FLOOD RISK MANAGEMENT RESPONSIBILITIES IN RELATION TO THE RHYL CUT AND PRESTATYN GUTTER
To consider a report by the Council’s Flood Risk Manager (copy attached) which presents the Committee with the conclusion of the joint study, led by Natural Resources Wales (NRW), into potential improvements in the management of the Rhyl Cut and Prestatyn Gutter. The report seeks members’ feedback on the study’s findings and conclusions.
11:05am – 12:05pm
The Lead Member for Waste, Transport and the Environment, supported by the Head of Highways and Environmental Services (HHES) and the Flood Risk Manager presented the Flood Risk Management Responsibilities in relation to the Rhyl Cut and Prestatyn Gutter report (previously circulated) to the Committee. In addition to Denbighshire County Council officers three representatives from Natural Resources Wales (NRW) were in attendance for the discussion - Keith Ivens, Daniel Bryce-Smith and Paula Harley.
The report presented conclusions of the joint study, led by NRW, into whether improvements could be made to the management of the Rhyl Cut and Prestatyn
Gutter, adjacent drains and sewers – a complex network of watercourses in the Rhyl and Prestatyn area, which comprised of natural watercourses, some of which had been modified as well as constructed waterways. The report also outlined each organisation’s responsibilities in relation to flood management and flood mitigation.
Following the flooding that affected parts of Rhyl and Prestatyn in July 2017, NRW commenced a review of the hydrology, management and maintenance of Rhyl Cut and Prestatyn Gutter, which are classed as “main river” watercourses. Denbighshire County Council (DCC) and Welsh Water (WW) agreed to support NRW with the project, which would also hopefully provide a better understanding of how each organisation’s assets interact, particularly during times of heavy rainfall.
The project was carried out in three phases.
(i) Phase 1 which involved a flood risk modelling study, to give NRW a better understanding of the hydrology of the river catchments.
(ii) Phase 2 that resulted in a catchment management report, which took a broad overview of the management of Rhyl Cut and Prestatyn Gutter and the areas surrounding the two watercourses.
(iii) Phase 3 built upon the recommendations within the Phase 2 management report and involved discussions within NRW’s operational maintenance teams to consider the impacts of maintenance within different sub-reaches of the watercourses. There was still some work to carry out in terms of producing a comprehensive maintenance and management plan and this would require a process of public and stakeholder consultation.
The Committee was shown a presentation by NRW officers outlining the work which had been carried out by NRW, DCC and WW. The first three stages had now been delivered, the findings of which would allow flood risk management teams to develop long term management and maintenance strategies.
The approach which was taken for the third phase was an evidence-based one using detailed hydraulic modelling. This work had included an assessment on the impact of channel vegetation (roughness), bed levels, and blockages at key locations. This has improved NRW’s understanding of localised maintenance and informed efficient risk-based management techniques within each sub-reach.
During the third phase NRW had also been able to identify potential opportunities for capital interventions to reduce flood risk. It recognised the current risk of flooding to the communities of Prestatyn and Rhyl and has plans in place to undertake a full appraisal of options for improvement works, commencing with a Strategic Outline Case (SOC) in 2022.
During the ensuing discussion:
· members thanked officers for the work which had been carried out, however some felt that aspects of the work should have been carried out sooner.
· NRW confirmed that issues such as the maintenance of property gardens and walls and the need to safeguard debris etc, from entering or falling into the Rhyl Cut and causing blockages was a matter for the riparian landowners i.e. individual property owners. NRW were not the owners of the Cut, it had permitted powers insofar as to undertake work to mitigate the risk of flooding from the watercourse. For this purpose, NRW had access points at certain locations along the Cut to enable it to gain access to undertake the necessary maintenance work. This avoided the need for it to seek the agreement of multiple riparian landowners in order to undertake essential flood maintenance work.
· The Monitoring Officer confirmed that he would liaise with the Council’s Legal Services Department to confirm whether the Council was a riparian land owner for any part of the Rhyl Cut or Prestatyn Gutter.
· NRW officers confirmed that the annual programme of flood maintenance work was carried out on both the Cut and Gutter from late August onwards, once the bird nesting season had ended. The maintenance worked commenced on the lower reaches working up towards the higher reaches
RESOLVED subject to the above observations to:
(i) receive the contents of the report, appendices and presentation; and
(ii) seek Denbighshire County Council officers to establish whether the Council itself was a riparian landowner for any part the Rhyl Cut or the Prestatyn Gutter.