Lake Taupō - a national treasure
Lake Taupō is a national treasure. It is a clean, clear lake, water quality is good for swimming and for the plants and animals that live in it.
- Lake Taupō was formed by a series of eruptions, the most recent of which - around eighteen hundred years ago - blasted out about 60 cubic kilometres of earth, rock and mud, leaving a massive crater.
- More than 30 rivers and streams flow into the lake, with only one outlet – the Waikato River.
- The full name of the lake is Taupō–nui–a–Tia, which means the great cloak of Tia. Tia, one of the great fighting chiefs of the Arawa Canoe, is credited with discovering the lake.
- Lake Taupō is 30 km wide and 40 km long. The lake's deepest point is approximately 160 metres, it contains 59 cubic kilometres of water and is between a minimum of 355.85 metres and a maximum of 357.20 metres above sea level (depending on inflows and hydro-electric activity).
- Lake Taupō is 622 square kilometres in area. Its catchment is about five times the size of the lake.
- The entire Lake Taupō catchment, including the lake, is 3487 square kilometres – 14 per cent of the Waikato region.
Lake Taupō continues to have high quality, clear water that is safe to swim in.
More than 30 streams and rivers drain into Lake Taupō from the catchment. An annual rainfall of between 1250 mm and 2000 mm over much of this land gives Lake Taupō a relatively constant source of new water.
But because it is such a large, deep lake, it can take a droplet of water 11.5 years to pass through the lake before it flows out into the Waikato River.
Waikato Regional Council tests the water from both the lake’s edge and a deep water site. However, since the mid 1970s, nitrogen has built up in the bottom waters.This could lead to reduced water clarity, blooms and scums of algae and could affect the amount of dissolved oxygen needed by the plants and animals that live in the lake.
Lake Taupō is home to many native plant species, at least 31 species of aquatic birds and a number of native and introduced fish, including koaro, common bully common smelt, rainbow trout and brown trout.
Catfish have been recorded in the lake since 1985. Catfish are a pest because they feed on freshwater snails, koura, bullies and smelt. They have been known to attack juvenile trout.
Native plant species don’t compete well with introduced aquatic weeds. Oxygen weed, pondweed and hornwort are a growing problem in the lake. These water weeds spread rapidly. Waternet is present in Kinloch marina, but low nutrient levels in the lake mean it is not likely to become a problem weed.
Waikato Regional Council is looking at ways to manage the effects of land use changes to protect Lake Taupō’s excellent water quality. Project Watershed includes soil conservation schemes that are designed to protect the lake’s water quality and reduce sediment loads to the lake.
Waste water from urban areas also affects the lake. Taupō District Council encourages residents to be careful about what they put into stormwater drains. The district council also has plans for the ongoing improvement of community sewerage systems.
Everyone can help look after Lake Taupō’s water quality by being careful about what they put into the stormwater drains. Stormwater is not treated and drains straight into the lake, or into rivers and streams that flow into the lake. Taupō District Council aims to reduce pollutants going into the lake, local rivers and streams through stormwater drains.
Landowners living around the lake can help by planting and fencing stream banks. Plants help to filter out nutrients and sediment in runoff, as well as providing shade and habitat for wildlife. Fencing streams prevents stock from:
- muddying the water
- depositing waste in streams
- causing bank erosion.
Boat–owners also need to carefully wash down boat keels, motors and trailers before putting boats into Lake Taupō. This reduces the chances of introducing water weeds.
If boats have seam leaks or loose stern glands, oily bilge water often dribbles into the lake. Automatic bilge pumps can release dirty water directly into the lake. To prevent these problems, boaties need to keep boat bilges clean and dry and ensure they dispose of rubbish and sewage on–shore.
- Don’t put everyday household or industrial products such as used oil, paint, pesticides, detergents or disinfectants, toilet cleaner, dairy products, fats and edible oils, down stormwater drains.
- Wash your car on the lawn so that soapy water soaks into the ground.
- Clean up chemical spills around the home by soaking up the mess.
- Take unused paint and domestic garden sprays to recycling centres.
- Use rubbish bins for your litter.
- Boat owners should dispose of rubbish and sewage on-shore, wash boat keels, motors and trailers carefully to remove water weeds and maintain bilge pumps to reduce oil leaks.
Since 1976, Whangamata Stream (at the northern end of the lake) has been fenced off and helped to revert to its natural state. This is one of Lake Taupō’s most important trout–spawning streams. It is now a haven for native plants and wildlife. The native plants and trees now growing on its banks have greatly reduced the amount of sediment getting into Lake Taupō.
As native plants such as flax, toetoe, and cabbage trees flourished they shaded out the weeds that often blocked the stream. Fish and other wildlife returned, and the first fernbirds in the area were recorded in the early 1990s.
This work was part of the Lake Taupō Catchment Control Scheme, designed to reduce erosion and sediment input to the lake. The scheme was originally funded by both the Government and landowners, and is now administered by Waikato Regional Council.
Human Health Risk Assessment
You can download the pdf below to read the report on Human Health Risk Assessment - an action plan to protect the health of Lake Taupō and its surrounding area.