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  • River Murray Barrages Environmental Flows - Lakes Need Water
    makes Over ten years ago in June 2000 the Murray Darling Basin Commission MDBC the precursor to the MDBA produced this insightful report cached The earlier 2000 MDBC report evaluated the environmental flow needs in the Coorong Lower Lakes and Murray Mouth CLLMM focusing primarily on the following two issues the altered input flows in the Lower Lakes and Coorong due to upstream river regulation the altered lake and estuary flows due to the construction of barrages separating the lakes from the mouth and the Coorong Four key issues driving the serious degradation of environmental values in the Lower Lakes and Coorong were identified namely 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 were identified as the most significant in terms of their impact and specifically the reduction of the tidal prism of the River Murray estuary i e the area of the Lower Lakes affected by tides to around 90 of its original pre barrage size Note that this was considered problematic in 2000 well before the onset of the most recent drought of 2003 2009 The report

    Original URL path: http://www.lakesneedwater.org/feature/river-murray-barrages-environmental-flows (2016-02-09)
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  • Biodiversity Loss - Lakes Need Water
    larger River Murray estuary that included the Coorong The barrages prevent seawater from mixing with the freshwater of Lake Alexandrina which has resulted in the destruction of 90 of the pre barrage estuarine environment In particular the installation of the barrages to retain freshwater in Lake Alexandrina has had a devastating effect on the mulloway fishery of the Coorong Olsen 1991 The Murray River Barrages Environmental Flows Report 1 75MB produced by the Murray Darling Basin Commission in 2000 identifies the following culprits that are a direct result of the barrages the current estuary comprising the Coorong and Murray Mouth areas is 10 of its former size brackish and saline habitats have been lost due to freshwater incursion abrupt changes in the water environment due to the drastic reduction in tidal range On 22 September 2009 DEH announced a 500 000 fish down with the goal of killing large numbers of carp before they die in Lake Albert Carp in particular have become a serious cause of biodiversity loss Carp were introduced into the Murray Darling system in 1964 and reproduce at such a high rate up to 5 million offspring per year they readily out compete native species The

    Original URL path: http://www.lakesneedwater.org/lower-lakes-coorong-problems/biodiversity-loss (2016-02-09)
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  • FAQ - Lakes Need Water
    evaporation The Lakes lose 750 to 950 GL annually ref MDBC which is approximately 4 times Adelaide s annual water consumption See fast facts for more water stats GL Gigalitre 1 000 Megalitres or 1 000 000 Kilolitres or 1 billion litres What are the water levels of the Lower Lakes See water level charts for average water levels for Lake Alexandrina Lake Albert and the Goolwa Channel What are the problems confronting the Lower Lakes and Coorong The main problems are acidification biodiversity loss soil salinisation and desertification Read more What is the proposed Wellington or Pomanda Weir The proposed Wellington Weir is a temporary weir near Pomanda Island that will separate the River Murray from Lake Alexandrina Read the Draft Environmental Impact Statement The Supplemental Environmental Impact Statement EIS 5MB Or the Executive Summary What is acid sulphate soil Acid sulphate soil ASS is the common name given to soils and sediments containing iron sulphides the most common being pyrite When exposed to air after being disturbed soils containing iron sulphides produce sulphuric acid and release toxic quantities of iron aluminium and heavy metals Read more on acid sulphate soils What is the acidification water level trigger This is the level at which acidity being formed in the lake sediments can no longer be neutralized by the alkalinity of the sediments and lake waters Any water levels below these will expose large areas of acid sulphate soils and any subsequent refilling including future freshwater inflows or the introduction of seawater will likely result in the acidification of the water body The current modelled critical acidification threshold water levels are minus 1 5m AHD for Lake Alexandrina and minus 1 0m AHD for Lake Albert What is paleolimnology Palaeolimnology is the study of past conditions in lake systems and

    Original URL path: http://www.lakesneedwater.org/facts/faq (2016-02-09)
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  • Fast Facts - Lakes Need Water
    GL The new desal plant is planned to produce 100GL Lower Lakes at 75 AHD full pool level hold 2 200 GL Lower Lakes evaporate between 750 950 GL per year The total amount required to fill and maintain the Lakes from their July 2008 levels to 0m AHD for one year is 1050 1250 GL Current active useable water in MDB storage the end of July 2009 is 1 470 GL 17 of capacity Current active useable water in MDB storage the end of Oct 2009 is 2 573 GL 30 of capacity Current active water in MDB storage as of 10 November 2009 is 6 715 GL 78 of capacity How much fresh water is required for a healthy ecosystem in the Lower Lakes From this senate submission by the Wentworth Group of Concerned Scientists Sept 2008 The most recent science estimates that to have a moderate to high probability of having a healthy southern connected river system in the Murray will require between 1 630GL and 3 350GL of new environmental flows If these estimates are extrapolated across the whole of the Murray Darling Basin we will need to recover between 2 116GL and 4 350GL of

    Original URL path: http://www.lakesneedwater.org/facts/fast-facts (2016-02-09)
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  • Pipelines - Lakes Need Water
    the agency responsible for the water supplies in South Australia According the SA Water website there are 5 major pipelines off the River Murray that supply South Australia As a result of the drought communities around the Lower Lakes were supplied with pipelines of potable water Information on Lower Lakes new pipelines Lower Lakes Pipelines Jervois to Langhorne Creek Drinking water to Hindmarsh Island and Pt Sturt About the private

    Original URL path: http://www.lakesneedwater.org/facts/pipelines (2016-02-09)
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  • Summary of Sea Water Intrusions into the Lower Lakes - Lakes Need Water
    been monitored by the automatic recorders installed during the drought These intrusions are caused by one of or a combination of tide ocean swells and wind The figure below shows EC water variations over the last 12 months at a monitoring location about 1 5km upstream of the Ewe Island Barrage These recordings show that there have been about 12 major intrusions over the past year and a similar amount of smaller intrusions These events can happen at any time of the year but as expected they are more frequent during the winter months because of higher swells and a greater number of storm events During the storm and subsequent period from May 22 2011 to early June the majority of the barrage gates were open and as a consequence the volume of saline water intruding was such that it extended past Point Sturt into Lake Alexandrina even though River flows were still high After this event the number of open gates was reduced to restrict the ingress of sea water during subsequent events It should be noted that during storm events the transmission of saline water once it has intruded into the Lower Lakes is aided by the effect of the wind over the water wind seiches Similar movement of water has been observed into and out of Lake Albert depending on the wind direction The relative water levels recorded over the period when the majority of the various barrage gates were open are shown below Plot B shows that even normal diurnal or semi diurnal spring tides will for a short period reverse even moderately high river flows C and D are water level plots during storm events in May and July where sea water intrusion penetrated further into the Lakes The July event also flooded the road

    Original URL path: http://www.lakesneedwater.org/feature/ian-s-corner/summary-of-sea-water-intrusions-into-the-lower-lakes (2016-02-09)
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  • Ramsar Convention on Wetlands obligations - Lakes Need Water
    website http www ramsar org defines wetlands to include marine and estuarine as well as lacustrine associated with lakes riverine and man made wetlands There is a recognition that wetlands may need to adapt to changing conditions in particular climate change There is even a special register the Montreux Record for sites at which changes in ecological character have occurred or are likely to occur So the organising bodies of the Ramsar Convention do not expect that any particular wetland will stay the same for ever In fact if seawater were to be allowed into the Lakes wetlands of a different but equally valuable nature would develop The species composition would change and it is conceivable that areas could contain large seagrass meadows which would support valuable nurseries for marine and coastal species as well as a haven for all kinds of wildlife and migratory birds There are plenty of other nearly enclosed coastal lakes containing seawater eg the Gippsland Lakes which are living examples of what Lakes Alexandrina and Albert could become given attention to some important aspects described below Some species which can only live in freshwater environments would gradually move elsewhere such as refuges which could be

    Original URL path: http://www.lakesneedwater.org/debate/ramsar-convention-on-wetlands-obligations (2016-02-09)
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  • Gippsland Lakes - Lakes Need Water
    listed wetlands February 2010 the Fishing Legislation Amendment Bill came up in the Hansard Darren Chester MP of Gippsland speaks about the fishing and tourism industry estimated at 200 million per year that is supported in the region of the Gippsland Lakes What should be of interest to South Australians is this What we have now is an artificial entrance into what was previously a freshwater lake system He speaks

    Original URL path: http://www.lakesneedwater.org/maps/gippsland-lakes (2016-02-09)
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