There may be situations where an Aquifer Test is not required before a groundwater application is made. 'Principles for exemption' have been developed by considering under which circumstances Environment Canterbury’s requirements can be satisfied without site-specific aquifer test data.
The applicability of any exemption will be determined by the purpose(s) for which an aquifer test is expected to serve.
In the context of applications for groundwater take permits these include:
• confirmation that a well is able to yield the rates being applied for
• determination of well interference effects
• determination of stream depletion effects
Testing requirements & exemptions as at October 2009:
1. Step testing2 is to be undertaken in all cases unless a reliable step test has been carried out in the last 15 years.
2. Aquifer testing, with observation wells, is required unless:
- There are no neighbouring wells within 2 km of the abstraction well, and there is no potential for direct stream depletion3;
- The transmissivity calculations from the step test are used in conjunction with the Theis (1935) drawdown model in a WQN10 assessment, and there is no potential for direct stream depletion;
- Written approvals are provided for all wells within 2 km, and there is no potential for direct stream depletion;
- An aquifer test with observation wells has been carried out in the same aquifer, within 500 m of the proposed abstraction location, the results from which are considered by Environment Canterbury to be reliable;
- The well has been used as an observation well in an aquifer test and a corrected drawdown greater than 0.2 m was observed in this well.
- The application is for a renewal with no change to pumping rates, or significant well location changes
Where the results from any aquifer testing are uncertain e.g. no response in observation bores, the interpretation and application these test results should be discussed with Environment Canterbury groundwater staff and will be considered case by case.
If you think you may qualify for an exemption please call Customer Services to discuss your specific situation.
For further assistance please contact Customer Service on 03 353 9007 or toll free on 0800 324 636.
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