17. Waitaki River downstream of Waitaki Dam
17.1 Introduction
This chapter summarises the Board's evaluation of the provisions in the Plan relating to the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam. 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.
17.2 Plan provisions
The relevant provisions of the Plan are:
- Policies 1, 3, 4, 5, 6, 45 and 46
- Rules 1, 2, 7, 9, 11, 15, 16, 19, 20 and 24.
17.3 Effectiveness
The Board's evaluation of the effectiveness of the provisions in the Plan relating to the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam is summarised in Table 87 below. In this circumstance, Objectives 1, 2 and 5 are relevant to the evaluation.
Table 87: Effectiveness of the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam
|
Objective |
Provisions |
Effectiveness |
|---|---|---|
|
1 |
The environmental flow and level regime provides for the retention of sufficient water in all but extreme climatic conditions to sustain the health and protection of the natural and physical qualities, safeguard the life-supporting capacity of ecosystems, maintain people's appreciation and enjoyment, and safeguard the integrity of the braided river system, of the Lower Waitaki River environment. Any undesirable algae and silt build-up resulting from the Lower Waitaki River flow regime will be mitigated by the required flushing flows. The environmental flow and level regime recognises the relationship of Ngāi Tahu and their culture and traditions with the Waitaki River, a taonga, and its associated sites and wāhi tapu. The environmental flow and level regime enables 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. However, with respect to existing resource consents, implementation will only occur if the consenting authority uses section 68(7) of the RMA to review the consents for Waitaki Dam. Implementation will occur through the assessment and consideration of resource-consent applications as either a discretionary or non-complying activity. |
Moderate |
|
2 |
A significant amount of water is available for allocation to activities above the specified minimum flow and level regime. Included within this is the potential to divert large volumes of water if the water is returned upstream of Black Point. The allocation limit provides for all existing, and reasonably forseeable future, needs to take (abstracting and not returning) water in the local area. Increased flexibility to manage the existing Waitaki Power Scheme resulting from the 1-hour rolling average measurement system, once implemented. The minimum flows in climatic conditions resulting in 1 in 20 year low inflows recognise hydro-electricity generation activities upstream of Waitaki Dam. The allocation limit does not restrict existing resource consents, or replacement resource consents for the same or less amounts of water. Essential drinking, stock drinking-water, maintaining fire fighting capacity and the processing of perishable produce are not restricted by the minimum flow. Micro hydro-electricity generation and fisheries and wildlife activities are exempt from the allocation limit. Any allocation cannot derogate from existing resource consents. |
Moderate |
|
5 |
The flow of the Waitaki River is artificially controlled because of the hydro-electricity generation facilities. Therefore the run-of-river reliability of the down-stream users is dependent on the pattern of flow releases from those facilities. The Plan prescribes the minimum flow releases through Waitaki Dam necessary during times of low water availability. The provisions of the Plan will be implemented through the consideration of resource-consent applications. |
Moderate |
|
Overall Effectiveness |
Moderate/High |
|
17.4 Benefits and costs
The Board's evaluation of the benefits and costs of the provisions in the Plan relating to the environmental flow and level regime of the Waitaki River downstream of Waitaki Dam is summarised in Table 88 below.
Table 88: Benefits and costs of the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam
| Benefits | Costs |
|---|---|
|
Environmental Natural and physical resources associated with the Lower Waitaki River are maintained, particularly downstream of Black Point. Existing braided character of the Lower Waitaki River will be maintained and protected and secondary characteristics associated with braided river (riffles, rapids, pools) will be maintained, particularly downstream of Black Point. The opportunity for people to experience the openness, naturalness, and magnitude of the dynamic, braided river will be retained. Any undesirable algae and silt build-up resulting from the Lower Waitaki River flow regime will be mitigated as a result of medium sized flushing flows. Riparian, backwater and wetland values will be maintained by ensuring connectedness and variation of flows thereby providing opportunity for riparian and wetland rejuvenation and enhancement. Supports coastal processes ensuring the physical and ecological functioning of the river mouth which, in turn, provides for whitebaiting and salmon runs. Recognises that the river mouth is an area of significant natural value in the Proposed Canterbury Regional Coastal Environmental Plan and associated natural values will be maintained. Maintains a supportive environment to threatened plant species namely Carmichaelia curta, Carmichaelia holliwayi. 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, particularly for:
Habitat and/or spawning areas for sport fish species are maintained, particularly for:
|
Environmental The Lower Waitaki River downstream of Waitaki Dam but upstream of Black Point may experience reduced variability in flow (to the extent not mitigated as per consent conditions). Minimum flows reflecting low natural flows may result in short term adverse effects on ecosystems. |
|
Economic Provides opportunity to derive economic benefit from new activities, including:
Retains economic benefit from existing activities. Retains economic benefit associated with the large braided river characteristic. Provides for operational management flexibility for the Waitaki Power Scheme associated with the 1-hour rolling average measurement system. Provides for operational management flexibility for the Waitaki Power Scheme in times of low natural inflows into the Waitaki catchment upstream of Waitaki Dam. Provides opportunities to derive economic benefit from micro hydro-electricity generation, essential drinking and stock drinking-water, and the processing of perishable produce. |
Economic Opportunity cost attached to existing hydro-electricity generation through a reduction in operational flexibility. |
|
Social Retains wide range of recreation choice for recreational users, including jet boating, anglers, and whitebaiting. Enhanced opportunities for secondary social wellbeing effects derived from new activities including temporary secondary social wellbeing effects associated with growth potential of new hydro-electricity generation upstream of Black Point. Retains secondary social wellbeing effects associated with existing activities. Existence value of the Waitaki River is maintained except in times of low natural flows. Enhanced secondary social wellbeing effects from micro hydro-electricity generation, essential drinking and stock drinking-water, and the processing of perishable produce. |
Social Reduced recreational opportunity during times of minimum flows reflecting low natural flows. Reduced existence values during times of minimum flows reflecting low natural flows. |
|
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 the Waitaki River. |
Cultural |
17.5 Efficiency
Following the consideration of the benefits and costs of the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam, it is the Board's judgement that the provisions are of moderate/high efficiency.
17.6 Appropriateness
The Board's evaluation of the effectiveness and efficiency of the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam is summarised in Table 89 below.
Table 89: Summary of the effectiveness and efficiency of the environmental flow and level regime for the Waitaki River downstream of Waitaki Dam
| Effectiveness | Efficiency | |
|---|---|---|
|
Environmental flow and level regimes |
Moderate |
Moderate/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 environmental flow and level regime for the Waitaki River downstream of Waitaki Dam is the most appropriate way to achieve the objectives of the Plan.
