Northern valley dams’ mixed fortunes in recent rain event

Northern valley dams’ mixed fortunes in recent rain event

22 December 2020

Major northern valley supply dams look likely to receive only minor inflows despite the most recent rain event to cross the region in the previous 24 hours

While widespread heavy falls, including 70-90mm across much of the Namoi/Peel River valleys, followed a similar rain event late last week, only Chaffey Dam and Keepit look set to receive inflows of note.

While the full impact will not be certain for another 24-48 hours, other regional storages including Split Rock on the Upper Namoi, Copeton on the Gwydir and the Barwon-Darling system further north-west will likely only receive very minor inflows.

The rain – which was largely confined to dam catchments in the state’s northern inland and not the southern basin - produced large flows downstream of Chaffey dam, which are likely to bring additional benefit in restoring flows along the Namoi River.

On the Peel River, Chaffey Dam – Tamworth’s major water source – could receive approximately 5000 megalitres of inflow in coming days, potentially lifting the storage from the current 35% of capacity to at least 40% by the weekend.

Keepit Dam on the Lower Namoi has risen one percentage point to 26% and will likely reach 28%, with the possibility of more as good upstream flows on the Macdonald River make their way into the dam storage.

Despite local rain totals of 50-60mm Split Rock Dam looks unlikely to rise beyond, 4.5% of capacity, while Copeton Dam (13.4%) will only receive small inflows despite similar falls in its upstream catchment.

In the Barwon-Darling system little in the way of river flows has been detected, with the exception of localised inflows into town weirs, notably Collarenebri.

WaterNSW had recently met with growers, landholders and communities in regional NSW in preparation for the coming months, with many of the state’s inland northern rivers already ceasing to flow prior to the recent rain events.

Multiple widespread rain events across the northern valleys, are in stark contrast to the southern basin where little rain was received, and the Bureau’s short-term forecast holding little prospect of more.

For more information on WaterNSW storages visit: www.waternsw.com.au

Media contact – Tony Webber 0428 613 478.

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