Healthy dams delivers healthy benefits
Posted on 23 August, 2021 by Ivan
Connecting Country was delighted to hold the third event for our Healthy Landscape project on Saturday 14 August 2021, after multiple COVID-related delays. We held the event live on-farm to a virtual audience by live streaming from a stunning property in Taradale VIC, on the Coliban River.
The event was kindly hosted by Chris Burgess and Martin Shaddick, who have worked tirelessly to control weeds and revegetate the property over the last 15 years. Chris is also the president of Taradale Landcare. The property features multiple dams and wetland areas, with plentiful birdlife enjoying the revegetation when we visited, and also signs of echidnas and a wombat!
Ecologist Karl Just, who has a fascination with aquatic plants and animals, gave an engaging and thoughtful presentation. He compared the two dams on the property, their water quality, vegetation, and the aquatic life you might expect to see within them.
For those who may have missed the live stream event on the day, it’s not too late. To watch online – click here
We have also provided the following summary of the information covered in the presentation.
Actions for a healthy dam
For a healthy dam consider the following actions where possible:
- Exclude stock from the water and where possible create an off-dam stock watering point. Less access for stock reduces added nutrients and disturbance. Excessive nutrient levels can be bad for the water as they can lead to algal blooms which suck out dissolved oxygen, depleting this resource for plants and animals.
- Create buffering vegetation between nutrient sources and water – the wider the better. Adding a diversity of plants increases filtering capacity. The more plant diversity the more habitat value and animals will use the resource. If you have a choice about the direction of the buffering vegetation, choose the western side of the dam to block prevailing winds and reduce evaporation.
- Include as many different habitat elements as possible such as plants, logs and rocks. Even old roofing tiles can also be useful. Place logs both vertically and horizontally. Horizontally to trap sediments and seeds, and create micro climates for plants to grow and vertically to increase access to water for animals. Logs that have some branches emerging from the water that offers perches for birds too.
- If building a new dam, keep in mind that the flatter the gradient the more different plants and animals will be able to use it. There will be less variation in water depth for plants and it will create shallow nursery sites for animals. It is also useful to wait and observe a new dam for 12 months to see what natural regeneration happens. Fauna can bring in different plants, and you can get an idea of high and low water levels, helping to determine where the different zones are and where to plant.
The layers or zones of aquatic vegetation:
- Submerged aquatics (below 400 mm from normal top water level) – such as pond weed, eel grass.
- Deep marsh zone (250-500 mm below normal top water level) – such as water ribbons, milfoils, tall spike sedge, river club sedge.
- Shallow marsh zone (edge of water to 250 mm below normal top water level) – such as spike sedge, swamp crassula.
- Riparian edge zone (plants can handle inundation but also seasonal drying) – such as sedges, rushes.
If want to start dam revegetation, start with the riparian edge as this is the easiest and most diverse strata. Source tubestock from local indigenous nursery.
Be aware steep sides can be difficult to revegetate because they dry/flood more quickly. For this reason, the best time to plant around the riparian edge is late winter or spring, as dams are usually at full capacity, giving the plants some time to establish before drying, and less chance of getting flooded. Plants that grow quickly such as sedges and rushes filter water and create habitat more quickly.
Plant deeper aquatics when the dam is at a lower capacity. These can be a little harder to establish but worth a try.
Plant shrubs in winter. However, avoid putting woody trees and shrubs on the dam’s retaining banks as the roots can create pathways for water to flow, and this can undermine your dam. Where this is not an issue (on high side of dam) you could try planting Yellow Box, Candlebark, River Red-gums and Wattles, lots of wattles such as Blackwood, Black Wattle, Silver Wattle, Lightwood or other shrubs such as Prickly Tea-tree, River Tea-tree, River bottlebrush or Hop Bush. These provide landing sites and refuge for animals to get close to the water and have a drink.
Useful resources on plant identification
Answers to audience questions during the presentation
How do you plant in the water?
You can push plants into the mud. In tough clay soils, it can be tricky to dig. Some plants such as water ribbons might need some protection for birds, such as ducks. You can use wire or netting, making sure that you check regularly to ensure no birds and other fauna become trapped.
Are yabbies and leeches bad?
Yabbies and leeches occupy a variable range of conditions of waterways and are not an indicator of poor or good health. Look for diversity of bugs to get a measure of water quality. There are lots of resources online or get involved in your local waterwatch – click here
How do a learn more about the little bugs in my dam?
Take a look at this resource from La Trobe University on macroinvertebrates – click here
Fish! Do you have any advice?
Make sure you don’t have European Carp! Try and remove if they are present as they will eat, animals and vegetation and stir up the water. Native fish that will grow to around 10 cm, have more chance of coexisting with tadpoles. Try small-bodied indigenous native fish such as Obscure/Mountain Galaxias or Southern Pygmy Perch. See the fish guide developed by the North Central Catchment Management Authority – click here
For more information on improving the water quality and habitat value for dams, as well as sustainable land management, please buy a copy of our Healthy Landscapes guide.
Copies of the guide will be offered to Landcare and community groups, and available for general sale (around $15 per copy) in Castlemaine through the Castlemaine Visitor Information Centre, Stoneman’s Bookroom and Mount Alexander Animal Welfare (MAAW) Op Shop. Please do not hesitate to contact us if you have any questions, or would like further information.
Connecting Country extends a big thank you to Chris Burgess and Martin Shaddick for hosting this event, and to Karl Just for sharing his knowledge and enthusiasm for healthy wetlands. We also acknowledge the Department of Agriculture, Water and the Environment, through funding from Australian Government’s National Landcare Program, for supporting this project.