Boosting Crop Production by Spreading Effluent
Tararua district farmer Jamie Harris milks around 400 cows using a split calving system on his farm, Crossdale Dairies.
Having a well-designed and constructed storage facility will save you time and money. The key is good planning and working with the right people.
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
◦ Compliance with legal requirements is an important part of any business. Environmental compliance is especially important to ensure the long term acceptability of dairy farming as a land use.
Do it once and do it right an an accredited system design company
Companies have been assessed for their competency and skills in:
◦ Soils and climate considerations
◦ Effluent block allocation
◦ Estimating pond storage volume
◦ Integrated management systems
◦ Hydraulic design of irrigation systems.
◦ Regulation and legislation
The design of the effluent pond is crucial
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.
While building the effluent pond, select 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, your options are:
Compacted clay
Pros
◦ May have suitable clay on site for pond construction
Cons
◦ 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)
Pros
◦ Less earthwork preparation required than with clay liners
◦ Flexible to withstand ground movement
◦ Withstands mechanical damage
Cons
◦ Relatively new product for effluent ponds in New Zealand
◦ Warranties may be difficult to obtain, engineering expertise is essential
◦ Moderate to high cost
Synthetic
Pros
◦ Good range of liners available
◦ Good warranties available
◦ Installation allows for gas and ground water dissipation
Cons
◦ Some variation in quality of synthetics on the market
◦ Moderate to high cost
Safety first
Pond safety cannot be over emphasised. In general the Health and Safety in Employment Act (1992) requirements relate to ongoing operation rather than initial construction, and therefore relate more to the pond owner than to the engineering or construction company.
The following safety features are recommended for all ponds regardless of size or type of lining:
Recommended pond safety features
Fencing - All ponds should be fenced off with a netting fence to prevent stock and children from accidentally falling into the pond.
Escape ladders - all ponds should have at least one permanently placed ladder or alternative escape means in case a person falls into the pond
Anchor Points - pontoons should have anchor points to improve stability
Signage and direct personal communication of hazards with farm staff, contractors and visitors.
Article information sourced from DairyNZ.co.nz
