The Queensland Government approved the Upper Condamine Water Supply Scheme in 1961 and Leslie Dam was completed in 1965. The first stage of Leslie Dam was designed to allow the addition of a second stage to provide increased storage capacity.
Following dry summers in 1969 and 1970 the Government approved the construction of Leslie Dam Stage II to increase storage capacity. This second storage was constructed between 1980 and 1986 and serviced water users along the Condamine River as well as providing alternative surface water supplies to irrigators along the North Branch of the Condamine River who had previously relied on groundwater supplies.
Uses of Water
Crops grown in the area include, cotton, sorghum, maize, soybean, sunflower, barley, oats, wheat, canary and lucerne.
Urban Water Supplies
The scheme provides water to the towns of Warwick and Cecil Plains.
Leslie Dam is the main water storage for the Upper Condamine Water Supply Scheme.
The dam is a mass gravity concrete structure.
In 1980 work began on the second stage which consisted of raising the abutments by 2.8 metres, constructing six concrete piers on the spillway crest and installing seven steel radial crest gates on the spillway. The radial gates are each 6.6 metres high, 12.8 metres wide and weigh 34 tonnes.
Completion of the Stage II works doubled the storage capacity of the dam.
To release floodwaters the gates are raised to allow the excess water to pass beneath them. The gate operation is controlled by a computer system which continually monitors the water level of the storage, and adjusts the gate opening to maintain an appropriate release rate.
Releases from the dam are made through two 900 millimetre diameter outlets pipes through the dam wall. Each outlet is fitted with a 900 millimetre upstream guard valve and a 750 millimetre downstream cone dispersion valve.