The benefits of a well-designed storage system
- Peace of mind
- Increased flexibility around irrigating
- Effective utilisation of nutrients and water
- Reduced risk of effluent non-compliance
- Environmental protection
Build the perfect effluent storage pond for you
To help guide your decision-making see A farmer's guide to building a new effluent storage pond. It covers everything from planning and design to post-construction. Below you will find detail on some areas covered by the guide.
Lined ponds and above ground tanks are the two options available when choosing an effluent storage system for your farm. Click below to see a pros and cons list for each...
Above ground tanks
- Can usually be installed year round
- Little costs associated with earthworks
- Not significantly affected by water table
- Can be more expensive than lined ponds
- May require a building consent from district council
- Some size restriction on what is available commercially
For more information about above ground tanks see A farmer’s guide to building a new effluent storage pond.
- Less cost than above ground options
- Can be less intrusive on the farm
- More accommodating of shape and design
- No size restriction
- Wider range of costs depending on lining options and earthworks needed
- Installation can be weather affected especially for clay lined ponds in some wetter parts of the country
A well designed storage pond is:
- sealed to avoid leakage to groundwater
- allows for ongoing operation and maintenance, and is appropriately sized for the volume of effluent produced now and in the foreseeable future
- compliant with regional and district council and Building Act requirements.
Selecting the right liner
Liners can be formed from compacted clay, concrete or specifically manufactured materials such as polyethylene (PE), polypropylene (PP), or rubber (EPDM).
To choose the right liner for you see the options below.
- May have suitable clay on site for pond construction
- Requires soil testing by a professional Requires technical expertise to compact clay correctly to achieve sealing requirement
- Cracking can appear when ponds are empty, risk of leaking
- Warranties may be more difficult to obtain
- Potentially high cost if importing clay from off-site
- May require periodic re-lining of the pond after cleaning
- Not favoured by all councils, you need to check first
Concrete (Engineered cement composite)
- Less earthwork preparation required than with clay liners
- Flexible to withstand ground movement
- Withstands mechanical damage
- Relatively new product for effluent ponds in New Zealand
- Warranties may be difficult to obtain, engineering expertise is essential
- Moderate to high cost
- Good range of liners available
- Good warranties available
- Installation allows for gas and ground water dissipation
- Some variation in quality of synthetics on the market
- Moderate to high cost
How much storage do you need?
Download the Dairy Effluent Storage Calculator (DESC) to determine storage needs. It contains a database of soil types and 30 years of daily rainfall records for many sites throughout New Zealand.
Converting storage calculator information to a working volume
DairyNZ has developed the Effluent Storage: Working Volume Calculator to calculate the dimensions and working volume of your effluent pond or tank, which is also useful for existing ponds or tanks.
The video playlist below shows the various aspects of designing and constructing an effluent pond including site selection, soil testing at the lab, and the construction process. A pond safety video is also included.
Dairy Effluent Pond Videos
IPENZ Practice Note 21 - Farm Dairy Effluent Pond Design and Construction has a strong engineering focus and covers design and construction principles, clay liners for ponds, geomembrane (synthetic liner) selection and details about ponds and tanks constructed on peat.
FDE Pond Design and Construction with Hauraki 'Marine' Clays
Constructing effluent storage ponds in Hauraki marine clay may require different construction techniques. This chapter describes the engineering process. The case study shows the first pond to be built using this method.