Protecting Christchurch's water quality through groundwater modelling, treatment and holistic decision making
Annual Conference
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Christchurch City is blessed with a groundwater supply of pristine quality, and this is enjoyed by all.
The onset of the Drinking Water Standards for New Zealand 2005, DWSNZ 2005 (Revised 2008), has required Christchurch City Council to assess a small number of water supply wells with regard to complying with the criteria for secure groundwater. This largely relates to some wells being too shallow.
In 2008, CCC asked Pattle Delamore Partners Ltd (PDP) and GHD Ltd to work in parallel on whether the most suitable option for CCC to address this was to drill deeper (to access aquifers with secure groundwater) or to treat the existing water using ultraviolet (UV) irradiation.
This joint paper outlines PDP’s involvement in advising CCC with regard to hydrogeological matters relating to compliance with DWSNZ, including development of an advanced hydrogeologic model and the methodologies involved. Peter Callander outlines how a specific methodology was derived for the CCC case.
Chris Taylor presents work relating to water treatment on this subject, building on work Chris delivered in 2005. Chris presents pre designs of UV systems from selected sites. Challenges were overcome as a number of sites have limited room for the UV installations and required pipework configuration.
Bryan Hickling presents CCC’s view and how decisions were made against the two options provided, balancing commercial, environmental and cultural sensitivities.