Arrow's approach to beneficial use of coal seam water aims to provide it to existing Condamine Alluvium groundwater licence holders.
Instead of pumping groundwater from the Condamine Alluvium, participants will use Arrow’s treated water. This arrangement is called the Condamine Alluvium Substitution Scheme Network.
The scheme is intended to offset potential impacts from drawdown on the Condamine Alluvium aquiferas a result of Arrows coal seam gas (CSG) extraction and maximise the beneficial use of treated coal seam water.
A portion of Arrow’s Surat Basin tenure lies across the Condamine Alluvium, a critical groundwater resource for agriculture.
A direct evaluation of connectivity between the Condamine Alluvium aquifer and the Walloon Coal Measures (Arrow’s target formation), conducted at two sites in 2013 and 2014, in addition to studies undertaken by the Queensland Government’s Office of Groundwater Impact Assessment (OGIA), demonstrated a low potential for groundwater impact from CSG extraction.
Groundwater modelling by OGIA has shown that, while connectivity between the Condamine Alluvium and Walloon Coal Measures is low, the volume of groundwater in the Condamine Alluvium will be slightly reduced because of CSG-related groundwater pumping from the underlying Walloon Coal Measures. The volume that is due to Arrow's activity is estimated at about 58GL over 100 years (or about a tenth of Sydney Harbour's volume). This may change over time, based on the amount of water extracted through CSG production and updated groundwater modelling.
- Ultimately, the amount of water removed from the coal seams during Arrow’s gas production will dictate the amount of water available under the scheme.
- The timing and amount of water available under the scheme also depends on the phasing of Arrow’s development activity across its tenure.
- The EOI has been completed and the formal selection process will commence in April 2022.
- If the formal selection process does not identify enough participants to achieve the full substitution target, Arrow may not proceed with the scheme, and may pursue other offset options.
Expressions of Interest closed 10 September 2021. As there was sufficient interest to achieve the substitution target, Arrow has progressed to the next stage which includes drafting standard agreement terms and undertaking the participant selection process.
All EOI respondents were invited to participate in a Condamine Alluvium Substitution Scheme Agreement Workshop in Dalby on 8 March 2022. The presentation from that workshop can be accessed here.