Water supplies affected by recent rain fall events in the district

Monday 07 January 2013

The high rainfall experienced of late has caused very turbid, strong flows to our natural waterways, many of which we have intakes for our drinking water schemes. Those affected to date are the Hanmer Springs supply, the Waiau Township supply and the Kaiwara Rural supply.

Waiau Township - TEMPORARY BOIL WATER NOTICE

Due to the detection of Ecoli in recent water samples for the Waiau Township Water Scheme, Hurunui District Council issued a precautionary temporary boil water notice on Saturday.  Drinking contaminated water has the potential to cause illness, including vomiting and diarrhoea. 

With immediate effect all drinking water, including water used for brushing teeth and washing vegetables etc, should be boiled for at least 1 minute before consumption. 

CURRENT SITUATION:

We have received one clear test result.

We are dosing continuously with chlorine, however even with this treatment and the clear result we will not be lifting the boil water notice until we have THREE clear tests. We will be monitoring closely until we have the three consecutive clear test results.

The problem was caused by the extremely turbid water conditions resulting from the high rainfall last week. Normally automatic increased chlorination would occur to compensate immediately, however the automation failed. Manual dosing has been in place until the fault was fixed. We are hopeful that there was sufficient residual chlorine in the supply to prevent the contamination causing illness however we are not taking any chances and the temporary boil water notice was enacted.

As results and/or further information comes to hand we will advise it here on this page.

Please phone 03 314-8816 if you have any concerns or Skype our customer services team during normal business hours use the Skype button on the home page or hdc_customer_services

Hanmer Springs had an e-coli count of 6.4 last week Friday, but subsequent retests have shown this to have dissipated as the purifications works have gradually adjusted and make their mark. Although we have high coliforms to this supply (non-dangerous to human consumption), the e-coli count has remained less than 1 per 100ml. This system has been tested three times and has three clears.

Kaiwara Rural Supply in addition to being on a permanent boil water notice, has two further concerns.

A. The first concern relates to the turbidity of the flow of this waterway. The intake pump can well manage the silt levels, but the pumps on-line are ill-suited to manage this (potential impelllar damage and pump burn-out). The supply was temporarily interrupted due to a power outage and Mainpower . didn't notify us of the situation immediately. The supply is up and running again however water is turbid (cloudy). Property owners need to check their filters and make sure these are cleaned and maintained.

Rural supply customers are required to ensure they have three days storage capacity. Capacity is linked to consumption demand, for instance dairy cattle require 70 litres per day so consumers need to ensure they have purchased sufficient units of water to cover their needs.

B. The second concern is the is the velocity of river water flow and the risk of losing the temporary sludge pump in the river to extract drinking water to this scheme. This concern seems to be alright currently, but a more permanent secure intake is necessary to resolve this issue. We are currently investigating this permanent solution (report to the next Cheviot Ward Committee meeting in Februray 2013) for placement, installation, extraction options (bore or gallery), costs and risk. The cover from our insurance policy should also give clearer direction in terms of affordability of intake installation.

 

Amberley drinking water supply - reservoir levels are being watched carefully for the Amberley drinking water supply and drinking water from the Kowhai River Road intake is being provided into this scheme as and when required. Although harder than the drinking water supply from the State Highway intake, it is certainly palatable and safe to drink. All residents are asked to prudently water their lawns and conserve this essential resource for human consumptions needs.