Water is the basis of all life on Earth and is particularly important in the arid Australian Outback. Understanding more about the water resources that are vital to life in the arid zone is the challenge we want to address.
Ultimately all freshwater systems are fed by rain, but that rain might have fallen hundreds or thousands of years ago, or last week.
Groundwater (the water stored beneath the Earth’s surface), is often regarded as ‘out of sight and out of mind’, despite its importance as a permanent source of water in otherwise dry landscapes.
We want to determine the role of groundwater in the persistence of waterholes (and much of the biodiversity) in central Australia.
We also want to know more about the variability of rain events and floods that characterise the arid Outback. How important was the last big rain in sustaining your local river pool?
We can start to answer these and other questions with a citizen science project that aims to collect water samples from sites across central Australia.
This project involves isotopic analysis (which is complex) but the collection of water samples is simple – and the project needs samples from as many sites across the arid zone as possible.
Scientists alone cannot easily collect so many samples – but citizen scientists can! Who are citizen scientists? Anyone who visits a waterhole, collects a water sample in the vial provided, records the location and date, and returns it to us, becomes a citizen scientist on this project.
You can also take a photo of the waterhole and submit it to our website. This will provide extra information that will be useful in recording the different types of waterholes across the arid zone.
The water samples will be analysed in the environmental lab at Charles Darwin University. We will measure the conductivity and stable isotopic composition (d18O and d2H) of each water sample.
The conductivity will indicate how fresh or salty the water is. The stable isotopic composition will provide information on local evaporation rates, humidity, size of rainfall events and the mixing of groundwater and surface water sources.
This information will allow us to understand the relative contributions of groundwater and surface waters in sustaining arid zone springs, rockholes, gorges and river pools.
The collection and analysis of water samples across the MacDonnell Ranges and surrounding areas, and over time, will enable us to create maps that indicate how fresh or salty the waterbodies are, and the relative contributions of groundwater and surface water.
This information will be freely available on the Outback Water Project Facebook page.
Note that we will not be able to determine how contaminated or polluted the water is. This type of information requires a different set of analyses that are beyond the scope of this project.