Geology, geography & channel form

UMDR straddles the north-south Murrumbidgee fault which divides the high altitude granite country to the west from the low lying volcanic rocks along the river.

The channel is diverse with frequent changes in channel and floodplain geomorphology as the composition of rock, sand, gravel and boulders varies. The river falls 230 m along the 100 km of demonstration reach.

Along the gorges, the channel is narrow, relatively straight and falls rapidly. The water is turbulent.

Where the landscape is more gently sloping, the river meanders across a broad channel. It has steep banks on the outside of the bends and broad sand banks on the inside of bends. High sediment loads have created sand 'slugs’ filling in some of the deep pools. In the slower flowing sections of the reach, the river is commonly shallow with a sandy bed.