Home » The region's water supply » Our Water Sources » Emigrant Creek Dam
22 November 2021
Recent sampling of blue-green algae at Emigrant Creek Dam has shown steadily declining algae cell counts over the last two weeks and the alert level has subsequently reduced from High to Medium in accordance with guideline levels for drinking water supplies
The water treatment plant at Emigrant Creek Dam is designed to treat water under these conditions and water provided from the treatment plant complies with Australian Drinking Water Guidelines.
However, people are advised to avoid contact with affected water upstream of the dam and around the dam. Animals are particularly sensitive to the toxins release by the algae, therefore care should be taken to ensure pets and livestock do not drink or swim in the water.
These toxins cannot be destroyed by boiling, and boiling may increase their toxicity.
Rous County Council will continue to monitor and test the water at Emigrant Creek Dam and provide notification when levels of algae return to safe levels.
Emigrant Creek Dam is located near Tintenbar, 11km north-west of Ballina. The water in Emigrant Creek Dam comes from a catchment that is an agricultural area with rural residential and some tourist development.
Water stored in the dam is used to supply drinking water to the Ballina and Lennox Head areas. It supplements the Rocky Creek Dam and Wilsons River supplies.
Earth-fill embankment abutments
|Year of completion||1968/2002|
|Embankment height||13 metres|
|Embankment length||140 metres|
|Catchment area||19 km2|
|Lake area||31 ha|
Emigrant Creek Dam was constructed between 1967 and 1968 and at that time, it provided the major water supply to Lennox Head and Ballina. In 1998 these areas were connected to the Rous County Council supply system however Rous County Council continued to use Emigrant Creek Dam to supplement their other sources.
In 2002 the dam was upgraded to new design standards so that it would safely withstand the "Probable Maximum Flood" - this is the volume of water flowing into the catchment from the largest flood event likely to occur. This would theoretically create about 5.5 metres of water flowing over the spillway. The upgrade involved raising the embankments, reinforcing the spillway and anchoring it to bedrock about 30 metres below the creek bed.
Emigrant Creek Dam is used to supplement the Rocky Creek Dam and Wilsons River supplies. Rocky Creek Dam is used for preference as it has the lowest operating costs. The other sources are brought on-line as the storage level in Rocky Creek Dam drops to help secure our water supply and avoid water restrictions.
Emigrant Creek Dam has a capacity of 820 mega litres at full supply level. The dam wall is 13 metres high and 140 metres long and is made up of about 6,000 tonnes of rock, soil, concrete and steel. Water is released via an integrated spillway which is designed to discharge 950 cubic meters of water per second under probable maximum flood conditions. The highest observed level at the reservoir was two metres above the spillway on July 9, 1985, corresponding to an outflow of 280 cubic metres per second.
The dam also releases environmental flows through two valves in the base of the dam. These are intended to mimic the natural flow patterns of the creek and minimise the impact on water quality downstream of the dam.
Emigrant Creek Water Treatment Plant is located adjacent to the dam. The plant starts and stops based on demand from the reservoirs in the supply network. When required, water is pumped directly from the dam into the plant for treatment.
For safety reasons, and to protect our water quality, there is no public access to the dam structure or lake. You can view the dam from a lookout at the end of the Water Walk which is accessed from Killen Falls Drive. There is also a walk that takes you to Killen Falls as well as car-parking facilities and picnic facilities. There are no toilets at this site. Learn more about the walks at Emigrant Creek Dam here.
The dam has a de-stratification (aeration) system. This system mixes the water in the dam, preventing layers of different temperatures or oxygen levels from developing within the water column. De-stratification reduces conditions favoured by blue green algae and prevents the bottom of the dam becoming anaerobic. Dissolved Oxygen and Temperature are measured at various locations in the dam each week to ensure the water is properly aerated and mixed. Water samples are also tested for blue-green algae weekly with increased testing in the event of an algal bloom. If a medium to high level algal bloom occurs, affected residents will be notified by phone and warning signs erected around the dam and at Kirklands Crossing. Further information about blue-green algae management and current NSW alerts is available from the NSW Office of Water.