# 6 | U-shaped cofferdam | Rivers
Installation parallel to the watercourse or U-shaped cofferdam
This is the preferred installation for riverbank construction and works that only use a section of the river/rivers that cannot be totally blocked.
How to perform the installation? The stages of the Maneuver
- Preparation of the installation area
Remove sharp objects, remove river mud/vase, position rocks or sandbags if the ground is slippery to increase the friction forces, install stops downstream if the current is strong, position the ballast bags upstream for the maneuver, clean the banks of the river. - Preparation on the bank
Unroll the flexible cofferdams, unfold them, and attach them to one another. - Positioning in the river
Pull the pre-attached cofferdams to the desired location keeping the leading edge out of the water.
Position the cofferdam as desired (L or U or diagonally). - Immersion
Immerse the leading edge to the river bed.
Stand on the leading edge until the cofferdam becomes pressurised. - Mooring
Secure the leading edge’ metal rings with stakes to facilitate placement until the flexible cofferdam is pressurized. - Ballast
Weigh down the leading edge with ballast bags or stones taken from the watercourse. - Securing the installation
If the banks are vertical, attach the ends of the removable cofferdam so that they do not fall back into the water. - Drainage of the work area
Start pumping the space to be dewatered.
