grass roots community organisation that aims to improve natural condition of the derwent catchment

Revegetation After A Flood

Revegetation after a flood...

  • Seek advice from local council land management officers
  • Revegetate bare ground with native grasses and shrubs
  • Plant deep-rooted native trees to stabilise riverbank
  • Regularly monitor for and remove weeds
  • Never use heavy machinery in waterways without a permit

Bare ground
Sow pasture grass as soon as possible on all bare soil to reduce soil run-off and outcompete weeds such as thistles. Ideally this is done with a spreader and harrow but can also be done with a hand spreader and a garden rake. The best grasses to sow are perennial grasses such as Victorian Rye, Cocksfoot and Phalaris.

Disturbed river edges and areas prone to regular flooding
Plant native sedges and rushes which will bind the soil and don’t mind wet feet. If banks are too steep to plant sedges, sow more grass. Suitable rushes and sedges include Club rush (Finica nodosa) Carex and Juncus species— plant with 1/2 metre spacing.

Next to the riverbank
Plant fast growing riparian native trees and shrubs to help restore a healthy, resilient ecosystem. In moist areas plant woolly tea tree (Leptospermum lanigerum) with a 3 metre spacing. In drier areas which only flood occasionally, you could also plant black-woods (Acacia melanoxylon), black gum (Eucalyptus ovata), yellow dogwood (Pomaderriselliptica) and tea tree (Leptospermum scoparium). Blackwoods and gums should be planted with a 10 metre spacing.

Weeds
Environmental and declared weeds will rapidly invade bare soil, so monitor and control regularly to stop the problem getting out of hand. Where you can, hand pull or dig the weed out. Cut/paste is also a good method: cut the main stem as close to the ground as practical and paste the stump with glyphosate (e.g. Roundup). If these methods are not possible, spray with broad spectrum broadleaf herbicide (e.g. Triclopyr) during active growing times i.e. Spring/Summer (unless it is Blackberry which is best sprayed in late Autumn when it is past fruiting but before the leaves drop). It is vital to spray away from the river to avoid herbicide entering the water. It is important to remove any weed fragments from the river edge as some species can resprout from stems.

Stock and native wildlife browsing
Fencing is vital to the success of revegetation projects if you have stock. All sections of the river with restoration works should be fenced off. If this isn’t possible, exclude stock for six months where pasture grass has been sown or 3-5 years where native trees and shrubs have been planted. Using tree guards and sturdy stakes is important to give your trees and shrubs protection from wallabies until they can fend for themselves. We use mesh guards and hardwood stakes so that if water levels are high in Winter the guards will let the water through. Solid plastic bag guards are not suitable for revegetation in flood prone areas.

Creating a more resilient river
River systems are naturally dynamic so they can respond to changing water flow. A healthy river system will better cope with flood situations and streams lined with native vegetation are much less affected by flooding compared with willow lined streams. Consider the future; if the area floods again you’ll need a stable, resilient riverbank.

If you would like any technical advice about river recovery/revegetation/weed control or further information on how to increase health and resilience in your surrounding waterways, please contact the Derwent Catchment Project on 6286 3211 or facilitator@derwentcatchment.org