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Dam or no-dam Scenarios for Waimea Plains Water Takes

This page provides an overview of the Waimea Plains Water Management provisions in the Tasman Resource Management Plan. The Plan describes what happens if there is - or isn't - a dam.

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Introduction

In 2001 the Tasman District endured one of the most notable droughts for decades. This was felt most in the Waimea Plains where the Waimea River ran dry having a significant economic and environmental effect on the area.

In response two actions were taken: the moratorium on all new water permits was confirmed in the light of the significant over-allocation of water while a holding pattern water management regime was instigated and in 2007 put in the Tasman Resource Management Plan (TRMP).

The second action was to set up a community group, the Waimea Water Augmentation Committee, to investigate and identify a means of augmenting the river and groundwater to ensure a secure supply of water for both current and potential water users in the future. This investigation programme has assessed augmentation options and has progressively focussed on the site in the upper Lee River for a major dam.

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Tasman Resource Management Plan Changes

There have been a series of changes to the TRMP since 2013 for Waimea Plains water management as the proposal to construct the Waimea Community Dam has been developed.

2013 and 2015

The Tasman Resource Management Plan (TRMP) was amended by Changes 45 – 48 in 2013, and Changes 54 to 56 (Waimea Water - Security of Supply) in 2015.

Both sets of changes were heard by panels of independent commissioners, whose recommendations were adopted by Council and on which appeals were received and resolved and the changes became operative on 19 September 2015. These changes establish water management objectives for quantity and quality and establish water take allocation limits in the Waimea plains water management zones.

The changes also provide for the Waimea Community Dam (the dam), a significant water augmentation work, as the preferred solution to the chronic over-allocation of the river and groundwater resources of the Waimea Plains. The dam would substantially improve both the environmental flows of the Waimea River and the security of access of all current users in low flow periods, as well as provide for long term future demand for irrigation, urban and industrial uses.

All water permits in the Waimea Plains zones are due for renewal from May 2016 and May 2017. All those expiring holders renewing have now re-applied and there are about 300 applications.

Two sets of provisions

The TRMP through these changes now provides for water management in the absence of any augmentation by the dam and also in the event of funding, construction and operation of the dam and its water releases on the Lee River under consents now granted.

The changes provide two sets of water management objectives and zones with allocation targets or limits, and minimum flows and rationing triggers that apply depending on whether the dam eventuates, and if it does, whether permit-holders make a financial contribution to the dam.

The changes establish two classes of renewing permits, those affiliated to the dam where the holder has a water supply agreement (WSA) that is linked to discharges from the operation of the dam; and those not affiliated. Different renewal restrictions on the water to be allocated, and low flow rationing of permits, will apply to affiliated and non-affiliated permits. If there is no dam, or if permits are non-affiliated, stringent rationing triggers will result in reductions in authorised use virtually every summer with cease take requirements potentially applying.

The changes specify a set of transitional periods triggered at certain dates where a check on outcomes for the dam applies, and where different water take rationing restrictions during low flow periods may apply to different classes of permits, yet to be implemented through water permit renewal decisions. These checks at a set of dates are:

  1. A check at a date on either a “with dam” or “no dam” result, arising from the provision of WSAs or not. For the “with dam” outcome at the first date check, the dam operator (which is yet to be named) must have been able to make water supply agreements (WSAs) with renewing permit-holders who have contracted through such agreements, to be affiliated to the Dam through shareholder status. Where not, the “no dam” outcome leads to new rationing and other take restrictions. Where at this transition point there are WSAs, the “with dam” outcome is then subject to:
  2. A check at a date on substantial progress with the construction of the dam where if there is no substantial progress, more stringent restrictions on the exercise of permits for community water supplies apply; and
  3. A check at a date on whether the dam has commenced operation or not, where if not, then the “no dam” regime applies for all permits for minimum flows and rationing triggers.

All these changes are operative.

2016 - Transitional dates changed

From 24 September 2016 Proposed Change 63 amended the dates applying to these transitional periods. The dates in the transition are now:

1 November 2018:

Availability of WSAs, either “with dam” or “no dam” and so either a less stringent bona fide review, and for those affiliated, rationing (after assessing the resource particularly saltwater intrusion risk); or for all renewals, a more stringent bona fide review, and the much more stringent five step rationing regime than under expiring permits

1 November 2019:

Substantial progress with dam construction, and if no substantial progress, restricting exercise of Council’s water permits for community water supplies only to land zoned urban or deferred urban as at April 2013; and limiting existing and new industrial and commercial uses in water supply areas to low rate (via bylaw or contractual means)

1 November 2022:

Check for commencement of operation of the dam. If the dam is operating, then affiliated permits are under a significantly less restrictive rationing and the “with dam” allocation limits can apply. But those permits not affiliated move to a more stringent three-step rationing regime resulting in cease take. If there is no dam commencement, then the “no dam” rationing restrictions for all permits apply.

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Water Management Without a Dam

Under the “no dam” regime, the new minimum flow for the Waimea River will be 800l/sec. This flow will not protect all the instream values fully and water quality declines at this flow because of higher temperature and algal growth. Maintaining a flow of 800l/sec will require rationing to begin earlier than previously required.

If there is no dam (or if the permit is non-affiliated), a new five stage rationing regime will apply from the summer of 2018/19:

  • Stage 1 (2750 l/s at Wairoa Gorge recorder): 20% rationing
  • Stage 2: (flow not specified): 35% rationing
  • Stage 3 (2300 l/s at Wairoa Gorge recorder): 50% rationing
  • Stage 4 (800 l/s in Waimea River at Appleby): 70% rationing
  • Beyond Stage 4: cease take order depending on salt water intrusion except for essential human needs and animal welfare

Based on historical flow data, we know that the Wairoa River flow falls to 2300l/sec practically every year.

This means that when the water flow at the Wairoa Gorge reaches 2750 l/s stage one rationing will be implemented. Users will be rationed by 20 percent of their new allocation.

Under the previous management regime, there was no minimum flow and only a stage one trigger was specified. Rationing did not start until the flow reached 2500 l/s.

Water re-allocation

In renewing water permits expiring 2016 and 2017, existing permit holders can retain some or all of their existing allocations. All water permits for irrigation and urban and industrial water supply are being reviewed and this is expected to result in a significant reduction in the availability of water for productive use and urban water supply. If there is no dam no new water permits can be issued.

In the case of productive land with a water permit for irrigation, the current crops being produced and the soil type will be taken into account in calculating the amount of water to be re-allocated. The rates are specified in the TRMP. The amount allocated will be based on water meter returns and the maximum weekly water use in the ten years between 2003 and 2013. The maximum that will be re-allocated will be the lesser of the maximum weekly amount during that time or the actual amount being used for irrigation based on soil and crop type. The rationing triggers will apply to the new amount allocated to that permit. Under the five step rationing regime, cutbacks will be imposed every year.

This new regime will affect users in different ways. Grape growers who have traditionally only used a small portion of their allocated water may lose a large portion of their current base supply. An orchardist who has historically used all of their water allocation may retain that same allocation, but will be greatly affected by the new rationing regime. This new allocation regime will mean landowners have very little scope for changing crops to higher water use crops.

The Council, as a water supply provider, will also be subject to the same the rationing steps, except that for the Council’s supply, it will not be required to go beyond step 3 rationing. Additional restrictions applying from 1 November 2019 mean the Council’s ability to increase the number of water users in any new development is severely restricted.

Development of any kind will have to occur within existing Council allocations and only in those urban zones currently supplied or signalled for future urban development in the TRMP. Any new connection would be limited to 15 cubic metres daily supply. Effectively, any new high water use development is limited or curtailed.

New permits issued in 2017/18 will have a new term of 20 years.

Security of supply

The new allocation limits for the Waimea Zones will be calculated after this permit renewal process has been completed and will be the sum of all water allocated in each zone. This in combination with the new minimum flow and rationing triggers means the security of supply for irrigators and other water users including urban water users is very low.

In addition to the new limits, the TRMP contains allocation targets. These are the allocations determined to be more sustainable for each of the zones, but they are still subject to the new rationing triggers. The new targets will apply where there are any new permit applications.

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Water Management With a Dam

A new chapter in the TRMP provides objectives and policies for managing significant infrastructure. At present, this chapter addresses only the proposed dam in the Lee Valley (the dam). The chapter describes the water demand and the shortfall in water supply to meet existing and new water demand. It acknowledges that the dam will cause adverse effects but the water issues are so significant, the adverse effects will be managed through conditions on resource consents.

The dam allows for an improved environmental flow in the Waimea River and the TRMP specifies that if the dam is built, a flow of 1100l/sec is to be maintained in the Waimea River at Appleby. With the dam, the allocation limits for each of the water management zones where water supply will be augmented, are all significantly increased. They allow for future urban demand and also full irrigation in these zones as well as new irrigation in adjacent zones such as Redwoods Valley and the lower Wai-iti.

Water re-allocation

Permits will be renewed in 2017/18 with a two stage approach to conditions. The amount of water allocated will be linked to whether the applicant is paying towards the construction and operation of the dam through the holding of shares and WSA and so being an affiliated permit-holder. Conditions will limit the use of water to quantities being actually or reasonably used up to 2013, until the dam is releasing water. This means the river is protected from further damage until the dam is operating.

For those who choose not to be affiliated, the amount allocated is decided on in the same manner as the “no dam” renewals.

Security of supply

Water allocation “with dam” means affiliated users have a very high security of supply. No rationing will be required unless there is a very severe drought that exceeds a 50-year probability.

For those non-affiliated permits, the rationing is as for no dam until the dam operates. From then onwards, the rationing regime for non-affiliated permits is a significantly more stringent three step rationing with step 3 – cease take – at 2050 l/s measured at the Wairoa River site. These takes may only recommence when the flows at the Wairoa site rise above 6000 l/s on a weekly moving average basis. This is a very low security of supply for these permit holders, and it reflects the need to separate the effect of augmentation by the dam and exercise of affiliated permits, from the remaining capacity of the water resource to sustain these takes.

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Irrigation Management Plans

In either dam or no dam situations, water permit applicants will be required to prepare Irrigation Management Plans.These will help ensure allocated water is used efficiently and also to help avoid nutrient losses.

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Water Quality

The TRMP includes new provisions that identify the need for further plan development in respect of managing water quality. Like the Irrigation Management Plans, this work is required whether the dam proceeds or not. There are new policies to guide how this work is to proceed and they signal a inclusive approach that involves stakeholders and the community. It also includes new provisions that require nutrient and farm production records to be kept and this information may be used in develop property and catchment scale models.

The Council has since set up the Waimea Water Quality: Freshwater and Land Advisory Group (FLAG) to further this work.

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