Road - Works underway to construct bypass culvert with associated temporary access and traffic management;
  • Merthyr Dyfan Road - Vegetation clearance completed, works on new highway drainage system underway;
  • Dyfan Rd Public Open Space - Works under way to construct new culverts and divert DCWW sewers crossing the site;
  • Robins Lane - Preparatory works underway;
  • Meadow Vale / Brookfield Avenue - Trial holes undertaken and construction of manhole commenced;
  • Catchment wide - Watercourse / bank clearance, intrusion / obstruction clearance and vegetation clearance.
  1. The Contractor is currently behind schedule by approximately 7 weeks but is considering appropriate mitigation measures and completion of the 40 week programme is still programmed by November 2016. Regular progress and risk reduction meetings are being held with the Contractor to manage these delays appropriately.
  2. Following concerns being raised over the impact of main site compound at Brock Street public open space the Contractor was instructed to relocate the compound to Court Road depot. The main relocation was undertaken over the weekend of 2nd/3rd April 2016, with the public open space subsequently reinstated over the following weeks under the supervision of Parks and Grounds Maintenance.
  • Llanmaes Flood Alleviation Scheme
  1. An initial scheme design was completed in 2012, comprising of a new culvert to intercept and convey flood flows through the village.
  2. Following a review of the hydraulic modelling and scheme design, in conjunction with NRW, a redesign of the scheme to incorporate additional flood storage was deemed necessary to improve the standard of service delivered and ensure no detriment elsewhere in the catchment.
  3. Additional modelling was undertaken to enable a re-appraisal of scheme options. The Option Appraisal Report was finalised in November 2014 forming the basis for an application to Welsh Government for an increase in grant funding. The preferred scheme option incorporates works to convey flows through village and storage downstream to mitigate any impact on flows downstream. The estimated total scheme cost was increased to £3,946,000, including a 55% optimism bias.
  4. Approval was received from Welsh Government in October 2015 for an increase in grant funding for the design and development phase, from £71,000 to £216,216.
  5. Initial discussions with NRW regarding scheme options, and potential collaboration regarding upgrading of existing flood storage structures on Llanmaes Brook commenced in January 2015, with initial inspections of the existing structures undertaken in September 2015. The potential impact on flood risk to Boverton and other communities downstream has been identified as a key consideration in scheme development, with betterment to be considered if achievable in the scheme design.
  6. The scheme will be built alongside and complement the scheme in nearby Boverton reducing risk to the wider catchment.
  7. The latest catchment flow models were obtained from NRW in February 2016. The scheme designers are liaising with NRW to develop appropriate baseline and design models as a basis for obtaining all necessary consents and approvals from NRW for the scheme to proceed.
  8. A feasibility assessment and negotiations are ongoing to reduce scheme construction and future maintenance costs by upgrading the existing storage structures managed by NRW on the Llanmaes Brook to accommodate increased volume of water. If this is not feasible then the scheme will revert to construction of a new storage area.
  9. The route of the proposed Northern Access Road to St Athan has the potential to impact on any proposed changes to the existing flood storage area, which is sited on Welsh Government owned land. The Llanmaes FRMS project team is currently liaising with all interested parties on this matter. If necessary the scheme will revert to construction of a new storage area to avoid delays to project delivery.
  10. Once the design is suitably developed negotiations will commence with landowners, and the local community will be updated on the final proposals.
  11. The detailed design, site investigations, surveys and ecological assessments are ongoing and all necessary consents / licences will be obtained during summer 2016. Procurement is planned for Autumn 2016 and construction programmed to commence early in 2017. The construction works are estimated to take 6 months, subject to confirmation of the storage area proposals and is subject to formal WG grant approval.
  • Boverton Flood Alleviation Scheme
  1. Following the latest significant flooding incident in December 2012 the Council and Natural Resources Wales have been working in collaboration to develop a suitable scheme and secure funding.
  2. An initial public meeting to keep the local community apprised took place on 19 July 2013, with further meetings on 6 February 2014, 11 April 2014 and 17 June 2016.
  3. NRW commenced a catchment wide flood risk modelling exercise in summer 2013 the outputs of which included a Strategic Options Appraisal Report (July 2014) and Culvert and River Channel Proposals Report (July 2014).
  4. The Council commissioned ground investigations and other surveys in 2013 and 2014 which revealed poorer ground conditions than anticipated.
  5. Initial revisions to an earlier design, developed jointly by the Council and Environment Agency Wales in 2006, were undertaken in-house, before commissioning consultants to further develop the scheme and prepare Design and Build tender documents.
  6. On 14 January 2016 (former) Natural Resources Minister Carl Sargeant announced that grant funding has been allocated for the next financial year in the Welsh Government's Draft Budget 2016-17 to complete an important flood defence scheme at Boverton in the Vale of Glamorgan. An application has currently been submitted to the Welsh Government for £1.79m.
  7. Procurement of a Design and Build contract is currently ongoing, pending Welsh Government funding approval, with an anticipated construction start date of September 2016 and 6 month construction programme.
  8. A Flood Risk Activity Permit for the permanent works was obtained from Natural Resources Wales in May 2016 with liaison ongoing to manage the environmental impact of the scheme during construction.

Resource Implications (Financial and Employment)

  • Coldbrook Catchment Flood Alleviation Scheme
  1. The Council has secured European Regional Development Funding (ERDF) and a Welsh Government Flood Risk Management Grant to address the management of the flood risk that exists within the Coldbrook Catchment in Barry.
  2. The current estimated scheme total cost is £3,408,976, although ongoing compensation events arising during the construction phase are likely to result in an increase in the final cost. The total construction phase spend to date is £959,390.
  3. The latest funding approval was received on 23 March 2016 offering a total of £2,715,408 Welsh Government and ERDF grant funding with match funding of £301,911 from Natural Resources Wales and £391,657 from the Council.
  • Llanmaes Flood Alleviation Scheme
  1. The Council has secured Welsh Government Flood Risk Management Grant to address the management of the flood risk that exists within the village of Llanmaes.
  2. The current estimated total scheme cost is £3,946,000, including a 55% optimism bias. Total spend to date on the design and development phase is £102,500.
  3. Welsh Government grant funding of £216,216 has been approved for the design and development phase of the scheme, with provision for grant funding, subject to formal approval, of scheme construction in 2016/17. The Construction Phase is also anticipated to attract85% Welsh Government grant funding.
  • Boverton Flood Alleviation Scheme
  1. The total scheme cost currently submitted to Welsh Government is £2,100,000, and the Council has allocated £310,000 capital budget to progress the scheme prior to achieving formal grant funding approval.  It is anticipated that Welsh Government grant funding will be provided for 85% of grant eligible costs.
  2. Total spend to date is £116,000 on scheme development and outline design.

Sustainability and Climate Change Implications

  1. The proposed schemes will be designed to accommodate the predicted impacts of Climate Change relating to flood risk.

Legal Implications (to Include Human Rights Implications)

  1. There are no Legal or Human Rights Implications in respect of this report.

Crime and Disorder Implications

  1. There are no Crime and Disorder Implications in respect of this report.

Equal Opportunities Implications (to include Welsh Language issues)

  1. There are no Equal Opportunity Implications or Welsh Language Issues in respect of this report.

Corporate/Service Objectives

  1. Corporate Plan Wellbeing Outcome, An environmentally responsible and prosperous Wales, Objective 4: Promoting sustainable development and protecting our environment are relevant to the flood alleviation schemes.
  2. Visible Services and Transport Service Plan 2016 - 2020 contains 3 relevant actions on p.27 for 2016 / 2017 namely:

Complete the delivery of Coldbrook Flood Alleviation Scheme;

Continue work to deliver the Boverton Flood Alleviation Scheme and

Continue work to deliver Llanmaes Flood Alleviation Scheme.

Policy Framework and Budget

  1. This matter is within the Policy Framework and Budget.

Consultation (including Ward Member Consultation)

  1. The local Members have been consulted on all projects and will continue to be engaged throughout delivery of the different schemes.

Background Papers


Contact Officer

Clive Moon, Principal Engineer (Flood and Coastal Risk Management)

Tel. No. 02920 673 277

Officers Consulted

Operational Manager, Legal Services

Accountant, Building and Visible Services

Responsible Officer:

Miles Punter

Director of Environment and Housing