SECTION 19 INVESTIGATION REPORT ON THE FEBRUARY 2020 FLOODS IN DENBIGHSHIRE
To consider the Section 19 Flood Investigation Report (copy attached) from the Head of Highways & Environmental Services and Flood Risk Engineer on the 2020 floods in Denbighshire.
10:15 – 11:00
In his introduction the Lead Member for Waste, Transportation and Environment in his introduction, Councillor Brian Jones, highlighted that the flooding experienced across Denbighshire in February 2020 had been a significant event. The Head of Highways and Environment (TW) introduced the Section 19 Flood Report (previously circulated) relating to the floods which had occurred as a result of Storm Ciara. Denbighshire County Council as a Lead Local Flood Authority had a duty under Section 19 of the Flood and Water Management Act to investigate flooding and publish the findings.
The majority of the flooding had occurred from main rivers – Ceidiog, Clwyd, Elwy and Ystrad - which came under the remit of Natural Resources Wales (NRW) for investigation. There was also some surface water flooding which was the responsibility of Denbighshire County Council to investigate.
The report sought to answer 3 questions in relation to each area that was flooded:
1. Why did the flooding happen?
2. How likely was it for that scale of flooding to happen again in that location?
3. What improvement actions were needed to ensure that flood risk in the County was appropriately managed in future?
The majority of the recommended improvement actions fell to NRW to progress (pages 33 to 35) as they had the authority and the powers to take action on main rivers.
Members expressed disappointment that the majority of information contained in the report related to responsibilities that were within the gift of NRW but there was no NRW representative at the meeting to respond to questions arising from it. Officers advised that the report itself contained the findings of the Council’s investigation into the flooding and its causes, the intention was to present the report, accompanied by the Committee’s comments to County Council in September 2021. If members wished representatives from NRW could be invited to attend that meeting. It was agreed to request an update from NRW on intentions relating to their recommended actions and timescales to be included in the report that was to go to full Council and that NRW representatives be invited to attend.
Members also requested that a historical report or presentation be provided by NRW on rainfall measurements over the previous 10 to 15 years (within Denbighshire), along with an analysis on the quality and reliability of data from rain gauges. This could assist the Authority to gauge the potential impact of climate change on flooding locally. This information could possibly form part of the business item at the County Council meeting in September, or presented to the Flood Risk Management and Riparian Land Ownership Task and Finish Group.
It was confirmed that NRW had already been invited to present the findings of their modelling work in relation to Rhyl Cut and Prestatyn Gutter, at Communities Scrutiny Committee on 9th September 2021.
Responding to members’ questions officers’ advised:
· Rain gauges and river level stations were the property of NRW. Clarification would be sought as to their degree of accuracy.
· With regards to data gathering DCC had some telemetry at key locations, their purpose was to notify the Authority of high river levels in order to respond to potential blockages. DCC were looking to add telemetry to smaller water courses in future.
· The Authority’s remit was to understand the pattern of risk of flooding within the County.
· The assessment of risk terminology adopted by NRW e.g. 1 in 100, could be confusing and potentially led to the belief that it was a low risk of flooding.
· New housing developments were covered by TAN15 planning guidance which sought to achieve a protection of 1 in 1000 annual exceedance probability. There were no national standards for existing developments.
· There was no clear indication that climate change was having a significant effect on flooding as weather behaviour tended to be cyclical.
· Where possible the technical mitigation should be identified to alleviate the risk of flooding existing developments. However, sometimes there was no possible technical mitigation or the cost of implementing it was prohibitive.
· Priorities needed to be established around places where there could be a defence through mitigation – noting that the risk would only be impacted, not removed.
· That every effort had been made by Council officers to assist individual residents and communities affected by main river flooding to enter into dialogue with NRW about reducing the risk of flooding in future.
At the conclusion of an in-depth discussion the Committee:
Resolved: subject to the above observations and the provision of the additional information requested when the report is presented to County Council in September 2021, to recommend that the Council -
I. seeks assurances from Natural Resources Wales at its September 2021 County Council meeting that the recommendations identified in the Natural Resources Wales’ flood investigation reports will be carried out, and that the anticipated timescales for their implementation and completion be confirmed; and
II. through the Flood Risk Management and Riparian Land Ownership Task and Finish Group, seeks assurances from Natural Resources Wales that flood risk from main rivers in Denbighshire is being appropriately managed.
- Feb 2020 Flood Investigation Report 010721, item 6. PDF 311 KB
- Feb 2020 Flood Investigation Report 010721 - App 1, item 6. PDF 312 KB
- Feb 2020 Flood Investigation Report 010721 Appendix A, item 6. PDF 990 KB
- Feb 2020 Flood Investigation Report 010721 Appendix B, item 6. PDF 23 MB
- Feb 2020 Flood Investigation Report 010721 Appendix C, item 6. PDF 2 MB
- Feb 2020 Flood Investigation Report 010721 Appendix D, item 6. PDF 2 MB