Barrages to protect fresh water in lakes Alexandrina and Albert built from 1935-40 at River Murray mouth

The River Murray mouth barrages spanned the Goolwa, Mundoo, Boundary Creek, Ewe Island and Tauwitchere channels.
Images courtesy South Australian government

Barrages to separate South Australia’s lower lakes, Alexandrina and Albert,  from the Coorong and the River Murray mouth, were built between 1935 and 1940, as part of the works of River Murray Agreement between the federal, New South Wales, Victoria and South Australian governments.

Commonly known as the Goolwa Barrages, they spanned the Goolwa, Mundoo, Boundary Creek, Ewe Island and Tauwitchere channels. The first three structures were intended to regulate the level in Lake Alexandrina with stoplogs in the sluiceway, with the other two closed except during floods or high river.

The designs for the structures were prepared by Engineering and Water Supply Department under former engineer in chiefs J.H.O. Eaton and then Hugh Angwin, and approved by the-then River Murray Commission.

Main purpose of the barrages at the Murray mouth was to maintain the freshness of the River Murray as far downstream as Wellington. They were meant to keep the water level high enough to enable watering by gravitation of areas reclaimed between Mannum and Wellington. They were also to prevent salt water from the sea when the river was low to help maintain the freshness of the water in lakes Alexandrina and Albert to protect agricultural properties on their shores.

The barrages were built away from the sea to minimise the risk of damage during frequent heavy storms along the coast. River Murray barrages were required to withstand pressure from two sides –  preventing salt water getting into the lakes at high tide and at other times retaining the fresh water in the lakes. They were required to allow a flood to pass without raising flood levels in the lower river.

The barrages also were built with the future possibility of a ship canal between Goolwa and Victor Harbour using a Murray port or a river outlet for shipping.