Key points

Lakes water quality is monitored to determine a lake’s trophic state – the ability to support freshwater plants and animals. Monitoring over time will tell us if a lake's trophic level has improved, deteriorated or remained unchanged.  Lakes are valued for their unique genetic diversity, cultural and spiritual importance, scientific interest, recreational use and intrinsic values. Many of the shallow lakes in the Waikato Region are valuable refuges for unique plant and animal species. Lake Taupo is nationally recognised as a symbol of near-pristine environmental conditions.

• The Waikato Region's shallow lakes are generally nutrient enriched as assessed by Environment Waikato, resulting in a relatively high trophic state and low oxygen levels.  The trophic state of most lakes remained unchanged or deteriorated between 1993 and 2001, nor did it change significanly between 2006 and 2010.
• Water quality for ecology in Lake Taupo remains largely satisfactory to excellent, with a gradual improvement over time.  Water clarity has generally improved in Lake Taupo in recent years and nitrogen levels have improved (subject to annual fluctuations), but levels of chlorophyll remain relatively high and oxygen depletion is only ‘satisfactory’ relative to Environment Waikato’s standards.

Source: Waikato Regional Council

Proportion of water samples collected in Lake Taupo which meet ‘excellent’, ‘satisfactory’ and ‘unsatisfactory’ standards for ecological health

Source: Waikato Regional Council

What agencies are doing

Shallow Lakes

• Environment Waikato manages and requires the monitoring of resource consents to take water or discharge wastewater to waterways.
• We track changes in shallow lake trophic state to update this indicator and to assist policy making and consent decisions.
• We are the lead agency in the Waipa Peat Lakes and Wetlands Accord. The Accord is an interagency agreement to work co-operatively with landowners, iwi and interest groups for the restoration and enhancement of shallow lakes and wetlands.
• Environment Waikato's Clean Streams project provides advice and financial support to encourage and support farmer efforts to reduce the impacts of farming on waterways through fencing and planting waterway margins.
• We provide staff time and expertise to support Care groups in the Region that are involved in riparian management such as planting and fencing.
• Environment Waikato’s Proposed Regional Plan seeks a net improvement of water quality across the region.

Lake Taupo

• Environment Waikato is proposing a variation to the Proposed Regional Plan for the Taupo catchment. The aim of the variation is to protect the Lake’s excellent water quality. Needs updating?
• Project Watershed involves Environment Waikato's land and river-based works and services in the greater Waikato catchment. It includes soil conservation schemes designed to reduce sediment loads to the lake and protect the lake’s water quality.
• Environment Waikato manages and requires the monitoring of resource consents to take water or discharge wastewater to waterways, or to dam or divert rivers and streams.
• Environment Waikato tracks changes in water quality for ecological health to update this indicator and to assist policy making and consent decisions.
• We support voluntary guidelines and codes of practice such as the NZ Fertiliser Manufacturer’s Research Association’s Code of Practice for Fertiliser Use.
• We support Care groups that are involved in riparian management such as planting and fencing.

What you can do to help

• Use sustainable farming and forestry practices (for example, follow the Fertiliser Code of Practice, our grazing guidelines, our land disposal of dairy-shed effluent regulations, New Zealand Forestry Code of Practice). Also check out our Landcare groups.
• Fence off waterways from stock access, provide water troughs for stock, and plant along water edges.
• Think before washing substances down stormwater drains. Household and industrial products (such as used oil, paint, pesticides, detergents or disinfectants, dairy products, fats and edible oils) can get washed into lakes through 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.
• Wash boat keels, motors and trailers carefully to remove lake weed, and maintain bilge pumps to reduce oil leaks.
• Dispose of boat sewage at land-based facilities provided at Taupo, Tokaanu and Motuoapa.

More information

More detail on this indicator, including how and where this information is collected, is available here.

What we want to achieve

The community outcomes we are seeking to achieve by measuring lake water quality for ecological health are:

• The iconic landscapes and natural features of our environment define and sustain us. We respect and celebrate them as taonga.
• Our natural environment is protected and respected. Its ecological balance is restored, its air, soil and water quality is improved and its native biodiversity is enhanced.
• The traditional role of iwi and hapu as kaitiaki is acknowledged, respected and enabled.
• Our region’s waterways have consistently high water quality.