Offal hole management

Offal holes or 'dead holes' as they are commonly referred to, are used in Southland for on-farm disposal of dead stock.

The biggest concern with decomposing carcasses and offal is the release of disease- carrying microorganisms which have a high level of environmental risk, and effect human health through direct contact or contamination of water supplies.

Now's the time to plan and prepare for how your farm is going to manage for upcoming lambing and calving disposal.

Check the information below to ensure you are meeting the relevant rule.

Good practice offal hole management

See the tips and advice below to ensure you're following best practice when it comes to setting up your offal hole or disposing of carcasses.

Select an appropriate site

• Avoid waterways and areas with a high water-table
• There should be at least 3 metres between the water table and the base of the hole.
• To protect groundwater, offal holes should not be located in soils containing gravel and limestone.
• Avoid poorly drained areas, gullies, critical source areas, and areas prone to flooding or ponding during high rainfall.
• Choose elevated ground where surface water can easily be diverted away from the hole.

Shallow trench

A trench is ideal for smaller properties and areas where water tables are high. A trench keeps the carcass decomposition in the top soil layer, avoiding possible contamination of groundwater.

• Dispose of stock as quickly as possible.
• Dig a long narrow trench - approximately 1 metre wide and up to 2 metres deep keeping within the topsoil layer. Volume should be no more than 30 cubic metres, so you may need more than one.
• Locate your trench along a fence line and install temporary fencing around area to keep stock out.
• Cover carcasses with 1 metre soil to avoid odour and prevent vermin. Or temporarily cover with plastic and soil, until the hole is full and can be capped.
• Once the trench is full to within 1 metre of the surface, fill with soil and slightly mound ground after backfilling. Then re-grass.
• If disposing of a large animal, open the stomach of each carcass to allow for faster decomposition. Remember to puncture the left side of the rumen to prevent the buildup of toxic gases.
• Avoid using lime as this can restrict the decomposition process.

Existing offal holes

• Existing deeper offal holes can be used, or new holes created, provided they meet the rules and can be effectively managed to prevent effects on groundwater and waterways.
• Do not use offal holes as landfills or to dispose of chemicals.

Burning of dead stock

• Burning is not recommended as it requires a high combustion temperature and can produce a large amount of smoke.
• Burning should be done in a way that meets the requirements of the Regional Air Plan.
• Burn only carcasses that have originated on your property.
• It is illegal to use tyres, oils or plastic as accelerants.
• Acceptable accelerants are hay and dry vegetation.

Rule

The following rule has been in place for some time, and requires that putting a carcass or offal into or onto land is a permitted activity provided;

1. The animal is discharged to the same land it perished on
2. The only contaminants discharged into an offal hole are carcasses, offal or a compost bulking agent. The carcass or offal is not discharged between a river and flood banks
3. The discharge does not occur within the bed of a river, artificial waterway, ephemeral waterway, lake, gully or a swale. The offal hole is should be;
4. • 50 metres from a waterway or waterbody including the coastal marine area (or 150 metres when the discharge is to loose gravels)
   • 100 metres from a water abstraction point (or 200 metres if the discharge is to loose gravels)
   • 100 metres from a place of dwelling, assembly or landholding boundary
5. • 250 metres from a drinkable water abstraction point.
6. Stormwater is directed away from the offal hole site
7. The offal hole does not intercept a subsurface drain and is not excavated below the water table
8. The carcass does not touch naturally formed limestone rock

Burial of a single animal must also comply with Environment Southland rules. If covered by soil or organic material, the burial must not occur within 20 metres of surface water, an abstraction point, a dwelling, a place of assembly or landholding boundary.

If there is a situation when a large scale burial of animals is required, or if something goes wrong, please contact Environment Southland on 0800 76 88 45.