Te Henga / Bethells Beach

The beach is approximately 37 km (23 mi) west of Auckland City, at the mouth of the Waitakere River where it flows into the Tasman Sea. One of several popular resorts in the area (others include Muriwai, Piha and Karekare), it is rated the 4th most dangerous beach in New Zealand to swim at due to its strong rips and currents. There have been many fatalities including in 2009, Rugby League star Sonny Fai, who was never located. It experiences a population explosion over summer with thousands of visitors. This has put a lot of pressure on the local infrastructure and environment with an increase in rubbish and parking issues.

Geology[edit]

7,000 years ago, when sea-levels rose after the Last Glacial Maximum, Te Henga / Bethells Beach and the surrounding area including Lake Wainamu formed a part of the Waitākere River tidal estuary. Over time, Tasman Sea sand accumulated at Te Henga, forming sand dunes and freshwater lakes.^[18] The sand dunes have accumulated in several phases over the last 4,500 years. These sands contain quantities of black titanomagnetite derived from the volcanic rocks of Taranaki and carried north by coastal currents. The dunes continually move in a dynamic coastal process. There are three dune-impounded lakes: Lake Wainamu, Lake Kawaupaku and Lake Waiataru.


The Te Henga wetlands originally formed as a freshwater lake during the same time period as the three remaining lakes. The lake was destroyed in 1910 with the construction of the Waitākere Dam and Reservoir, which made water-levels rise and the water to become more silty. The wetlands began forming in the mid-1920s.^[10]

The Waitākere River catchment consists of roughly 70 km² of the bush-clad Waitākere Ranges. Located on the west coast of the Auckland Region approximately 75% of the catchment consists of native vegetation in spite of extensive milling, farming and settlement.


The major features of the catchment are:


The Waitakere River has two main tributaries, the Mokoroa and Waiti streams. The headwaters of the river are in the vast and steep Waitākere Ranges and drain out at the Bethell's Beach river mouth.


In comparison with other North Island beaches, and to some extent even the west coast beaches of Muriwai and Piha, settlement at Bethells has been minor with most development revolving around horticulture and agriculture.


With the exception of the Waitākere Reservoir the catchments resources have largely escaped development.


In 1990 the Auckland Regional Water Board developed and prepared a Waitakere River Catchment Water and Soil Plan. This pre-Resource Management Act document aimed to deal with the competing water and soil resource demands within the catchment in terms of "conservation, allocation, use and quality of natural water and in terms of soil conservation and preventing damage from flooding." Although this document reached its quarter-century in 2015, many of its principles still apply.