What is Secure Yield?

    Secure yield is a term used to describe how many properties can be supplied from a water supply source. It’s a theoretical calculation that is based around a number of factors including the records of flows in the water source, rainfall records in the catchment of the water source, average household water usage, assumed severe drought conditions and moderate water restrictions being in place.

    Does Mulgum Creek have enough water to provide secure yield for Nimbin?

    Yes. Mulgum Creek provides enough water to meet secure yield requirements for Nimbin’s current population and level of development.

    Does Mulgum Creek have enough water to provide secure yield for further expansion/development of Nimbin?

    Some. Calculations show that there is sufficient capacity in Mulgum Creek to cater for some further expansion of the village. This would be new dwellings constructed on land already approved for development.

    What about dual occupancy?

    Some. There would be some capacity to cater for dual occupancy in the village. How much would depend on how much of the approved development referenced in the question above has been built.

    What happens when the theoretical secure yield has been met? Will Nimbin run out of water?

    No. The secure yield calculation is not a measure of when water will become unavailable. It’s a calculation of how much water can be supplied (how many dwellings can be supplied) with water in a severe drought with moderate restrictions. What it means is that in an extended dry period or drought, there is likely to may be a need to introduce restrictions earlier than normal. In a severe drought, alternative measures to supply water such as trucking water in, would need to be introduced earlier than otherwise needed. In an average year or wet year, there would be little or no difference.

    What is Council doing to improve the secure yield for Nimbin?

    Council has allocated funding to construct a new water treatment plant for Nimbin. This will allow us to be more efficient in the way that we use water from Mulgum Creek. For example, after long periods of rain, or heavy rain, Council has to flush its supply main to D E Williams Dam to clear out the dirty water. The new treatment plant and supply main will remove the need for this. Council is also looking at alternate water supply options e.g. Council has a licence to extract water from a bore near the swimming pool.

    What is Council doing about Environmental Flows in Mulgum Creek?

    Council is not the regulatory authority for waterways in NSW and therefore has no ability to directly regulate how/if or when water is extracted from the creek and by whom. Council has a licence to extract water from Mulgum Creek for the purposes of supplying water to Nimbin and follows the terms and conditions of that licence. What Council can do is seek to minimise the amount of water it does extract from Mulgum Creek, thus leaving more water available for environmental flows. The construction of the new water treatment plant will allow Council to remove or modify some inefficient maintenance practices that we currently have to employ (e.g. as described in the previous question) and therefore reduce the amount of water extracted from the creek. Staff will also explore other opportunities to reduce the need for extraction from Mulgum Creek as the water treatment plant project progresses.                        

    Who can I report suspect activity for people pumping directly out of Mulgum Creek to?

    Please visit https://www.industry.nsw.gov.au/water/what-we-do/contact-us to make an online report or: