Repairs are due to start on Monday at a flood defence which protects properties and farmland in Somerset.
The four-month project aims to improve the river outfall
Contractors were scheduled to begin a £172,000 project to rebuild the Pill River outfall near Minehead.
The Pill drains into Blue Anchor Bay and there is a risk of flooding when high tides meet increased river flows.
A second tunnel will also be built to improve drainage into the bay as part of a four-month project to improve flood protection.
Contractors Van Oord will also replace a defunct debris screen that stops objects washed down the river from causing blockages.