Hurry Save The Murray!

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There are two sides to the Clayton Bay Dam/Regulator. On the Goolwa side boats that have been high and dry for well over a year and now washed by the rising water.

On the Lake Alexandrina side, boats remain high and dry.

At Milang, the winter rains raised the Lake levels but boats are still stranded. (Note the lush regrowth on what was dry cracked soil. Note the lake has not acidified. Note the water has diluted not mobilised the acids.)

The Dam/Regulators at Clayton Bay and on the Currency Creek are creating new hydrological and aquatic niches.   At the Clayton Bay, the plume of pumped water is pushing against the retaining mud skirt, while the wind is whipping the water back against the Dam/Regulator. The pelicans are loving the new complex of water flows on the Goolwa side of the Clayton Bay structure.

The birds are busy at the inflow point to Snug Cove on the Lake Alexandrina side of the Dam.

But the only water that is reaching Dunn’s Lagoon is being driven by wind. The levels vary dramatically and this once raucous ecological hot spot, now that it is cut off from the fresh water from the tributaries, has fallen silent.

The water either side of the Currency Creek Dam/Regulator is also of a different quality. Today, on the upstream side the salinity level is lower (11,640 EC) than on the down stream side (13,500 EC), indicating that the salinity from the Goolwa Channel is reaching into the tributaries and not being mixed as it would have been before the closure of the Clayton Bay structure. On the other hand the water currently being pumped from Lake Alexandrina has been refreshed by winter rains and may help lower the salinity for a short period of time.

The force of fresh water coming down the Finniss River is still sufficient to keep the readings lower (7996 EC at Clayton Beacon 60) but the reading at the other end of the Goolwa Lake at the Hindmarsh Island Bridge was 16,841 EC this morning. The wild winds of the weekend have stirred the waters and we might expect to see the salinity within the new Goolwa Lake begin to even out and rise.

Readings taken on the weekend indicate that pH levels in the Lake and tributaries, on the up and down stream sides of the dams are close to or above neutral. The once cracked soils are saturated. The water bodies have not acidified. The shores are covered with lush new growth. There is no emergency.

So, what is happening at the Finniss River Dam/Regulator site? The access road is built. A construction work area has been cleared but the Dam/Regulator is on hold. One story from within the SA Government states that there is no longer any need for the structure. The hot spots have been managed with strategic liming, the acid sulfate soils (ASS) are saturated,  the winter rains have diluted rather than mobilised the acid. Another story states that come summer, the danger posed by the ASS will be even greater and once the current flows has slowed, construction will begin.

NB. The reason given by the SA Government for the “Regulators” on the Currency Creek and Finniss River was to catch the “first flush” of water after the winter rains. It was asserted this “first flush” would pick up the acid from the dry cracked ASS and overwhelm the water in the Goolwa Channel.  But the Currency Creek “Regulator” was not closed until September 8, long after the “first flush” had roared down the tributaries. The Finniss River “Regulator” is yet to be built. Where is the emergency?