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Ways to improve natural assets on a farm Enhance farm dams

Dams are essential infrastructure for many farming operations, including for livestock and irrigation. Enhancing a farm dam can lead to improvements in water quality and provide habitat for a wide variety of native wildlife.

Photo of a fenced dam with stock visible under the trees behind a fence on the far bank.

Why enhance a farm dam?

Farm dams have become essential infrastructure for water storage on farms across Australia over the past century, with a focus on digging more and bigger dams in recent decades. There are now around 1,765,000 farm dams in Australia, including more than 650,000 in the Murray-Darling basin alone (Malerba et al. 2021 and Srikanthan et al. 2015).

These dams store a huge amount of water, yet traditionally there has been minimal investment in improving the quality and retention of water in these dams.

In recent years, some farmers have taken steps to enhance existing dams and have noticed the benefits this brings to water quality and to biodiversity on their farms.

Sustainable Farms research is now beginning to demonstrate these benefits through science. By comparing enhanced and unenhanced farm dams, our research shows that enhanced dams have better quality water and support more wildlife than traditional, unenhanced dams.

Photo of Jenny Bell by enhanced dam

“The fenced dam seems to have the most life around it and all sorts of reeds in it, and it’s really clear. It didn’t go dry in the drought – the dam kept giving, it was good water. We underestimate what an asset good water is to animals’ weight gain and general wellbeing.” Jenny Bell, sheep farmer near Breadalbane, NSW

What is an enhanced farm dam?

Traditional farm dams are usually set within a paddock, in a low point in the landscape where they collect and store water for use for livestock, irrigation and sometimes household use. Stock often congregate around dams, pugging the edges and sometimes polluting the water. As a result of grazing impact, the wall and shores of such dams are often bare of vegetation.

An enhanced dam is usually, but not always, fenced to manage the impact of stock on the dam. It has healthy, native vegetation in and around the dam, providing many benefits for water quality and wildlife. As a result of stock exclusion and vegetation, the water is cleaner. An enhanced dam may also have other features such as a hardened access point for stock, variable depths, islands or snags.

Enhanced dams can provide better quality drinking water, retain water for longer, support native plants and animals, and provide ecosystem services to the surrounding landscape.

What the research shows

Water quality benefits of enhanced farm dams

Sustainable Farms researchers have surveyed 57 farm dams in NSW and Victoria. The study will continue for a further two years, but initial results show:

  • Enhanced dams have lower levels of nitrogen and lower turbidity, factors which can contribute to algal outbreaks, reduced palatability and animal health issues
  • Enhanced dams have significantly lower coli counts and fewer thermotolerant (faecal) coliforms. 65% of unfenced dams actually had coliform counts that exceeded guidelines for water quality for stock.
  • Enhanced dams support more waterbug species and greater number of individual waterbugs than unfenced dams. The presence of waterbugs, and of certain less tolerant species, in enhanced dams is a good sign of higher water quality.

Read more about the farm dams study here.

Sustainable Farms ecologists collected water samples from 125 dams and natural waterbodies across 35 farms in NSW and north-east Victoria. The samples were on a range of measures that indicate water quality.

Photo of SF researcher sampling water

Piping water from a fenced enhanced dam to a trough is an effective way to provide clean water to stock.

Why are farm dams important for biodiversity?

Some native animals, particularly water birds like the Australian wood ducks, will use almost any dam in the landscape regardless of its condition. However, there are many other species that are rarely observed on traditional dams but can be found on healthy, enhanced dams.

For example, platypus are generally found in streams and rarely in dams, but have been observed by Sustainable Farms researchers using enhanced dams. Birds like the spotless crake, little grassbird, golden-headed cisticola, diamond firetail and white-faced heron all use enhanced, well-vegetated farm dams – but not traditional dams.

In many agricultural landscapes, natural, healthy wetlands are extremely rare. But there are many farm dams, and when these dams are carefully managed, they can play a similar role to natural wetlands – helping restore biodiversity by providing much needed wetland habitats for native wildlife.

The eggs and tadpoles of Perons Treefrog (sometimes known as the Maniacal Cackle Frog due to its distinctive call) can be found in farm dams. Photo by Damien Esquerre.

Other benefits of fenced, enhanced dams

  • By supporting more wildlife, healthy dams support increased nutrient cycling, pollination and other ecosystem services.
  • Vegetation around a dam captures sediment from inflow, so the need to muck out dams may be reduced in the long term.
  • Farmers with enhanced dams generally saw better water retention in these dams during the 2018-2019 drought. The presence of fringing vegetation shelters the dam surface, reducing evaporation from wind.
  • Enhanced dams can become an oasis on the farm – a place to visit and enjoy lush vegetation and wildlife even during times of drought.
  • Farm dams in poor condition can release large amounts of greenhouse gases. Early research is beginning to show that revegetating dams can reduce emissions. Researchers from Deakin University’s Blue Carbon Lab are working with Sustainable Farms researchers to investigate this further.

Do birds prefer to breed where water and vegetation exist together?

A specific bird breeding study undertaken by Sustainable Farms is beginning to show that where farm dams and native vegetation are co-located in the landscape, bird breeding activity and success are greatly increased.

This doesn’t only apply to waterbirds – a range of other birds like stubble quails, golden-headed cisticolas and Australian reed-warblers (pictured) breed more often and more successfully when dams and vegetation are co-located.

Read more about this study here.

How to enhance a farm dam

An enhanced farm dam is well-vegetated both within and around the dam. Usually, this requires fencing to exclude livestock, although in some cases dams can retain good surrounding vegetation with sensitive grazing management.

Click each step below to find out more about how to enhance a farm dam.

Fence to exclude or limit livestock access

Establish fences to exclude or limit stock access to the dam. This reduces fouling from faeces and pugging, limits sedimentation of the dam, and enables persistence of vegetation around the dam.

Provide alternative access to water via a trough or hardened access point

Water from fenced dams can be piped to troughs.

However, if a backup supply of water is required when troughs can’t be checked, partially-fencing a dam can allow limited stock access.

In this case, a hardened access point can minimize pugging and sedimentation, as well as reducing the amount of time stock spend in or on the edge of the water.

Revegetate in and around the dam

Once a dam is fenced, vegetation will begin to regrow naturally. This can be supplemented with strategic planting or seeding. In particular, riparian and wetland vegetation might need a helping hand to re-establish, particularly if the dam is a long way from other water bodies.

Download our guide, Enhancing farm dams: What to plant in and around your dam for more detailed information.

Vary the depth of the dam

When constructing a new dam or mucking out an old one, this is a great chance to vary the depth of the dam.

A deep ‘borrow pit’ – the main excavated area of the dam – is important for water storage and retention. Shallow shelves in other parts of the dam, particularly the inflow zone, are important for enabling aquatic vegetation to establish. This vegetation will play an important role in filtering inflow, keeping the water cleaner and providing habitat for wildlife.

Add an island or snags & logs in the dam to support more wildlife

Islands, either solid or floating, provide safe nesting sites for waterbirds and turtles away from predators like foxes. The addition of semi-submerged timber (snags) in a dam provide great habitat for native fish, basking sites for animals such as turtles, and acoustic platform for calling frogs.

Watch our video on building artificial islands here.

Features of an enhanced farm dam.

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