During construction large stones were used in the wall to save concrete and tram rails were used to reinforce the upper section. The Barossa Reservoir was formed by damming the Yettie Creek gorge in the northern Mount Lofty Ranges, a feat that took over 400 men. Its water comes through a tunnel, carved by horse power, from the South Para River and Reservoir, and is supplemented by the Warren Reservoir and the River Murray. In addition to Gawler and country, a filtration plant constructed in 1982 allows the Reservoir to supply the suburbs of Munno Para and Elizabeth.