Northumbrian Water Group
NEC 3 Engineering and Construction Contract (April 2013) Option C
Emergency repairs (145m x 22m) were completed to the river bank due to a 30 inch water main which had become exposed following erosion. The scheme reshaped the river to redirect the flow and protect the water main.
The water main served 100,000 properties and the construction works included:
- Installation of a temporary cofferdam using 700 sand / gravel dumpy bags (1 tonne)
- Fish rescue completed using a specialist supplier with electro fishing equipment
- Significant earthworks carried out including excavating 2.25m below the river bed level to provide suitable foundation for the rock armour wall
- New 320m access road to reach the site area
- Rock armour (1900 tonnes) wall with clay infill (250 tonnes)
- Concrete protection slab constructed over the water main
Permissions were required from the Environment Agency and one of the requirements of being granted permission was the works had to be supervised by a geomorphologist and an aquatic clerk of works. The waster quality was very important and sampling was undertaken 3 times per day to check water turbidity.