Patawalonga Lake

Tide Level Close

Note

The heights used here are all based on the Australian Height Datum (AHD). They are different from the Chart Datum figures used in Tide Prediction charts. Subtract 1.452m from Tide Prediction chart values to find the equivalent AHD value.

Tides take about 6 hours to change from low tide to high tide and about the same again to the next low tide. The highest tide recorded at Glenelg was 2.25m AHD in July 1981.

How tides affect the lake

Normally some seawater is allowed into the Patawalonga Lake each time the tide rises. When the tide level rises over 0.6m AHD, the Glenelg Gates close and keep out theSea Water.

However high tide levels will affect the operation of the system because they may:

delay release of stormwater flows via the Barcoo Outlet.
delay release of water from the Patawalonga Lake via the Glenelg Gates.

Tide forecasts

You can look up forecast tide levels at www.bom.gov.au/australia/tides/#!/sa-glenelg

Figures in these tide tables are in Chart Datum (remember to subtract 1.452m from the chart figures to obtain the AHD level).

Warnings If a public warning has been issued about a predicted high tide, it will appear on this web page www.bom.gov.au/sa/warnings/ under "Warnings current".

Patawalonga Lake

The Patawalonga Seawater Circulation and Stormwater Outlet System was completed in 2001 and controls water levels in the lake between 0.1m (low) and 0.6m AHD (high).

Managing flood risk
Occasionally stormwater flows into the Diversion Basin or the Collection Pond cannot escape to sea via the Barcoo Outlet either because it is already flowing at maximum capacity or because high tides temporarily prevent its release.

Stormwater is then allowed to enter the Patawalonga Lake where it can be stored until tide levels fall and it can be discharged through the Glenelg Gates and the Barcoo Outlet.

Note that there is no risk of flooding to nearby properties until the lake level reaches at least 1.6m AHD. The risk will be compounded with continued rainfall and high tides.

Diversion Basin

Normally the Diversion Basin receives seawater from the Patawalonga Lake via the Northern Gates and when the tide level in the Gulf has fallen sufficiently, it passes down the Barcoo Outlet back to the sea.

The Diversion Basin also receives stormwater from the Sturt River Weir and if the Barcoo Outlet is closed or running full, stormwater will be stored in this pond. If the level of stormwater in the pond exceeds 2.0m AHD, the Northern Gates will open and it will be allowed to flow into the Patawalonga Lake for storage until it can be released via the Glenelg Gates.