Ashburton water consents review

Environment Canterbury is reviewing around 90 resource consents that take surface water or stream-depleting groundwater in the Hakatere/Ashburton River catchment.

This review is designed to implement the minimum flows which were developed with the community to protect the waterways’ values and to ensure there is a reliable source of water for the environment, community and consent holders.

Engaging with the community

At recent community meetings, attendees had the chance to find out more about the waterways in the catchment, how minimum flows are set and achieved, and what this means for river users.

Separate meetings were held in late July for those affected consent holders. We are contacting them directly with further information.

River modelling and stream depletion

Hakatere/Ashburton River Modelling for Consent Review

This document outlines how we used hydrological modelling to estimate the impact that the consent review will have on consent holders’ ability to abstract water.

Desktop estimate of stream depletion in Canterbury

A desktop exercise has been undertaken to estimate potential stream depletion in the Canterbury Region.

Because of the lack of real, site specific testing, the Theis (1941) stream depletion solution model has been used as the calculation method of stream depletion rates.

This solution requires the least number of input parameters and is a good first estimate because of the conservative assumptions used in the model.

These assumptions will tend to overestimate depletion, however, a storativity value of 0.1 which is considered to be high (when compared to aquifer testing) has been used.

This value reduces the amount of water that the model will predict is coming from surface water (i.e. stream depletion).

The potential for the Theis model to overestimate stream depletion means that this model is a good initial method for determining which consents should be subject to minimum flows, and included in allocation blocks, however, a consequence of the conservative estimation of stream depletion is that the surface water allocation blocks may appear more utilised than will be the case in reality.

Field-testing (aquifer tests and stream conductance surveys) would refine the estimates of stream depletion, and this could result in lower estimates of stream depletion.

Method

The Theis (1941) stream depletion solution has been used to estimate stream depletion rates over 7 and 150 day pumping periods.

The resulting depletion rate is then used to classify the hydraulic connection of the takes using Schedule 9 of the Canterbury Land and Water Regional Plan (LWRP).

Inputs for the stream depletion model were obtained from the Environment Canterbury wells database, Environment Canterbury consents database and Environment Canterbury GIS layers.

Key points:

  • The wells which have been modelled are linked to active abstraction consents to take and use groundwater.
  • The Q7 (short term (7 day) pumping rate) and Q150 (long term (150 day) pumping rates were obtained from Environment Canterbury databases, and represent maximum pumping regimes for the granted consents.
  • All wells screened less than 35 metres, were considered. Where no screen information was available a maximum well depth of 40 metres was used.
  • Distance to the nearest river as shown by Environment Canterbury GIS layers; primarily the River Classification layer with adjustments made for River Zones and alpine river extents. No maximum distance from the river was applied.
  • Aquifer parameters derived from aquifer tests or estimates of T derived from Winsorized mean specific capacity data within 2.5 km of the subject bore using Bal (1996) this has been constrained to a lower limit of 500 and an upper limit of 10,000 m2 day. T estimates where no specific capacity data or aquifer test data is present a T of 1500 m2/day has been adopted.
  • Assumed storativity of 0.1

References

Bal, AA., 1996. Valley fills and coastal cliffs buried beneath an alluvial plain: evidence from variation of permeabilities in gravel aquifers, Canterbury Plains, New Zealand. Journal of Hydrology (NZ) 35 No. 1.Environment Canterbury, 2015. Canterbury Land And Water Regional Plan volume 1 December 2016.Theis, C.V., 1941. The effect of a Well on the Flow of a Nearby Stream. Transactions of the American Geophysics Union, Vol. 22, pp 734-738.

Stream depletion chart for consent holders

Supporting information for stream depletion chart including a key to help you understand the chart.

This information is designed to be read together to give you a better idea of how we have calculated stream depletion.

If you would like more information or want to contact staff about the Ashburton consent reviews, please email us at consentsreviews@ecan.govt.nz.

Key

WAP - Water abstraction point (your bore number)

T m²/d - Transmissivity (metres²/day)

S -   Storativity

Q7 - The maximum rate which can be pumped over 7 days, or the average rate of daily or weekly volume (if applicable)

Q150 - The average rate of take required to pump the full annual volume over 150 days, or volume entered in the consents database where no consented annual volume. 

SD -  Stream depletion rate – this is the rate considered to be coming from the water body over 7 or 150 days.

% SD -  The stream depletion effect over 7 or 150 days, recorded as a % of the pumping rate for the same timeframe.

Degree of connection - As per Schedule 9 LWRP

Points to note/Matters for you to explore

  • You can use Version 3 of the stream deletion tools found at: https://ecan.govt.nz/your-region/your-environment/water/tools-and-resources/.
    Use the Theis Jenkins sheet within this document.
    Assumptions – irrigation efficiency (100%) and separation distance/L2 (0m).
  • Estimation has been done at the recorded location of the WAP, not the consented location. You may wish to confirm that your bore is located at this location.
  • Where the actual location differs to the location specified on your resource consent, you may wish to investigate updating your consent to the correct location.
  • Schedule 9 of the Canterbury Land and Water Regional Plan sets the methodology to determine the degree of connection a hydraulically connected groundwater abstraction may have.   
  • If you have carried out an aquifer test, you may be able to use these results to determine your degree of classification.

Find out more about the consent review

Frequently asked questions

What is the scope of the resource consent review?

Resource consents to take water in the Hakatere/Ashburton River catchment will be reviewed to ensure they are consistent with the minimum flow, water metering and telemetry requirements set in the Land and Water Regional Plan (LWRP).

How many resource consents need to be reviewed?

There are about 90 resource consents that need to be reviewed to implement the LWRP minimum flow requirements. This includes consents to take and use surface water or groundwater that is hydraulically connected to the Hakatere/Ashburton River mainstem or tributaries. Of these, approximately half have no existing minimum flow condition.

Who pays for the resource consent review?

The cost will be met by Environment Canterbury, however, if a consent holder decides to engage a consultant to assist them with the process then they will have to pay for the consultant’s costs. There are Resource Management Regulations that address water metering.

Why is Environment Canterbury reviewing my consent to put new water metering conditions on it?

The Resource Management (Measurement and Reporting of Water Takes) Regulations came into effect in 2010 to enable water users and regulators to easily determine compliance with water take consents and provide accurate water use information.

The Regulations apply to holders of resource consents which allow fresh water to be taken at a rate of 5 litres per second or more. While the Regulations apply directly to resource consent holders, Environment Canterbury has more stringent water metering requirements than set out in the Regulations. This means that these can only be applied to resource consents when they expire and are replaced, or if they are reviewed.

The LWRP (Policy 4.54) requires all resource consents with a minimum flow or trigger level that signifies a restriction on take, to include a condition requiring water use records to be telemetered to Environment Canterbury.

This means that for all resource consents with a minimum flow condition, regardless of the rate of take, water use records must be recorded and telemetered to the Canterbury Regional Council or its nominated agent to enable compliance with the minimum flow conditions. 

Telemetry is an essential requirement for consent holders wishing to form a water user group, as it provides real-time data of who is taking and at what rate.

What information was considered in making the decision to review consents?

The following information was considered when making the decision to review the consents:

  • Priority outcomes sought for the Hakatere/Ashburton River catchment developed by the Ashburton Water Zone Committee with the community
  • The relevant provisions of the Land and Water Regional Plan, the Resource Management Act 1991 and Resource Management (Measurement and Reporting of Water Takes) Regulations 2010
  • Technical advice regarding hydrology, including water availability
  • Environmental benefits to the waterbodies
  • Environment Canterbury’s Long-Term Plan (page 18)
  • The impact on consent holders.

The resource consent review will mean that I have new conditions on my resource consent. When will they apply from?

The minimum flow provisions in the LWRP apply from 1 July 2023. If a resource consent currently does not have a minimum flow condition, new minimum flow conditions will be added and these will apply from 1 July 2023. The consent will continue to have no minimum flow condition until 30 June 2023.

If your resource consent currently does have a minimum flow condition, new updated minimum flow conditions will be added and these will apply from 1 July 2023. Your existing minimum flow condition will apply until 30 June 2023.

The new water metering and telemetry condition will also apply from 1 July 2023 to align with the new minimum flow conditions. Many consent holders will already have telemetry operating on their abstractions and will be considering installing it. If this is something you are considering, you are welcome to install telemetry before this date.

I already have a minimum flow condition on my resource consent. Why is Environment Canterbury reviewing my consent to put a new minimum flow condition on it?

The LWRP sets minimum flows for the Hakatere/Ashburton River mainstem and some tributaries that must be met from 1 July 2023. The LWRP was developed through a public process under the Resource Management Act and there is an expectation that its provisions are implemented. The minimum flows set in the LWRP can only be applied to resource consents if they expire and are replaced, if they are reviewed, or if resource consent holders voluntarily add them by changing their consent conditions.

The resource consents in this catchment have a variety of minimum flow conditions on them; few of these are compliant with the LWRP minimum flows and many have no minimum flow condition. Most resource consents in the catchment expire between 2028 and 2040, and it won’t be until all resource consents have the LWRP minimum flows that the benefits envisaged for the catchment will be realised. In addition, applying the minimum flows to all resource consents at the same time ensures equitable access to water for all users.

I have a resource consent to take groundwater. Environment Canterbury has said it is connected to a surface water body. How was the stream depletion calculated?

Actual stream depletion can only be determined using an aquifer (bore) test which is designed to calculate aquifer parameters unique to the abstraction location. Without an understanding of location specific bore parameters, Environment Canterbury uses a desktop assessment to determine the potential stream depletion classification on surface water bodies. This is undertaken in accordance with Schedule 9 of the LWRP.

I don’t agree that my groundwater take is connected to a surface water body. What should I do?

If you think that your groundwater take is not a stream depleting groundwater take, we recommend that you seek independent advice from your consultant. They would review the stream depletion calculation undertaken by Environment Canterbury and advise you what action you could take. They may recommend undertaking an aquifer test, but there is considerable cost associated with this approach. There may be alternative options for you before undertaking an aquifer test.

It is important that you advise us immediately if you are concerned that your groundwater take has been incorrectly classified, as Environment Canterbury’s staff will also be able to assist you.

Can I object to my resource consent being reviewed?

A consent that is being reviewed is treated as if it were an application for a resource consent. This means that it is possible to object to certain decisions that are made during the consent review process. If you wish to pursue an objection, we recommend that you discuss your concerns in the first instance with Environment Canterbury staff. You may also wish to seek independent advice.

Can I object/disagree to the new conditions that are proposed by Environment Canterbury?

The Resource Management Act sets out the formal process for completing a consent review and provides 20 working days for the consent holder to consider the new conditions and propose alternative conditions. Any alternative proposed conditions must also give effect to the provisions in the LWRP.

Environment Canterbury has extended the time period for consent holders to propose alternative conditions from 20 to 40 working days. This provides more time for consent holders to understand the review conditions and seek advice if they choose. The date that any proposed alternative conditions must be provided to Environment Canterbury is Thursday 12 September.

Will the consent review cost me money?

While the costs of the consent review process will be met by Environment Canterbury, a consent holder will need to meet the costs of any independent experts they choose to engage. There may also be costs to the consent holder to implement the new conditions. For example:

  • Engaging a service provider to provide advice and installation of a suitable water metering and/or telemetry system, as well as ongoing metering and data management services;
  • Engaging a consultant to provide advice on water use efficiency in order to adapt farming practices to respond to any changes in water availability.
There may also be costs to the consent holder if they wish to pursue alternative water source options, such as deep groundwater or water storage.

What are the environmental benefits that will be gained from the consent review?

There are many environmental benefits that will be gained from implementing the minimum flows set in the LWRP. The minimum flows will ensure that an open river mouth will be maintained. This will result in free migration for fish, as well as improved water quality, particularly at the mouth or hāpua reach. There will be improvements in water quality throughout all the waterbodies in the catchment and improved habitat for indigenous species and sports fish.

The proposed new water metering condition will not work with my intake system. What do I do?

The proposed new water metering condition has been determined for the type of intake system that we have in our records for your water intake. The condition will be for either a piped or open channel intake system. If the proposed new water metering conditions will not work with the type of intake system that you have, please get in touch with us and we will update our records and replace the proposed new condition with the correct one for your intake system.

I have a resource consent to take water from a tributary of the Hakatere/Ashburton River. What will the proposed new minimum flow condition look like?

A resource consent to take water from a tributary of the Hakatere/Ashburton River will be subject to the minimum flow on the tributary water body and the minimum flow for the Hakatere/Ashburton River mainstem. This means that you will be subject to restriction as soon as either of the tributary or mainstem minimum flows are triggered.

How do I know if the flow in the river is low and I’m meant to be on restriction?

River flow and restriction information is available here. Restriction information for the following day becomes available at 3pm for rivers that have a flow calculated via a telemetered system, and at 5pm for rivers that have a flow gauged or assessed by staff in the field.

The information on the website is collated from a number of Environment Canterbury’s databases that record resource consent and river flow information. Search for your resource consent number, then click on the flow restrictions tab. This will show you the flow at the low flow site today, as well as the expected flow for tomorrow. This page will tell you the level of restriction you are on (if any applies at that time), as well as what tomorrow’s expected restriction may be.

During the irrigation season you will need to check the website daily to see if you need to restrict your rate of water take

What changes can consent holders expect to their ability to take water?

There are eight Surface Water Abstraction Zones (SWAZ) in the Hakatere/Ashburton River catchment. The new minimum flow conditions will impact consent holders in every SWAZ by changing the availability of water.

For most, this means that consent holders will be on full or partial restriction during the irrigation season more frequently and for longer periods of time.

My farm is affected by Mycoplasma bovis. Do I have to go through a consent review at the moment?

We understand the significant effect and stress the Mycoplasma bovis outbreak has had on affected farmers. It is likely that the consent review process may apply to some properties that have been infected or that are under MPI restrictions.

We have issued the Notice of Review to all relevant resource consents to take water in the Hakatere/Ashburton River catchment. As we do not have a record of the farms affected by Mycoplasma bovis, please get in touch and let us know if you are affected by the Mycoplasma bovis outbreak so we can discuss the consent review process with you directly. We will keep your details confidential and no other agencies will be provided with this information.

Our primary concern at this time is to support farms to limit the spread of the disease and to rebuild healthy herds.

Who to contact if I have further questions about the review

Please email Environment Canterbury at consentsreviews@ecan.govt.nz in the first instance with your query so that we can work out the best person to correspond with you either by phone, email or in person. This may be a Consent Planner or one of our Science Team if your question is about a technical matter.