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Murray-Darling Basin "Flow Tracker"

Northern Rivers Drying and Southern Rivers Rising

By Tony Sharley

Good rains in the headwaters of the River Murray in the recent weeks have sent pulses of water into Hume and Dartmouth Dams. The River Murray above Hume Dam is experiencing its highest flow in 4 months and has triggered releases from Hume Dam to create airspace in anticipation of further rain. High flows in the Kiewa River and Ovens River are flowing direct to the Murray and will help combine with flows in the upper Murray to maintain flows in the mid Murray reaches around 20,000 ML/day for the next month.

Recent releases from Burrinjuck Dam in anticipation of more winter and spring rain have seen the volume in Burrinjuck reduced from 94% full to 89% full and created a pulse of flow down the Murrumbidgee River that reached 32,000 ML/day at Gundagai 3 weeks ago, now travelling down to Balranald and on into the Murray at around 9,000 ML/day.

While storages in the northern basin remain full, flow in the south western Queensland rivers — Paroo and Warrego — has almost ceased due to low rainfall over the past month. A small pulse is moving through the Barwon River in northern NSW that will ensure the Darling River continues flowing and Menindee Lakes remain full over winter.

As River Murray flows of 25,000 ML/day pass through Euston and combine with flows in the Darling at Wentworth, flows into South Australia can be expected to remain around 20,000 ML/day over the next month. Currently, Lake Victoria is receiving inflows around 6,000 ML/day to ensure it is full prior to spring and summer. The strategy to fill Lake Victoria on the recession of the recent floods in preference to during the floods, ensured that the spread of flood water was maximised thus ensuring all wetlands and lakes were filled during the February peak of 93,800 ML/day.

Closer to home, the Lake Merreti wetland complex (see Landsat images) which fills off the Ral Ral Creek anabranch system is now full and slowly drying. Ibis rookeries were established during the floods and the lakes are famous with locals for the cream coloured yabbies they produce. The Lake Merreti complex on Calperum Station comprises Lake Woolpolool, Lake Merreti and Clover Lake. These lakes currently have a water surface area of more than 1,000 hectares and contain significant Black Box and Red Gum communities around their margins. Clover Lake is full for the first time since 1993 as it requires a river flow between 85,000 and 90,000 ML/day to commence filling. Millions of tiny red gums have germinated in the mulch layer deposited at the high water marks around the margins of Lake Merreti and Clover Lake and only time will tell if they can survive the summer period.

The Merreti Lakes complex lies within the Riverland Ramsar Site and is managed by the Australian Landscape Trust. Future water management strategies will be consistent with the new Ramsar Management Plan and will aim to fill the lakes when water is available and allow them to dry when flows are low, just as they did for thousands of years, although trigger points will be in place to ensure that the lakes do not remain dry beyond the tolerance level of the vegetation communities.

During the spring, Lake Merreti and Clover Lake can be expected to hold thousands of waterbirds as new food sources emerge around their shallow margins. Calperum Station is the gateway to the lakes and should be approached to gain access to see this spectacle.

Media Release

16 February

THE PEAK IS HERE

Tony Sharley, Flow On Business

The much awaited flood peak into South Australia arrived at the border last Sunday and flow peaked at 93,900 ML/day. Floodwaters have spread over 70% of the first big floodplains to receive this water at Chowilla Station and Calperum Station above Renmark.

Earlier reports of flow peaks of 85,000 ML/day were correct until massive rains on the 5^th and 6^th February (as high as 100 mm to 200 mm) from the Sunraysia to the Riverland pushed the flow higher.

The new peak has filled all of the major wetlands on Chowilla and Calperum Stations – and more than a thousand wetlands downstream can be expected to top up or fill over the next 2 weeks as the pulse of water makes its way slowly through the Riverland to the lower lakes.

I’ve said it before and its worth emphasising – this is the most significant environmental event to occur on the River Murray in 130 years because it follows the longest dry sequence of years. It’s a medium sized flood covering most of the floodplain including all of the red gum forests and most of the black box woodlands. It’s also risen very slowly and will fall very slowly ensuring that water will be on the floodplains for more than 4 months and that’s good news for plants and for fish, waterbirds, frogs and reptiles who will all complete their breeding cycles, and in the case of waterbirds – more than once.

The significance of this flood is also due to its energy – it is big enough to flush accumulated salts, silt, and sediments out to sea which will improve many of the in-stream river habitats for native fish. The downside — and it’s only a small downside — is the massive load of leaves and organic matter accumulated on the floodplains over 15 years – which has deoxygenated the water as it decomposes and releases tannin into the water. There have been a few victims – several Murray Cod and callop have died in the deoxygenated water and yabbies and shrimps too have died or surfaced to breathe some oxygen. But most will survive as they have done over the millennia.

It is anticipated that the black water will pass though South Australia in 2 to 3 weeks time.

DarlingMurrayIOJimage001 (1).jpg

The mixing of muddy water in the Darling River is helping to dilute the black water in the Murray River at Wentworth. Photo courtesy of Ian Oswald Jacobs Aerial Photography.

Flood flows generated in Queensland 4 and 6 weeks ago are peaking in the Darling River at Bourke — and creating a massive waterbird breeding event in the Narran Lakes above.

A point worth making — the recent drought and long sequence of non-flood years has been so severe on wetlands and floodplains that its impact will not be completely repaired by this flood — however, without the significant investment in research and active management by the Murray Darling Basin Authority, SA MDB NRM Board, several Government agencies, Local Action Planning Groups and landowners to save red gums and aquatic animals by improving flow and pumping water into severely stressed wetlands in the past decade — the recovery we see today would not have been possible.

So it’s really good news all round and we should be celebrating.

Heavy rains in the headwaters of the Murray River last weekend have created new flow peaks in the Ovens and Goulburn Rivers — and pushed Hume Dam to almost full again as well as creating the first major increase in storage level in Dartmouth Dam in the past 2 months.

Heavy rains in the headwaters of the River Murray are filling storages and sending new flood flows down the Ovens and Goulburn Rivers.

These inflows together with the continuing inflows from the Darling River will ensure that the flows into South Australia will recede very slowly. It is estimated that the flows will remain above 50,000 ML/day for another 4 to 6 weeks — making this the most perfect time for people to come and see the benefits of a high river in the lead up to Easter.

This is also great news for irrigators as it is rare to see such full storages in the middle of summer. The turnaround in flows and increased storage capacity should provide confidence for everyone anticipating a much better water year in 2011/12.

An opportunity has been created — a get out of jail card has been dealt — our river is alive again and we are optimistic — so let’s learn from the last 15 years to ensure our river and our communities cope better with the next dry sequence.

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Friday, 21 January 2011

MURRAY-DARLING BASIN WATER FLOWS NOW EASIER

TO TRACK IN AUSTRALIAN “FIRST” INITIATIVE

Crucial water flows throughout the entire Murray Darling Basin can now be tracked more accurately and easily by an Australian-first initiative officially launched today.

“Flow Tracker” is the brainchild of former Murray Darling Basin environmental scientist and former Banrock Station Wines manager, Tony Sharley, who identified a need to track – via a single map – river flows in the major rivers of the Basin that have been in flood over the past year.

His approach collates a host of information on river flows at different collection spots housed on several State-based websites — and compiling it all into a single map that shows where rivers are flooding in the Basin at a single point in time.

The map can be updated as frequently as required to show how far floodwaters have moved downstream.

Information available from Mr Sharley’s initiative is expected to be an invaluable source of data to hundreds of rural river based businesses, residents, governments and local councils that rely on the many rivers and waterways of the Basin’s one million square kilometres catchment area.

“The Murray Darling Basin Flow Tracker has been designed to make it easy for people to track flows along the many river systems that make up the Basin, through four states on its way towards the Murray mouth about 2000 kilometres downstream from its original source,” said Mr Sharley, who owns environmental consultancy business, Flow On Business, at Renmark, in South Australia’s Riverland.

“When I first started investigating the recent flood flows I wanted to gain a sense of how much water was on its way to South Australia, following our longest low flow period on record — and soon realised that the data was not available from any one single source,” he said.

“It was a bit like having different rail gauges in different states – and I wanted to compare flows in rivers in different states and all on the one map.

“Flow Tracker has already created enormous interest in the Riverland community, but I believe many different businesses and people, for many different reasons, throughout the Basin region will get great benefit from using Flow Tracker.

“All of the rivers in the Basin are connected – and the further downstream you live in the Basin, the more rivers you have above you — so the ability to see how much water is coming downstream towards us will enable communities to be better prepared for any flood threats or opportunities, such as increased diversions for environmental purposes.

“I believe Flow Tracker is another important form of reporting the weather, and as such, can help people take whatever action is required if large flood flows are heading their way.”

Mr Sharley said it was almost impossible, from any one location, to determine where the heavy rains and flood flows are in the Basin’s rivers, which drain over a million square kilometres and help maintain many environmental assets and play a major role in the economy of the Basin, which covers four states, as well as the Australian Capital Territory.

“Water politics” and the highly topical Draft Basin Plan have sparked much interest and debate – if not controversy - in the Basin’s rivers and how much water is flowing in them, he said.

However, Mr Sharley said many people were not aware that these river systems are all connected - especially people who live in capital cities, which are all outside the Basin area.

“For example, the current floodwaters in the Condamine Balonne Rivers in Queensland are a product of the late December rains that generated flooding in Rockhampton followed by the mid January rains that devastated Brisbane – some 400 kilometres away,” he said.

“The mid-January rains on the western side of the Great Dividing Range has fuelled the Condamine-Balonne rivers in the northern Murray Darling Basin, and sent a massive pulse of floodwater inland through the towns of Warwick, Condamine, Surat and St George, and on downstream where it will eventually join the Darling River above Bourke in New South Wales.

“The October, November and December 2010 rains in Victoria generated massive flooding in the Victorian rivers that drain to the Murray and completely filled Hume Dam which was only 21% full in July.

“Heavy December rains in New South Wales created major floods in the Murrumbidgee River at Wagga Wagga and in one of its tributaries — the Queanbeyan River upstream of Canberra. Further north the same rain events caused flooding in the Bogan River and the Castlereagh River, and in the Macquarie Rivers which created a major flood in Dubbo.

“All of the Victorian, NSW and Queensland floodwaters are driving the high river in South Australia at present, and will ensure high water levels are maintained along the Murray in SA for several months.

“People are genuinely interested in whether South Australia may experience the same flood levels we saw in 1956 - the largest on record – which were created by flooding in the Darling River and Murray River catchments, which all arrived at the same time, where the two rivers meet at Wentworth, in New South Wales.

“Flow Tracker creates an opportunity to see how much water is in each of the Basin’s major rivers at a point in time and can be updated weekly or fortnightly depending on weather events.”

For more information, contact Flow On Business on (08) 8595 8151 or email tsharley2@gmail.com

Latest update from Flow On Business

10 February 2012 (see below to compare this with previous updates)

(To download a pdf version, click here)