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Below is a detailed response to the points raised by Cathy Farr in her letter of 12 December 2019 and 9 January 2020. Cathy’s points are numbered and the NRW response is bullet pointed.

  1. The potential destruction of ancient woodland and the ecological and leisure/well-being ramifications that would result from such;
    • This is acknowledged and assessed in the options appraisal in the draft OBC.
  2. The costs of said dam from the public coffers, that range wildly from £7m to £750,000, which gives little confidence;
    • £7m was a sensitivity analysis and £750,000 was an initial construction estimation, excluding wider scheme costs. The draft OBC will include latest estimates of both the construction cost and additional scheme costs.
  3. The recent and somewhat relentless rain that we have endured since October that thus far has not flooded any homes in Dinas Powys, with the exception of one event early October when river levels did cause some worries to residents, though the banks were not breached;
    • We were not expecting the recent weather to pose a high flood risk. For context, the 1:100 chance flood event is based on a storm of 71mm total rainfall over 13.25 hours. The recent rainfall has not been at that level, although the near miss event in early October is obviously a reminder that flooding could occur if a heavier storm was experienced.
  4. Your own hydrology report that has been exaggerated by 23% and is based on the flow of the River Ely, which at 39km long is almost five times longer than the Cadoxton (8km) and falls from a higher elevation;
    • Please be assured that we are not using River Ely flows in the modelling of the Cadoxton River for Dinas Powys.
    • Flows for the Cadoxton River were calculated using the Flood Estimation Handbook (FEH), which considers the specific catchment characteristics of the Cadoxton (not the Ely), such as its size, altitude, steepness, geology / soil composition, presence of water features, rural / urban. Hence flows are very much based on the Cadoxton catchment. In accordance with standard practice, this is then reviewed and adjusted if necessary by the best data available, which sense checks the prediction with actual data from the UK’s extensive gauging network and site-based observations / experience.
    • For some locations a monitoring station on the river in question may be used, but in other locations an alternative site, known as a donor, is appropriate, for example if there is not a monitoring station in the catchment. The donor is typically a site with similar hydrological characteristics to the location in question and / or nearby. The Lanelay station on the River Ely is both in the instance of Dinas Powys.
    • Additionally, the hydrology and hydraulic modelling has been reviewed by our staff and two independent consultants knowledgeable in this specialism and all agree the method follows current practices. Hence it is unlikely that the approach would be revised and data from the Cadoxton River used if gathered instead of the Ely in the short term, due to the relative strength of the Ely data.
  5. The fault that appeared in the Cowbridge FSA in October: a structure that has long been promoted by your officers as being an example of what we might get in Dinas Powys;
    • This was a minor fault that was straight forward to rectify. The flood storage area functioned as purposed and has done for over 13 years.
  6. The flagrant lack of adherence to the Welsh Governments guidelines on public consultation;
    • We obviously aim to follow these guidelines. We believe that our consultation to date, ongoing and planned further engagement abides by the principles of the guidelines and is suitable for the project and community but are happy to discuss this further.
  7. The shifting sands of the information delivered by your officers (e.g. The Project Officer for the dam has now told me twice that the 2015 JBA report that appears to have formed the cornerstone of NRW’s subsequent proposals for Dinas Powys is out of date, yet despite requests, (and offers from him, himself) new/up-to-date information has not been forth-coming;
    • The project is delivered in stages. The 2015 report was appropriate to that pre-feasibility stage. We are currently in the appraisal stage, and the forthcoming OBC will conclude this stage. Updated modelling, and other studies, have been produced to inform this stage and Gavin Jones has provided these as appropriate when requested. Most notably the Woodland Trust’s consultant has reviewed the updated hydraulic model and reported on it.
  8. The firm public perception that one of the key drivers of this project is to improve land downstream for future housing development, namely the land either side of the footpath leading from the car park in Dinas Powys, and Sully Moors;
    • This isn’t correct. We are a Welsh Government funded body tasked with managing flood risk to existing communities. We do not facilitate new development. Our flood schemes do not typically manage flood risk to the requirements of TAN 15, so could not be relied upon to form part of a planning application.
  9. The total dismissal of NFM measures by NRW officers when The Environment Agency in England is embracing this approach;
    • NFM is a valid technique to manage flood risk, but as with all options it has its limitations. We have assessed NFM in the Cadoxton catchment and identified what flood risk reduction it can achieve. Unfortunately it is not sufficient for Dinas Powys. We believe that the Environment Agency would draw the same conclusion on this project. Please note that the Environment Agency utilise a range of flood risk management options, including flood storage and flood defences, based upon the individual and specific location issues.
    • As an organisation we are keen to embrace NFM, but it has to be the right solution to the problem in the right place. We are keen to explore a nature based solution on the East brook tributary at Dinas Powys, because we believe it is an appropriate solution there. Similarly we consider NFM as an option on all our flood schemes and continue to explore it, for example at Ffrwd Wyllt.
  10. The hydrology report for the Cadoxton River commissioned by NRW that appears to be raising more questions than it has answered;
    • There are always uncertainties in hydrology, but we understand the data and issues as best we can and have allowed for this in our assessments. If you have any specific concerns, I can arrange for our team or their hydrologist to discuss them with you.
  11. Recent communication with the residents of Millbrook Road and Cardiff Road informing them that they are also at risk of flooding, which has simply been perceived as scare mongering as a prelude to the unveiling of the long-awaited OBC
    • These properties are predicted to be at medium flood risk and have been informed accordingly.