Managing water in the dry – northern Australia

This second article in our series on planning for tough seasons focuses on monitoring water and calculating requirements for livestock in hot, dry weather.

Geoff Niethe, who coordinates MLA’s grassfed cattle research programs, said managing surface water is a challenge for many northern producers currently.

“If feed reserves are still holding, it is important to take steps now to conserve surface water to get the most out of available resources ahead of any seasonal break,” he said.

“Assess the quantity of receding surface waters and try to estimate roughly how long it will last. This will depend on the number of stock present, the evaporation rate, and the depth and surface area of waterhole/dam. 

“However, while the rough rule of thumb is that grazing animals will drink on average 10% of their body weight/day, this is highly variable and depends on the species and class of stock, feed available, and temperature.”

Diet naturally plays a big part in water requirements.  While lush  green pasture can supply nearly all an animal’s water needs in a good season, during drought, when feed is more fibrous and  completely devoid of moisture,  stock need to get their entire  daily requirements  from the water they drink.

Depending on existing property infrastructure and available resources, there may be some strategies that could extend water availability. These could include fencing off surface water and watering stock via troughs. This prevents animals stirring up silt and contaminating the remaining water supplies, reduces the risk of livestock becoming bogged and reduces the risk of algal toxicity.

There may be opportunity to pump larger shallow waterholes into a deeper, smaller ones to reduce the impact of evaporation.  Evaporation rates increase markedly with higher temperature and exposure to wind.

Other factors to consider when managing water in dry seasons include:

• Monitor flow rate into troughs as livestock can become impatient and damage water infrastructure if it fills up too slowly.
• Examine the cost/benefits of water monitoring technology that provide regular, real-time readings and reduce stress, labour and costly water runs.
• Evaporation increases salinity in some dwindling water supplies.
• Feeding salt or salt-based licks or blocks increases water intake.
• Shallow surface water contaminated by faeces increases risk of blue green algae blooms.

Planning

If finances permit, it is a good time to desilt dams while they are dry in preparation for filling rain. The ideal batter/slope of a dam is 3:1. It must be steep enough to ensure stock don’t walk too far into the water when they drink but it must allow easy exit for all stock.

Guidelines on dam construction are available in a booklet by Jim Addison and co-authors from the Department of Food and Agriculture Western Australia - Dam design for pastoral stock water.

Distance between watering points also influences frequency of drinking and amount of water consumed, so consider this when planning property developments.

Resources

• Water quality for stock water: Outlines principles of livestock water requirements and management, including contacts for water quality testing.
• Guidelines for the development of extensive cattle stations in northern Australia: Remote water monitoring technology is one of the strategies used in The Pigeon Hole project, located in the Victoria River District of the Northern Territory, to improve the profitability and sustainability of large cattle stations in northern Australia.
• Nutrient requirements of domesticated ruminants: This guide by CSIRO draws on the most up-to-date research on the energy, protein, mineral, vitamin and water requirements of beef and dairy cattle, sheep and goats.

More information:

Geoff Niethe E: g.niethe@bigpond.com

Read last week’s article on planning for tough seasons: Plan ahead for pasture management – northern