Car washing puts rare dune lake at risk in Far North

Ngati Kahu's Tawakeiti Reti (left) Hikitia Laing and Kiri Brown inspect tyre tracks leading into Lake Waiporohita with regional council catchment advisor Will Trusewich (right). Photo/Supplied

People washing their vehicles in a rare Far North dune lake are threatening its outstanding ecological status.

The practise is a main reason steps are being taken to fence Lake Waiporohita,
near the Rangiputa junction on Inland Road on the Karikari Peninsula.

One of only 12 dune lakes in Northland with outstanding ecological status, the lake's riparian zone will be planted, along with other work to protect the immediate environment.

Far North runanga Ngati Kahu and the Northland Regional Council (NRC) are two of the partners working to protect the 6.9-hectare lake.

Last September the council approved $52,850 via its Environment Fund for a project to improve the lake's water quality and ecology, as well as Lakes Rotokawau east and west on the north-western corner of the peninsula.

Anahera Herbert-Graves, Te Runanga-a-Iwi o Ngati Kahu chief executive, said dune lakes are under multiple stresses, including nutrient runoff, invasive pest fish and water weeds, and cumulative effects from use by the wider public.

However, Lake Waiporohita has an added threat in being one of only a few dune lakes in Northland that are easily accessible to the public.

"Unfortunately, this means that the lake is all-too-often used as an unofficial car wash by passing 4WD vehicles that have used nearby beaches or boat-ramps."

The project will include fencing, exotic tree removal and riparian replanting to allow the lake to filter land-based nutrients.

Ms Herbert-Graves said the next phase would involve landscaping the waterside strip in the open area along Inland Road where four-wheel drives tend to access the lake.

"This area will be landscaped shortly using locally sourced materials, native plantings and signage to let the public know that vehicle and boat access will no longer be tolerated in the lake."

Peter Wiessing, NRC Kaitaia area manager, said vehicles getting in the lake increased the risk of introducing water weeds and pest fish, as well as exposing it to oil and other lubricants.

The Department of Conservation, the manager of the lake-bed and marginal strip, and Landcorp which farms the Rangiputa Station surrounding the lake, are also involved in the protection project.

The partners are also are keen to work with Fish and Game to better manage large numbers of Canada geese which gather at the lake and foul it with their waste.