Your Dam Your Responsibility (PDF~1.2MB)

7 Operation and Maintenance of Dams
7.5.10 Vegetation
(a) Trees
Self-sown plants, trees or other deep-rooted plants should not be permitted within 5
metres (or the anticipated height of the mature growth) of the embankment or spillway.
The roots of this type of vegetation could provide a path for leakage through the dam
and, ultimately, result in its failure.
Planting trees and shrubs can provide windbreaks, which prevent wave action and,
therefore, soil erosion, and also give shelter for wildlife.
If trees are required, they should be planted around the foreshore of the water storage,
well away from the dam embankment and spillway. The dominant wind direction needs
to be considered. (Refer also to booklet ‘Trees at Work – Improving Your Farm Dam’ from
Greening Australia).
(b) Total Catchment Area Protection
To maintain the required depth and capacity of a farm dam, it is necessary that inflow be
reasonably free from sediment.
Selective plant use can be used to trap silt and improve water quality. The best protection
from sedimentation is to control erosion of the surrounding catchment area. Land with
a permanent cover of vegetation, such as trees or grass, makes the most desirable
catchment areas. If the catchment area is denuded and eroding, you may need to utilise
cultivated areas that are protected by appropriate conservation practices, such as contour
tillage, strip-cropping, conservation cropping systems, and other land improvement
practices.
(c) Weed Control
Aquatic weeds in farm dams can block pump and pipe inlets, deter stock from drinking
and, in some cases, taint the water. If weeds are treated when they first appear, dams can
be kept relatively free of some of the more troublesome species. All plants can become a
problem and each may require a different control method. However, in all situations the
same factors should be considered in deciding what control methods, if any, should be
used.
In each case:
• determine whether there is a problem and, if so, what it is;
• identify the specific plant causing the problem;
• find out what control methods are available and which of them could be used;
• investigate whether these control measures could cause any other problems (eg.
toxicity to fish and livestock) and, if so, whether they can be avoided; and
• decide whether or not all factors considered, control is practical, desirable and
worthwhile.
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