Refurbishment of Combwich Wharf for Hinkley Point C

Client: Nuclear New Build Generation Company (NNB)

Duration: October 2022- December 2022

Situation

The main technical challenge was the River Parrett’s tidal range of 11m, causing significant risk and operational difficulty for barge offloading.

Challenge

M Group was tasked to modify the wharf to allow for safe, efficient delivery of heavy components.

This involved raising the berth bed so delivery barges could float in on the high tide and settle level with the wharf as the tide receded. This solution would increase the unloading window and reduce the risk that came with the tidal variation.

Solution

Following the design of the new berth, our team raised the main berth with granular fill to match the barge draft, covered with anti-scour concrete mattresses.

With safety our top priority and an awareness of difficult working conditions, including working in adverse, muddy and dark conditions, we put robust rescue and recovery plans for both our people and machinery into place. 

Tasks were planned around tidal windows to maximise productivity within the three-month window (October-December) and site investigations, including ultrasonic readings and geo-structural assessments for various load scenarios took place to ensure the works were suitable for a varied range of deliveries.

Throughout the works, we considered environmental factors within our planning. This included wildlife safety, particularly for molting shelduck and otters within the area.

We ensured that all plant involved were using biodegradable oils and hydraulic fluids in case of any leakage. We had a plant mechanic on site at all times to carry out repairs should a breakdown occur, and as a last resort we developed a plant rescue plan so that, should the worst happen and an element of plant could not be repaired quickly, it could be recovered from the wharf before being covered by the tide.

South Moor Main Brook joins the River Parrett at Combwich, immediately adjacent to where we raised the berth bed. In our methodology we ensured there was no point where the brook could be obstructed by materials or plant, to prevent flooding upstream.

Result

The refurbishment was successfully completed within the three-month timeframe despite severe weather and site constraints.

On 3 January 2023, the test barge arrived and settled level with the wharf, demonstrating the precision of the design and construction.

The work delivered by our team has ensured a significantly longer and safer unloading window for large, high value components, leading to reliable logistics for Hinkley Point C.