PLANS to improve the drainage in Cyfarthfa Park and at the castle have just been submitted.
Listed building consent is being sought for drainage works which include the Grade II listed park and the Grade I listed castle
It is proposed to install a new below-ground surface water drainage network to take water run-off away from the building to an existing Welsh Water connection at the south-east of Cyfarthfa Park.
The heritage statement submitted with the application said that the castle was in a “significant state of deterioration” with multiple examples of water ingress throughout the structure, mainly attributed to poorly performing rainwater goods, gullies and flat roofs.
In 2022, a condition survey by Purcell and a structural survey identified the need to protect the building, and suggested a tented scaffold be erected to prevent further water ingress and associated deterioration, whilst giving the building the opportunity to dry out.
The heritage statement said it was recognised that a drainage solution would be needed to allow for the controlled discharge of rainwater from the scaffold.
It added that the design of a new drainage strategy also provided the opportunity to develop a permanent solution to existing issues with the drainage running across the site.
Most drainage routes for the discharge of surface water within the park are historic and many are undersized and in poor or defective condition, according to a CCTV survey.
The heritage statement said the result of inadequate drainage was that rainwater ran off the sloping land to to the north of the castle and entered the basement.
It said that the parkland had also suffered in recent years, with trees lost as a result of waterlogged ground.
It said: “The proposed drainage strategy has been designed to allow for the discharge of water run-off from the tented scaffold (for which listed building consent/planning permission will be sought in the future).
“It also aims to provide a permanent solution to the wider problem of inadequate drainage within Cyfarthfa Park.”
The statement said that the archaeological impact of the proposed drainage improvements had been mitigated through the location of the new runs in a less archaeologically sensitive area of the park.
The proposed routes of new runs have been designed to minimise impact on existing landscape features and known archaeology, and may be further mitigated through planning conditions.
It said that drainage routes had been designed to minimise the visual impact on the historic landscape of the park, which had the potential to be affected by the removal of trees.
Consultation with Cadw’s inspector of historic areas (registered parks and gardens) and the council’s arborist has enabled the design of a route which minimises impacts on key views within the park and prioritises the removal of lower value trees.
The statement said: “Improving drainage within the park will be of overall benefit to fabric of the castle, which is currently suffering (particularly at basement level) from heavy water run-off from the higher ground to the north of the building.
“It will also protect the integrity of the historic landscape into the future, helping to halt the loss of trees due to saturation and uprooting.
“Beyond the benefits the scheme offers to the significance of the castle and park, it will also enhance the special interest of the Cyfarthfa Conservation Area.
“The castle is identified as the ‘centrepiece’ of the Cyfarthfa Park South character area, and the conservation area appraisal recognises the value of the wider estate in illustrating the wealth and power produced by the natural resources of the area during the 18th and 19th centuries.
“The preservation of the castle and the protection of its historic setting within Cyfarthfa Park will also benefit the special interest of Cyfarthfa Heritage Area and Urban Character Area 5: Cyfarthfa Park and Ironworks.
“Both (non-statutory) designations are heavily informed by the survival of Cyfarthfa Castle and the integrity of Cyfarthfa Park, and their intimate relationship with the surrounding industrial landscape of Merthyr Tydfil.”
The proposals include the installation of new drainage channels around the perimeter of the castle.
These runs will be connected to new drainage routes running south-east away from the castle and beneath the tree boundary
around the pavilion and bowling green into a below-ground attenuation tank.
New drainage runs and yard gullies will also be built to capture existing above-ground water run-off just north of the castle.
It is proposed to replace the existing drainage run east of the old bandstand and this renewed pipework will be connected to a new
run taking water from the play area north of the bandstand southwards through the woodland and parkland to the bandstand.
An additional connection will be made to direct water from these two runs to the principal route leading southwards across the parkland
to the existing Welsh Water connection.
To help with the construction of the new runs, it will be necessary to remove several trees but the statement said that these had been assessed by an arborist as “low value.”
All existing drainage runs will be kept and some runs, which currently provide drainage for both foul and surface water, will be used only for foul drainage following the implementation of the new drainage runs.
The majority of the run leading southwards across the parkland to the Welsh Water connection will be abandoned.
