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  • The Weirs - Lakes Need Water
    maintain the pool height for the water intakes for Adelaide This structure would be different from the locks upstream by having a spillway over which water would flow into the Lakes for most of the time and only be retained if water levels fell below the level of the spillway Since the drought has cont inued and the spectre of acid sulphate soils has loomed the possibility of opening the

    Original URL path: http://www.lakesneedwater.org/debate/the-weirs-and-barrages (2016-02-09)
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  • The problems of a dry Lake bed - Lakes Need Water
    river which fed the Sea caused the area of the Sea to r educe so much that former fishing villages to be left high and dry Salt and pesticide laden winds caused many heath problems in the surrounding areas If Lake Alexandrina is reduced to a series of isolated salty and acidified pools and Lake Albert drie s completely whether the lack of water is due to overuse upstream or

    Original URL path: http://www.lakesneedwater.org/debate/the-problems-of-a-dry-lake-bed (2016-02-09)
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  • Engineering aspects of seawater in the Lakes - Lakes Need Water
    open channel would be a larg e scale and expensive operation and it is likely that it would need to be at least as extensive than at Lakes Entrance since I would expect that the open ocean at the mouth of the Murray would have similar wave energy Another model which could be considered is that used at West Lakes where the sea is allowed into the Lakes at High tide and drains out of the other end of the system during falling tide This maintains the water in the syste m in a state not too dissimilar to that of fresh sea water unless there is polluted stormwater coming in from the paved surfaces If an artificial outlet could be constructed as an exit for seawater say from Lake Albert through the Coorong and through the Younghusband peninsula then a system of maintaining circulation of s ea water in the Lakes could be set thereby preventing the build up of salinity If navigability were sacrificed these channels could be much narrower than the one discussed above perhaps even large pipes There would presumably also be a much small er requirement for sand dredging There would have to be an

    Original URL path: http://www.lakesneedwater.org/debate/engineering-aspects-of-seawater-in-the-lakes (2016-02-09)
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  • Summary of Murray Futures "Securing the future" report - Lakes Need Water
    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

    Original URL path: http://www.lakesneedwater.org/feature/murray-futures-securing-the-future-summary (2016-02-09)
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  • Acid Sulphate Soils and Seawater - Lakes Need Water
    Cross GeoScience Southern Cross University NSW An excerpt from the abstract of this paper says The effects of restoring marine tidal inundation to a severely degraded acid sulfate soil landscape were investigated Five years of regular tidal inundation led to substantial improvements in a range of key parameters used to assess soil and water quality The pH of estuarine creeks improved dramatically following reintroduction of tidal inundation The abstract continues This study demonstrates that marine tidal inundation can be an effective method for remediating acid sulfate soils at a landscape scale However there are a range of potential geochemical complexities which need to be considered prior to implementing this technique The paper goes on to say Tidal inundation of ASS is a potentially lowcost landscape scale remediation technique which has recently been trialled in far north Queensland It is well suited to situations where the site is close to a large marine source where the elevation of ASS is close to mean sea level and conventional agricultural landuse has been abandoned Loveday Bay SA 200 ha of acidic water as of August 2009 Loveday Bay 200 ha has already turned acidic Lake Albert s clayey centre is also at high

    Original URL path: http://www.lakesneedwater.org/feature/acid-sulphate-soils-and-seawater (2016-02-09)
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  • Fencing on public land - when is a fence a deathtrap? - Lakes Need Water
    absolutely have the right to enter water frontage crown land and use it for passive recreational purposes such as walking riding or birdwatching Setting aside the legalities for just a moment what about the damage done by cattle to potentially acidic soils After all fences go to the water s edge in the first place presumably so cattle can drink Experts agree that the lakebed soils should not be disturbed Damage by cattle hooves in soft mud has it s own special name pugging DEH is aware that pugging by cattle causes ASS disturbance and recommends that livestock should be fenced away from lakebed not lead to it Alexandrina Council brushes it off claiming it is crown land and not their responsibility Councils and landowners on Lake Alexandrina and Lake Albert should not be so cavalier though Accidents are already happening and law suits will undoubtedly follow The LakesNeedWater team has been forwarded the following photographs from a person who was injured when they came across a man trap style fence on the dry lakebed Out for a slow ride around the lake s edge this person was unable to see the single strand of barbed wire until it was too late The strand he ran into spanned 18 metres without a single intermediate star dropper Not even a piece of construction tape as a warning Can you see the wire in the photo at left This person was extremely lucky to survive 10 cm to the left or right and he would have bled to death on the lakes edge As it was he was hospitalized for two days and has lasting injuries The photo at right is the detail of the distant lump in the lefthand photo Notice the pugging or damage to the lakebed floor by livestock

    Original URL path: http://www.lakesneedwater.org/feature/fencing-on-public-land (2016-02-09)
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  • Ramsar Convention on Wetlands - Lakes Need Water
    action and international cooperation for the conservation and wise use of wetlands and their resources The Ramsar 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 for sites the Montreux Record 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

    Original URL path: http://www.lakesneedwater.org/feature/ramsar (2016-02-09)
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  • Lower Lakes Bathymetry - Lakes Need Water
    habitats in the region under different intervention strategies and therefore the distribution of shorebirds and estuarine fish species What the levels mean For the Lower Lakes it is interesting to us because it shows us the area of soil which would be left dry as water levels recede It shows whether you would have steep banks or shallow wading pools and it tells you whether you ll have water under your jetty at different AHDs It also tells scientists a lot about the habitats that will be created or lost at different water levels What is bathymetry Bathymetry measures the depth of water in oceans or lakes AHD Australian Height Datum levels are given relative to mean sea level which has an AHD value of 0 Positive values of AHD mean that the water level is above mean sea level eg at high tide and negative values mean that the water level is below mean sea level eg at low tide A bathymetric map shows the contours of different depths displayed in our map by different colours What species would we gain Although t he CLLAMM 2009 report focuses on the Coorong the scientists recommend that a similar investigation be

    Original URL path: http://www.lakesneedwater.org/feature/lower-lakes-bathymetry (2016-02-09)
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