Situated about 250 kilometres southeast of Alice Springs, Witjira-Dalhousie is the most northerly group of springs in South Australia. It is a complex of ‘mound’ springs, which means the groundwater flow deposits calcium and other salts from the mineral-rich waters. These deposits, combined with wind-blown sand, mud and accumulated plant debris, settle around the spring outflow forming mounds that resemble small volcanos. Great Artesian Basin groundwater movement rates are slow, between one to five metres per year. As a result some water in the centre of the basin is more that one million years old. Dating techniques that measure groundwater flow reveal that the Witjira-Dalhousie Springs appears to be recharged by thousands of years old water that has percolated down through the beds of Finke River, and adjacent arid zone rivers, where they overlie outcrops of the Great Artesian Basin aquifer. As a geological feature the Witjira-Dalhousie Springs complex is unique in Australia. It illustrates on a huge scale an artesian spring’s system, with faults, impermeable confining beds, aquifer outcrops, mound spring deposits, and the large pools and rivulets of artesian water.
Witjira-Dalhousie Springs NP
Government evidence of impact of climate change:
Australian Government, Australian Heritage Database Great Artesian Basin Springs: Witjira-Dalhousie, Dalhousie ruin via Oodnadatta,SA, Australia
Ecologically GAB artesian springs are considered an evolutionary refuge as they allow wetland dependent (specialised habitat) species to persist as their original geographic range becomes uninhabitable due to drying over an extended period of time because of climatic change.
Government of South Australia, Department of Environment and Heritage Management Plan, Witjira National Park
The increased temperatures associated with climate change also threaten the biodiversity of the Dalhousie Mound Springs complex (and mound springs in general).
The decreased flows in most mound spring groups; due to water extraction from the Great Artesian Basin; is such that mound springs are far more vulnerable to evaporation because of the increased temperatures associated with climate change.
This vulnerability will only heighten with climate change.
Hence; changes in fire regimes and negative impacts of grazing threaten the biodiversity of the Dalhousie Mound Springs complex.