Taharoa Domain.
With its clear sparkling lakes, the domain is a shining jewel on Northland's west coast. the freshwater dune lakes of Kai Iwi, Taharoa and Waikare are renowned for their beauty and clear waters.
The 538 Hectare recreation reserve offers camping, a wide range of recreational opportunities and supports a rich variety of native bird, animal and plant life.
There are about 170 dune lakes in two series between Otaki and Hawera, and Waiuku and North Cape. The lakes are small and shallow, usually being under 400 acres in area and less than 15 m in depth. All lakes have a common feature of an impounding barrier of sand. The lakes are of two types-basin and dammed valley lakes. Basin lakes lie between the fore-shore dunes and the consolidated sandstones (e.g., Lake Kereta) or fill depressions in the consolidated dunes (e.g., Lake Waingata). Streams draining the consolidated dunes have been blocked by moving sand to form dammed valley lakes (e.g., Lake Herengawe). Water levels appear to be maintained by rainfall and seepage from the drainage basins. Levels fluctuate about two feet annually. Few have inflowing or outlet streams and outlet streams are often intermittent in flow. The mean annual rainfall varies from 30-50 inches, which is spread over the whole year, with a drier period over the summer. The mean monthly air temperatures range from 47¡ to 63¡ F. The majority of the lakes are exposed to the prevailing westerlies and water turnover occurs at all seasons. Less frequent eastern storms also assist water turnover.
The Kai Iwi Lakes are basin type dune lakes formed in consolidated sand of late Pleistocene geological origin. They were formed by the accumulation of rainwater in depressions of sand underlain by relatively impermeable ironstone pans. Dune lakes are one of nine major lake types found in New Zealand and are the predominant type found along the west coast of the North Island. Lake Taharoa which covers 237ha is the third largest dune lake in New Zealand. Lake Waikere covers 35ha and Lake Kai Iwi 33ha. Together the three lakes occupy well over half the total area of the domain.
Lake Kai Iwi and Taharoa are connected by a narrow channel and are about 70 metres above sea level. Lake Waikere is more elevated and about 79 metres above sea level. Lakes Taharoa and Waikere are the deepest known dune lakes in the country. The NZ Oceanographic Institute bathymetric chart of lakes record the maximum depth of Lake Taharoa to the 37 metres, and Lake Waikere 30 metres. Lake Kai Iwi is considerably shallower than the other two lakes and has a maximum recorded depth of 16 metres.
Water temperatures vary considerably, with extremes of 12.8 deg C and 21.8 deg C recorded. Thermal stratification sometimes occurs in summer, forming distinct water layers with different temperatures. The oxygen level of the surface waters is always close to saturation. When stratification occurs there may be deoxygenation of the hypolimnion and oxygen concentrations fall to 10 per cent of the saturation. The lake margins vary considerably running from free flowing sand to exposed wave-cut banks, to sheltered shores supporting dense stands of emergent vegetation. The lake beds of the littoral region are usually sandy. The sub-littoral consist of soft organic muds of a considerable depth. The sub-littoral vegetation is usually well developed with bottom plants growing over most of the area. Transparency is very low.
The Kai Iwi Lakes have no known natural inlets or outlets. Their principal source of water is likely to be rain which falls directly onto the lake surface. As a result their levels fluctuate considerably with climatic conditions. Seasonal lake level movements of 400-600 mm have been recorded on Lake Taharoa.
This also makes the lakes very susceptible to pollution, meaning that care and vigilance are needed in their management and use.
Question 1.
From the co-ordinates above, which lake are you looking at?
Question 2.
There are two types of sand lakes - basin and dammed valley lakes. Which is this lake?
Question 3.
From the posted coordinates walk down to the lake and establish if this lake is a littoal or sub-littoral example of a dune lake.? What visual evidence have you used to make your decision?
Question 4. (Optional)
Please attach a photo of yourself and your GPS at the listed coordinates with the lake in the background.
Thank you for visiting.