Effluent management

Sealing

It is important that effluent storage facilities meet the sealing standard specified the Waikato Regional Plan rules. There are a variety of different storage options that require certification and re-certification at various timeframes (refer to Figure below).

Dairy Industry Best Practice and the Council both recommend the use of synthetically lined effluent storage ponds.

Dairy Industry Best Practice recommends the sealing standard of clay lined or earthen effluent ponds are re-tested every three years and as the regulator, Council is guided by this. The environmental risk from a clay lined or earthen pond is much higher than for a synthetically lined pond and therefore more regular testing is required to confirm it remains sealed to the required standard, especially as the pond ages.

Effluent storage and disposal on your farm is regulated by Waikato Regional Plan permitted activity rule 3.5.5.1. One of the conditions of this rule is that you provide information to demonstrate that the permeability of the sealing layer of your pond(s) complies with the rule when requested by Council.

Council is requesting certification (and re-certification) of the sealing for all clay lined/earthen ponds in our region and updating each farms records to reflect these results.  The same will apply for other types of pond lining systems as they age.  The National Fresh Water Farm Plan, Waikato Regional Plan PC1, and Farm Environment Plans will also require farmers to demonstrate how they are achieving compliance with environmental regulation, and the same frequency of effluent storge pond testing will be required by those plans when they eventually become live.

Feedlots

Feedlots are areas where cattle are kept for at least 80 days in any six-month period and are fed exclusively by hand or machine. All feedlots require resource consent under the Resource Management (National Environmental Standards for Freshwater) Regulations 2020 (NES-F).

Stock holding areas

Stock holding areas include feed pads, standoff pads, loafing pads and wintering pads, but exclude feedlots. Ensure that these areas meet the standards set out by the NES-F and Waikato Regional Plan permitted activity rule 3.5.5.2, or alternatively you will need a resource consent.

Regulations 12 and 13 of the NES-F outline the permitted activity conditions for stockholding areas and can be found in full here.

A link to the stock holding guidance document from the Ministry for the Environment can be found here.

The stock holding area or effluent from it, must not create any odour or discharge outside your property boundary as per Waikato Regional Plan permitted activity rule 6.1.8

Council actively encourages farmers to develop an EMP for their particular farm. To get value from the EMP it should be tailored to your farm effluent system, farming operation and resources. All farm staff should be inducted and trained in operating the farm effluent system and understand the content of the EMP.

A guidance document for developing an EMP specific to your dairy farm can be found here [PDF, 86 KB].  

DairyNZ and other industry professionals also provide useful guidance regarding effluent management and a template EMP which can be found here.

• Check irrigator performance by measuring the application depth and rate. The bucket test is a useful calculation you can do to help determine this information which can be found here.
• Ensure that your effluent pump is suitably sized to adequately pump effluent around your effluent block.
• Adjust irrigator speed and application rate as required to ensure good pasture uptake of applied effluent nitrogen and to avoid ponding/runoff.
• Expand the effluent irrigation area if possible.
• Have sufficient effluent storage for your farming operation so that it can be applied to land at optimal times.
• Avoid irrigating effluent over wetlands and watercourses, including farm drains, by having reasonable setback zones (at least 20 m).
• Ensure that spray drift is not getting into nearby watercourses.
• Spread effluent evenly on flatter areas that are less susceptible to run off.
• Hump and hollowed paddocks require extra care when irrigating effluent as there is an increased risk of ponding and run off to surface drains.
• Cover water troughs when irrigating effluent.
• Ensure fail safe and monitoring mechanisms are installed on the irrigator and/or pump.

• Instruct your contractor on the application rate and depth required and ensure that they are aware of their responsibilities under the relevant Waikato Regional Plan rules when applying effluent.
• Identify risk areas and setbacks. Monitor their performance on your farm.
• Ensure you book contractors in early to lower your ponds instead of waiting until you find yourself in an emergency situation. Have a contingency plan in place in case there is a delay.
• Consider utilising paddocks that have never had effluent applied and send the contractor there.
• If you still need to spread effluent to manage pond levels between contractor visits, consider installing a low-rate effluent irrigation system.

• Divert rainwater from the farm dairy catchment areas before it reaches the effluent system (i.e. install a stormwater diversion system).
• Reduce effluent volume with efficient wash down practices in the farm dairy shed / feed pad. Consider whether it is necessary to wash down after every milking. Can you scrape down your feed pad instead of washing?
• Consider using a greenwash system.

• Ensure effluent storage bladders are fit-for-purpose and are set up in accordance with recommendations and warranty documentation provided by the installer. Have a stringent process for monitoring and managing effluent levels within the bladder, which may include the use of a measurement system. It is also recommended to have a good solids management process and a contingency bund around the outside of the bladder.
• Consider how soil drainage characteristics, landscape contour, and climate affect effluent management on your farm. The DairyNZ website provides useful resources around soil risk for farm dairy effluent application, and a pocket guide can be found here.
• Regular maintenance of the irrigator, pump, and pipes.
• Ensure all staff involved in effluent management receive appropriate education/training. You should include this in your EMP.
• Contingency plans for when things go wrong – breakdowns, power outages, significant weather events etc.
• Consideration to any district or local council rules and set back distances.

• There are no current Waikato Regional Council rules for a required size or number-of-days of storage. However, there must be sufficient storage so that the storage facility never overflows, and so that irrigation can be deferred when the soil is saturated. You may not irrigate to saturated soil because it is likely to result in ponding or run off.
• All stored dairy effluent must be contained on/within a sealed surface that restricts the seepage of effluent contaminants into ground or surface water. Issues do not arise just at the dairy shed, wherever effluent is concentrated or stockpiled there can be contamination of water. Feed pad or stand-off pad effluent must be contained and spread appropriately. This requirement also includes effluent sludge removed from ponds, sand traps and other holding facilities.

• The size of storage required is unique to each farm and is influenced by several factors. These include the local rainfall and evapotranspiration rates, topography and soils, catchment and herd sizes and nutrient loading rates. It is also influenced by how the farm chooses to manage effluent and water to fit with other aspects, such as calving, available labour and power supplies.
• Simply put, effluent storage must be sufficient to allow for deferred irrigation when weather/soil conditions are unsuitable, and in the event of any unforeseen circumstances.
• This can be calculated using the Dairy Effluent Storage Calculator (DESC) which is available on the DairyNZ website. WRC recommends using an accredited designer or dairy effluent WoF assessor to calculate specific storage requirements to meet individual farm circumstances.
• It is important to remember that even if a system has sufficient storage, it needs to be managed appropriately to ensure compliance. If there are changes in the way in which the farm operates, storage may need to be increased or managed differently.

• Possibly – some effluent storage ponds are very large, requiring extensive earthworks to both construct the dam and to clay line the impoundment (where required). Consents may be required by the regional council for the construction earthworks, the damming and diversion of existing watercourses depending on the scale, nature and location of the impoundment and associated earthworks.
• Even if no consents are required, appropriate erosion and sediment controls must be installed and maintained for all earthworks to be a permitted activity.
• If the maximum potential (at dam crest level) exceeds 20,000 m³ and 3 m depth, then a building consent is also required from WRC. Consent requirements in relation to earthworks, damming and diversion are very site and project specific and you should always seek specific written advice from WRC at the earliest possible stage when planning your effluent storage pond.
• You may also need to meet additional requirements from your district council so you should consult with them before constructing any effluent pond or tank.

Waikato Regional Council compliance staff are not technical specialists in effluent system design or construction and therefore cannot provide specific technical design advice. They are skilled in assessing the system for non-compliance and will be able to tell you if your system is compliant at the time of the inspection. Dairy companies and DairyNZ are also key drivers in industry standards so can provide some on farm services and access to advice. There are also a number of accredited industry professionals who provide on farm advice around effluent systems.

Diverting rainwater from the effluent system can help reduce the amount of storage required and the volume of effluent to manage. Options to consider are:

• Gutter and divert existing roof catchment areas.
• Consider diverting stormwater off the dairy yard and/or feed pad. However, only clean water can be diverted so you must ensure that these catchment areas are free of farm animal effluent before the diversion is opened.
• Use cambers and cross drains to divert rainwater off raceways to prevent it collecting in yards.
• There are also opportunities to make use of rainwater in other aspects of the farm system DairyNZ have developed a guidance book ‘Smart Water Use In The Farm Dairy’.
• Any stormwater diversion installed should have procedures and fail safes in place to prevent contaminated stormwater being discharged.

• The Waikato Regional Plan rules do not specify where an effluent storage system should be located, however there are rules that specify that any odour associated with effluent must not cause an adverse effect beyond the property boundary.

• The dairy company you supply to will have rules around where effluent storage systems should be located, in relation to the dairy shed.

• Consideration should also be given to the placement of effluent storage facilities relative to surface waterbodies.
• District Councils and the NZ Food Safety Authority have some specific rules relating to the distance of facilities from certain features. It is important that you confirm these setback requirements before commencing construction.
• You may wish to refer to The Farm Dairy Effluent (FDE) Design Standards and Code of Practice. This document provides best practice industry guidelines on setback distances. Microsoft Word - FDE Design Standards_review_Final_22May2013 (gw.govt.nz)

• Useful guidance can also be located on the DairyNZ website: a_farmers_guide_to_building_a_new_effluent_storage_pond_web_dnz40_119.pdf (dairynz.co.nz)

• If the infrastructure provided to farm staff/farm managers is inadequate to manage the effluent, and a breach of the rules occurs, then the owner of the property is more likely to be liable. It is the owner’s responsibility to provide compliant infrastructure. It is the farm staffs’ responsibility to inform the owner of compliance issues with infrastructure, that may need repairing, upgrading or replacing. It is sensible to make a note in a diary or keep a record of what the owner has been told and when. However, it is still the staff members responsibility to take all possible steps to prevent non-compliance occurring. When starting work on a new farm either as the owner, share milker or as a staff member, it is important to assess the effluent system and be confident that it is fit for purpose. If the system is not compliant with relevant rules and regulations, then any person working with that system has the potential to be held accountable or any non-compliance.
• Waikato Regional Council recognises that it may take time to upgrade farm effluent systems and that breakdowns do occur from time to time, however forward planning and careful management of farm effluent systems should enable you to plan for and mitigate most adverse effects.

• Waikato Regional Council staff are not qualified to audit the design of an effluent system and confirm whether or not it will meet regulations. As the regulator, Waikato Regional Council is able to offer advice on compliance related matters and will direct farmers to appropriate industry professionals for specific advice on farm effluent system design and management practices from independent accredited effluent consultants and designers, dairy supply companies, DairyNZ, and other dairy industry organisations.
• Waikato Regional Council compliance inspections look at whether an effluent system is compliant with relevant rules at the time of the inspection. Factors such as climatic conditions (for example prolonged wet weather), a change to the farm system (for example an increase in cow numbers or introducing a feed pad), or mismanagement of the system may result in the farm being non-compliant. Where it is established that an aspect of your farm effluent system is not compliant, or there is an on-going risk of non-compliance, Waikato Regional Council will draw your attention to this fact and may direct you to make improvements.