Newfoundland and Labrador Hydro (Hydro) will be undertaking extensive rehabilitation work to modernise the dam at the hydroelectric plant in Grand Falls-Windsor over a three year period, starting this month.

The primary work includes the reinforcement of the existing concrete structure and the installation of a new 1 meter high inflatable spillway on the crest of the dam. This work will stabilize the dam, allow greater control for spilling, better assist fish passage, and make ongoing maintenance activities much safer.

The main purpose of the dam is to divert water to the power canal. The dam, which extends across the Exploits River, currently uses timber flashboards to increase pond elevation for additional generation and fish passage. These flashboards need to be replaced often and it is challenging and dangerous work.

The inflatable overflow spillway  – the first of its kind in the province – will replace the flashboards and allows greater spill capacity/control. It is designed to improve the ability to adjust water flows and levels for power production, fish passage and safety reasons.

It will be installed in three sections which can control flows independently along the dam – this will make it easier to control ice and other debris which could impact power generation.

The generation facility at Grand Falls-Windsor is the largest of three hydroelectric facilities on the Exploits system and has an electrical generating capacity of 75 MW for the island grid.

Upgrading the dam is essential in terms of ensuring generation supply and reliable service for customers.

For more information and project updates, please see here.