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Proposed National Environmental Standard for Water Measuring Devices

Acknowledgements

Executive Summary

1 Introduction

2 Why Measure Water Takes?

3 Why Do We Need a National Environmental Standard for Water Measuring Devices?

4 Content of the Proposed National Environmental Standard

5 A Discussion of Costs and Benefits

6 Future Actions to Complement the National Environmental Standard

7 What Next?

Appendix 1: Definitions

Appendix 2: Current Measuring Practice at Regional and Unitary Councils

Appendix 3: Actions Being Developed Under the Sustainable Water Programme of Action

4 Content of the Proposed National Environmental Standard

This section details the proposed subject matter of the National Environmental Standard and what it would require in practice.

The National Environmental Standardseeks toprescribe minimum requirements for:

• water measuring devices, including accuracy
• installation and maintenance of the equipment
• data recording and data transfer to regional councils.

The proposed Standard would set out the minimum requirements needed to achieve a consistent and comprehensive regime of water measurement. Regional councils may require more stringent or specific standards pertaining to water measuring devices depending on catchment-based factors.

4.1 Scope of the standard

As a mandatory regulation, a national environmental standard would take precedence over water conservation orders and rules in regional plans, unless the standard allowed those mechanisms to be more stringent. In that case, the most stringent provision would be followed.

To ensure that accurate information is gathered about the actual water taken in all catchments, it is proposed that the proposed National Environmental Standard apply to all takes that currently require resource consents under operative or proposed regional plans. The Standardwould apply across all regions and all catchments or aquifers.

There are three types of water takes for which resource consent is not required. It is proposed that the Standard would not cover these:

• RMA section 14(3) (b, c,) allows takes for an individual's domestic purposes and for animals' drinking water, provided there are no adverse effects on the environment
• RMA section 14(3) (e) allows takes for fire-fighting purposes
• permitted activity takes that are allowed for in a regional plan.

These takes are generally small and not directly measured. Instead, regional councils estimate both section 14(3) takes and permitted activity takes for resource management purposes.

A timeframe for applying the proposed National Environmental Standard to existing consents is in section 4.7. Regional councils would need to plan how the requirements of the Standard would be achieved in their region, either by addressing specific catchments or by phasing in the application of the standard by the size or level of take.

Discussion of proposed scope

Regional councils are responsible for controlling water takes to achieve sustainable management of the resource. To achieve nationally consistent and accurate data on the volume of water taken, it may be appropriate to measure a large proportion of the actual takes and to estimate the remainder. However, the estimated portion must be small enough to avoid compromising accuracy for the overall water take figure, and there must be confidence in that estimate.

The possibility of the Standard applying to all takes that currently require resource consent ("consented takes") has been considered by the Reference Group, as has the use of a national cut-off threshold - for example, relating to size of take. The proposed scope acknowledges that catchment-specific factors, such as the relative number of small consented takes, will influence the uptake of the Standard.

The Reference Group recognised that regional councils are best placed to evaluate what needs to be measured to gain an accurate picture of actual water taken at the catchment level. Where the costs of requiring water measuring devices on all consented water takes outweigh the benefits, there is a need to consider who should be exempt from the Standard and on what basis. The following factors were considered to be relevant to assessing exemptions:

• whether the volume of actual take can be estimated easily and accurately
• whether the level of allocation is very small compared to resource availability
• whether the effect on the environment is minor.

Permitted activities and takes allowed by the RMA under section 14(3)(b)-(e) are generally of low volume and it is proposed that such takes would not need to be measured. However, it is acknowledged that the threshold for permitted activities may be different across and between regions (see text box below). There may be some cases where all takes in a catchment or aquifer need to be measured to understand cumulative effects.

4.2 Proposed minimum standards for measuring flow in pipes

Various water measuring devices are currently available and in use, ranging from mechanical systems to ultrasonic and electromagnetic flow meters. There is no New Zealand standard for such devices and the commonly used international standard - the International Organisation of Legal Metrology (OIML) Recommendation 49 - relates only to cold, potable water.

Rather than stipulating a particular type of equipment, the National Environmental Standard would include a series of minimum requirements for all new pipe water measuring devices installed after the Standard is enacted. Such devices must:

• be capable of continuous measurement
• measure volume in cubic meters
• have data storage capability
• have an accuracy standard of ± 5%
• be capable of recording daily volume
• be fit for purpose
• be tamper-proof and sealed.

Discussion of proposed minimum requirements

All water measuring devices must be capable of continuous measurement

To measure the total volume of water abstracted under a resource consent, the measuring device must record the amount of water moving through the system. Accuracy will not be achieved by a sampling and extrapolation method. Therefore, it is recommended that all newly installed measuring devices must be able to measure continuously.

All water measuring devices to measure volume in cubic metres

In New Zealand, flow is traditionally recorded in metric units as litres per second, cubic metres per second for large volumes, and cubic metres per day. The proposed National Environmental Standard requires daily measurement; therefore, the volume measure should be cubic metres.

All water measuring devices to have data storage capability

It is proposed that all systems (new and replacement) installed after the Standard is enacted are able to automatically record and store data. It is advantageous for new measuring devices to be able to store data for a specified period so there is less potential for errors in recording or the non-recording of data from the device. Data storage also provides an audit trail. Data loggers may be able to be fitted onto existing water measuring devices to enable data storage.

Accuracy of measurement

Most councils already require the accuracy of water measuring devices to be ± 5%. The Water Meter Code of Practice sets accuracy standards for various classes of meters for cold, potable water which range from ± 1% to ± 5%. It is recognised that, in the applications where this proposed National Environmental Standard would apply, the water may be dirtier than potable supply. This can cause wear and reduced accuracy in the measuring device. At the same time, an error rate of ± 10% may be unacceptably high to achieve the required level of data accuracy and veracity. It is recommended that the accuracy of ± 5% be adopted for measuring devices in situ for piped intakes.

Fit for purpose, tamper-proof and sealed

Measuring devices need to be suitable for the purpose and water they are measuring. For example, to measure geothermal ('dirty') water, a meter needs to be capable of handling temperature variations, sediment and weather exposure. The measuring device must also be sealed and tamper-proof to provide confidence in the data.

4.3 Proposed minimum standards for measuring flow in channels

While channel takes make up a small number of consents (estimated at 1%), the actual proportion of water abstracted in such takes is high (estimated at 20%). [Aqualinc (2006),Water Measuring Devices - Stocktake of existing situation.] In an open channel, the water level is measured either in the channel itself or in a v-notch weir or flume. The water level data is converted to flow by a calculation using a water level (flow rating curve). Flow is converted to volume by calculation.

It is proposed that all new channel measuring devices installed after the National Environmental Standard is enacted:

• continuously measure water levels
• have a water level accuracy of ± 10mm
• maintain a rating curve to convert water levels to flow
• fit a data logger to store the water level data.

Discussion of proposed minimum requirements

There are a number of international standards relating to the measurement of flow in an open channel and the conversion of that data to a volume. Regional councils will be able to choose and specify standards appropriate to their catchments, providing they meet the minimum requirements of the National Environmental Standard.

4.4 Installation and maintenance standards

Poor installation has a direct influence on the accuracy of the measurement. Current installation of equipment is of a variable standard. Any national environmental standard for measuring devices needs to recognise the impact of poor installation.

It is proposed that:

• proper installation of water measuring devices is required as a condition of a water take consent
• installation should strictly comply with the manufacturers' installation instructions
• measuring devices should be installed as close as possible to the take point, and before the first outlet point
• the accuracy of all measuring devices must be independently verified every five years.

Discussion of installation and maintenance requirements

The measurement device must capture all of the water abstracted, so it should be located as close as practicable to the take point, and before the first outlet (or use) point.

It is recommended that the proposed National Environmental Standard require verification that the installation is appropriate. The method of compliance checking could be determined by the regulatory authority and could be by direct inspection, indirect methods such as photographic evidence, or some other method determined by the regional council.

Water measuring devices are subject to wear which compromises accuracy. Studies undertaken by regional councils have found significant accuracy and reliability problems over time. These studies have demonstrated a need to recalibrate and test water measuring devices for accuracy. The NZWWA Code of Practice refers to the need to service (recalibrate) measuring devices every six years, but this relates to measuring devices suitable for measuring water of a potable standard. As many water consents take water of lesser quality, it is recommended that the proposed National Environmental Standard requires the accuracy of water measuring devices to be independently verified every five years.

4.5 Data recording and transfer

It is proposed that:

• responsibility for recording the water measurement rests with the consent holder
• responsibility for transferring the data to the regional council rests with the consent holder and should occur on at least an annual basis
• data recording should occur at a minimum of daily intervals.

Discussion of data recording and transfer requirements

Just as a permit to take water provides a benefit to the consent holder, information provided by the water measuring device also offers benefits to the consent holder in terms of better business management. It is therefore appropriate and practical that responsibility for recording and transferring data to regional and unitary councils should rest with the consent holder.

The interval at which data is recorded will reflect the purpose for which the data is collected. It is recommended that the National Environmental Standard prescribes daily recording as the minimum interval because this is the most flexible option. However, councils could prescribe a shorter period to meet particular circumstances - for example, more frequent information may be required at times of low flows.

There are essentially two options for data recording methods:

1. A manual, paper-based system, where the operator physically visits the measuring device at the prescribed recording period to write down the data from the measuring device.
2. Electronic storage on 'data loggers' that hold data at preset intervals for a given period, generally dependant on the capacity of the logger and the frequency of recording. That data is subsequently downloaded by the attachment of a computer or telemetry device.

Many regions have reported poor reporting rates. To address this, the most direct system for data transfer should be applied to avoid errors in data handling and to minimise human intervention and cost. The reference group considered requiring electronic data collection and transfer; however, this option is not being pursued because of cost and changing technology.

As the National Environmental Standard would aim to allow assessment of total water abstracted from the resource in any year, the proposed minimum requirement for data transfer is annual. The timing of data transfer is a factor for a regional council to determine and will be influenced by the ability of their systems to store and process the data.

For national reporting, the national stock water accounting year begins on 1 July. It is likely that any national reporting will be on annual volumes taken during the 1 July-30 June year.

4.6 Summary of the requirements of the proposed National Environmental Standard

4.7 How would the National Environmental Standard be applied?

The National Environmental Standard would be a minimum standard to be applied to all new resource consents to take water. Resource consents to take water would only be able to be granted with conditions that complied with the Standard. All new water take consents (including those that replace an expired consent) would have to meet the National Environmental Standard.

Existing water take consents would need to meet the proposed National Environmental Standard within five years of the gazetting of the regulations. To implement the National Environmental Standard for existing consents, regional councils would be required to review the conditions on existing water take consents within five years so that they complied with the National Environmental Standard using section 128(1)(ba) of the RMA.

4.8 What the proposed National Environmental Standard would not cover

The proposed National Environmental Standard would not prescribe the type of equipment, for measuring, storing or transmitting data. It would not address water take or use at a household level. The Standard would apply only to measurement associated with consents to take water, not to measurement of water quality.