Fractured rocks

In fractured rock aquifers, groundwater is stored in the fractures, joints, bedding planes and cavities of the rock mass. About 40 per cent of groundwater in Australia is stored in fractured rock aquifers, and much of this may be available for irrigation, town water supplies, stock watering and domestic use.

Approximately 33 per cent of all bores in Australia are in fractured systems, representing about 10 per cent of total extraction. Groundwater yield is extremely variable, and dependent on the distribution of major fractures. However, rates of groundwater movement in fractured rock systems are difficult to quantify.

Characterising groundwater flow in fractured rock aquifers is difficult with existing techniques, and groundwater flow direction can be related more to the orientation of fractures than to the hydraulic head distribution. Recharge in fractured rock aquifers is usually local and intermediate.