An enhanced dam is one where livestock access is managed to limit the impact of stock on the water body and on the surrounding vegetation.

Image: Key features of an enhanced farm dam

 

Key aspects to enhancing a farm dam

 

  1. Grazing management (if required)

    Reducing grazing intensity by fencing off the dam will reduce
    the inflow of faeces, nutrients and sediment. Aim to fence at least 10m back from the highwater mark of the dam to provide sufficient room for a grass filter and to plant other vegetation, as well as room for effective management. Include a gate into the fenced area to allow access when needed.

  2. Provision of alternative stock watering points (if required)

    Ideally, a reticulated water system can be installed to provide water points for stock. A hardened access point can be used as an alternative to allow managed stock access to the dam, minimising pugging, and sedimentation, as well as reducing the amount of time stock spend in or on the edge of the water.

  3. Revegetation

    Revegetating the area around a dam with appropriate species will help filter runoff containing sediment and nutrients and therefore improve water quality. Once a dam is fenced and livestock are excluded, many species of aquatic plants and fringing rushes and sedges will naturally re-establish, as these species have long-lived seeds that will be present in the soil. However, active revegetation may be required to establish native trees and shrubs around the dam.

    Different zones of a dam are suited to different types of vegetation (see image below).

Image: Cross-section of a dam showing dam zones and vegetation types

 

Be sure not plant trees close to the dam wall, leave a space of at least 10 meters. The Dam and banks of the tributary can be revegetated with suitable terrestrial and aquatic plants, sourced from an indigenous plant nursery.

Plant list of suitable vegetation for planting around the dam  and tributary edges include:

● Bidgee-widgee, Acaena novae-zelandiae
● Water Plantain, Alisma plantago-aquatica (aquatic)
● Tassel Cord-rush, Baloskion tetraphyllum
● Square Twig-sedge, Baumea tetragona
● Bulbine Lily, Bulbine bulbosa
● Tall Sedge, Carex appressa
● Tassel Sedge, Carex fascicularis
● Leafy Flat-sedge, Cyperus lucidus
● Tasman Flax-lily, Dianella tasmanica
● Knobby Club-sedge, Ficinia nodosa
● Spiny-headed Mat-rush, Lomandra longifolia
● Weeping Grass, Microlaena stipoides
● Long Purple-flag, Patersonia occidentalis
● Slender Knotweed, Persicaria decipiens (aquatic)
● Common Tussock-grass, Poa labillardierei
● Kangaroo Grass, Themeda triandra
● Water Ribbons, Triglochin procera (aquatic)

 4. Habitat features to support biodiversity

Where possible, create varying depths in your dam to provide a range of habitat zones for aquatic life. Also place partially submerged logs to provide perches above the water surface where invertebrates and turtles can perch and frogs can use to call from.

Islands provide a safe haven for turtles and waterbirds to bask and nest on, free from interference by predators. Establishing plants on and around islands increases the area of vegetation for the purification of water and improves the microbial flora of the dam and provides additional habitat for aquatic or semi-aquatic organisms.

For more information visit: https://www.sustainablefarms.org.au/docs/kb/farm-dams-technicalguide/how-to-enhance-a-farm-dam/