Grave concerns at plans for Roath park dam

Questions to answer for @natreswales @cardiffcouncil and @dwrcymru

Roath Mill Gardens Conservation Society responds to plans

Roath park lake. Picture credit: Richard Szwejkowski

Roath Mill Gardens Conservation Society have written to the authorities about their plans for works on Roath park dam. Their concerns relate to:

  • The way in which the Council is consulting on and managing the project
  • The rationale behind the project
  • The design and impact of the project

Here is the full text of their letter to the authorities:

Dear Sir/Madam,

We are the area advisory group for one of the neighbouring conservation areas to Roath Park. Following your recent Zoom presentation, and the ‘drop in’ events held on the Promenade in Roath Park, we would like to make the following observations for your consideration, which reflect the views of a number of our members who attended the aforementioned consultations.

How – the way in which the Council is consulting on and managing the project

 1.  We strongly object to the lack of representation from the relevant public bodies at the consultation events. Cardiff Council, as the public body managing the project, must be held democratically accountable for its planning and implementation, and the absence of elected representatives or officials from any of the events is an obstacle to the proper exercise of this accountability. Moreover, as the regulatory body whose initial assessment underpins the whole project, Natural Resources Wales ought also to have been represented, especially given that this agency has recent experience of major infrastructure works in an adjacent section of the watercourse. These functions cannot be properly carried out by Grasshopper Communications, and we would be grateful for copies of any documentation explain the rationale for the appointment of an external agency to manage this consultation, with a clear cost-to-benefit analysis.

 2. It seems that the project managers, Arup, have already been appointed and are responsible for both the detailed modelling of the hydrology and the delivery of the project itself. There seems to be the potential of a contract of interest here, and we would be grateful for clarification as to the exact demarcation of responsibility between Arup, the local authority and Natural Resources Wales. Furthermore, we would appreciate more information of the procurement process which selected Arup, which does not seem to have been particularly transparent, with details of their bid relative to other options explored.

 3.  What are the payment terms for this project and what protections have been put in place to ensure public funds are only paid to external agencies for works which have been completed satisfactorily? This is a particularly pertinent question given the recent experience of Natural Resources Wales, when a significant amount of public money was paid to the contractors, Dawnus, before the project’s final delivery, and which was subsequently lost without recourse to recovery when that contractor went into administration before the completion of outstanding projects.

Why – the rationale behind the project

 1.  The hydrological modelling which underpins the project must be made public to facilitate proper scrutiny at this early stage. During the course of the consultation, it has repeatedly been said that the primary reason for the project is to provide capacity in the waterfall/spillway for a theoretical extreme weather event  occurring within the next 10,000 years, but without being provided with the data consultees cannot properly scrutinise the basis of this decision-making. The propriety of using such a time interval for decision making, while on the face of it somewhat absurd, also cannot be properly scrutinised without this data.

 2.  When asked why measures in other parts of the water course were not been considered at the same time, Arup advised it was due to the fact that the Council only has responsibility for this section of the watercourse, and that measures elsewhere would have to be undertaken by Welsh Water and Natural Resources Wales separately. This seems diametrically opposed to the rationale behind the initial formation of Natural Resources Wales, that being to provide a strategic overview and ensure that parochial inter-departmental demarcation of responsibility did not hinder proper management of the watercourses.  It was noted that there seemed to be much scope for mitigation of the impact of the scheme in Roath Park by introducing corrective measures elsewhere in the watercourse, including the following proposals:

    * The lake is heavily silted and should be dredged to increase capacity. Could this extra capacity not be used to mitigate pressure on the spillway by more actively controlling the level of water kept in the lake?
    * Welsh Water has recently undertaken a number of improvements at the upstream reservoirs in Llanishen and Lisvane. While these reservoirs naturally could not collect rainwater introduced further downstream, could the water they contribute to the watercourse not be pro-actively reduced during times of particular pressure to the spillway?

    * The introduction of artificial beaver-style dams has shown considerable promise elsewhere in mitigating the impact of extreme weather conditions. Given the local and controlled nature of the watercourses which feed into the lake, all of which exist wholly within the Cardiff Council boundaries, has the impact of such measures been assessed?

3.  At different points during the consultation it was said that there was no structural concern for Roath Park Dam, but also that the aversion of dam failure is the primary reason for works to the spillway. This seems to relate to the 10,000 year metric previously mentioned, although from a structural perspective it is highly improbable that anything in the immediate area would be capable of surviving for 10,000 years without regular maintenance and rebuilding, including the dam. Moreover, how has this assessment been made before the outcome of the forthcoming investigatory works is known? It is vitally important that the outcome of these works is made public, along with the hydrological data, and the nature of the relationship established between the two in the assessment of risk.

What – the design and impact

 1.  The works will cause ‘permanent changes’ to be introduced to a broad area, including the waterfall, weir, and the downstream bank of the prom. This area is within a listed park and a conservation area, and moreover included several listed structures including the dam and waterfall. It was stated that they would make an effort to retain those features they could, but that change would be inevitable and considerable. While a broad assurance that changes would be ‘in keeping’ was given, there was little detail provided about how this was to be achieved, other than an assurance that planning permission would be sought, which seems wholly inadequate for works of this scale and impact. We would welcome assurances that all the relevant heritage bodies will be consulted, including the Design Commission for Wales, the Victorian Society, local heritage and civic groups, and the architectural and history departments of local universities, to ensure that any works both appropriately replicate the existing infrastructure, or where necessary contemporary examples elsewhere. A key consideration in this will be building materials, including using the correct stonework and ironwork, and representatives from Arup were unable even when pressed to provide assurances that this would be so. Indeed, there seemed to be an acceptance even at this early stage that original materials would be replaced with modern ones, with the only, clearly inadequate, rationale given being that the skills involved in working with more heritage appropriate materials can be hard to source. 


 2.  The impact of the scheme downstream seems to have been inadequately considered, and no reassurances could be given that increasing capacity in the spillway would not lead to issues further south in Roath Park and Penylan. Of mention are the facts that, during recent heavy rain, there was localised flooding south of the dam in Roath Park, even though the spillway was not at capacity, and that recent clearance works in Roath Park Recreation Ground have shown that the Roath Brook has been allowed in this section to halve in width and become greatly reduced in depth, greatly reducing its capacity. Even further downstream, in Penylan, the suspension of the Phase III flood defence works has left a section between Penylan Road and Waterloo Road which still by Natural Resources Wales’ own assessment has inadequate capacity, an issue which will surely only be worsened if capacity at the spillway is increased. While we fully appreciate that the relationship between dam safety and flooding prevention projects is tangential, Natural Resources Wales does have overarching responsibility for both, and there is no evidence that these wider impacts have been given any consideration.

 3.  The area identified includes several examples of mature and rare trees, which will have to be felled to provide access to the spillway. While to some degree this may be necessary, any trees which can be preserved must be so, especially given the historical importance of the Roath park Arboretum. Other recent projects which involved the felling of trees involved the loss of too many mature specimens, and moreover saw their replacement by poorer quality specimens without proper management plans in place to ensure their establishment. A full ecological survey must naturally be conducted before any trees are felled, and proper programmes put in place to ensure that in the medium term there is no considerable loss of biodiversity or amenity.


It should be noted that, due to the lack of detail provided on the proposals, the above only represents our initial responses and are confined to a very high-level or analysis. We expect further consultation one more details are known, and will certainly provide more minute observations once we are able to do so.

We would appreciate it if you could keep us up-to-date of any further developments.

Best wishes,


Geraint Denison-Kurg
Chairperson
Roath Mill Gardens Conservation Society

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