Tarraleah No. 1 Canal was originally designed to convey a maximum flow of 25.5 cumecs (900 cusecs) into No. 1 Pond. However due to freeboard constraints in the canal, the design flow rate has only been achieved four times in the history of the canal, when it was first commissioned in 1938, in 1963 and 1977 after extensive clearing and in 1987 after relining.
The aim of the project was to restore some capacity to the canal by installing additional coping blocks and some aluminium sheeting at key locations to ensure minimum freeboard levels are maintained.
The project for Hydro Tasmania included the installation of coping blocks to the existing canal and flume walls to increase the free-board capacity of the flume/canal. A total of 3,500 blocks were installed (400x190x100) on top of the canals and flumes to increase water capacity.