River wall restoration

Background

In October 2023, severe storm events caused extensive damage to the quayside retaining wall at Blackpool Mill because of combined tidal and fluvial flooding. A significant section of the wall was destroyed.

As an interim measure, and following receipt of the necessary permissions from Natural Resources Wales (NRW), we installed temporary rock bag protection in 2024 to stabilise the affected area and protect the riverbank.

Scope of Works

The project involves the full reconstruction of the retaining wall along the river frontage at Blackpool Mill. The works include:

• Removal of the existing temporary rock bag protection
• Installation of a temporary cofferdam (river dam) to allow dry working conditions within the river channel
• Excavation down to wall foundation level
• Underpinning works to the adjacent storeroom structure
• Construction of new concrete foundations
• Construction of a new masonry retaining wall with drainage and backfill
• Reinstatement of paths, terraces, railings, and hard landscaping
• Removal of all temporary works and site infrastructure on completion

The overall programme is approximately 10 weeks, with in-river works commencing on 15 July and the project targeting completion by 13 September 2026.

Tidal and In-River Working

Blackpool Mill sits within a tidal reach of the Eastern Cleddau. This fundamentally shapes how the in-river works can be planned and executed.

The river presents a workable low-tide window of approximately three hours, occurring twice each day. All in-channel activity — including cofferdam installation, excavation, and foundation pours — must be planned and sequenced around these tidal windows. Foundation pours will be timed to coincide with the best midday low tides to ensure safe and controlled working conditions.

This tidal dependency also means that the programme carries inherent flexibility risk: adverse weather, unexpected site conditions, or tidal variations could affect sequencing. The contractor is required to obtain official 2026 tidal data from the Port of Milford Haven before works commence and to plan accordingly.

Regulatory Approvals and Environmental Controls

The works are subject to a Marine Licence which restricts in-river and in-channel working to the months of July, August, and September 2026. This restriction has been a key driver of the programme, and the July start date is the earliest point at which in-river works can lawfully commence.

All works will be carried out in compliance with the conditions of the Marine Licence and all other applicable NRW and Milford Haven Port Authority (MHPA) environmental licence conditions throughout. Key environmental controls include:

• Strict restriction of in-river working to the permitted season (July–September)
• Use of a cofferdam to isolate the working area from the active river channel, minimising disturbance to water flow and riverbed
• All materials, plant, and waste to be managed to prevent contamination of the watercourse
• Contractor environmental responsibilities clearly defined under the terms of the Principal Contractor appointment

We are committed to ensuring that the works are delivered in a manner consistent with the conservation objectives for the Cleddau catchment and with the least practicable impact on the river environment
 
For more information, please email Liz Weedon, Head of Projects at Bluestone Resort: lweedon@bluestonewales.com