Key steps to manage dairy effluent systems after flooding
During the recent floods, dairy effluent systems may have reached capacity or may be damaged.
It is important that dairy effluent is managed effectively so it remains within the property boundary. If it does leave your property, this should be reported to the Environment Protection Authority (EPA) and actions put in place to prevent this continuing.
There are several aspects to consider in the short and longer term regarding dairy effluent management.
In the short term, it is extremely important - when safe to do so - that effluent systems, especially ponds, are inspected for any damage and that damaged pond walls, effluent pipes, or other compromised components are repaired to stop the risk of future leakage.
Strategic irrigation of effluent and reducing additional water from entering the effluent system are two short-term actions that can help reduce the risk of effluent leaving the farm.
There are also additional actions and planning that can be taken to prevent overflow in the longer term.
Strategic irrigation
The first action to take if your pond is full is to make regular applications of effluent to the driest parts of the farm to stop the pond overflowing, if this is possible.
It is important to note that extreme caution needs to be taken around pond structures that might have been comprised by flood waters and where machinery access is limited.
Where possible, aim to apply low application rates over large areas and ensure there are buffer distances between application areas and waterways, channels and drains. If the standard effluent application pipes aren’t long enough, consider other short-term methods such as additional pipe or utilising contractor’s equipment to take effluent further away to drier areas of the farm.
Reduce additional water
The second key action to reduce the risk of the pond overflowing in the short term is to consider reducing any unnecessary water entering the effluent system. Whenever you are considering reducing water use in the dairy, this needs to occur without compromising cow health or milk quality.
One method to reduce water use involves cleaning the yard once a day or dry scraping the yard prior to hosing. For rotary dairies, the cup and platform sprays are on for long periods and contribute large amounts of water to the effluent system. Therefore, consider reducing the time the cup and/or platform sprays are running. Instead of running all milking, consider whether they could be turned on and off periodically or used in conjunction with a timer.
Sometimes there can be additional rainfall that enters the effluent system from surrounding paddocks. Consider diverting rainwater away from the effluent system where possible. Rain that falls in the surrounding paddocks can be excluded from entering the pond by constructing levee banks or diversion drains. Be mindful of diverting water onto any neighbouring properties.
Long-term planning
In the longer term, if your effluent system is unable to store effluent during high rainfall events and is overflowing, this indicates that you may need to increase the capacity of the effluent system.
An effluent system designer can help you with effluent system upgrades. A list of designers can be found at Effluent system designers.
A freeboard of at least 600 mm should be kept on effluent ponds. This space provides capacity for storage during high rainfall events and should be available year-round. If at any stage the pond loses this freeboard capacity, effluent should be strategically applied.
Reducing the rainfall entering the effluent system through installation of gutters on the roof of sheds, or by installing a rainwater diverter on the dairy yards, can also help to limit the impact associated with high rainfall events. Installing gutters on the dairy shed roof provides a benefit by reducing rainfall entering the effluent system and providing a source of high-quality water that can be used in the dairy.
Long-term effluent planning also includes regular soil testing of effluent application areas to assess nutrient level changes and adjust fertiliser plans accordingly.
Further information
Further information on managing dairy effluent visit Managing effluent or contact Rachael Campbell at Rachael.campbell@agriculture.vic.gov.au or 0447 347 162.