Although often used, the term ‘gnamma-hole’ is a tautology; the concept of ‘hole’ is already incorporated in the word ‘gnamma’.
The word ‘gnamma’ is from the Western Desert aboriginal language. Also namma hole from the Nyungar word ‘nama’.
Gnammas are a peculiar type of hole that occur in rock outcrops, particularly granite. They usually have a small opening on the surface of the rock with a larger bowl shaped cavity beneath. They are usually small, holding anything from a few litres to a thousand litres or more, although the larger holes are rare.
They are formed by eons of chemical weathering by water. Some were made by natives.
Gnammas are not a soak; they fill after rain. They were used by aboriginals who often covered them with sticks to prevent access by native animals. This had the bonus of minimizing evaporation. Gnammas were vital to explorers and prospectors and are an important water source for all kinds of fauna.
In Darkest West Australia: A Guide To Out-back Travellers, H.G. Mason wrote:
“In desert spinifex, gnamma holes and soaks may be found in patches of scrub mulga, which occur here and there throughout the interior, generally low-lying formations of granite and desert sandstone, clothed with weeds, silver grass and scattered small narrow-leafed salt bush with occasional quondong and kurrajong trees.”