Performance goal: Minimise the contamination risks to surface water.
Description: Surface water is water that collects on the surface of the ground and includes water from rivers, streams, dams and reservoirs. Water quality is highly variable.
Performance criteria: Contamination risks to surface water are controlled.
Best practice range: Nitrate (as nitrogen): 0–10mg/L
Maximum acceptable level: Nitrate (as nitrogen): 5mg/L
Minimum requirements
Water source location is chosen to minimise the risk from any likely contamination sources.
Minimise water source exposure to:
wild birds
other poultry
pigs
cattle
sheep
humans
other wild animals.
Algae blooms and cyanobacteria:
If a bloom is suspected, use an alternative supply of water for stock until the algae is identified and/or controlled.
If there is no alternative, use water from deeper in the river or dam, or from areas not covered by scum, as this water may be less contaminated.
Additional water pre-treatment and disinfection may be needed to control the risks from blooms.
Black water (hypoxic event):
Use extra disinfectant to achieve a disinfectant residual and manage the effects of black water.
Best practice options
General
Prevent turbidity and erosion by maintaining a high level of ground cover in the water supply catchment.
Prevent livestock access within 50 metres of surface water by fencing.
Prevent contaminated drainage and wastewater flowing into the catchment.
Apply any pesticides following the advice on product labels and immediately clean any spills that occur near water supply catchment.
Prevent nutrient leaching from irrigation or fertiliser application. Match application rates to plant uptake near water supply catchment.
During a black water event, aerate source or water storage.
Dams
Reduce evaporation of water source, for example:
Establish windbreaks adjacent to dams to reduce evaporation
Place floating balls on the dam
Install an impermeable cover if the water is pumped into a dam
Store saline water in tanks rather than in dams
Construct sediment traps to protect dams during high-risk periods
