10. Lakes Tekapo, Pūkaki and Ōhau
10.1 Introduction
This chapter summarises the Board's evaluation of the provisions in the Plan relating to environmental flow and level regimes (minimum lake levels) for Lakes Tekapo, Pūkaki and Ōhau. The effectiveness, benefits and costs, and efficiency of the provisions are examined. Consideration is given to the circumstances where there is uncertain or insufficient information, as identified in section 4.2.6 of this report. Based on these evaluations, having regard to effectiveness and efficiency, the Board's overall judgement of whether the provisions are the most appropriate to achieve the objectives is recorded.
When Lakes Tekapo, Pūkaki and Ōhau are referred to, included within this reference are the canals leading from these lakes.
10.2 Plan provisions
The relevant provisions of the Plan are:
- Policies 1, 3, 4, 5, 6, 35, 36 and 37
- Rules 1, 3, 9, 11, 12, 17, 18, 19, 20 and 24.
10.3 Effectiveness
The Board's evaluation of the effectiveness of the provisions in the Plan relevant to the minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau are summarised in Table 57 below. In this circumstance, Objectives 1 and 2 are relevant to the evaluation.
Table 57: Effectiveness of the provisions in the Plan relevant to the minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau
| Objective | Provisions | Effectiveness |
|---|---|---|
|
1 |
Provisions in the Plan retain the existing environmental flow and level regimes for Lakes Tekapo, Pūkaki and Ōhau. They reflect the long-standing agreed minimum levels. The environmental flow and level regimes recognise the relationship of Ngāi Tahu and their culture and traditions with the Waitaki catchment, a taonga, and its associated sites and wāhi tapu. These environmental lake levels maintain people's appreciation and enjoyment of these water bodies. However, the temporary reduction in lake levels for the purposes of the maintenance or rehabilitation of electricity generation infrastructure may create short-term adverse effects on the qualities of the lakes. The environmental flow and level regimes enable the provision of water for an individual's reasonable domestic needs, the reasonable drinking-water needs of an individual's animals, and for fire-fighting needs. Implementation will occur through the consideration of resource-consent applications as either a discretionary or non-complying activity. The taking of water beyond the environmental flow and level regime prescribed in the rules of the Plan is a prohibited activity, except for the temporary reduction in lake levels for the purposes of the maintenance or rehabilitation of existing dam infrastrucuture, which is a discretionary activity. |
Moderate/High |
|
2 |
A significant amount of water is available for allocation to activities above the specified the minimum lake levels. In relation to Lake Tekapo, additional water of the highest value for hydro-electricity generation can be taken and diverted in times when the aggregate storage for the nation, or for the (electricity) region that includes Waitaki catchment, is below the second (emergency) zone established by the Electricity Commission. Additional water can be taken or diverted in order to temporarily lower the lakes for the maintenance and rehabilitation of electricity generation infrastructure if resource consent is obtained. Town and community water supplies, tourism and recreation facilities, stock drinking-water, maintaining fire fighting capacity and the processing of perishable produce are not restricted by the minimum levels. |
High |
|
Overall effectiveness |
High |
|
10.4 Benefits and costs
The Board's evaluation of the benefits and costs of the provisions in the Plan relating to minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau are summarised in Tables 58, 59 and 60 below.
Table 58: Benefits and costs of the provisions in the Plan relating to minimum lake levels for Lake Tekapo
| Benefits | Costs |
|---|---|
|
Environmental High degree of natural character of the glacial lake is maintained. Landscape value of the lake is maintained. Islands of Lake Tekapo are protected. Feeding and/or roosting and/or breeding habitats for bird life are maintained and/or enhanced, particularly for:
|
Environmental Existing lake-edge erosion will continue. Potential short term adverse effects on the environment from the temporary reduction in lake levels for the purposes of maintenance or rehabilitation of electricity generation infrastructure subject to mitigation required to be undertaken to comply with any resource consent. |
|
Economic Retains highest value water for downstream hydro-electricity generation. Enhanced opportunity to derive economic benefit from hydro-electricity generation in times of low hydro storage. Provides for the maintenance or rehabilitation of electricity generation infrastructure necessary for continued hydro-electricity generation. Provides opportunity to derive economic benefit from new activities. Provides opportunity to derive economic benefit from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Retains economic benefit from existing activities. Retains economic benefit from tourism and recreation activities.
|
Economic Forgone opportunity to derive economic benefits from new activities taking water within the minimum environment flow and level regime. |
|
Social High recreation values of the lake are maintained. Moderate fishing values for trout are maintained. Retains the secondary social wellbeing effects from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Sustains existence value of this natural lake. Enhanced opportunities for secondary social wellbeing effects derived from new activities. Retains secondary social wellbeing effects associated with existing activities. |
Social Forgone opportunity to derive secondary social wellbeing effects from new activities. |
|
Cultural Recognises the relationship of Ngāi Tahu and their culture and traditions with the Waitaki River, a taonga, and its associated sites and wāhi tapu. Has particular regard to the kaitiakitanga of Ngāi Tahu. Sustains the habitat of mahinga kai species. Recognises the Statutory Acknowledgement for Lake Tekapo. Recognises the iconic nature of Lake Tekapo. |
Cultural |
Table 59: Benefits and costs of the provisions in the Plan relating to minimum lake levels for Lake Pūkaki
| Benefits | Costs |
|---|---|
|
Environmental The high degree of natural character of the glacial lake is maintained. The landscape value of the lake is maintained. Feeding and/or roosting and/or breeding habitats for bird life are maintained and/or enhanced, particularly for:
Habitat and/or spawning areas for native fish species is maintained and/or enhanced, particularly for:
|
Environmental Existing lake-edge erosion will continue. Short term adverse effects on the environment from the temporary reduction in lake levels for the purposes of maintenance or rehabilitation of electricity generation infrastructure. |
|
Economic Retains highest value water for downstream hydro-electricity generation. Provides for maintenance or rehabilitation of electricity generation infrastructure necessary for continued hydro-electricity generation. Provides opportunity to derive economic benefit from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Provides opportunity to derive economic benefit from new activities. Retains economic benefit from existing activities. Retains economic benefit from tourism and recreation activities. |
Economic Forgone opportunity to derive economic benefits from new activities taking water within the minimum environment flow and level regime. |
|
Social High recreation values of the lake are maintained. Retains the social wellbeing effects from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Sustains existence value of this natural lake. Enhanced opportunities for secondary social wellbeing effects derived from new activities. Retains secondary social wellbeing effects associated with existing activities. |
Social Forgone opportunity to derive secondary social wellbeing effects from new activities. |
|
Cultural Recognises the relationship of Ngāi Tahu and their culture and traditions with the Waitaki River, a taonga, and its associated sites and wāhi tapu. Has particular regard to the kaitiakitanga of Ngāi Tahu. Sustains the habitat of mahinga kai species. Recognises the Statutory Acknowledgement for Lake Pūkaki. Recognises the iconic nature of Lake Pūkaki. |
Cultural |
Table 60: Benefits and costs of the provisions in the Plan relating to minimum lake levels for Lake Ōhau
| Benefits | Costs |
|---|---|
|
Environmental The high degree of natural character of the glacial lake is maintained. Minimum level recognises the natural minimum range of the lake. The landscape value of the lake is maintained. Feeding and/or roosting and/or breeding habitats for bird life are maintained and/or enhanced, particularly for:
Habitat and/or spawning areas for native fish species are maintained and/or enhanced, particularly for:
Habitat and/or spawning areas for sport fish species are maintained and enhanced, particularly for:
|
Environmental Short term adverse effects on the environment from the temporary reduction in lake levels for the purposes of maintenance or rehabilitation of electricity generation infrastructure. |
|
Economic Retains highest value water for downstream hydro-electricity generation. Provides for the maintenance or rehabilitation of electricity generation infrastructure necessary for continued hydro-electricity generation. Provides opportunity to derive economic benefit from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Provides opportunity to derive economic benefit from new activities. Retains economic benefit from existing activities. Retains economic benefit from tourism and recreation activities. |
Economic Forgone opportunity to derive economic benefits from new activities taking water within the minimum environment flow and level regime. |
|
Social The high fishing values are maintained. Contact recreation values maintained. Retains the secondary social wellbeing effects from town and community water supplies, stock drinking-water, tourism and recreation facilities and the processing of perishable produce. Sustains existence value of this natural lake. Enhanced opportunities for secondary social wellbeing effects derived from new activities. Retains secondary social wellbeing effects associated with existing activities. |
Social Forgone opportunity to derive secondary social wellbeing effects from new activities. |
|
Cultural Recognises the relationship of Ngāi Tahu and their culture and traditions with the Waitaki River, a taonga, and its associated sites and wāhi tapu. Has particular regard to the kaitiakitanga of Ngāi Tahu. Sustains the habitat of mahinga kai species. Recognises the Statutory Acknowledgement for Lake Ōhau. Recognises the iconic nature of Lake Ōhau. |
Cultural |
10.5 Efficiency
Following the consideration of the benefits and costs, it is the Board's judgement that the provisions in the Plan relating to the minimum lake levels for:
- Lake Tekapo, are of high efficiency
- Lake Pūkaki, are of high efficiency
- Lake Ōhau, are of high efficiency.
10.6 Appropriateness
The Board's evaluation of the effectiveness and efficiency of the provisions in the Plan relating to minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau is summarised in Table 61 below.
Table 61: Summary of the effectiveness and efficiency of the provisions in the Plan relating to minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau
| Effectiveness | Efficiency | |
|---|---|---|
|
Lake Tekapo |
High |
High |
|
Lake Pūkaki |
High |
High |
|
Lake Ōhau |
High |
High |
Having regard to this information, and taking into account the benefits and costs and the risk of acting due to insufficient information, it is the Board's judgement that the minimum lake levels for Lakes Tekapo, Pūkaki and Ōhau are the most appropriate to achieve the objectives of the Plan.
