Tools offered to monitor dam levels

FARMERS keen on keeping better track of water levels in their dams can do so with a range of online tools supplied by Agriculture Victoria.

They can also to determine how long dam water may last – an advantage with summer starting in a little more than two months.

Agriculture Victoria land management extension officer Clem Sturmfels said assessing how much water there is in a dam can be difficult due to a dam’s odd shape and formulas used to measure their volume.

“Farm dams generally hold less water than expected and in a dry year, it’s important farmers have a good understanding of how much water is left in their dams and plan accordingly,” Mr Sturmfels said.

“The volume of a dam is closely related to its length and width. A stable, well-built dam has gently sloping sides which nearly meet in the middle of the dam’s base.

“For example, a rectangular dam measuring 33 metres by 22 metres has a depth of approximately three metres and volume of approximately one million litres or one megalitre.

“A triangular shaped dam with similar measurements has a volume approximately half this amount..”

Mr Sturmfels said evaporation will cause a loss of about 60 per cent of that volume, leaving enough water to carry about 200 sheep or 20 cattle for one year.

“Many dams rely on a regular top-up of water during autumn or spring, however this year has seen dry seasonal conditions, making the chance of a top-up less likely due to depleted soil moisture and less runoff,” he said.

Agriculture Victoria’s tools can help farmers calculate dam volumes based on shape, length, width and depth. They include the Farm Water Calculator and the Summer Water Calculator.

The Summer Water Calculator also helps to calculate how long the remaining water may last.

The depth of a dam can be measured using a depth sounder or fishing line measuring device.

A how-to video for making and using the fishing line measuring device – and the two calculators – can be accessed on the Agriculture Victoria website at agriculture.vic.gov.au.

Information on preparing a farm for dry seasonal conditions is also available.