Objective 1: Maintenance of the current water quality of Lake Taupo
The effects of nutrient discharges in the catchment are mitigated such that by 2080 the water quality of Lake Taupo is restored to its 2001 levels as indicated by:
|Water Quality Characteristic||Mean||Standard Deviation|
|Total Nitrogen (mg/m3)||70.3||19.1|
|Total Phosphorus (mg/m3)||5.57||1.4|
|Chlorophyll a (mg/m3)||1.18||0.6|
|Secchi depth (m)||14.6||2.7|
Note: Statistics based on Lake Taupo data set, January 1999 to December 2003 inclusive
Objective 2: Effect on Lake Taupo water quality from land use activities
Land use activities which result in nitrogen leaching, particularly farming, are managed to facilitate the restoration of the water quality characteristics of Lake Taupo to their 2001 levels.
Objective 3: Avoidance of near-shore effects from wastewater
No greater concentrations of domestic wastewater nitrogen or pathogens in shallow near-shore waters of Lake Taupo in the vicinity of wastewater treatment and disposal systems.
Objective 4: Economic costs minimised and social and cultural effects mitigated
Economic costs of managing land use activities to achieve Objective 1 are minimised, and spread across local, regional and national communities. Social and cultural effects of managing land use activities to achieve Objective 1 are mitigated.
Principal Reasons for Adopting the Objectives
Objective 1 sets a long-term goal for Lake water quality. The baseline date for water quality characteristics to be compared against is centred on 2001, as this was the year that Waikato Regional Council made a public resolution that regulatory action would be taken to protect water quality of Lake Taupo.
There is a long time lag between nitrogen leached from land uses and the effect on the Lake because of the time taken for nitrogen to travel through the soil profile into groundwater and then eventually into the Lake, where it is fully mixed. This means that there is some nitrogen leached from land use change that occurred decades ago that has entered groundwater, but hasn’t yet entered the Lake. Objective 1 sets long-term water quality characteristics which reflect a sustainable load of nitrogen to the Lake. This load to the Lake has been estimated to be 1200 tonnes of nitrogen per year. It is expected though, that this amount will rise over the next few decades as nitrogen in transit eventually reaches the Lake. This nitrogen in transit is estimated to be 20 percent of the nitrogen load coming from human-generated (and therefore manageable) sources.
The objective lists the water quality characteristics that will be used to characterise the water quality of Lake Taupo when the effectiveness of the objective is assessed. Waikato Regional Council undertakes regular monitoring of a wide range of water quality characteristics, but Total Nitrogen, Total Phosphorus, chlorophyll a and secchi depth have been chosen as most directly related to nitrogen in the Lake.
Objective 2 recognises that in order to achieve the long term water quality goal in Objective 1, activities which result in nitrogen leaching, particularly farming activities, need to be managed. This is in recognition of the large proportion of manageable nitrogen in the Lake Taupo catchment which results from farming activities.
Objective 3 recognises that discharges from community wastewater treatment plants and cumulative discharges from on-site wastewater treatment plants can cause localised increases in nitrogen and wastewater pathogens in shallow, near-shore waters, in addition to their overall contribution to nitrogen levels in the catchment. Satisfying the objective will mean that adverse health and amenity effects from increased discharges are prevented. The degree to which the objective is met can be measured by comparing water quality (nitrogen and pathogen levels) near discharges, with water quality in areas that would not be affected by discharges, accompanied by other tests such as dye tests as necessary.
Objective 4 recognises that managing land use activities to achieve Objective 1 could make some existing rural land uses unviable if they were required to achieve reductions in nitrogen, leaving many people in financial hardship. If no action is taken to reduce the impact on particular sectors of the community, there will be significant adverse social, cultural and economic effects on those sectors. Flow-on effects to the wider community, such as decline in local business, may also result. The objective seeks to minimise these impacts and ensure costs are spread across local, regional and national communities. The objective also creates an expectation of a higher level of involvement in managing change between the regulatory authority and affected landowners than has historically occurred.