Plans submitted to allow quarry to drain surplus water into castle mill pond

Bruce Sinclair, local democracy reporter

Plans to allow a quarry to drain surplus water from its operations into a mill pond below a historic castle has been lodged with Natural Resources Wales (NRW).

In an application to NRW, Templeton-based A & C Aggregates Limited seeks to vary an existing abstraction licence at Carew Quarry, Carew Newton.

The NRW consultation may be viewed on its website.

A supporting document on behalf of the applicant says: “Carew Quarry is an operational quarry that has consent to quarry limestone to 30m below Ordnance Datum that requires the quarry void to be dewatered. The operator has an environmental permit allowing for a maximum of 10,000m3day of dewatering water to be discharged to a naturally occurring sinkhole in the field between the quarry and the mill pond.

“It would appear from observations that at least part of the water discharged to the sinkhole drains ‘directly’ to the northern bank of the Mill Pond via a fissure in the limestone. It is understood to alleviate flooding of Butts Lane from the overtopping of the sinkhole, the previous operator of the quarry installed an overflow pipe that discharges directly to the northern bank of the Mill Pond.

“Since dewatering commenced in 2024, the capacity of the sinkhole has been observed to vary with seasonally, presumably in response to varying groundwater levels, from circa 4,000m3day and 7,500m3day.

“This has hampered the ability of the operator to dewater the quarry and to maintain levels in the quarry over the wetter winter months. It is for this reason that a permit variation is being sought to allow a direct discharge to the mill pond via the overflow to supplement the capacity of the sinkhole initially during the dewatering phase and then over the winter months to maintain groundwater levels in the base of the quarry void.

“This application is currently being determined. The purpose of this variation is to ensure the discharge permit and the abstraction licence have the same discharge locations. The variation required is therefore to add a discharge point on the abstraction licence at National Grid Reference SN 04582 03925 in addition to the current discharge point at SN 04595 04048. No other changes to the current abstraction licences are proposed.”

Details of the application were also lodged with Pembrokeshire Coast National Park planners, the authority’s role to act as an observer of the overall application.