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Why industrialisation is incompatible with Nullarbor karst
Onshore portion of the Eucla Basin showing the extent of Nullarbor limestones (bright yellow and green) which coincide with the Nullarbor and Hampton biogeographic regions (IBRA). Also shown are reserves, marine parks, pastoral leases, settlements, transcontinental railway, and State border. The proposed 22,000 square kilometre Western Green Energy Hub footprint (red-pink shading) sits atop the central portion of the karst which contains a notably high density of recorded karst features including many highly important and sensitive caves.
Across the entire Nullarbor, more than 13,000 karst features (purple dots) have been recorded during 70 years of exploration by Australian speleologists. Large portions of the limestone remain unexplored for karst features.
The high density of recorded features in the central portion of the karst coincides with concentrated and systematic exploration efforts by speleologists in recent decades (= sampling bias) and thus the apparent lower density of features west, east, and north of the proposed WGEH footprint almost certainly under-represents the true density of features across the Nullarbor. This interpretation is supported by the obvious alignment and clustering of recorded features alongside vehicle tracks and around settlements. Similarly, the high density of features identified in the southwest corner (Mardabilla Plain) is the result of intensive air photo study of this portion of the plain. One conclusion to draw from this map is that large-scale wind and solar industrial developments proposed anywhere on the Nullarbor limestones (bright yellow and green) will almost certainly intersect with, and impact upon, a significantly greater number of karst features than is currently known and recorded.
Across the entire Nullarbor, more than 13,000 karst features (purple dots) have been recorded during 70 years of exploration by Australian speleologists. Large portions of the limestone remain unexplored for karst features.
The high density of recorded features in the central portion of the karst coincides with concentrated and systematic exploration efforts by speleologists in recent decades (= sampling bias) and thus the apparent lower density of features west, east, and north of the proposed WGEH footprint almost certainly under-represents the true density of features across the Nullarbor. This interpretation is supported by the obvious alignment and clustering of recorded features alongside vehicle tracks and around settlements. Similarly, the high density of features identified in the southwest corner (Mardabilla Plain) is the result of intensive air photo study of this portion of the plain. One conclusion to draw from this map is that large-scale wind and solar industrial developments proposed anywhere on the Nullarbor limestones (bright yellow and green) will almost certainly intersect with, and impact upon, a significantly greater number of karst features than is currently known and recorded.
Inside the proposed Western Green Energy Hub development footprint, more than 4,500 karst features have been recorded, including >400 caves, >500 rock holes, >1,900 blowholes, > 1,470 dolines (sink holes).
More than 70 years of systematic exploration and research by cavers and speleologists have documented more than 13,000 karst features and mapped more than 150 kilometres of cave passage to date, however, this is just a fraction of what lies undiscovered beneath the surface of the Nullarbor. Independent scientific estimates of the total number of blow hole caves on the Nullarbor range between ~20,000 and ~100,000 suggesting, conservatively, that between around one-quarter to around one-half of total karst features have been found to date.
The blank areas on the map do not mean there are no caves or karst features present, only that cavers and speleologists have not yet searched these areas.