NRW Gauging Station Improvements
Client: NATURAL RESOURCES WALES
- IMPROVEMENTS TO EXISTING ACCESS TRACK TO THE GAUGING STATION
- FLOOD RISK ACTIVITY PERMIT IN RIVER WORKING
- BLOCK STONE REVETMENTS
- GAUGING STATION REFURBISHMENT
- SSSI (SITE OF SPECIAL SCIENTIFIC INTEREST) AND SAC (SPECIAL AREA OF CONSERVATION)
NRW appointed Walters to carry out works to improve access to a key gauging station which monitors water levels within the Irfon River. The scheme involved the removal of failed gabion baskets upstream of an existing weir and installation of block stone revetments to protect the banks and the weir walls from erosion. The project also required the introduction of a further block stone revetment and block stone retaining wall downstream to create a turning area for NRW vehicles delivering the new ARC-boat utilised to monitor river levels to give advance flood warnings.
The track improvement included new drainage and gabion basket retaining wall and regrading works to create a usable access for NRW.
The gauging station building was also refurbished in line with current building regulations.
Walters ensured a short lead in to capitalise on dry weather. The site team worked efficiently and productively to complete the river work during low flow conditions. The project was completed in line with the temporary Flood Risk Activity Permit granted by NRW requiring control measures to ensure the works could be carried out safely, in an environmentally friendly manner and without risk of flooding adjacent land. A specific emergency incident plan was implemented to ensure the safety of the operatives working in the river that involved continual monitoring of weather and upstream river levels. The team worked closely with the NRW designer to ensure a high-quality finish in line with their requirements and advised on value engineering opportunities to reduce the overall cost of the project.
Walters consulted with all landowners in the vicinity of the works to ensure minimal disruption, agree access to the works and rent land for temporary compounds.
SUSTAINABLE USE OF LOCAL MATERIALS
The river revetments and turning area retaining wall were constructed from locally sourced block stone we suggested as a value engineering alternative to the specification which would have needed to be sourced over 40 miles away. This change helped reduce the carbon footprint for the project and promoted local business.
SAFELY WORKING IN SSSI AND SAC WATERCOURSE
Temporary works to enable river working including flow deflection from jumbo sand bags and a silt curtain to retain any silt generated by the operation. Health and safety controls included life vests, buoys and catch lines. These were incorporated following risk assessment in accordance with HSE guidance.
SENSITIVELY WORKING IN SSSI AND SAC WATERCOURSE
Ecological issues included surveys to establish the presence of Nesting birds, Otters, White claw crayfish and fresh water pearl muscles all known to be in the area. All works were carried out under a watching brief and in line with guidance from experienced, local ecologists