“SA natural icons dying from thirst,” The Independent Weekly
“Govt in damage control over Murray-Darling report,” The World Today, ABC news
“SA alone can't save lower Murray, Coorong: minister,” Yahoo news
“ACF urges emergency action for Murray Lower Lakes and the Coorong,” prismwebcastnews
“SA urged to lead Murray revival,” ABC news
“Murray-Darling Basin is dying: report,” Ninemsn news
“Murray lakes may be lost,” The Age
“Murray on verge of last gasp,” Sydney Morning Herald
“Murray-Darling raindance,” Blogocracy blog
The only floods around here lately are headlines. What the lakes and Coorong need is water.
The Lower Lakes are at the lowest ebb in recorded history:
"In May this year Lake Alexandrina water levels were as low as 0.69 metres below sea level. Lake Albert was as low as 0.74 metres below sea level, placing it in danger of ecological disaster."( Dr Simon Benger, researcher, Flinders University School of Geography, Population and Environmental Management.
"In 2002 it was estimated that median freshwater flows at the Murray Mouth had been reduced to 27% of natural flows... No water releases through the barrages have occurred since October 2006 but saline intrusion has occurred back into the Lakes as a result of the level of the seawater on the downstream side of the barrages being higher than the lake level...The lakes are now at "(- 0.5m AHD), about 1.2m below their normal pool level. Based on geological evidence the Lakes have never been below sea level in the 7 500 years since they formed." Substantial amounts of fresh water are needed in the lakes by October if irreparable ecological collapse is to be avoided. (Lakes Alexandrina And Albert Ecological Condition Progress Report. SA Murray-Darling Basin Natural Resource Management Board, April 2008)
Highly reactive acid sulphate soils
Over 3 000 ha of sediment on lake fringes and wetlands has been exposed to the air. (NRM Porgress Report) There is real danger of forming "sulphuric acid which can then leach into the soil, wetlands and the lake itself killing organisms and ecosystems." (Dr Simon Benger)
There is a likelihood that the water and sediment chemistry can "release a range of heavy metals and toxic metalloids into the water body at concentrations hazardous to human health, water ecology, livestock, flora and fauna...CSIRO data shows that over 1 000 ha of the dried lake margins is currently sulfuric (pH<4).>
High salinity levels
"Salinity levels currently stand at 4258 EC (electrical conductivity) units in Lake Alexandrina and 4168 in Lake Albert, or approximately four times accepted maximum levels for Adelaide drinking water."(Dr Simon Benger) This is Raukkan and Narrung's water supply.
Contaminated ground water
"There is some evidence of local shallow groundwater becoming acidic." (NRM Porgress Report)
Dredging at the Murray Mouth
"Some $2 million per year" has been spent since 2002 on dredging sediments at the Murray Mouth, once scoured clear by Murray River flows. This "is the only thing keeping many species alive within the Coorong as tidal seawater flows in and out of the Mouth. " (Dr Simon Benger)
Damaged Ngarrindjeri burial grounds
Falling water levels have exposed Ngarrindjeri burial grounds. The Ngarrinjderi community is distressed by damage and looting.
"Cattle have been walking through them, people have been picking up skulls and bones and taking them home as trophies..."observed Ngarrindjeri elder Matt Rigney.
Dying vegetation
"Large stands of water milfoil (Myriophyllum sp.) situated to the north of Hindmarsh Island have died as a result of increased salinities in this region. This species provides valuable habitat for small bodied native fish, and a food source for birds such as swans. ...If freshwater returns to the Lakes then wetland plants, which are good
seed dispersers, may return providing sediment conditions are favourable"(NRM Porgress Report)
Endangered fish
"There is potential under the ‘no improvement’ scenario that water quality conditions will deteriorate sufficiently (elevated salinity levels, decreasing pH, heavy metals being mobilised together with elevated temperatures in summer reducing dissolved oxygen) that a major fish kill in the Lakes could result."(NRM Porgress Report)
A captive breeding program is rescuing "endangered native fish found in the lower lakes of the Murray in South Australia." (Mike Hammer, of Native Fish Australia)
Endangered frogs
"The lack of water and habitat has greatly reduced frog populations." (NRM Progress Report)
Endangered birds
"Waterbird numbers for most species declined in 2005, 2006 and 2007. (David Paton, 2008) Australia has an obligation under the Ramsar treaty to protect the habitat of migratory wading birds.
Endangered mussels
"The freshwater mussel is washing up dead on the shores of Lake Albert in large numbers." This occurrence is likely to spread to Lake Alexandrina. (NRM Porgress Report)
Endangered invertebrates
"These species show a reduction in diversity and abundance when salinities exceed 2 500 EC and significant impacts may occur if lake salinities exceed 5 000 EC." Invertebrates are a major food source for fish and birds. (NRM Porgress Report)
Invasion by marine polychaete worms
"Larger creatures such as crabs and turtles are being overwhelmed by the weight of worm formations on their shells and are dying in large numbers. Such effects are thought to be due to rising salinity levels throughout the Lower Lakes." (Dr Simon Benger)
Increased likelihood of algae blooms
"Physical conditions in the river and the Lakes (low flows, temperature stratification, low turbidity) are conducive to algal bloom formation." (NRM Porgress Report)
Low dissolved oxygen
"Temperature and salinity stratification due to low flows could result in depletion of dissolved oxygen in the bottom waters and deeper pools of the river.... could result in large amount of phosphorus being released from the sediments and this may trigger algal blooms... Persistent low dissolved oxygen (less than 5mg/l) levels would impact on fish growth and further reduction (less than 1 mg/L) would result in fish kills." (NRM Porgress Report)
Urgently needed water flows
In excess of 600 GL of water is needed to raise lake levels to +0.3m AHD to improve the "health of the Lakes ecosystems... This would still not be sufficient to achieve reconnection with the Coorong, which would occur at around +0.65m AHD and require approximately 800 GL. Once Lake levels reach +0.65 m AHD, all fishways are operational. Regular flushing and fishway operation would begin to restore connectivity between the
Mouth, Coorong and Lakes enabling fish to migrate and complete their life cycles." (NRM Progress Report)
Artificial life support for the disconnected lakes
In May 470 ML were pumped from Lake Alexandrina to Lake Albert each day. In June it's expected 360 will be pumped, dropping in August to 200Ml and pumping stops at the end of September when funding ceases. The pumps are currently run on bio-diesel with pumping costing $600,000 a month.
"After this time, a greater volume (up to 1 GL per day) will be needed to prevent the lake level from dropping or other options will need to be considered...The decline in ecological character can only be halted and reversed if substantial freshwater inflows are received within the next six months." (NRM Progress Report)
Limited management options
"...we don't have the water in this state to be able to fix these problems; it must be dealt with at a national level," said SA Water Security Minister Karlene Maywald.
"Management options for the lower lakes are limited," Environment Minister Peter Garrett told Parliament, after the fourth-driest autumn on record had left "storages in the lower Murray-Darling ... at record lows.
So without significant flows into Lake Alexandrina, what will happen to Lake Albert at the end of September when funding for the emergency pumping of water stops?
Seawater pumping into Lake Albert?
"This would only be considered as a last resort if Lake Albert was definitely going to
become acidic... flooding Lake Albert with seawater would also lead to permanent ecological change:-
"Loss of freshwater species and food chain impacts.
"Salt intolerant and emergent vegetation species would be degraded and depleted contributing to the nutrient load.
"If seawater was put into Lake Albert and there was no connection to Lake Alexandrina, then a large fish kill would most likely occur.
"After 12 months it would change to a totally marine system. "(NRM Progress Report)
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