Best Practices and Drilling Info
Environment Southland has put together a pamphlet called “How well is your well” covering these points in more detail.
Drilling for Water
Access to water of adequate quality and quantity is crucial for domestic, farm and stock supply. Drilling a bore or well to access groundwater for water supply is a large capital expense. The following section contains information to assist landowners ensure the quality and reliability of their water supply investment.
Construction of a Bore or Well
A resource consent is required before constructing or altering a bore or well
Environment Southland has introduced new rules into its Proposed Regional Freshwater Plan. These rules require landowners to obtain resource consent from Environment Southland before drilling or altering a new or existing bore or well.
The resource consent process is relatively simple and low cost and it allows Environment Southland to collect data to enable effective management of the resource and provide landowners advice on appropriate siting, construction and maintenance of their groundwater supply.
To find out more about the consent process, or obtain a copy of the application form, contact our consent staff.
In 2001 a technical standard was released covering drilling in New Zealand (NZS 4411:2001 Environmental Standard for Drilling of Soil and Rock). This standard prescribes best practice for the drilling and construction of bores and wells. Prior to drilling you should ensure your contractor is familiar with the requirements of this standard.
This document can be viewed at Environment Southland’s offices, Cnr North Road and Price Street, Invercargill.
Protecting your Groundwater Quality
Localised contamination of groundwater through poor well-head protection is a major cause of groundwater quality problems in Southland. Taking a few minutes to check the condition of your bore may help prevent you or your family getting sick, and will help protect the quality of our groundwater resource. Here are some simple steps you can take to ensure the quality and reliability of your groundwater supply.
The casing should extend at least 0.3m above ground level
The casing should extend above the surrounding ground level to prevent stormwater runoff from entering the bore or well. Ideally a concrete apron should be put around the base of the casing to deflect stormwater and prevent weed growth.
Ensure the top of the bore or well is securely sealed
The top of your bore or well should be securely sealed to prevent entry of foreign material. Something as simple as sealing around pipes and cables with silage tape, can help reduce the potential for contamination of your water supply.
Enclose the wellhead in a shed or other form of cover
Enclosing the wellhead within a shed (preferably with a concrete floor) will help prevent entry of contaminants and help prevent damage due to frost.
Ensure stock are excluded from the area immediately around the bore or well
Preventing stock access to the area immediately around the bore or well reduces the potential for entry of contaminants into or around the casing.
Store chemicals away from your bore or well
Storing chemical well away from your water supply will help prevent accidental or inadvertent contamination of your water supply.
Fit a backflow prevention device
Fitting a backflow prevention device (available from plumbing and pump suppliers) to your bore or well will prevent back-syphoning of contaminated water from stock troughs into your water supply. A backflow prevention device is also essential to eliminate contamination when filling sprayers directly from the bore or well.
Avoid spraying herbicide around your bore
Herbicide should not be sprayed immediately around your bore or well to control weed growth. The use of these chemicals significantly increases the potential for contamination of your water supply.
Maintaining your Bore or Well
In many cases problems with the reliability of bores and wells can be avoided through regular maintenance. Regular maintenance may also help reduce pumping and equipment replacement costs. Here are some simple tips for maintaining your bore.
Flush pressure tank regularly
Regular flushing of the pressure tank will remove sediment and ensure sufficient air is retained. Insufficient air in the pressure tank reduces its ability to hold pressure resulting in frequent running of the pump to maintain pressure. This increases power consumption and wear and tear on pumps.
Flush out bore at least once every ten years
Over time bores and wells become less efficient as the casing corrodes and fine sediment accumulates around the well screen. This progressively reduces the rate water is able to flow into the bore until it can no longer keep up with the pump and the bore effectively "runs dry". Regular flushing by an experienced contractor will maintain yield and extend the life of your bore.
Check pumps, pipes and fittings for leaks
Leaking oil from pumps or leaking water from pipes and fittings may introduce contamination into your water supply. It is a good idea to protect pumps, hoses and fittings from frost damage in order to prevent leaks.
Have your water quality regularly tested
Bores and wells utilised for potable supply should be tested to ensure they are free from contamination. Having the microbial (bacterial) quality of your water supply tested is particularly as many waterborne illnesses can be transmitted via contaminated water supplies.
Aquifer Pump Tests
Aquifer pump tests are a reliable, effective way of quantifying groundwater flow and determining aquifer properties at a particular location. A resource consent is required before undertaking an aquifer pump test if you are going to take more than 20m3 per day. You can apply for a consent at the same time you apply for your drilling permit if you wish. Download the factsheet for more information.
Environment Southland is the brand name of Southland Regional Council.