Council To Investigate Stormwater & Wastewater Systems

Next week Council contractors in will begin a thorough street investigation of the stormwater and wastewater systems in Oamaru and Weston. The investigation aims to stop stormwater entering the wastewater system and avoid large costs for ratepayers.

Council’s Assets Manager for Water and Wastewater Services, Martin Pacey, says the need for the investigation became apparent after staff discovered stormwater has been entering the wastewater system from unknown locations.

“Normally stormwater and wastewater are collected separately. Stormwater flows out to sea and wastewater is piped to the plant in TY Duncan Road for treatment. If stormwater enters the wastewater network it takes up part of the pipe capacity needed to carry wastewater to the plant. This has the potential to cause some serious problems and unnecessary costs for Council and the community in the event of heavy rainfall.”

If the wastewater system overloads, wastewater can overflow into properties and streets. The unnecessary treatment of the stormwater is costly to the ratepayers.

During investigation, manholes in the streets and road reserve will be opened and accessed, fire hydrants will also be used.

“Householders in Oamaru and Weston will receive a letter advising them of the programmed survey and potential work within the road reserve at least a day before the investigation takes place in their area. Council will provide updates over the coming weeks, including a map of each area where the survey will take place,” Mr Pacey said.

Council expects work to take around two months. Contractors will carry out most of the work during the day. Some of the network in the commercial area will be surveyed at night to minimise inconvenience to motorists and businesses.

Contractors will use dye to search for areas where stormwater flows into the wastewater system. The dye that will be used is environmentally friendly, non-toxic and biodegradable dye. The Otago Regional Council has given the Council consent for the dyes use.

Council apologises in advance for any inconvenience caused by the wastewater inflow investigation. Council appreciates the co-operation of those affected.