38 | REGIONAL Kaipara District Council Project Management Civil Engineering Environmental Asset Management hoskingroup.co.nz T T Virginia Wright Protecting a ‘unique environment’ Taharoa Domain is the official name of an area commonly called Kai Iwi Lakes, which includes the smaller Lake Kaiiwi, the main Lake Taharoa, and Lake Waikare. “The three lakes are all dune lakes, with Lake Taharoa one of the largest in New Zealand. Dune lakes are fed by natural ground water rather than a river. It’s a unique environment with wonderful clear water. It’s a jewel in the crown of the Kaipara District.” With the opening of the upgraded Taharoa Domain treatment system at Pine Beach in July, a significant stage of one of Kaipara District Council’s infrastructure projects is fully complete and operational with the next phase now underway. The wastewater treatment system serves both the campground and the Pine Beach dayuse area, and its upgrade reflects the council’s determination to handle seasonal visitor surges, while protecting the health of the lake and the local environment. Located on the North Island’s west coast, about half an hour north of Dargaville, Taharoa Domain is the official name of an area commonly called Kai Iwi Lakes, which includes the smaller Lake Kaiiwi, the main Lake Taharoa, and Lake Waikare, which lies slightly to the northwest of the others. Darren James of Hoskin managed the project on behalf of Kaipara District Council, with design support from Trine Kel and physical works by Innoflow. Bryan Hagan has been manager of project delivery for Kaipara District Council for the last two years. He and his family have been camping at the Taharoa Domain campground every summer for the last 20 years and have a deep appreciation of what Taharoa Domain has to offer. “The three lakes are all dune lakes, with Lake Taharoa (main lake) one of the largest in New Zealand. “Dune lakes are fed by natural ground water (aquifer) rather than a river. It’s a unique environment with wonderful clear water. It’s a jewel in the crown of the Kaipara District,” Bryan says. The increased capacity of the wastewater system future-proofs the Pine Beach facility for campers, as well as the day visitors, who also use its shower and toilet block, Bryan says. “The camp can accommodate 450 campers and the day visitors double that number on good days, so on New Year’s Day there’d be in excess of 1000 people. It’s a huge volume. “The capacity of the old system was 37.5 cubic metres per day and we’ve increased that so that it could treat up to a maximum of 55 cubic metres a day. The system should always operate below that level, but it has been designed for peak use.” Already at the end of last year, the area’s upgrade had begun with a new day visitors’ toilet block installed just outside the campground, complete with three unisex toilets, one of which is accessible, and which also connects through to the new treatment plant. It features a water catchment tank designed to reduce the water take from the lake. The lake provides the campground with its water and reducing its take is an integral part of the upgrades, including the next stage, which is the refurbishment of the campground’s ablutions block. Along with new partitions, the new toilets will have reduced flush volumes and aerated taps and showerheads to reduce the amount of water per user. A 10,000-litre rainwater tank is being installed to further reduce the water take from the lake. “The new system also has the capacity in the future, to potentially re-use the treated water for greywater. For example, water from the treatment plant could be used for flushing toilets but that’s not currently utilised.’ “We’re mindful of lake levels, especially at peak times, and in terms of the overall management of the asset we want to reduce our outtake as much as possible.” Due for completion in time for this summer’s influx of visitors, the latest upgrade is well underway. Along with the other upgrades it’s improving the facilities for use by both locals and visitors to the area, reducing the take from the lake, and making the Taharoa Domain fit for purpose and ready to welcome users now and for the foreseeable future.
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