The water we store in Karangi and Shannon Creek Dams to supply our drinking water is pumped from the Orara and Nymboida Rivers. There are two vital aspects to river water in these catchments which Council assesses to ensure our community has a safe and secure drinking water supply – water quantity and water quality.

Following heavy rain events, quantity may be well above minimum licenced environmental flow levels but quality issues can arise which prevent the pumping of this water into our dams for a period of time. Council monitors the water quality including turbidity levels – a measure of how much dirt is in the water - and will begin pumping once the quality tests indicate the river water is clean enough to pump from the rivers into our storage dams for our drinking water supplies.

Prior to the rainfall event in mid-January 2020, the last pumping from the Orara River occurred end of October, 2019. After the January rain, flows in the Orara River increased enough that Council was able to begin pumping after just a few days of waiting for the turbidity results to fall to clean water levels. This pumping ceased after 15 days – even though turbidity levels were good, the flows in the Orara River fell below environmental flow requirements. Following the rainfall in early February, Orara River levels have again increased above environmental flow requirements but turbidity levels are currently still too high to be able to pump from the river. It is hoped that the large amounts of rainfall across the catchment will cause the river flows to remain above environmental flow minimums long enough to allow Council to pump clean water to fill Karangi Dam back to 100% in the near future.

The last time we were able to pump water from the Nymboida River was early August, 2019. Unfortunately, due to potential water quality issues caused by the devastating bushfires around Nymboida in November, 2019, Council was unable to pump any water from the Nymboida River following the January 2020 rainfall event. Even though this rain also increased flows in the Nymboida River above environmental flow levels, additional water quality tests were required to ensure rain runoff over the burnt catchment areas was not washing pollutants into the river which could negatively impact drinking water quality.

These tests were run again following further rain in February and have now indicated water in the Nymboida River is not being made unsafe for drinking by the bushfire disaster. However, turbidity levels in the Nymboida River are still too high and pumping will only commence once turbidity levels fall to indicate the water is clean enough to start re-filling Shannon Creek Dam. It is hoped that with the large amounts of rain received across the catchment, river flows will remain high enough for months and allow Council to pump clean water from the river so that Shannon Creek Dam can be once again filled to capacity.

Shannon Creek Dam is a storage dam built in the Shannon Creek catchment but only water pumped from the Nymboida River is permitted to be stored in Shannon Creek Dam. The water licence from the NSW Government for Council to operate the Shannon Creek Dam requires that any rainfall which falls on the dam has to be released from the dam to continue its normal flow through the Shannon Creek catchment. This is to ensure that Shannon Creek Dam has minimal impact on the local Shannon Creek environment. Even if we are on water restrictions at the time, releasing the water from the dam is a critical process to minimise the environmental impact of the dam and comply with our licence requirements.

Following the intense rainfall events in February, the levels in Shannon Creek Dam increased despite there being no pumping from the Nymboida River. This means that the increase was as a result of rainfall on the dam and all of this water must be released to the Shannon Creek environment.

Water Restrictions are based on the combined storage level of both dams and will remain in place until all quantity and quality conditions are met to allow pumping from the Orara and Nymboida Rivers to commence and storage in the dams is re-filled to adequate levels.

Council may also consider climate forecasts to ensure lifting of water restrictions is the best option for the long-term security of our drinking water supplies to avoid situations where restrictions are re-introduced shortly after lifting them.