LakesNeedWater

Historical Science c. 2000

2011-11-18T19:26:00.001-08:00

How scientific advice can change after 11 years, a millenium drought and a change in political parties.

Eleven years ago, the best available science, was telling us the Lower Lakes and Coorong were not in the best of condition. In addition to acknowledging lower river flows from upstream, the barrages were also acknowledged as causing environmental harm.

The Murray River Barrages Environmental Flows Report (1.7 MB pdf) wasproduced for the Murray-Darling Basin Commission in 2000. The scientific panel’spurpose was to provide guidance to the Commission.

In this report, under ‘LongTerm Changes’:

"Considerremoval of present barrages and investigate options for new structures atWellington or Pt Sturt. This would greatly enlarge the estuary and returnit to its historical form. More information onhydrology, geomorphology and biology of the system is needed beforethis major change could be implemented." (pg 64)

A few more excerptsbelow are from the report and clearly acknowledge that the Lower Lakes wereonce part of a much larger estuary that included the Coorong.

Key Issues: (pg 10)

"TheScientific panel identified four key issues driving the seriousdegradation of environmental values in the Lower Lakes and Coorong. Theseare:

   • the reduced area of the estuary
   • changed water regimes of the lakes and river
   • freshening of brackish and saline habitats
   • reduced habitat for aquatic plants

The first two issues are the most significant in terms of their impactand their influence in driving the other key issues."

From page 43:

The barrages havecontributed to the silting of the Murray Mouth.

"The reductionin the size of the estuary has reduced the size of the tidal prism byaround 90% of its original pre-barrage size. In 1914 the lake areaaffected by tides was 97.3 km2 (75 000 hectares), with a springtidal prism of 20 000 ML (Walker 1990). These figures indicate thatthe original tidal prism produced a twice-daily exchange of similarmagnitude to the flows of 20 000 ML/day for a month or more which would nowbe required to substantially clear the mouth of accumulated deposition(Harvey 1988)."

From ‘Opportunitiesfor Improvement” (pg 44)

Options forrehabilitation measures to address the key geomorphological issues - LongTerm

"Enlarge the diversity of habitat in the estuary by increasing thesize of the tidal prism and the flushing effects of tides at the mouth. Anoption for management is to relocate the barrage system to Wellingtonor to Pt Sturt–Pt McLeay."

From ‘Ecological Needs:’ (pg 62)

"The changesin water regime and the presence of the barrages have both led to areduced extent of the estuarine system, now approximately 11% of theformer area (Bourman ibid). Along with the changes, there has been anincrease in the extent of the freshwater environment behind the barragesand an increase in the spatial and temporal occurrence of hypermarineconditions in the Southern Lagoon. There has been theestablishment of unvarying marine salinities for long periods inthe remnant estuary when the barrages are closed. Clearly, managementof the region needs to enhance the environment for estuarinemacro-invertebrates and for estuarine-marine fish."

The underlying facts about the sustainability of the Lower Lakes and Coorong have not changed in eleven years, so why is no one considering the impact of the barrages?

Goolwa Barrage Construction c .1937

Dolphin at Tailem Bend

2011-11-09T02:23:00.000-08:00

What of the legend that there was a sighting of a 'dolphin as far as Murray Bridge'? Is it fact or fiction?

We do know that dolphins used to visit Goolwa, at least before the barrages were constructed in 1940.
In an interview for Alexandrina Council Oral History Archive, the late Bert Lundstrom describes what Goolwa was like before the barrages and about the dolphins near the Goolwa wharf.

“Across from the ferry, there were dolphins there. Big old fisherman used to put nets out there and catch mulloway. A lot of the tidal waters, a lot of these places are now dry, especially down on South Lakes, and out there. “

Dolphins are known to follow big schools of mulloway into an estuary. We know now that the barrages decimated the mulloway fishery.
In another oral history interview, this one from Jim Marsh, Barrage Superintendent, in 1999.

“You’ve got fresh water coming down - it pushes the sea water out and everything’s hunky dory, but if you get a dry year and the river doesn’t flow, then the tides push the sea water in, and , as in 1915 it was a bad drought year, the sea water penetrated up to Mannum - they were catching mullet at Mannum, and there was a sighting of a shark at Tailem Bend, and a dolphin at Murray Bridge...”.

The earliest recorded siting of dolphins or porpoises is in this1902 article.

DOLPHINS ON THE LAKES

November 18, 1902 The Advertiser
Meningie

Great excitement was caused here this morning by the report that a shark had been seen in Lake Albert. A number of townspeople turned out with guns and rifles to dispatch the intruder. After a little chase two large creatures were captured, and proved to be dolphins, the largest being 10 ft. long.

And another report in 1914:

PORPOISE IN LAKE ALEXANDRINA

Saturday, May 2, 1914 The Advertiser

A correspondent writes:-"Woolfitt Bros, of Milang, caught a large porpoise in the lake on Friday. It was 7 ft. long, and weighed 170 lb. It is the first porpoise caught in Lake Alexandrina."

Below is a historical photo of a porpoise at Tailem Bend in 1927. Could this be where the 'dolphin at Murray Bridge' legend comes from?

Schoolboys standing around a large dead porpoise caught at Tailem Bend, 27th August 1927

The caption for the photo from the State Library of South Australia:

“In his reminiscences of growing up and working as a fisherman on the River Murray, Doug Hattam recalled how during a period of drought in 1926, the waters of the Murray became saline as far upstream as Murray Bridge. Before the barrages were built between 1935 and 1940, saltwater could reach as far upstream as 250 kilometres from the Murray Mouth, and river levels could fluctuate considerably. In 1926, two porpoises were found to be living in the salty water around the Tailem Bend area. The porpoises lived there for several months, until the freshwater returned. One of them died at Tailem Bend before it was able to return to the sea. It was common to refer to the creatures as 'porpoises', but it is now thought that they could have been a variety of pygmy whale.”

Let’s hope the other porpoise got away. Unfortunately we know that the one in the photo did not make it back to sea.

PORPOISE AT TAILEM BEND

Tuesday, August 30, 1927 The Register

Writing on Saturday, our Tailem Bend correspondent said:— For the past week a porpoise had been attracting much attention by hovering around the vicinity of the ferry at Tailem Bend. It was the first time that such a visitor had been seen about these parts. This morning Mr. P. J. Tiller went out in a boat with Mr. A. E. Temby (ferryman), and harpooned the porpoise with a pitchfork. It was then towed in, and is now on view in front of the ferryman's residence. Mr. Temby, who measured the porpoise, stated that is (sic) was exactly 8 ft. It is believed that the fresh water coming down made the mammal unable to see, and also confused it, as it appeared to be unable to dive, thus accounting for its easy capture, which was impossible several days ago, when there was plenty of salt water here.

Perhaps this unfortunate porpoise was part of a group seen two weeks earlier near Wellington.

STRANGE SCENE IN THE MURRAY

Tuesday, August 16, 1927 The Register

Speaking from Mr. G. MacFarlane's Brinkley Station on Monday night. Mr. P. Cudmore stated that an aboriginal fisherman observed a school of seven porpoises proceeding up the River Murray on Sunday morning. They presented a unique sight, sporting in the water. The strange visitors went upstream toward Wellington Lodge, and returned during the afternoon. Mr. A. MacFarlane of Wellington Lodge, said he had never previously seen porpoises enter Lake Alexandrina, nor had any of the natives seen them in the river before. Many hundreds of pelicans which were fishing in the river promptly left the water on the arrival of the porpoises.

Side Effects Of No Tides

2011-09-29T01:23:00.000-07:00

Lowlying land of Hindmarsh Island 2011
Surrounded by elevated levels of fresh water since 1940

The main purpose of the 7.6 km of barrages across the River Murray Estuary in South Australia has been to keep the Lakes fresh year round for agriculture and prevent seawater from entering the Lower Lakes.

We know now that seawater enters the Lower Lakes even when there is a high flow of freshwater coming down the river. This was observed this year by monitoring the EC readings on numerous telemetry beacons around Lake Alexandrina and the Goolwa Channel during storm and high tide events.

Is it possible that the Goolwa Barrages are not doing the job the engineers in 1930 designed them for? And that the side effects of the barrages are being felt after 70 years of operation?

One side effect is the ongoing issue of salt build up in the Lakes. The other issue is when there is not enough freshwater available to keep the Lakes full, they dry down to below sea level exposing acid sulphate soils.

In the 1904 Letter to the Editor below, Mr. Thomas Dodd points out the fact that any barrage will not be able to stop the sea completely, and any barrage will also have the side effect of retaining the sea water in the Lakes on low tides, not allowing the sea water and salts to escape. And while the barrages that were eventually built are much taller than the ones Mr. Dodd is writing about here, we have been getting seawater intrusions (also referred to as seawater backflow events ) during storm and high tide events.

The Dodd brothers, Thomas and James Dodd, originally from Norfolk Island, established a horse breeding and beef operation near Lake Albert. They purchased 4000 acres in 1866 and named their station ‘Lallawa’. For years Thomas Dodd opposed the construction of the barrages based on the 1903 plan and wrote numerous letters to the editor.

Those letters Thomas Dodd wrote are below and can also be found at the National Library of Australia, Trove website.
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THE RIVER QUESTON. (1904, September 8). The Register

To the Editor

Sir— Reading your explanation of the Murray Barrage Bill, I notice the settlers and landowners on the lower river are to be rated to pay interest on the cost of the river improvements, so that the river may be kept navigable all the year round. I am certain that anything in the form of barrages near the Murray Mouth, instead of being an advantage to landowners on the Lower Murray and round the lakes, will be a decided injury.

It will not be an improvement, to those properties, for if a high river has an obstruction to the out flow it will submerge all lowlying lands, and no barrage that can be constructed to prevent the lowlying lands from being flooded will keep out the high tides in rough weather with westerly winds; and if saltwater gets over the barrage the same will prevent the saltwater from flowing out at low tide levels, as it does now without that obstruction. A barrage as proposed will mean that all lowlying lands will be submerged or a continual salt lake. If Parliament is a friend to the lower settlers it will leave the lower river as Nature formed it, and pay attention to the upper parts by constructing locks where the banks are higher and the river narrower.

Most of the settlers round the lakes and in the lower river have supplied their stock with water from wells and waterholes, and nothing that can be constructed at the Murray Mouth will grow a blade of grass more than is grown at present, but will prevent owners from using their lowlying properties, as they will be under water, and what food is now grown on it destroyed by the floods, while, the owners will be rated to pay for the destruction of their own properties, for which they have paid the Government.

I am, Sir. & THOMAS DODD
………

Previous to the above letter, Mr. Thomas Dodd had written several letters to the Editor explaining in detail the effects of the tides upon his lowlying land near Lake Albert and Hindmarsh Island.

NOTES AND QUERIES (1903, September 5). The Register

Mr. Thomas Dodd writes: “Since I wrote my last letter on the Murray Mouth barrages I have made further enquiries from my son about the rise of spring tides, accompanied by strong south-west winds, which often occur at Ihe Murray Mouth. He reports that such tides raise the water fully 4 ft. at the Mundoo Jetty; so with a 2 ft. 6 hi. barrage plenty of sea water would flow into the lake, most likely monthly, which would cause tbe lake to become salt, as the barrage would stop the salt water from going out to sea again to the level of the barrages. Another thing, in good river seasons the river levels at Morgan and Overland Corner are reported to be from 6 to 8 ft. higher than the present levels in those places. So what would become of that high water if the lakes were raised the 2 ft. 6 in., as these barrages are designed to do? It would put the embankments of Morphett Brothers, Jervois, and others under water, and all the flats on the river, cover up all Mundoo Island, lots of Hindmarsh Island, and all the low-lying lands around the lakes. I respectfully submit these facts to the public, members of Parliament, and the Government before this proposed expensive experiment is undertaken.”

NOTES AND QUERIES. (1903, September 19). The Register

Mr. Thomas Dodd writes:

“I notice with pleasure that a petition has been presented to Parliament against the Murray Mouth barrage, and that Mr. McDonald has asked if a modified barrage could not be erected. Even the first proposed would not keep out the sea water at high spring tides. The river now at Mundoo Island is pure; but with the high tide and high wind, although the river is 18 in above summer level, this tide comes up the Mundoo channel and makes it as salt as the sea. If any obstruction were erected all these channels and the lake would be continually salt, or the fresh water could not force the salt water back again only to the level of the barrage, while with the higher fresh water the salt water would go back to low tide level."

________________________________________________________________________________

A Diverse Land, A history of the Lower Murray, Lakes and Coorong, by Rob Linn, published by Meningie Historical Society 1988, pg.125-126.

NOTES AND QUERIES. (1903, September 5). The Register(Adelaide, SA : 1901 - 1929), p. 8. Retrieved September 24, 2011, from http://nla.gov.au/nla.news-article60006754

THE RIVER QUESTON. (1904, September 8). The Register(Adelaide, SA : 1901 - 1929), p. 10. Retrieved September 24, 2011, from http://nla.gov.au/nla.news-article57353057

NOTES AND QUERIES. (1903, September 19). The Register (Adelaide, SA : 1901 - 1929), p. 4. Retrieved September 24, 2011, from http://nla.gov.au/nla.news-article60001704

Local Opinion on the Barrage

2011-09-21T21:49:00.000-07:00

Farm buildings on Mundoo Island 2011

Local opinion varied as to whether the barrages would be a benefit or a curse.

The article below from The Advertiser on July 26 1933, carries the opinions of several 'old river settlers'.

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LOCAL OPINION ONBARRAGE

How Mouth Of River Changes

INUNDATION FEARED

By Our TravellingStaff Representative

GOOLWA, July 26 1933

Opinions conflict asto the efficacy of the proposed barrage at the Murray mouth. Someresidents hail the scheme as an excellent idea; others fear what willhappen when the engineers begin to interfere with the course of thestream at the mouth.

I spoke to several oldriver settlers today and, of course, detected signs of self-intereston both sides. "If the river can be kept fresh without inundating ourlowlying country, we will be satisfied." said one man. "If the Governmenthas money for this work, it might as well spend it here," said others.Nobody sets himself up as an authority on the proposal, although thislay opinion, formed after years of experience, is worth respect.

Mr. Walter Grundy saidthat the late John Probert had told him that he had seen the riversalt for six or seven months of the year, long before the locks wereconstructed and the big pumping stations were installed.

Shifting Murray Mouth

Mr. Grundy took me tothe Murray Mouth and pointed out the every varying course of the stream. Ahut erected originally on the Coorong side of the sandhills near themouth is now on the sea front, sand having drifted. A water holewhich 20 years ago was on Mundoo Island, is now 200 yards away on theother side of the river. "Nobody can tell what will happen when engineersstart to interfere with Nature here," Mr. Grundy declared."There are five channels where the water gets away, and if theyare blocked some thing must happen elsewhere."

Properties onHindmarsh and Mundoo Islands, in which Mr. Grundy and his sons areinterested, include 3,000 to 4,000 acres of samphire and grass country.They said that they would welcome fresh water if it could be providedwithout flooding their low lying land for too long. The water, despitewhat the report said, would immerse both the samphire flats and grasslands, because each was almost on the same level.

Describing the schemeas an excellent one, Mr. E. B. Rankine, of Hindmarsh Island, said that theMurray Mouth adjusted itself to what Nature intended. It was twice as widein flood times as when there was not much water going through it. Assoon as a barrage was erected and the streams blocked, the mouthwould partially close up. That discounted the theory that the land wouldbe swamped by salt water.

Another Site Advocated

Mr. W. Sumner, who hasspent 50 years on the River Murray, said that the general opinion wasthat the barrage should be erected from Point McLeay to Point Sturt. He hadbeen round the island in this vicinity hundreds of times and he doubtedthe success of the proposed barrage near the mouth of the river because ofthe uncertainty of its holding.

Mr. Sumner said thatbream could be caught almost daily near Goolwa at one time and saltwater was such a rare occurrence that when it did come up, residentspassed the word round to go down to the stream to see the sick breamaffected by it. When he had been engaged in snagging, further up theriver when the stream was at low level, he had been surprised at the numberof springs from which salt water flowed from the banks.

Mr. John McBeath hasbeen on Hindmarsh Island for 70 years, and he welcomes the proposedbarrages. "I think we want them." he said.

"Onebetween Point McLeay and Point Sturt," I suggested.

"No," heanswered. "Have it down here or else we will not get any fresh waterat all. “

Mr. D. W. Merrett, thepunt master here who has had a lifelong experience en the Murray,also declared that the scheme would make a big improvement to thelower end of the river. "If the barrages were built." he said,"we would get fresh water for nine months of the year. It is notthe down water but the up tide that will trouble the barrage. If youhave not the river to rush the water up into the lakes, it will takea tremendously high barrage to hold the sea water back, especially whenwe get a strong south-westerly blow.

Great SuccessPredicted

"I think thescheme will be a great success," said Captain E. H. Dodd. who hasbeen actively associated with the river for more than 40 years. He said thathe was satisfied that the barrage system would keep the stream constantly atnormal height.

"The only thing Iam doubtful about is the foundation of the barrage," he said,"but I think that after their experience with locks the engineers know whatthey are talking about."

Captain Dodd addedthat he had owned land on the Lakes. When the river fell the wells wentlow and salt water from the soaks flowed into theLakes. If under the newscheme, the level of the lakes was kept high, this flow of salt waterwould be checked and the supply of fresh water in the wells would"always remain at normal. It was a mistaken idea to think that thebarrage would cause flooding of the low-lying ground."

LOCAL OPINION ON BARRAGE. (1933, July 27). TheAdvertiser(Adelaide, SA : 1931 - 1954), p. 10. Retrieved September 22,2011, from http://nla.gov.au/nla.news-article46990266

Keeping the Murray Mouth open

2011-09-15T18:51:00.000-07:00

The silting of theMurray Mouth and attempts to keep the mouth open go back to the early days ofSouth Australian settlement. Many reportsclaim that the first time the Murray Mouth closed was in 1981. However, newspaper articles show that the silting overof the Murray Mouth was also a concern back in 1908.

Below is a story by a Mr. Molineux who felt it was his obligation tofuture generations to bring to the attention of the local authorities that theoverstocking of sheep and cattle on the fragile Coorong sandhills causederosion thus contributing to the silting over of the Murray Mouth in 1908.

Mr. Molineux, someone has taken note, this oneis for you.

Albert Molineux, c.1890
Photo from the State Library SA

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RUIN NEAR THE MOUTH
The Register, June 11, 1908

'Any business,gentlemen?' asked the Chairman of the Advisory Board of Agriculture ofmembers on Wednesday afternoon.

'Yes, sir,' said Mr.A. Molineux. 'I have just come from the Coorong, and it is about time somearrangement was made to put, a stop to the wholesale silting up of the MurrayMouth.’

'There have been serious removalsof sand from the hummocks at the mouth. The position is really dreadful.There were two great hills, I suppose; as big as this building (theExhibition Building), both carried away completely into the Murray Riverat the mouth. A few days ago it was possible to walk across the Murrayfrom the Hummocks to Hindmarsh Island and across the other side beyond the MundooChannel, without getting wet above the knees. Since then narrow channelshave been naturally scoured through, and there is a much greater depth inthem. But, the sea has been breaking through at various places forfour miles on this side of the Murray Mouth.'

'Soon, I am convinced, thosehummocks will be washed into the Murray, and instead of having therivermouth with a navigable channel for boats, we shall have a four-mileshallow shoal over which about a foot of water may flow. All thehummocks within four odd miles of the mouth will be gone. On the furtherside of the mouth great ridges of sand, hundreds of yards long andseveral feet in depth, are falling down from the cliffs into the water. Whenthe Coorong is filled up by the Murray there will be a great flat stretch, over which the sand will blow on to the pasture lands behind. They, willbe ruined.'

'Some time ago therewas one long ridge from the mouth of the river to 40 miles southwards. Thiswas known as 'The Sandhill.' It was covered by vegetation, and affordedsustenance for cattle and sheep. But the sheep cut up the loose soil, andfurther disturbed it by pulling out the close-cropped herbage, and asad denudation came about...'

Mr. J. Miller,asked ‘How about the rabbits?'

‘Rabbits be hanged. Itwas the sheep! with their sharp hoofs. ‘ said Mr. Molineux.

Mr. Miller refuted, 'But the rabbits dig burrows.'

‘So do worms and beetles. It was thesheep and careless stocking, and the omission to properly plant marramgrass that lost to the people these bulwarks along the shiftingcoast. It is all of no interest to me; I shall be dead by the time the damageis complete. But I thought that the people who are to come would like to knowthat there was at least one person who took note of the growing ruin.'

Mr. Molineux'sstory aroused little other comment than that marram grass could yet save theCoorong and the country behind.

________________________________________________________________

RUIN NEAR THE MURRAY MOUTH. (1908, June11). The Register (Adelaide, SA : 1901 - 1929), p. 4.Retrieved September 16, 2011, from http://nla.gov.au/nla.news-article56868797

COORONG SAND-DRIFT. (1908, October 15). TheAdvertiser(Adelaide, SA : 1889 - 1931), p. 11. Retrieved September 16,2011, from http://nla.gov.au/nla.news-article5193537

Will Barrage Benefit Blockers?

2011-09-14T06:04:00.000-07:00

It’s 1933, the Public Works Committee is taking evidence from community members. Opinions over the issue of the barrages isdivided between lakefront landowners and others with competing interests.

Dairy farmers, settlerswith lakefront properties, landowners with large properties have much to gain from Lakes that have year round fresh water.

Other South Australiansettlers, like fishermen, prosper when estuarine fish are plentiful, working with thetidal influences of the sea upon the lakes. They expect the Lakes to be ‘salt’for a few months each year, and benefit from the bounty the tides bring. Local rainfall provides more than enoughfreshwater for household needs and they have no need to use the Lakes as freshwater reservoirs. They live within the constraints of the natural environment.

Lucky not to be a cod or mulloway

The Lower Lakes are 'artificially raised' by nearly a metre because of the barrages. That means to keep them 'healthy' and 'fresh' an extra metre of freshwater is required over the entire natural surface of Lake Alexandrina. The current shoreline of Lake Alexandrina is above the natural level. A lake level of +.85 metre AHD is the goal of the current water regime, enough to provide for the evaporation of water over summer.

Is removing salinty fromthe Lakes an issue when you are a fishermen, fishing for estuarinespecies? Or is salinity only an issuewhen you are trying to maximize the profits of a dairyfarming, cropping or cattle operation.

Below is the original articlefrom the 27th of July, 1933 Advertiser newspaper explaining the opinons of local Milang basedfishermen about the future barrages and what they think it will do to their livelihood.

They predict the Murray Mouth will silt up as a result of the barrages, they question the efficacy of using freshwater to dilute salt, and they point out how the reclamation of Lower Murray swamp lands have destroyed the cod fishery.

With hindsight, we can add the decimation of the mulloway fishery to their predictions.

__________________________________________

WILL BARRAGE BENEFIT BLOCKERS?

Scheme Denounced By Milang Pioneer

'WILL SWAMP LAND'

By Our Travelling Staff Representative

MILANG, July 27, 1933

Contending that the proposed Murray barragescheme will not benefit settlers higher up the river, that low-lying countrywill be flooded and that the livelihood of many licensed fishermen betweenTailem Bend and Goolwa will be jeopardised, the Woodrow brothers of thistown strongly oppose it.

We can assume that 40 years' practical experience onthe river enables Mr. Jim Woodrow to speak with authority. "Thereport is somewhat contradictory,' he said today. "It gives thesummer level as 106.80 ft., and the proposal is to raise it 2 ft. 9in. above that. If that were done, the low-lying country round LakeAlexandrina would be submerged. We are of opinion that after the barragesare erected, the Murray mouth will silt up to an extent that when a higherriver comes down, there will not be an opening for water to get away, andflood levels will be higher than they have ever been known before. Further more,the only inlet for the incoming tide will be the Coorong. At present, whenwe get heavy westerly gales, especially in winter, sea water runs in tothe Goolwa and Tauwichere channels, at the rate of four to five miles an hour.What will happen when the other channels are blocked, so that sea water hasto go up the Coorong is hard to estimate."

Mr. Woodrow foresaw trouble in the event of aflood coming down and reaching its crest about October, when thestrong westerly winds and high tides were common. If water could not get throughthe barrage, all swamps along the river to Murray Bridge would be underwater in a few hours. He had seen an attempt made to remove a portion ofthe barrage at No. 3 Lock at flood time, but without success.

Removing Salinity

"The scheme is to deal with the salinity of thewater to safeguard dairymen and blockers." Mr. Woodrow said. "Frommy experience, the more they irrigate the more salt the water be comes,because of the seepage into the river. I worked on the construction at No.3 Lock when the river was low, and the water was so salt that blockerswere unable to irrigate. To reduce salinity, they released a millionacre-feet of water from Lake Victoria. That raised the river lockabout 6 ft, and irrigation was possible. What became of the saline waterin the river before they released this storage water? There is only oneanswer; it must flow down, to the lower reaches of the river into thelakes and out to sea. I further maintain that difficulty arises asmuch in the river as it does from the encroaching sea water, whichonly effects the lake in the river as far as Tailem Bend.''

Cod Will Not Return

Several Goolwa residents affirmed that as aresult of the scheme Murray cod would return to Lake Alexandrina, butMr. Woodrow challenged this theory. "They can do what they like, butthey will never get fresh water here." he said. They cannot stopsaline water coming down the river in the summer months. The codneeds fresh water to thrive, but it can live in slightly brackish water,if it comes in gradually. Thirty years ago, before the swamps werereclaimed, Murray cod was very plentiful along the river and in both lakes.Reclamation has robbed the fish of its main feeding and breeding grounds,and during the abnormally low river in 1914 fish died in tens of thousandsthrough nothing else but saline water." Mr. Woodrow added that the Adelaidefish market had long ceased to consider Murray cod as a commercial fish,because of its scarcity. That going to market now was mainly callop.

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WILL BARRAGE BENEFIT BLOCKERS?. (1933, July 28). The Advertiser (Adelaide, SA : 1931 - 1954), p. 23. Retrieved September 30, 2011, from http://nla.gov.au/nla.news-article74025373

1941 One year after

2011-09-06T21:46:00.000-07:00

One year after the barrages were completed a newspaper article in the Adelaide Advertiser, 25^th of January 1941 gives a glowing recount of the success of the barrages and the benefits to the community. That article is online here.

However, not everyone is happy with the changes brought about by the barrages. In these ‘Letters to the Editor’ a local fisherman and grazier describe in detail the impact the barrages have had on their livelihoods and property.

D. Cremer of Milang writes to the editor on the 30^th of January 1941,

“EFFECT ON FISHING INDUSTRY”

Sir—Re your article on the 25th about the benefits derived from the Murray barrages, two professional fishermen spoke against them from the fisheries standpoint to your representative. Adverse fishing conditions, which did not previously exist, have been caused by the barrages. Twelve months ago the Murray mouth was about 350 yards wide and 16 feet deep. Now it is about 20 yards wide, and there is only 3 feet of water. Fish will not cross this shallow water. They will cross only at high tides. It is not the low lake that cause the erosion, but the high lake held up to an artificial level; also the breaking of the river banks. The fishing industry in the lakes is fast declining. We have had over 12 months of fresh water or partly fresh (about 50 grains of salt to the gallon) and cod and callop have never been scarcer. The green slime which covers the lake would make it impossible to fish even if the fresh water fisn were about. It remains to be seen how the big landowners will deal with a big flood covering a wide extent of country.

And W. P. McANANEY. West Creek, of Langhorne's Creek is not too pleased in his letter to the editor either titled “GRAZIER'S COMPLAINT”.

Sir—As I have a frontage of about ten miles to Lake Alexandrina, I disagree with parts of your article on the advantages of the Murray barrages. Until the barrages were closed. I could graze my frontage for 10 months of the year, and have the use of about 50 acres of reeds for most of the time. Since the barrages were closed the reeds have been under water. From May till the end of September I had 2,000 acres either under water, or surrounded by water, which gradually receded, until last week I had only 50 acres under water, and this in a drought year, -with very little water, if any, coming down the Murray, In the usual spring floods. During last week I was extremely fortunate in that I did not lose hundreds of sheep, instead of an odd few, when the wind banked the lake water up and cut them off from the mainland, and the Bremer floodwaters nearly inundated the small piece of land remaining for them to stand on. I cannot agree with the remarks in your article about erosion, because there has been much more in the last six months, than in the previous six years. The Government has reduced the rent for all Crown leases adjoining the lake, owing to the flooding, including 800 acres leased to me. In regard to 1,500 acres of freehold, a letter from the Engineer in-Chief informs me that I am not suffering any disability at all, as, anyway, the land is only good for grazing for a few months of the year—which is inaccurate—and that my only redress is to take the matter to the courts. It would appear that a lot of the land will be under water for a considerable period now, perhaps until next year.

Captain Dan Cremer, Milang 1935

Murray Barrages - A Report by Experts 1903

2011-08-26T19:20:00.000-07:00

After the drought of 1895-1902 South Australian settlers around the Lower Lakes were desperate for a way to preserve their fresh water supplies. The proposal for the barrages was under consideration. Advice was sought of senior engineers from New South Wales and Victoria by the South Australians and the report below was produced in 1903.

In the section titled "Some Startling Results Expected” the engineers warn:

"The construction of a weir or dam in the tidal compartment of a river has invariably been found to result in the shoaling not only of the portion of the river immediately above the dam, but also below it. In the case under consideration, however, the area of the lakes is so immense that shoaling above the barrage would not be appreciable for a very long period of time. Below the weirs the effect would be more quickly noticeable, especially as the sandhills which separate the river from the sea below the proposed site for the barrage in the Goolwa channel are drifting badly. During dry periods, when there would be little or no discharge over the weirs, the Murray, mouth would become so shoal as to be unnavigable; indeed, were it not for the long stretch of water in the Coorong which would enable the tide to propagate itself up a distance of many miles, the Murray mouth after the barrage is constructed might be expected to shoal up completely."

The report in it's entirety is below, and also available online at the National Library Australia Trove

Aerial view of the River Murray Barrages, 1940

THE MURRAY BARRAGE

REPORT BY EXPERTS

Thursday, August 20, 1903

Messrs. T. W. Keele (Principal Engineer of Harbors and Rivers of New SouthWales), W. Davidson (Inspector-General of Public Works of Victoria), and A. B. Moncrieff (Engineer-in-Chief) have submitted the following joint report to the Government on the proposed Murray River barrage:

We have the honor to inform you that by your direction we have investigated certain proposals for the construction of a barrage in the vicinity of the mouth of the River Murray, by visiting the sites of the several sections of which it is suggested it shall be composed, the examination of sections and preliminary plans, and the consideration of former suggestions of a similar nature. The scheme now to be dealt with has for its immediate object the exclusion of sea water from Lakes Alexandrina and Albert, which it has been urged have suffered much from the influx of salt water during recent years. This subject was enquired into at some length by the Inter State Royal Commission on the River Murray. On page 34 of the Commission's report the fol lowing appears:-"Several very positive statements were made in evidence by residents in the neighborhood of Lake Alexandrina of the increasing saltness of the lakes at the Murray mouth. Apart from verbal statements, the evidence of facts is against the hypothesis that there has been any increase of saltness in the Murray lakes by reason of diversions, of water from the river channel. We are of opinion that the proper course to maintain a supply of fresh water is the construction of a work at the outlet to exclude the sea, so designed as to discharge river floods over its crest." The Commission did not suggest any scheme by which this might be accomplished, but at least it has put before the authorities a definite issue.The former suggestions referred to appear to have been made almost entirely in the interests of the River Murray navigation. So far back as 1856 Mr. G. W. Goyder, Surveyor-General, proposed to cut the rock bar in the Mundoo channel, and so concentrate action of river water for scouring a channel through the bar at the river month. In 1857 Mr. George Abernethy proposed by piling to direct tile tidal scour more effectively across the bar; and in 1874 Mr. H. C. Mais recommended the cutting of a canal direct to the sea just below Goolwa. In 1876 a breakwater and other works for the establishment of a port inside thebar at the river mouth was recommended by Mr. Hickson at a cost of £1,500,000. Sir John Coode's project in 1879 was for the construction of two breakwaters projecting from the shore and parallel to one another, which, with their contingent works, were estimated to cost not less than £2,000,000. It is obvious that by neither of these would the lakes' condition have been altered. But in 1890 a scheme was formulated by a member of this board which, while providing for the maintenance of facilities for shipping in the river, contemplated more particularly the stoppage of the inflow of sea water to the lakes. It appears to the board that in any obstruction that may be erected against the passage up the river of sea water, the shipping interests, trifling as they are at present below Goolwa, should receive recognition, and in the recommendations which are submitted herewith provision therefore will be found.

THE SITE OF THE BARRAGE

The points in the scheme as placed before the board which demanded early and special con-sideration were those of site. For reasons that need not be dwelt on at any length, it was considered to be impracticable to construct a barrage to exclude tidal effects acrcss the actual mouth of the river; the alternative being in the blocking of the several channels from the lakes which converge on the river mouth. In respect of such blocking work on the most important of these the Goolwa channel-two sites were examined, the board deciding that all the elements of safety which were lacking in the lower, are to be obtained in the upper one about half a mile below Goolwa township. And it may here be noted that it is proposed to insert in this section of the barrage a lock for the passage of river vessels. The board considered the advisableness of so designing or locating the barrage on the eastern side as to exclude the Coorong from the Alexandrina Lake system, and decided that the circumstances of the Murray River volumes to be anticipated would not warrant the inclusion of an evaporating area of 90 square miles additional to that of the lakes for what at best would be an extremely problematical, if any, advantage. The flood waters of the River Murray, before reaching the sea, spread over 284square miles of'low-lying land, thus forming Lakes Alexandrina and Albert, having an average depth of about 6 ft. The discharge from these lakes is between prominent headlands known as Point Sturt and Point McLeay, and thence through several channels, which pass between and around low lying islands, and finally conjoin about seven miles south-east of Goolwa, emptying through one opening in the sandhills into Encounter Bay. The discharge of fresh water from the River Murray to the sea in the flood of 1890 reached the enormous total of nearly 4,000,000 cubic feet of water per minute, but in a dry season falls off to such an extent that the sea water, meeting no opposing stream, flows in through the channels referred to above, and diffuses the salt water over the lakes, the tidal influence being felt at Milang, where the reduced level of low water is 106.50, and is marked as zero on the gauge by which the rise and fall of the lake waters is measured. The datum is 100 ft.below low water at Port Adelaide.

WHAT THE SCHEME IS TO DO

Further preliminary surveys have been made and tidal observations recorded to form the basis for the preparation of a scheme to meet existing four-fold requirements.

1st. Of shutting out the salt water of the sea from Lakes Alexandrina and Albert and the chan-nels leading therefrom.

2nd. Of retaining fresh water from the river in these lakes and channels approximately up to R.L. 109, or 2' 6" above zero on the Milang gauge.

3rd. Of allowing floodwaters to pass equal in volume to the 1890 flood at least; and,

4th. Of providing for navigation in such a manner as to admit river steamers to pass through the barrage to and from the sea.

When the subject was previously considered, the depletion of the fresh water supply for irrigation works in New South Wales and Victoria had not been undertaken, and one part of the proposition was to close the Coorong from tidal action, thus keeping it fresh as long as possible after each heavy flood, but as there is no southern outlet to the Coorong the salt water could never be completely scoured out. In view of the limiting of the quantity of fresh water in dry seasons it is desirable to exclude the Coorong, not from the sea, but from the evaporating area of the lakes, the whole of which it is desired to render,available as a fresh water storage; and this branch of the question is more fully dealt with in the evidence given to the River Murray Inter-State Royal Commission-vide answer to question No. 5,215, in which the reason is given for the necessary raising of the level of the stored water to 109.00 R.L. The exclusion of the Coorong from the evaporating area necessitates the closing offive openings, or channels, as shown on the accompanying plan, through which the sea water at present reaches the lakes, and through which, inaddition to the overflow of the adjoining islands, the floodwaters, overcoming the tidal action, ultimately reach Encounter Bay. Owing to the varying physical conditions, the erection of the barrage will require individual treatment in regard to each of these openings, care being taken to maintain the uniform reduced level of 109.00 as the top of the crest, which is intended to secure the impounding of the fresh water.

A LOCK

The most important of these outlets is that known as the Goolwa channel. At the site selected by the board and shown on the plan as suitable for the erection of the barrage the width is 2,680 ft. between rather prominent headlands. The reduced level of high water is 109.00, and the rise and fall of the tide is 2 ft. 6 in. The river at this place contains a large deposit of sand andmud, there being two clearly-defined channels of a maximum depth of 20 ft, "one at either side of the stream, divided by a bank, which is covered to a depth of only a few feet at low water. At this place it is proposed to erect a sheet-pile structure, protected with rip-rap; and as this channel provides the most suitable site for a lock to admit of the passage of river steamers, it is suggested that this accommodation should be provided at the northern bank of the river, the dimensions of the said lock to be 150 feet by 50 feet, providing a depth for the passage of boats of, say, 5 feet draught, which, we are given to understand, will be sufficient for the vessels to be considered.

THE OTHER OPENINGS

The opening between Mundoo and Hindmarsh Islands is the next in importance, being the most direct outlet from the lakes to the sea. The width of this opening at the place chosen for the barrage is 1,900 feet the maximum depth at low water being 4 feet; but in this case, owing to position and the influence of westerly winds, the tide rises to R.L. 110.70, or, considerably higher than at Goolwa. The foundations for the whole width of the river in this instance would be solid rock.

At this place it is proposed to erect a construction of sheet-piling, but the main portion of the structure must be planted in holes drilled into the rock, and wliile R.L. 109.00 must be maintained as the crest for the outflow of fresh water, it will be necessary to provide shutters to keep out the salt water from the lakes to about R.L. 110.70. These shutters have been designed as hinged to the crest of the main structure, so that by simply removing the catches the outflow of the fresh water can be secured immediately in case of flood.

The channel known as Boundary Creek is comparatively insignificant, being only 950 feet wide. The foundations would be on the reef of hard rock. The rise and fall of tide at this place are very similar to those in the Goolwa channel, and it is proposed to put in an earthen wall, pitched with stone to the proper grades, so that the sea water may be excluded and the fresh water retained to R.L. 109.00 by a simple structure.

The openings between Tauwitcherie and Ewe Islands are shallow throughout, and should be treated on the same principle as at the Goolwa channel. The longest opening is the channel between Tauwitcherie Island and Pelican Point. In this opening there is an average depth at low water of 1ft., and the total width amounts to about 8,500 ft. For a considerable portion of its length the foundations would be on the reef of limestone, which crosses Boundary Creek and Mundoo Channel, but for the remaining distance the rock is absent and the foundations are of a treacherous character. The treatment proposed for this opening is the erection of a composite structure, partly as in the Goolwa channel and partly as in Boundary Creek, admitting of the overflow of the fresh water at R.L. 109.00.

BARRAGES NOT TO BE WATERTIGHT

The above named works, if erected, will keep the sea water from entering the lakes, and the permanent crest of each portion of the barrage being R.L. 109.00, will retain the fresh water to the required level, equal to a depth of 2' 0" above zero, on the Milang gauge. It should be understood that the proposed structures form a barrage only, and not an absolutely watertight dam, which the board considers unnecessary, and which would be extravagantly costly. The placing of the barrage across the outlets will form occasionally submerged weirs, and, therefore, lead to the raising of the level of floodwaters to an appreciable extent. Calculations which have been made show that the total length of outlets available for floodwaters of the River Murray, after the completion of these works, would be about 35,000 ft., or over six miles; but this provides not only for utilising the overflow weirs, but for the floodwaters to rise over Pelican Point, Tauwitcherie, and Ewe Islands, and part of Mundoo Island, as it did during the flood periods of 1871 and 1890.

SOME STARTLING RESULTS EXPECTED

The carrying out of such a work as that described above may bring about some rather startling results, which, apart from the strictly engineering enquiry, may be referred to for the information and consideration of the Commissioner. The first and most apparent of these results will be the permanent raising of the level of the fresh water over lands closely adjoining the lakes and outlet channels, always supposing fresh; water to be available to supply evaporation; but, it is stated that the damage to property due to this cause would not be serious. The influence of so raising the water would probably be felt as far up the main river as Wellington, but in periods of extreme flood, based upon information obtainable for the year 1890, there would be a temporary submergence of land, as approximately indicated on a plan which the Engmeer-in-Chief will prepare to accompany this report. The only possible arrangement lor preventing the submergence ofthis additional land would be the erection of very, costly failing weirs which in periods of flood would leave all the existing channels uninterrupted, and the board has to express the opinion that the additional expense would in no sense be justifiable. Another point of view to which we would call attention is the fact that the low-lying flat islands will be more frequently used as a by-wash then heretofore. These islands are composed of clay, covered for the most part with samphire, but having occasional pickings of good grass for sheep. The tenure of these islands is now leased from the Crown, and the value of these leases would undoubtedly be decreased; but this is a question which can more properly be dealt with by the Surveyor General. The construction of a weir or dam in the tidal compartment of a river has invariably been found to result in the shoaling not only of the portion of the river immediately above the dam, but also below it. In the case under consideration, however, the area of the lakes is so immense that shoaling above the barrage would not be appreciable for a very long period of time. Below the weirs the effect would be more quickly noticeable, especially as the sandhills which separate the river from the sea below the proposed site for the barrage in the Goolwa channel are drifting badly. During dry periods, when there would be little or no discharge over the weirs, the Murray, mouth would become so shoal as to be unnavigable; indeed, were it not for the long stretch of water in the Coorong which would enable the tide to propagate itself up a distance of many miles, the Murray mouth after the barrage is constructed might be expected to shoal up completely.

A DISQUIETING POSSIBILITY

The most important of the possible results of the erection of the barrage is the effect which may be produced under possible conditions in the lakes and channels in which it is sought to ensure a continuously fresh supply of water. At present, all the channels being open, the water in the lakes is fresh when the supply is sufficient to overcome tidal action, and when the supply of fresh water falls off the sea water takes its place.

Supposing the barrage to have been erected, if the supply of fresh water is not sufficient to provide for evaporation, the surface level of the lake will fall below that which is now maintained by the influx of the sea, large areas of the foreshore may be left dry, and the remaining submerged areas become little better than salt swamps. If the supply of water from the upper reaches of the river is not sufficient to keep the lakes reasonably full, the effect of the erection of the barrage as described above would be serious injury to the condition of the lakes instead of being an improvement.

In view of the experience of the recent drought, there can be no doubt that if the barrage referred to had been erected five years ago it would have required nearly the whole available flow of the river to keep the lakes sweet and open for navigation. In this relation the physical feature must not be overlooked, that the subsoil water of the lakes is itself salt and that soakage waters from the banks of the river have been shown to be off such a character that continued evaporation would render the resulting supply unfit even for stock.

Vide evidence given before the River Murray Inter State Royal Commission, page 21.

It is submitted, therefore, that these possible results require the most careful consideration, and the establishing of a definite policy in regard to a regular supply of fresh water from the river before such work as that of erecting the simple barrage described above should be undertaken.

ESTIMATES OF COST

The estimated cost of the erection of a barrage at the mouth of the River Murray, as described in the preceding report, forming a composite structure of timber sheet-piling and earthen-pitched embankment, is £113,300, which may, however, be modified as a result of closer investigation, after further surveys and borings. Such a structure would, doubtless, entail expense in maintenance after a series of years.

Estimated cost of barrage and lock, £98,130.

Engineering, supervision, &c. 5 per cent, £4,906

= £103.036.

Contingencies, 10 per cent, £10,303. Total, £113,339; say, £113,300.

Ends

THE MURRAY BARRAGE. (1903, August 20). The Advertiser(Adelaide, SA : 1889-1931), p. 8. Retrieved June 29, 2011, from http://nla.gov.au/nla.news-article4987833

Background:

History behind the Royal Commission

Murray Mouth Barrages Scheme Opposed, Part 4

2011-08-22T21:19:00.000-07:00

From this news report of October 13, 1933, more information is being gathered by the Public Works Committee regarding the building of the barrages. Opinion on whether the barrages would be a positive or negative infrastructure project for the young state of South Australia was mixed. It seems that opinion varied depending on where your land was located around the lake, and whether you were a farmer or a fisher.

Cattle grazing on the shores of Lake Alexandrina, 1905

Fishing catch and fishermen D. Cremer, J. Graney, C, Pavy with their catch at the Jetty,1938

MURRAY MOUTH BARRAGES

Public Works Committee Takes Evidence

SCHEME OPPOSED

From Our Special Staff Representative

MILANG, October 13.

Although opinion was not unanimous, a strong body of witnesses opposed the construction of barrages near the Murray Mouth when the Public Works Committee took evidence here today regarding the proposal. Milang fishermen and several landholders near the township criticised the project, but Point Sturt farmers advocated it.

Before taking evidence the committee, accompanied by the engineer for irrigation and drainage (Major Tolley), inspected the samphire flats adjoining Lake Alexandria, and the rich low lying grazing areas farther inland near the Rivers Angas and Bremer. Several landholders complained that with the banking up of the lake water, because of the barrages, floods on those two rivers would not be given their natural outlet to the lake, and would flood the land.

Major Tolley explained to them that usually the flooding of streams occurred between May and October. In that period the gates in the barrages would be open, so that the natural flow of the water would not be interrupted, and as the water in the lake would not be banked up, floods from the Bremer and the Angas would not be worse than now.

Analysis For Salinity

At the Milang Institute, before the committee examined witnesses, Major Tolley told a gathering of residents that an analysis of water from the lower river, taken by his department, showed that under normal conditions there was a saline content of 30 or 40 grains to the gallon, which was not bad. When the lake became salt, and there was a strong wind from the south-west or west, the proportion of salt increased to 180 or even 250 grains to the gallon as far up as Mannum. That was evidence that the salt water came from the sea, and the barrages were intended to combat its entrance. Unless some thing were done the river would become salt as far upstream as Blanchetown and totally unfit for domestic uses or irrigation. There would be more than two miles of gateways in the barriers so that in the biggest floods the barrages would not hold up the water more than three inches on the lake. At Murray Bridge the difference would be negligible. The barrages would not be closed during the winter, and there would be a free flow of water. When it was noted that the level of the river was dropping, the opening would be closed, and the level behind the barrages would gradually be raised to the maximum. Then as irrigation and evaporation lowered the water, the gates would be opened again in April or May and the water in the lakes would resume sea level. At full storage the level in the lake would be 13 inches higher than it was at nine a.m. that day. There would be a boat lock in the barrage in the Goolwa channel so that boats could pass up or downstream without charge. Nothing had been decided yet about the Tauwitchere channel, but provision might be made for boats to pass over the barrier there.

Local People Apprehensive

Councillor H. C. F. Kruse. chairman or the Milang District Council, said that local people were apprehensive of the combined effect of barrages and unfavorable winds. They were certain that the lakeside country and roads would be inundated. The authorities could not give them continuous freshwater in the lake. The present condition of the lake and lower river was due in a large part to the seepage of magnesia impregnated water from the irrigation settlement upstream. It could be seen at Waikerie, where it had undermined a large part of the bank. To show that bad water came from up stream, rather than down-stream, he had evidence that in recent years there was a pocket of good water, 15 miles long, beginning about 10 miles above Mannum. Above the pocket, the water was as bad as it was down-stream. The proposal for a fresh water lake would not give landholders the satisfaction they expected. Barrages might improve the position during flood times, but they would not provide fresh water sufficiently long to give the lakeside the vegetation of 30 years ago. A barrage across the Goolwa channel would cause silting.

Would Ruin Fishermen

Mr. John Woodrow. who said he had had 25 years' experience of fishing on the lake, prophesied that the construction of barrages would ruin the Milang fishermen. Their gear could not be used in the Coorong channel because it would be ruined by crabs there. Opening of the gates in the barrages in winter would not help, because it was only between December and March that butterfish from the sea entered the lake. He estimated that the fishing industry was worth £5,000 a year to Milang. The construction of barrages would give a slight benefit to the settlers upstream, but he did not think it would be sufficient to justify the expenditure the barrages would involve. They would not make the lakeside carry more than it would today.

Speaking from 50 years experience on the River Murray, Captain Cremer said that the stream was silting up, and the construction of a barrier in the Goolwa channel would cause sand to lodge there and choke it. There was not sufficient water coming down the Murray. The raising of the level of the lake by a barrage would endanger the reclaimed areas on the lower river if the effect were accentuated by winds.

" I have no faith in the proposed barrages," he said. "In their place I would suggest that a barrage be constructed near Brinkley."

He thought that the release of water from the barrage might scour the channel for a short distance, but the effect would disappear after half a mile.

"Channels Would Silt Up"

Mr. W. Woodrow agreed that the construction of barrages would cause the channels to silt up. He did not think sufficient provision had been made for the combined influences of wind and tide. The Mundoo barrage, which was 8 feet 10 in. high, was insufficient to keep the sea in. Now it was proposed to build a barrier 2 feet 9 in. high in the same place to keep the sea out. The disappearance of reeds from the lakeside country was attributable more to stock than the conditions of the water. Engineers had failed in their calculation of the depth of water in the river, as a result of locking, and they would be as wrong in their calculations of the outcome of the erection of the barrages. Sandbars would form at the Murray Mouth, and settlers from the lake to Mannum would be ruined. He did not think that butterfish spawned in Lake Alexandrina now, as some fishermen at Goolwa had said. They might if the lake became more salt. He thought that the Murray reclamation scheme had been a failure.

Major Tolley told the witnesses that the top of the Mundoo barrage in some places would be five feet above the storage level of the water in the lake.

Mr. Woodrow—lt still won't prevent the sea coming over.

Major Tolley—A little splash might come over.

Mr Woodrow—lt will be more than a splash. It would have to be ten feet high to keep the sea out.

Question Of Expense

Mr. S. A. Goldsworthy said the problem was whether the results would justify the expense. He did not think that they would. Two or three thousand acres of samphire land in the Milang district might receive benefit from the construction of the barrages, but they were held under perpetual lease at one shilling an acre, and if their value were improved two or three times the result would be only £300 a year. Most of the Point Sturt farmers favored the proposal.

Giving evidence on behalf of sixteen farmers holding lake or river frontages in the Hundred of Alexandrina Mr. W. Yelland said that they were in favor of the scheme. They asked that they should have a lake as fresh as possible. Salt water had been the prime factor in the destruction of the lakeside reeds, which were good fodder. Occasional flooding of the samphire flats by fresh water would be a benefit.

Mr. E. Bagley dairy farmer, who manages his mother's property with a lake frontage, near the outlet of the River Angas, said he feared that the higher level of the lake, because of barrages and the flooding of the river would cause a large part of the lake side country to be flooded. Some would be lost land, and would not be benefited if it were flooded, and the water remained there a long time. The building of barrages would spoil a big area of lakeside country, said Captain A. Ferguson.

Councillor W. S. Day supported the scheme.

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Source:

MURRAY MOUTH BARRAGES. (1933, October 14). The Advertiser (Adelaide, SA : 1931 - 1954), p. 20. Retrieved August 17, 2011, from http://nla.gov.au/nla.news-article36449421

Nets as Evidence, Part 3

2011-08-18T18:28:00.000-07:00

The fishermen are trying to have their voices heard at the Public Works Committee Barage Inquiry in 1933 by staging a display of their boats and nets. These same fishermen would have been coping with the disapperance of Murray cod from the Lower Lakes in 1912. Some of them blame the state government’s decision to drain the Lower Murray swamps on why the cod are no longer about.

Today we know that many of the Lower Murray wetlands contain acid sulphate soils. These soils can become toxic when exposed to oxygen. We may never know the details on what if any effect draining these wetlands and swamps might have had on the quality of the water and the fate of the fishery.
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An area of swampland at Mannum, South Australia, 1905

A trench excavator used for reclaiming swamps in Mannum area, 1915

BARRAGE ENQUIRY TODAY
Opposition By Lakes Fisherman
NETS AS EVIDENCE

From Our Special Staff Representative
MILANG, October 13, 1933.

Before members of the Public Works Committee take evidence here tomorrow about the proposal to build barrages near the Murray mouth, they will be shown what is considered to be the best display of mesh fishing gear in the Commonwealth.

Local fishermen have arranged it to support their evidence against building barrages. Nine cutters have been anchored near the jetty, and hundreds of nets have been hung on seven drying lines on the shore at the lake. Probably 200 more have been draped over the railing at the shore end of the jetty. It is an impressive proof of the value of the fishing industry to the town. It is estimated that the value of the gear is £8,000. The material for 90 per cent of the nets came from Ireland, the home of the world's best nets; and if the local fishing industry passed out of existence, it is considered that use could not be found for the nets in Australia, because most of them are specially adapted for butterfish fishing in the lakes. In addition to part of the gear, members of the committee will see there about 30 dinghies and several fishermen use motor lorries in their work.

"Barrages would mean the end of the fishing industry here," said Messrs. W. and John Woodrow, two leading fishermen of the town today. They would rob an average of 25 licensed fishermen of their living, as well as a few young men who help their fathers with nets. "We do not agree with those who say that fishing on the lakes is dying," said Mr. John Woodrow. "It is true, some of the men with the most efficient, gear have gone out of the industry, and that some who have taken their places have not been so successful, but it served us and our fathers before us and we have no complaints to make about it."

Importance Of Industry

As evidence of the importance of fishing to Milang, 272 cases of fish were sent to Adelaide from the local rail way station last month. In the city market they brought from 6/ to £2 a case, the price being governed by supply. Besides those consignments, others sent by Milang fishermen working in the Coorong might be sent from Tailem Bend or taken to the market on a motor lorry.

Normally, butterfish are caught in the lake only between December and March or early in April, and then only under a combination of favorable circumstances, which are secrets known to experienced fishermen. Days may pass without any return, but when fish are there, bed and meals are forgotten while the harvest is reaped, for fish are capricious, and there is no knowing how long they will remain.

Disappearance Of Cod

Lakes fishermen have all manner of theories to explain the disappearance of Murray cod from the lake, where they were caught in big hauls until 1912. Milang men attribute their absence to the increasing alkalinity or the lake water, and say that the tendency is due to the combined effects of the reclamation of the Murray lands and increased irrigation. Irrigation, they say, permits water to absorb magnesia, and other chemical constituents of the reclaimed soil, and when the proportion of the moisture seeps back into the stream it pollutes it. Thus cod and other river fish, are slowly poisoned, because they have been accustomed to fresh water. Similarly, it is argued, it is the alkali impregnated water, and not the inflowing sea water, which causes lake and lower reaches of the Murray to become brackish.

Thus, local fishermen say, barrages will fail to keep the lakes and lower river fresh, because the trouble comes from upstream, and not downstream. They say they have definite proof of this contention to place before the committee tomorrow.

The belief that with the construction of barrages Lake Alexandrina might again become a breeding water for Murray cod had no prospects of realisation, said Mr. John Woodrow. A few landholders in the Milang district might benefit from the barrages. The opinion of the township, expressed at a ratepayers' meeting to discuss the project, was:—For. none: against 42.

Probably witnesses examined tomorrow will be Councillor Kruse chairman of the local district council Messrs. John and W. Woodrow. S. H. Goldsworthy, and Captains Ferguson and Cremer.
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(1933, October 13). The Advertiser (Adelaide, SA : 1931-1954), p. 20. Retrieved June 30, 2011, from http://nla.gov.au/nla.news-article36449223

Wetlands below Lock 1 - Map

Barrages would kill butterfish, Part 2

2011-08-18T05:04:00.000-07:00

Almost 600 tons of butterfish (mulloway) were caught in the Lower Lakes and Coorong in 1938/1939. There are reports that mulloway were trapped in the coffer dams while the barrages were being built. The barrages were finished and closed in 1940. This eliminated 89% of the mulloway’s estuarine habitat.

In 2008/2009 the annual commercial catch of mulloway in the Lakes and Coorong Fishery was 30 tonnes. For comparison the now freshwater Lakes commercial catch of European carp in 2008/2009 was 792 tonnes.

The newspaper story below is from the Adelaide Advertiser in October 1933. The article describes the testimony from the Fisheries inspector before the Public Works Committee investigating the building of the barrages.

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"BARRAGES WOULD KILL BUTTERFISH"
Evidence Of Chief Fisheries Inspector

25 October 1933

In evidence before the Public Works Standing Committee on the Murray River barrages, at Parliament House yesterday, the Chief Inspector of Fisheries (Mr. W. D. Bruce) said that if a barrage were erected in the channel into Lake Alexandrina butterfish would not be able to get up there, but freshwater fish might be bred.

Mr. Bruce said that there were about 40 to 44 men at Goolwa dependent on fishing for their sole livelihood, 20 to 30 at Milang, four at Langhorn's Creek, who fished at Mulgundawa, and about four at Narrung. If the barrage were built it would practically wipe out the butterfish, and men would be thrown out of employment at Milang, Mulgundawa, and Narrung, and twelve to four teen men would be affected at Goolwa.

The Chairman (Mr. Blackwell) —It has been said that when the Mundoo channel was erected more butterfish were caught that year than previously.

Mr. Bruce —I was not aware of that, but if the fish could not get through the Mundoo channel they were no doubt forced into the Goolwa channel, and possibly the men who were netting there and at the other end of the Mundoo channel did very well. The fish would certainly try to get up to the Coorong or wherever the tide was flowing, but they would not have the large expanse of water and the feeding ground. If they got up as far as Lake Alexandrina and got into the brackish water they would get an abundance of food.

In answer to a question by Mr. Anthoney as to whether butterfish would climb up tbe fishways, Mr. Bruce said that be knew of no salt-water fish that would go through a fishway. The spawn would come in, but the water would eventually be fresh, because the bulk of the water would be fresh and the salt water that came in would only lift the level. He had seen fishways in England, Germany, and France, but in those countries they were constructed altogether differently from those used for slow moving fish, such as Murray cod.

In answer to a question by Mr. Morrow, M.L.C. Mr. Bruce said that Murray cod and trout could be bred artificially if the barrages were erected. There would be a prospect of breeding fresh-water fish that could not be bred now on account of the salt water. If the water was fresh it should be kept fresh and the water allowed to come in the other way. He had read to a report that it was the intention of the engineers to allow a certain amount of salt water to go into the lake. That would kill everything there.

Asked what effect the barrages would have on Lake Albert, Mr. Bruce said that if sufficient water were received to keep it fresh it would be all right but he did not think that they would get sufficient fresh water for that purpose. If the proposed barrage were built near Goolwa the position regarding butterfish would be satisfactory provided there was sufficient ebb and flow of tide and provided that the Murray mouth was kept open.

End

A large catch of fish, Goolwa 1939

"BARRAGES WOULD KILL BUTTERFISH". (1933, October 25).The Advertiser (Adelaide, SA : 1931 - 1954), p. 22. Retrieved August 16, 2011, from http://nla.gov.au/nla.news-article36452028

Economic Indicators for the Lakes and Coorong Fishery 2008/09
Report for PIRSA by Econsearch, 16 June 2010

Olsen, A.M. 1991 The Coorong - A Multi-species Fishery. Part 1 – History and Development

Fisherman Oppose Murray Barrage, Part 1

2011-08-17T02:24:00.000-07:00

I’ve been searching for information on the internet about the history of the barrages. Why did South Australians decide to build 7.6km of barrages across the bottom of the River Murray estuary in the late 1930’s? What were they thinking? How can history help us understand the situation we find ourselves in today.

This is the first in a series of newspaper stories from the 1930s. I’ll start with the mulloway, also called ‘butterfish’, and the fishers who eventually lost out.

FISHERMEN OPPOSE MURRAY BARRAGE
"Would Mean Ruin"

MILANG June 27, 1933

Most local fishermen are strongly opposed to the proposal to build a barrage across the mouth of the Murray. They declare that it would completely block the supply of butterfish about the lakes.

Mr. James Woodrow, who has had 40 years experience as a fisherman on Lake Alexandrina, said the barrage would mean ruin for a hundred or more licensed fishermen and render their plants useless. About 40 years ago the lakes teemed with cod and calop, and the Murray Mouth and nearby channels with butterfish. About 1911 Murray cod became extinct in the lakes and two years later fishermen invested in heavy nets to catch butterfish. Some plants in use today were worth £2,000.

"Reclaiming the swamps destroyed the chief breeding and feeding places of the cod and calop, and stopped the gradual feeding of fresh water when the main river fell, which kept the butterfish about," Mr. Woodrow said.

"The locks impede the free passage of the fish during low water periods, and the seepage of salt water from irrigation turns the water, impounded by locks and weirs, stagnant and salt, and kills the fish. This water is pushed down into the lower reaches and the lakes when water higher up is released to sluice the river."

Fisherman holding a 91 pound Mulloway caught at Milang c 1938

FISHERMEN OPPOSE MURRAY BARRAGE. (1933, July 1). The Advertiser
(Adelaide, SA : 1931 - 1954), p. 20. Retrieved August 16, 2011, from
http://nla.gov.au/nla.news-article46984420
Photo courtesy the SA State Library

Time for an estuary

2010-10-17T23:19:00.000-07:00

Every river needs a healthy estuary. And yet the River Murray, Australia's iconic river, has lost 90% of its historic estuary. This was not always the case. Prior to the construction of the Barrages in 1940, the Lower Lakes (Lake Alexandrina and Lake Albert) were part of a vast River Murray estuary. The Barrages have artificially disconnected the Lower Lakes from the Coorong and Murray Mouth, devastating the ecosystem of the region.

So why do so many Australians accept the ongoing presence of these unnatural barriers? The Lower Lakes have existed in their present form for at least 6,000 years, but the Barrages have been around for only 70 years, the merest blip in time. Prior to the Barrages seawater naturally flowed through the Murray Mouth and into the Lower Lakes with high tides, mixing with river flows to create a vibrant estuary, teeming with mulloway and other species that thrive in estuarine conditions. During times of low river flows, the estuary encroached over 200km inland, to present day Swan Reach.

Of course, the Murray River and its tributaries have always been fickle; it's an erratic system with highly variable, undependable flows. Australia's pioneers abhorred this fact. The River needed to be tamed, to be made dependable for river transportation and irrigation, and so they built a complex system of dams, locks and weirs. And the Barrages – the ultimate barrier designed to extract every possible litre of water out of the Murray Darling Basin for human usage.

In hindsight, the Barrages were never a particularly good idea, but in the era of riparian irrigation and river transportation there was at least some method to the madness. Back then, domination of nature was considered the proper thing to do. It's now the 21st century though and we have highways and water pipes, not paddle steamers and open irrigation ditches (well, in theory). Most of the irrigators around the Lower Lakes are now supplied by water pipes and ones that haven't yet made the switch soon will, because even with the Lakes near “full”, the water is still too salty to irrigate. So there is no longer any economic justification for the existence of the barrages.

Which begs the question, why does the Murray Darling Basin Authority's (MDBA) recently released Guide to Proposed Murray Darling Basin Plan not even mention the Barrages? Not once! The Barrages are the largest engineered structures along the entire length of the Murray Darling, yet even the history of basin's development on page 25 fails to mention them. More importantly, the report misses the point that there is much more to a healthy river system than so-called sustainable diversions. After all, returning all the water in the world to the River Murray won’t restore it’s estuary, as long as water is only allowed to flow in one direction over the top of the Barrages.

Over ten years ago, in June 2000, the Murray Darling Basin Commission (MDBC), the precursor to the MDBA, produced a remarkable report, which identified the dramatically reduced area of the River Murray estuary as a significant environmental issue, caused by the presence of the barrages. The MDBC 2000 report was farsighted enough to recommend as a long-term goal the removal of the barrages back to Wellington. How could the MDBA completely ignore this earlier report’s findings? Ignore it to the point that the word “barrage” is not mentioned even once? The last time I checked, “barrage” is not a taboo word.

It's high time we had a real debate about restoring the health of the Lower Lakes and Coorong, not this phony debate about preserving freshwater levels in the Lower Lakes at any cost. The MDBA admits that in times of drought there will not be enough water for all the iconic wetland sites and choices are going to have to be made. Do we water Chowilla or the Barmah–Millewa Forest or do we water the Lower Lakes? Do we let the Lower Lakes dry down to dust,again? Did we learn anything from the last drought at all?

It should be obvious that the Lower Lakes can be restored and managed as estuaries, as they were only 70 years ago before the barrages.

Let’s give our river its estuary back.

Drying Lake Alexandrina, May 2009

Lakes need water, and rivers need estuaries

2010-08-12T18:03:00.000-07:00

Since we started LakesNeedWater over one year ago, our core message has consistently been that the Lower Lakes should have, well, water. This is hardly rocket science after all. Why anyone would believe that holding back seawater and allowing the lakes to dry out is preferable to allowing seawater to mix with freshwater defies logic. Among the great rivers of the world, such as the Nile, the Amazon, the Yangtze, and the Mississippi, the River Murray is alone in being cut off from its mouth. Does anyone honestly believe it is healthy for a river to be separated from the ocean by kilometres of barrages, resulting in the loss of 90% of its historic estuary?

The scaremongers have it all wrong with their single-minded obsession with fresh water in the Lower Lakes. The River Murray needs a healthy estuary, not artificially maintained freshwater lakes. Rivers need estuaries. It really is that simple.

Securing the future of the Coorong, Lower Lakes and Murray Mouth?

2010-06-05T23:33:00.000-07:00

DEH released its long-awaited report "Securing the future: a long term plan for the Coorong, Lower Lakes and Murray Mouth" (CLLMM) on Friday June 4th 2010.

The purpose of the report is to provide a "clear direction for the future of the CLLMM region as a healthy, productive, resilient Wetland of International Importance" [sic]. Regrettably, the report's length is no substitute for the clarity of its direction nor the vision of its recommendations.

The recommendations contained in the report are numerous, but the key recommendations, in order, are:

Lake Alexandrina and Lake Albert remain predominantly freshwater and operate at variable water levels.
The Murray Mouth is predominantly kept open by end-of-system river flows.
There is a return of salinity gradients along the Coorong that are close to historic trends with a corresponding response to species abundance.
There is a dynamic estuarine zone.

What is not clearly stated in the report, but is implied, is that it is business as usual as far as the operation of the Barrages is concerned. In other words, the Barrages will continue to hold back seawater in times of low river flows, i.e., creating the same situation that currently plagues the Lower Lakes.

Taken separately, at face value, the above recommendations seem like worthy goals. Taken collectively, the conflicting and inconsistent nature of these goals becomes readily apparent.

Firstly, there can be no "dynamic estuarine zone" while "Lake Alexandrina and Lake Albert remain predominantly freshwater", for as long as the barrages hold back seawater, the estuarine zone is limited to the Murray Mouth and Coorong, a mere tenth of the area of the historic (pre-1940) Murray estuary.

Secondly, operating the Lower Lakes at variable (fresh)water levels, is an artificial and ugly solution in stark contrast to nature's own. Absent the barrages, the water levels naturally vary in accordance with the ebb and flow of the tides through the Murray Mouth, regardless of river flows. In other words the much ballyhooed freshwater "wetland of international importance" is actually a man-made construct, that would otherwise be an estuarine wetland, mixing freshwater and seawater in harmony with the seasons.

Thirdly, the report glosses over the deleterious impact of the Barrages on the ecosystem of the Coorong and Lower Lakes. While the "return of salinity gradients along the Coorong that are close to historic trends" is a stated goal, the return of the historical salinity gradients that existed in the channels of the Lower Lakes is abandoned, thus condemning the estuarine habitat to a fraction of its former size. In other words, more freshwater carp and less mulloway.

Finally, the credibility of the report is undermined by its almost complete reliance on the 2004 Sim and Muller paper "A fresh history of Lakes" and the 2006 Phillips and Muller paper "Ecological Character of the Coorong, Lakes Alexandrina and Albert" as evidence for the freshwater history of the Lower Lakes. While these papers begrudgingly acknowledge that before the barrages were constructed, seawater did enter the Lower Lakes when there were severe droughts, they downplay the significance and extent of such reverse flows. In reality, there is ample evidence both from historical records of explorers, such as Sturt and 1900's fishermen as well as scientific evidence, from scientists such as Gell, for an estuarine view of the Lower Lakes.

In summary, we find the report's recommendations both inconsistent and short-sighted.

What do you think?

Hypersalinity Hysteria

2009-12-16T22:46:00.000-08:00

The DEH has released the draft long term plan through the Murray Futures program titled: "Securing the Future, A Long-Term Plan for the Coorong, Lower Lakes and Murray Mouth." (3MB) This report is 122 pages long. It was first made available to the public to read starting 15th of December. The public has until 15th of January for comments. Not much time given the time of year.

A quick search for 'seawater' (pg 94 in the pdf) produces this reference below.

"If the barrages were opened in the absence of adequate freshwater flows, the evaporation of water from the surface of the Lakes, coupled with the limited mixing of water that can take place through the Murray Mouth, mean that there would be an increasing concentration of salt, leading to extremely saline conditions. Modelling indicates that if seawater were to enter Lake Alexandrina in sufficient volume, then in the absence of adequate freshwater flows, the great majority of the Lake will be hypersaline within two years (39). Without adequate freshwater flows, letting seawater enter Lake Alexandrina is a recipe, not for a healthy estuarine or marine ecosystem, but for an increasingly degraded hypersaline one.

Removal of the barrages would also make the Lower Lakes more vulnerable to projected sea level rise."

Wanting to learn more about this statement, and find data to support it, I followed the reference. The reference for this statement is this report titled, "Risk assessment of proposed management scenarios for Lake Alexandrina on the resident fish community".

At first, I couldn't find the statement "the lake will be hypersaline in two years", nor supporting data for this conclusion in this report.

Then I found the reference to “hyper-salinity” it begins on page 57 of the report. A closer look at this report and it says that two options of ‘seawater delivery’ were studied. One option the authors deemed ‘absurd’. That option was to allow seawater to spill “over the top” of the Goolwa Barrage. The second method of ‘seawater delivery’ is to have seawater spill ”over the top” of the Mundoo and/or Tauwitchere barrages. The authors go on to say that it would be preferable to have barrages gates ‘open’ or remove ‘whole’ sections of barrage gates.

These authors concluded that (pg 97)

“The feasibility of using alternative options for saltwater delivery must be investigated. The current proposed mechanism is ecologically absurd and will likely produce no ecological benefit. Removing ‘whole’ barrage gates or utilizing automated radial gates at Tauwichere and Mundoo must be investigated as saltwater delivery via these pathways provides greater ecological connectivity.”

And by only letting in enough seawater to cover the acidic soils the full benefit of the seawater as a haven for fish is doomed at such shallow depths.

The following two items (pg 98) were targeted for further investigation:

“Maintaining the lake levels higher than -1.5 m AHD should also be investigated. Options for allowing the volitional passage of estuarine species in and out of Lake Alexandrina are far greater if lake levels are to be maintained at a greater height. However this may have a greater impact on the ability of the LL to recover from saltwater intrusion.”

“Investigate and consider changes to the method for saltwater delivery”

So returning to that original DEH statement,

“Modelling indicates that if seawater were to enter Lake Alexandrina in sufficient volume, then in the absence of adequate freshwater flows, the great majority of the Lake will be hypersaline within two years".

This means that the DEH (and/or the work group advisors) have directed the scientists to assume:

That the seawater will be coming in ‘over the top’ of the barrages and not through gates

There is no widening of the Murray Mouth or any additional channels to the sea to enhance tidal flow

There will be less than 696 GL a year of freshwater coming across the SA border

What if a different set of assumptions were used? Let us assume:

That the barrages can be modified and automated gates fitted.

In the event that gates cannot be fitted, dismantle the barrages so that full tidal flow can enter the lakes.

There will be less than 696 GL a year of freshwater coming across the SA border

Sand accretions at the Murray Mouth are removed, not only a channel cut through with an ancient dredger.

What then? Would these scientists come to the same 'hypersalinity' conclusion?

Or maybe we should look at the other assumption, what if only 696 GL of freshwater flows across the SA border? How long will it take for the Lakes to evaporate to nothing given that evaporation rates are between 750-950 per year?

Little Mermaid goes walkabout

2009-12-07T17:48:00.000-08:00

So, is the famous Little Mermaid statue still in Copenhagen? Or has she set out on her trip to China?
The Danish government has plans to send her packing to China for the World Expo 2010 in Shanghai. The Danes are planning to import one million litres of Danish seawater so that the Little Mermaid feels right at home.

In any case, seeing as how she’s going walkabout, I would like to invite her to come here, down under. I wonder what she would make of a visit to Lake Alexandrina in South Australia?

While the climate change conference and debate goes on, many will point to South Australia as the poster child of climate change. Yet, for those of us close to the Lower Lakes, we know it isn’t just the drought that has destroyed the environment here. Between the man-made barrages, forcing the Lower Lakes to become freshwater, and using more water than we have, it’s more than just a change in the weather causing such a catastrophe.

Conjuring up Water

2009-11-25T22:20:00.000-08:00

A few days ago yet another report was released by a group of scientists. Basically the report states that the Lower Lakes and Coorong are doomed unless we get freshwater, and lots of it, 3800 GL. Although the scientists did qualify that by saying that 3000 GL already goes to the barrages, and all they were really asking for was an additional 800 GL. By the way 800 GL is about how much evaporates from the Lower Lakes every year.

The report then goes on to recommend that the government should just release the water to fix the problem. Don't you wish you'd thought of that?

Penny Wong then said in the Senate Debate during Open Question time, what many of us have been wanting to ask all those insisting on a 'freshwater solution'. She said, "This is the essential question: how do we conjure up this water when over the last three years we know we have been at one-fifth of the long-term average?"

Minister Wong also said this, "Rejecting the science is a proposition that pretends not to notice that we do not have enough water. " So why do so many of our water experts, government officials, and local councils "pretend not to notice" that we do not have enough fresh water to keep the Lower Lakes artificially fresh any longer?

Perhaps they really believe that someone can conjure up water.

Framework for the Science

2009-11-25T15:38:00.000-08:00

Few would argue that global warming and changing weather influences has a lot to do with the drought today. The condition of the River Murray, Lower Lakes and Coorong is compounded by a massive over allocation of the resource, together with our worst drought ever recorded. Our best weather people are saying, we better get used to these new and dramatic weather conditions.

At the same time we have to consider that government wheels turn slowly and therefore it may take years to craft a water sharing arrangement that fulfills all needs including those of our vital food production.

Projected sea level rises will mean changes to coastal infrastructure. Few coastal boundaries will escape. Property protection will become one of our most expensive outcomes. There will be the need to completely reshape the 7.5 km long barrages, and that alone will be laborious and expensive.

It will be even more expensive if we delay returning the lakes back to being estuarine. The huge project of reshaping the barrages will take years to plan and act upon, but the problems could be greatly reduced in an estuarine environment where seawater is involved.

The transition should be planned and acted upon now. The construction of a weir near Wellington with a lock should commence immediately. Remodeling of the barrages should be done in tandem to the building of the weir to provide for the scouring of the channels. This will provide for the seawater resources necessary to deal with sulphuric acid mobilisation which is already occurring in various regions of the lakes. It will also mean that we had planned and built to suit rising seas.

The transition commencement date is here.

2009-03-10T20:15:00.000-07:00

Welcome to the Lakes Need Water blog, the companion blog to the web site LakesNeedWater.org, covering the environmental crisis happening at the Lower Lakes (Lake Alexandrina and Lake Albert), Lower River Murray and Coorong.