During 2004‐2007, the Gladstone region experienced its driest consecutive 3‐year period on record. Average annual inflows during this period were 29,942MLpa, which represented the lowest consecutive 3‐year inflows and were 43% lower than the driest 3‐year period previously recorded. Before the drought broke in February 2008 the level of Awoonga Dam was at 32.6% of total capacity.
There are two types of droughts (as the term is informally understood) on the rainfall record.
"Short-term" droughts where there was a severe rainfall deficit over periods of up to 12 months and typically with several months with zero rainfall and zero or very low flows in the Boyne River. The worst short-term droughts with annual rainfall less than one half of the annual mean rainfall were in 1941 and 1969.
"Long-term" droughts with a series of very weak wet seasons and subsequently low annual flows in the Boyne River, sometimes (but not always) coinciding with short-term droughts. The long-term droughts on record occurred during 1964–67, 1969–70, 1984–85, 1993–95, and 1997–2003.
The decades of the 1950s and 1970s had relatively high rainfall. GAWB has carefully reviewed experiences from the imposition of water restrictions in 2002 and consulted with customers in setting its approach to managing the impact of drought on the volume of water available for supply.
GAWB will not enter into contractual obligations to sell more water in a year than permitted by the Boyne ROP. The term "drought" can be defined as meaning a period of time where, having regard to predicted inflows, there is insufficient water stored within Lake Awoonga to provide Contracted Supply (which includes meeting customer reservations) some time within the next 60 months as predicted using GAWB's drought model.