Report updates irrigation water availability in the Gascoyne

The Department of Water and Environmental Regulation (DWER) has updated the aquifer status for Gascoyne growers, confirming projected irrigation water availability for 2021.

The department’s Gascoyne River aquifer status update indicates sufficient water to meet irrigation demands in the year ahead.

However, growers are encouraged to consider their water budgets moving into 2021.

DWER mid-west Gascoyne region manager Fleur Coaker said that despite the next few months having the highest probability for a river flow, growers should evaluate their water budgets for the year ahead with the potential of there not being a groundwater recharging river flow even.

“Projections indicate that without a recharge event, the borefield supply would meet irrigation demand but the Subarea A supplies would likely become limited towards the end of the year,” Ms Coaker said.

Average groundwater salinity of Subarea A bores over the last quarter of 2020 was 615mg/L TDS.

Information from the Gascoyne Water Cooperative indicates average salinity of scheme water over the same period was 569mg/L TDS.

Water use tracking by DWER revealed that the volume of water taken from Subarea A was above average over the last three months of 2020.

“We are expecting that the demand from this area will be slightly above average for the first quarter of 2021,” Ms Coaker said.

Last year 5.4GL of water was used from Subarea A (see Table 1 at bottom of page), 5.7GL from the Subarea B southern borefield, and 2.4GL of water from the Subarea B northern borefield.

This does not count the water taken during unrestricted pumping from the Riverbed Sands for two months in early 2020.

“In the coming year we expect for water use to be roughly the same but anticipate greater volumes to be taken from the northern borefield and reduced volumes taken from Subarea A,” Ms Coaker said.

Unrestricted pumping declared for February

A river flow reached Nine Mile Bridge on Friday February 5, 2021.

Unrestricted pumping was declared on February 8 for Carnarvon Sub Area A Licensees.

The declaration applies to all bores and spears screened in the Riverbed Sands in Subarea A, in line with the

Lower Gascoyne water allocation plan 2011.

Water abstracted during this month will continue to be metered but will not count towards a licensee’s annual water entitlement.

MORE INFORMATION

For further information please contact DWER on (08) 9965 7400.

To receive Gascoyne river flow advice email midwestgascoyne@dwer.wa.gov.au. Current river levels across WA are available from the DWER website, https://dwer.wa.gov.au/

TABLE 1. GASCOYNE IRRIGATION WATER USE 2020.

Water resource sub area

Sub area A 6.1

BL-southern borefield 6.0

BL-northern borefield 7.1

2020 production water use Jan–Dec (GL)

Sub area A 5.4

BL-southern borefield A 5.7

BL-northern borefield 2.4