Is Ngurrara's water safe to drink?

Our old people knew that the taste of water in the desert changes, depending on the time of year. They knew that jumu fill and flood in the wet, then disappear in the dry. They knew that jila don’t disappear, but that the water level sometimes fluctuates.  

These observations are part of our traditional ecological knowledge, or TEK, and they’ve now been corroborated by an important scientific study. 

Steve Bolton, a Senior Hydrogeologist with Rockwater Pty Ltd, has been working closely with Yanunijarra Aboriginal Corporation to gather information for an academic thesis. Steve’s thesis explores the relationship and connectivity between our culturally significant water sites and presents findings on whether the water from jila and jumu is safe to drink. 

All up, Steve worked with Ngurrara Rangers and Traditional Owners for two years, starting in early December 2014. The start date was significant—Steve wanted to make sure his test result data captured the lowest seasonal water fluctuation, before the wet season really kicked into gear. Water was tested for major ions, nutrients and metals at five significant places: Wili, Kurnajarti, Purluwarla, Lumpu Lumpu and Lake Pirnini. Monitoring bores were also installed at Wili, Puluwala and Lumpu Lumpu, with the other water testing trips happening in May 2015, December 2015 and March 2016.  

Based on the results of these tests, Steve found that our jila and jumu are good to drink for most of the year. The only time of the year when the water doesn’t meet the Australian Drinking Water Guidelines for human consumption, is after a long, hot dry, when a lot of water evaporates. At this time, dissolved ions in the water become concentrated, giving the water a salty taste. Concentrations of dissolved metals and nutrients that naturally occur in the water may also become concentrated and exceed health guidelines. Traditionally, we tasted water to determine its quality, and a strange salty taste meant the water was no good to drink. 

Steve also recommended capping the artesian bore at Puluwala Jila. At the moment, the water continually flowing from the bore and evaporating, will eventually cause an increase in salinity at the jila. A cap would allow for the natural groundwater flow system to be restored. 

The other aspect of Steve’s research, was to create hydrogeological models to understand the connectivity between our significant water sites. Steve found that due to faults in the rocks beneath the earth, our groundwater is often split up, or divided. From this information, it’s possible to conclude that there’s not a lot of connectivity between the different jila in the study. 

Steve’s study is the first documentation of the variations in water levels and salinity of our cultural water assets over a set period of time. This is important for us, as we now have a benchmark to measure any impacts from mining, tourism or pastoral activities on our jila and jumu. We have a western study, that complements our traditional knowledge, which we can use for effective management and monitoring of our water. It’s significant that our jila tap one of the largest groundwater resources in Western Australia—The Canning Basin. Ngurrara country extends across the Basin, which holds a whopping 12 million gigalitres of water.

We’d like to thank Steve Bolton for his time and efforts on Ngurrara Country. His study is an important tool for us to understand water in a Western sense so that we can look after Ngurrara country in the decades to come!