Effluent Management Plan
Contents
Reviews
In accordance with 21 (1) (a-c) of the Otago Regional Plan for Water:
This effluent plan was prepared in October 2024 and will be reviewed by October 2025 with the results noted in this section with changes recorded automatically. The contents of this Effluent Management Plan are available to the regional council on written request.
Location and Ownership
In accordance with 21 (2) (a-e) of the Otago Regional Plan for Water
The physical location of the farm where the effluent system is located is 62 Harvey's Rd, Island Cliff and the effluent is applied to the same address. Refer to the legal descriptions below for further details.
Land Owner:
Derek Dewar Chalmers, HC Trustees 2007 Ltd, DD Chalmers Trust, VJ Chalmers Trust.
Farm Operator:
Sealach Ltd
Person in Charge:
Nathan McLachlan
027 292 4380
Legal descriptions:
LOTS 1, 3 DP 461559 PT SEC 6 BLK II MAEREWHENUA SD
Existing Consents
RM23.271.01 and RM23.271.02 Intensive Winter Grazing
Map
In accordance with Schedule 21 (2) (e) of the Otago Regional Plan for Water.
Effluent Discharge Area: 66ha through pivots.
The system features gravity feed from the shed through a weeping wall into a sump then pumped to the storage pond from where it is pumped to the pivots, to storage, or back to the yard as greenwash.
Backflow preventers are installed and storm water diversion is available to minimise the volume of effluent generated unnecessarily during rainfall events to reduce the risk of over filling the effluent storage.
No effluent is to be discharged within:
20m of the farm boundary, or further if necessary to prevent spray drift crossing the farm boundary.
50m of any surface watercourse.
50m of any subsurface drainange.
100m of any water abstraction point.
200m of place of dwelling or assembly not on the property - don't apply effluent when wind conditions will carry odour to neighbours.
Cows: Up to 850 cows milking twice a day and up to 300 for winter milking.
In addition to the effluent map with CSA's below is the Irrigation Map and there is also an Environmental Risk Map.
Effluent Map Overview
Dairy Shed Effluent Components
Soils
In accordance with Schedule 21 (2) (e) (iv) of the Otago Regional Plan for Water
Soil Types and Risk Profiles
Click here to access the S - Map for Whitecliff. The effluent application area consists of Kauru soils which are high risk Category C. According to Dairy NZ industry best practice the maximum effluent irrigation depth allowed is 10mm when a soil water deficit is identified that is greater than the application rate. This is achieved by application using low rate tools, specifically centre pivots which apply as little as 1.5mm and up to 10mm. Bucket tests are used to verify application rates and soil moisture deficit is determined online a minimum of 24 hours after rain by SCADA Farm probe. The application rate must not result in exceeding Field Capacity.
Shallow silt loam.
Well drained.
High profile available water (58mm).
FDE risk category C
Subsurface Drains
There are no subsurface drains within the effluent area.
Critical Source Areas
Lower ends of the CSA's are excluded from the effluent application area as shown on the map above. Higher ends of the CSA's are irrigated by pivot at low rates to minimise the risk of run off. Refer to the CSA Management Plan.
Operational Procedures
In accordance with Schedule 21 (2) (f) of the Otago Regional Plan for Water
The effluent pump is maintained in accordance with the Effluent Maintenance Schedule and issues solved through the Effluent Troubleshooting. Major issues that can't be repaired in-house are referred to Waterforce and electrical issues are referred to Calect Electrical.
All maintenance and repairs are recorded in the monthly recording sheets, or as a photographic record.
Operation
Establish there is a soil moisture deficit using SCADA Farm. This doesn't need to be done every time - only if there has been rain since the last reading. Do not apply effluent if there is already ponding, if cows will graze it within 24 hours, or if the ground is frozen or covered in snow.
Check that effluent will not enter a waterway - including over land, directly or indirectly or through storm water or pipe. Only apply effluent within the effluent area on the map above.
Consider wind direction to prevent effluent spray or odour leaving the boundary. Do not apply effluent within 50m of the boundary upwind of the boundary in more than fifteen knots of wind.
Check the irrigator is set up.
Start pump. Listen for unusual noise which may indicate a fault.
Inspect system as detailed below.
Record effluent application on monthly recording sheets.
Minimisation of Effluent
Limit flow on D gate to minimum.
Pre-wet concrete ahead of milking to speed up hose down at the end.
Cooler water used for washdown.
Use greenwash to recirculate effluent for yard wash and reduce water use.
Risks
All paddocks have slopes which can cause potential run-off. Application depth to be adjusted according to soil moisture deficit.
Storm water divert risks effluent flowing out of the effluent system. Have two people responsible for each use of the storm water divert. Use signage at cups on, and put in group message when putting storm water divert on so all staff are aware.
Solids
Solids are spread annually, and cannot be spread on the same area more than once every two months, preferably by incorporating into cultivation of land.
Solids are not spread onto land when the soil moisture exceeds field capacity; or within 20 metres of waterways, or the farm boundary.
Solids are also not spread where previous applications are still visible on the ground, or where soil moisture exceeds field capacity.
Hazardous substances, hazardous waste and human effluent is not to be added to the effluent system.
Inspection, Monitoring and Reporting
In accordance with Schedule 21 (2) (g) of the Otago Regional Plan for Water
Inspections
Inspect the system for leaks, ponding and run off each time the pump is started up and in passing during the day. Check that the nozzles are not blocked and are under pressure, the irrigator is moving and operating normally. Ensure the irrigator is not siphoning when stopped. Leaks, ponding, run off, or flow through drainage can cause the effluent to enter a waterway which must not occur.
As part of the scheduled inspection check the area below the storage pond for wet patches, areas of grass that are greener than the grass surrounding it or any other signs of leaking from the pond. Include a check of the stone traps to ensure they aren't becoming blocked. Check for cracks in concrete or other signs of deterioration that may lead to leaks.
Bucket tests are completed on the irrigators to verify application depth and rate. Application rate can be adjusted on the centre pivots between 1.5mm and 10mm.
Monitoring
In addition to the checks after start up staff are to check the same components while the effluent is running if they are passing the irrigator during the day.
All staff are to report any odour from the system to the farm owner if it reaches the farm boundary, or if any complaints are received about the effluent system including odour.
Reporting
When a leak, ponding or run off are discovered the pump must be turned off immediately and the fault reported to the farm manager within half an hour. Where possible the problem should be fixed immediately and recorded.
For major issues that can't be repaired in-house contact Waterforce or if it is electrical contact Calect.
Effluent applications are recorded in the monthly recording sheets and reported at audits for the irrigation company, ORC and Fonterra.
Pond Drop Test Records
In accordance with Schedule 21 (2) (h) of the Otago Regional Plan for Water
Date of last test: 8th August 2022
Date next test is due: 8th August 2027
Storage is a permitted activity.
Visual inspection next due 13th June 2028.
Contingency Measures
In accordance with Schedule 21 (2) (i) of the Otago Regional Plan for Water
The effluent system has several measures to prevent discharges to water:
Monitoring
Low pressure/high flow automatic pump cut out.
Low rate application systems.
Large storage pond. We never know when we will need to pump to storage or when we can empty the storage so we use every opportunity to get the storage as low as possible and apply to the paddocks. If there is effluent in storage and the soil has the appropriate soil water deficit to irrigate then lowering storage is a priority.
Low water use creates less effluent with greenwash in the yard and recirculated cooler water for the wash down hoses.
Storm water diversion prevents fresh water from unnecessarily occupying capacity in the effluent system during heavy rain.
Leak Response
In accordance with Schedule 21 (2) (j) of the Otago Regional Plan for Water
When a leak, ponding or run off are discovered the pump must be turned off immediately and the fault reported to the farm manager within half an hour. Where possible the problem should be fixed immediately and recorded.
For major issues that can't be repaired in-house contact Waterforce.
If a leak is detected in the effluent storage pond it must be emptied as soon as possible within the limits of the soil water deficit and the leak found and repaired.
Leak Response
A register of effluent complaints must be available to the Otago Regional Council on request. If a complaint is received use this form to collect the following information:
(a) The date, time, location, and nature of the complaint
(b) The name, phone number and address of the complainant – unless the complainant elects not to supply, this information
(c )Action taken by the consent holder to remedy the situation and any policies or methods put in place to avoid or mitigate the problem occurring again.