Working Farms

Is water affected by algae safe to drink after it has bee... Boiling algal water will NOT make it safe to drink. Do not drink or swim in it.
Read more

Working Farms

The following advice is of a general nature only and intended as a broad guide. The advice should not be regarded as legal, financial or real estate advice. You should make your own inquiries and obtain independent professional advice tailored to your specific circumstances before making any legal, financial or real estate decisions. Click here for full Terms of Use.

Do I need a license to build a dam?

Generally a license is required from your local water authority before you may dam a gully or hillside location, especially if it is defined as a waterway. It’s important you make enquiries with local authorities before beginning construction.

Altering the natural flow of water can have significant impacts on downstream native habitats and neighbours.

When looking at rural property for sale, you may wish to search for those with dams and watering holes as this could be more convenient than building a dam after buying the farm.

What types of dams can I build and what are their relative costs of construction?

Gully dams are generally built where naturally formed valleys or hollows occur on your property. Soil used from the excavation is typically used to form the dam wall and this type of dam is suitable for capacities between 1 and 50 megalitres.

Gully dams are generally one of the less expensive options but they have an elevated risk of failure. Causes range from excess water, spillway erosion, overflow, insufficient water, leakage, or bank failure. The higher the wall, the more important the quality of design, construction and materials necessary. If you’re planning higher than 3 metres, get expert advice.

If your property doesn’t offer a suitable gully, a hillside location is usually the next choice and is suitable for stock access. Where sufficient water inflow may not be reliably sufficient, graded banks are often used to intercept flows and direct them into the dam.

Hillside dams are less prone to failure than gully dams and are best positioned where they may receive reticulated water from other larger dams located on your property. They’re suitable for capacities from 0.5 to 10 megalitres.

What types of algae problems can occur in dams and waterways on my farm?

Water can change colour overnight when different types of algae float to the surface. There are various forms, which are best described as:
  • Sky blue coloured acrylic paint-like scum that appears on rocks or plants, generally on the leeward side of your dam or streams
  • Green, blue-green or khaki green scum that turns brown/green or white as it dies
  • Scums that appear at dusk or dawn and disappear during the day
  • Producing a strong, earthy smell as the bloom breaks down
  • Small green flecks that appear throughout the water in the early stages of the bloom

What is blue-green algae and what makes it occur?

Blue-green algae is the common name for a range of algae with similar characteristics. Outbreaks occur when:
  • Still, clear water allows enough light to penetrate
  • Water flow rates are too low
  • Temperatures are warm
  • Excess nutrients like phosphorus and nitrogen are present
Some types of algae can produce toxins, thick scums and bad odours. The toxins can be poisonous both to humans and livestock, and, as the algae decompose, they use up oxygen in water, frequently killing fish in the process.

What are the effects of blue-green algae on humans and livestock?

There can be serious implications for humans, livestock, birds and pets when affected water is consumed or skin exposed to some species of blue-green algae. Symptoms include:
  • Gastroenteritis
  • Diarrhoea
  • Vomiting
Contact with skin can cause:
  • Irritations and rashes
  • Swollen lips
  • Eye and ear irritations
  • Sore throat
  • Hay fever symptoms and asthma
Unless alternative water sources are provided, livestock are at great risk of poisoning by blue-green algae. Death can occur within minutes of drinking, in extreme cases. In mild cases, there can be productivity losses, losses of appetite and milk yields.

What can be done about outbreaks of algal blooms?

Farmers should check their dams and water troughs two or three times a week during hot, dry weather. If an outbreak is suspected:
  • Isolate the dam or water supply from people and livestock
  • Provide stock with alternative water sources
  • Contact your local water authority if no alternative exists
  • Take samples for testing
  • Seek the advice of a vet if livestock show symptoms of poisoning
Make sure gloves are worn when taking samples and collect from the windward side of your dam or water source. You’ll need approximately 1 litre for your sample and leave a space for air at the top of the bottle before securing the cap.

Is water affected by algae safe to drink after it has been boiled?

Boiling algal water will NOT make it safe to drink.

Do not drink or swim in it. Don’t rinse vegetables or fruit or cook with it. Don’t wash clothes in it. Don’t eat shellfish or fish caught in it. Do not spray or flood irrigate pastures or crops with it.

How can I avoid a blue-green or general algal outbreak on my farm?

Soil erosion or runoff of sediment can help phosphorous get into your farm’s dams and streams. Once in the water system, phosphorous becomes available for plant and algal growth in the right conditions.

Take care to avoid excess fertilizer getting into your water systems. Maintaining good vegetative cover helps prevent problems so stock should be moved to other pastures when cover reaches low levels.
  • Minimise the amount of time soil remains exposed to wind and water. Don’t work soil too much or too far ahead of planting
  • Use minimum cultivation techniques so you maintain soil structure, enhancing soil and water conservation
  • Avoid cultivating steep slopes
  • Use green manure crops and work them into the soil where appropriate
  • Use cover crops between crops
  • Use buffer strips of dense vegetation in steep locations to catch runoff
  • Use surface drains or diversion banks alongside dams and rivers
  • Leave natural drainage areas grassed
  • Build culverts and bridges or hard crossings for stock and vehicular crossings
  • Maintain quality of stream banks with solid grass cover, trees, shrubby plants and native grasses
Exclude stock from streams with fencing, either traditional or electric.

What are the fundamentals of managing drought?

Planning is vital to protect your animals, land and livelihood. Important questions to ask yourself are:
  • Is there enough water to carry animals through to winter?
  • Do I have enough money, time & equipment to feed daily for the next six months?
  • Is it worth keeping all my animals or better to lighten the load?
  • How much will it cost to replace animals at the end of the drought?
  • How much will all this cost me?

How can I calculate the water and feed requirements of my farm?

The Victorian Department of Environment & Primary Industries website offers useful tools to help calculate water and feed requirements as well as how long your dam water will last.

In drought, remember that when it does rain, there may not be sufficient runoff to restore your dam’s water levels. It is better to seek alternative water sources or sell stock at an early stage, if possible.
Results 11 - 20 of 31