A $15 million programme to replace shallow wells supplying water to 80,000 residents in northwest Christchurch is progressing well, with all those residents now receiving water from 14 new deep wells.
The remaining unconfined shallow wells are being upgraded as it is possible that microbiological contaminants in surface water could seep into the aquifer.
In September last year, Christchurch City Council agreed to fast-track work to drill deeper wells in northwest Christchurch as a response to the contamination event in Havelock North which heightened concerns about water quality nationwide.
Council Planning Delivery Manager Three Waters and Waste John Moore said the programme was progressing well, with 14 out of 28 new wells already commissioned and in use.
“In terms of the physical drilling, we are half way there which is great progress and on target for our planned finish in June 2019.
“We’ve already been able to decommission six of the old wells and have turned off the remaining old wells. As a health and safety issue, we need to retain the option to turn those old wells back on until work is complete on all 28 of the new wells and we have them all fully functional.”
Mr Moore said the current water grading on the shallow wells was D, compared to a B grading across the rest of the city where drinking water is sourced from secure, deep wells.
The northwest water supply zone stretches from Belfast through to Yaldhurst and includes parts of Riccarton and Addington, supplying 80,000 people.
“We’ve got an excellent working relationship with the Canterbury District Health Board and they’re happy with the progress we are making on this programme. It is a huge project that started in 2012 and is going to continue for two more years, costing around $15 million. In the end we will have a secure supply of high-grade drinking water for the north west of the city.”