Your Dam Your Responsibility (PDF~1.2MB)

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C
Appendix C
For the purpose of assisting owners of small farm dams two standard spillway size
options have been provided on the following pages. These are related to catchment sizes
and must be used within the limitations identified.
These standard sizes should only be applied if the dam:
• is located in the State of Victoria;
• does not exceed 3 metres in height;
• holds 20 ML (20,000 cubic metres) or less at full capacity;
• will have negligible impact on any other person, property or the environment if it
fails;
• has a spillway discharge channel slope of less than 15%; and
• is not located in the very high rainfall areas such as:
• the Otway Ranges between the coast and the township of Forrest;
• around the area of Pyalong; or
• in the area between Gisborne and Bacchus Marsh.
Advice from a suitably qualified engineer should be sought for dams (even if less than 3m
in height or 20 ML in capacity as follows:
• in the high rainfall areas mentioned above;
• where the dam has a catchment larger than 50 Hectares; and
• where a different form of spillway is used.
Remember: The consequences of dam failure must be negligible to be able to apply
the spillway sizes presented below. Where this is not the case then seek advice from a
suitably qualified engineer.
For dams that have a catchment area of 25-hectares or less the following size may be used:
Figure C-2
Where a long entry channel is required this channel width must not be less than the
width the spillway crest and the level must not be higher than the crest section.