"Salinity Squad" Monitoring Groundwater
Mid Macquarie Landcare and salinity experts join forces to revive groundwater monitoring in the Narromine-Trangie-Warren region.
Capacity building - LEP23-005-MidMac_LLC_BP
The issue
Salinity remains a significant issue across the heavily cleared slopes and plains of Central West NSW, where patches of salt-affected land continue to emerge across the landscape. When saline groundwater rises close to the surface, it can scald the soil - creating bare, often boggy patches where few plants can survive. The resulting decline in soil health means that most crops and native vegetation struggle to grow, reducing both agricultural productivity and ecosystem resilience.
Causes of Rising Groundwater
In the Narromine-Trangie-Warren region, situated in the lower catchment of the Wambuul Macquarie River system, groundwater levels can rise due to a combination of factors:
- Land clearing: With fewer trees to absorb groundwater, the water table can gradually rise.
- Irrigation practices: Leaking irrigation channels, storages, or excessive watering can cause water to infiltrate and raise the groundwater table.
- High rainfall: Extended wet periods can compound the problem, with salinity often appearing years later due to the slow movement of groundwater.
Monitoring Groundwater Levels
Tracking groundwater levels is vital for identifying trends - whether groundwater is rising, falling, or stable - and for taking early action to prevent salinity impacts.
The data is collected from piezometers in the landscape. Piezometers are narrow, drilled holes that go down to underground aquifers. Some piezometers are telemetered - equipped with data loggers that automatically transmit readings online. Most piezometers however are manual, requiring field staff to visit each site, lower a measuring tape until it contacts the water, and record the depth by hand.
A Data Gap in the Region
In the Narromine-Trangie-Warren region, more than a hundred piezometers are installed across the landscape. Yet, aside from a handful of telemetered sites, data from most of these piezometers has not been collected for 17 years. This lack of up-to-date data leaves a major gap in understanding how groundwater, and therefore salinity risk, is changing across the region.
The solution
Enter the "Salinity Squad": Mid Macquarie Landcare has joined forces with soil and hydrogeological experts from Sustainable Soil Management (based in Warren) and the NSW Department of Climate Change, Energy, the Environment and Water (NSW DCCEEW) Salinity Project to start monitoring piezometer data again.
With funding and technical advice from the NSW DCCEEW salinity team, and access to historic data, site locations of all the piezometers, and local salinity knowledge from Sustainable Soil Management, the "Salinity Squad" was ready for action.
Armed with maps, tape measures, and enthusiasm, staff from Mid Macquarie Landcare and Sustainable Soil Management set out on a 294-kilometer journey around the countryside. Over a long but productive day, data from 22 piezometers was collected. While the data is yet to be fully analysed, there appeared to be no significant rise in groundwater levels that indicate a potential salinity risk.
In addition to collecting data, this initial field trip will help with planning and estimated costs involved in collecting data from all the piezometers in the region, so that Mid Macquarie Landcare can seek more funding - ideally to collect data from all the piezometers twice a year.
The impact
With a clearer picture of the region's groundwater now emerging, Mid Macquarie Landcare and our partners are in a stronger position to plan future salinity management and continue expanding the monitoring program. This proactive approach will support early intervention, reducing the likelihood of severe salinity impacts on our landscape and communities in the future.