Burrendong holds back huge volumes after near-record inflows

Burrendong holds back huge volumes after near-record inflows

29 November 2021

Burrendong Dam is holding back huge volumes of water from the Macquarie valley downstream after near-record inflows over three days pushed the dam towards its operating capacity.

The dam is currently safely surcharged beyond the flood mitigation zone (~146%) having received 279 gigalitres (GL) since Friday, during an extraordinary inflow event that peaked at a rate of 220 GL/day on Friday afternoon.

During that period the storage level rose 10 percentage points in less than 24 hours - including a 0.5% rise per hour for 5 hours.

While 279 GL was received into the dam from Friday, releases in that period totalled just 50 GL.

(Burrendong’s 100% full supply level is 1189 GL, while the flood mitigation zone can temporarily capture an additional 500 GL. The minor flood level flow rate at Dubbo is approximately 50 GL/day).

With major tributaries including the Bell, Little and Talbragar Rivers and Coolbaggie Creek increasing river levels in the Macquarie River downstream of Burrendong, holding back large volumes in the dam greatly mitigated the potential flood impact on communities and farmers.

Despite inflows comparable to the highest rates ever received into the dam over Friday and Saturday, releases never approached half the inflow rate, thereby greatly reducing the downstream flood height.

It was not until Sunday when the downstream tributaries had peaked and were receding, that releases were increased to a rate of 35 GL/day, still well below inflows being received into the storage at 53 GL/day. Burrendong has been capturing large volumes of inflow throughout 2021 without making large releases, converting potential flood events into future water security, including in March when the storage rose from 40% to 55%, July-August when the storage rose from 60% to 107% and from 8-27 November when the storage rose from 98% to 146%.

The next meeting of the Macquarie Regional Airspace Reference Panel will be held on Tuesday.

WaterNSW is working closely with the Bureau of Meteorology and the NSW State Emergency Service to monitor weather and inflows.

Find more information on WaterNSW storages or for river heights and flow data visit: WaterInsights

Agency

Information

Website

Bureau of Meteorology (BOM)

Weather forecasts and warnings

BOM

NSW State Emergency Service (SES)

Flooding and severe weather warnings and advice

NSW SES

Loading

96.7
Tuesday 18 January
-0.1
2,497,329 ML
2,581,850 ML
9,342 ML
1,335 ML
-3,171 ML
Tuesday 18 January