Emigrant Creek Dam

Alert: Potentially toxic levels of blue-green algae detected in Emigrant Creek Dam. Keep up to date here...

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.

Facts and Figures

History

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.

Operations

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.

De-stratification

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.

Info Sheets

ECD 7 Our Water Supply
ECD 8 Water Treatment (at Emigrant Creek Dam)
ECD 13 Emigrant Creek Dam (dam technology)