As interest in developing water resources to expand irrigated agriculture increases, we need to better understand how groundwater abstraction could impact the Fitzroy River and surrounding areas.
The Fitzroy groundwater investigation will help with water allocation planning and provide certainty for water users, Traditional Owners and the environment by providing new, targeted hydrogeological information. All on-ground works are complete, and the final report is now available.
The Fitzroy groundwater investigation is a joint project under the State Groundwater Investigation Program (SGIP), Water for Food, and the Commonwealth funded Northern Australia Water Resource Assessment (NAWRA) program.
What we did during the investigation
During this investigation, we:
- drilled 35 holes and installed 26 groundwater monitoring bores in the Grant-Poole aquifer, Fitzroy alluvium, Fairfield Group, Erskine Sandstone and Noonkanbah Formation
- collected and analysed 75 samples from 61 groundwater bores to understand regional groundwater quality and identify where and how groundwater recharge occurs
- collected 80 water samples along a ~ 300 kilometre stretch of the Fitzroy and Margaret Rivers, from Willare to Margaret Gorge, to assess how surface water and groundwater interacts
- collected groundwater level data from 34 bores to determine how different wet seasons affect groundwater recharge, seasonal groundwater level fluctuation and the surface water groundwater interaction
- completed an airborne electromagnetic survey over 20,000 square kilometres.
Key findings and how we are using the information
We now have a good understanding of:
- where the potential groundwater resources of the Grant-Poole aquifer are
- where the Noonkanbah Formation may prevent or reduce impacts to the Fitzroy River from groundwater abstraction in the Grant-Poole aquifer
- the variable nature of the Fitzroy River alluvium
- where increased groundwater use potentially impacts the Fitzroy River, Margaret River and significant tributaries, or other significant places
- where and when groundwater recharge is highest, indicating most prospective areas
- the times of year for groundwater use with the lowest level of environmental risk.
We will use this information to support groundwater licensing rules and allocation volumes while protecting environmental and social values.
Where to get more details
You can download a summary of the investigation's findings.
Data from monitoring bores installed as part of this investigation are accessible at the Department of Water and Environmental Regulation's Water Information Reporting portal.
All government commissioned airborne geophysical surveys are available via the Department of Mines, Industry Regulation and Safety website and can be downloaded free of charge from 'Geophysical Surveys' in GeoVIEW.WA or from the Geophysical Archive Data Delivery System (GADDS).
Internal technical reports prepared as part of this investigation can be requested by emailing groundwater.info@dwer.wa.gov.au, including:
- Bore Completion Report - Lower Fitzroy Drilling Program 2017, HR393 (Clohessy, 2017).
You can read more about our groundwater investigations by region across Western Australia.
