Watch the Drops status changes for some Central Otago communities
The Omakau, Ophir, Naseby and Ranfurly communities have moved into the Red Drop water conservation status.
Low water level in Falls Dam is affecting the availability of water in the Manuherekia catchment, and as a result, the Central Otago District Council (CODC) is moving Omakau and Ophir into the highest conserve water setting, the red drop status.The same setting also applies to the Naseby and Ranfurly townships to reflect the very low water levels in their water supply source.
The Otago Regional Council recently advised of near-drought conditions across much of the South Island and is cautioning Otago farmers, along with rural and urban communities to consider conserving water in the weeks ahead.
The Red Drop requires a total ban on sprinkler use but does allow for minimal handheld hose use with a trigger nozzle for garden watering only.
“We are reaching out to the community to do our part within the Manuherekia catchment,” CODC Three Waters Director Julie Muir said.
“As well as the sprinkler ban, we are asking the community to check how they can reduce their water use throughout our homes and business.”
Taste and odour issues at Omakau
The decrease in river level has seen an increase in complaints related to the taste and odour of the water supply in Omakau and Ophir - an issue these communities have been experiencing for periods over the past year.
An initial event occurred in Omakau/Ophir in March 2023 when the CODC received reports of musty/muddy smelling and tasting water. An investigation was carried out with the cause found to be an a naturally occurring chemical called Geosmin, which is produced during the breakdown of algae and other micro-organisms in the raw (untreated) source water.
“Geosmin has a distinct earthy or musty odour which most people can easily smell and causes most taste and odour outbreaks in drinking water. Seasonal increases in naturally occurring algae or bacteria in water can cause geosmin levels to increase above the tasting threshold,” CODC Three Waters Customer and Compliance Team Leader Philippa Bain said.
“Although the taste and odour can be unpleasant, geosmin is not harmful to health.”
The community also experienced taste and odour issues in early January this year and a review of the cause was undertaken.
Given dropping river levels and hot conditions, laboratory testing for cyanobacteria was undertaken to ensure the safety of the water source. Geosmin can be produced during the breakdown of algae and can be linked to a cyanobacteria event. All lab samples have showed no levels of concern.
Unfortunately, due to the low river levels, taste and odour issues may continue until flows in the Manuherekia River increase again and temperatures drop.
Since this event, CODC has had contact with residents in the community who have noted that the severity of the taste and odour issue has fluctuated over the past two months.
“People within the community do have different levels of sensitivity to the taste and odour, some noticing it more than others,” Ms Bain said.
There had been concerns raised from the community about the safety of the water.
“When the Central Otago District Council receives a taste and odour complaint, we arrange for water sampling as soon as possible. We check for treatment plant operational issues or network issues. We also check all our routine monitoring information and water quality data.
“We acknowledge the frustration and discomfort related to the taste and odour issue but want to assure the community that the water supply is being monitored closely. Any concerns that water is unsafe are taken very seriously and we will ensure the community are aware of any issues.”
See Watch the Drops table for your status. More info and advice on Water Conservation is available at: https://www.codc.govt.nz/services/water-services/water-conservation.
