Water Supplies

Water for Rural Properties

Harvesting it, Storing it and Using it efficiently.
Saturday 19 May 2018
Notes taken during a Water Field day by Ian Meyer 


Morning Session - Cook’s Tour of several dam location out Winnejup Rd way.
Presenter: Peter Brown, Dam Designer and Sinker

 

  • Test drilling holes is a great way to confirm a good location, in terms of ground type – clay, how far to rock etc.

 

  • Clay lining of the dam to be waterproof is vital. Smaller dams sometimes might have insufficient clay material to complete this.

 

  • If you do not hit clay within 1000mm of the natural ground level (NGL), it is likely that not enough clay will be un-earthed to seal the dam properly – applies to dams up to 300 to 400 cubic yards.

 

  • A dam of 2000 cubic yards would cost around $3,500 in today’s prices.

 

  • 1 in 3 slope on the inside wall of the dam is the industry standard. Minimises issues later and is the ‘natural slope’ which over time the wall gets to.

 

  • Optimum slope of the land for a dam is 5%. Good wall construction allows for a water level retention of between 500 and 1000mm above the NGL.

 

  • Free board is the dam wall height above the intended dam capacity. It should be between 1000 and 2000mm above the intended capacity point.


  • In the photos is a 2000 cubic yard dam. Using road drainage as its main water source. Includes a silttrap, immediately uphill to extend the life of main dam. The pipe between the silt trap and dam has a downturned elbow at the silt trap end. This keeps silt and organic matter from getting into the dam, thus reducing the frequency that silt needs to be removed from the dam, and reducing the possibility of having an algal bloom.

 

  • Past practices mean that salt can be an issue in gullies. To overcome this the dam design can include a mechanism to overcome this, as salty water sinks. Use a pipe with an end close to the bottom (not at the bottom otherwise silting can become an issue) which can draw the saline bottom water out – either through a pipe through the dam wall installed during construction or syphoned over the wall of the dam in a poly pipe.

 

  • Dams can need permits, so consult your local Shire and/or Department of Water. The Department will advertise if necessary.

 

  • Soaks and Gully dams on unnamed drainage lines generally do not need permits. If a creek is named, it is likely to need some sort of permit for a dam to be constructed. Hillside dams (‘Three siders’) are less likely to need permits since they interfere far less with environmental flows down creek lines.

 

  • Sometimes it might be a couple of years before a dam holds water, as the final compaction is achieved. “Sheep foot compaction” is a technique used by farmers. Sheep do a great job at achieving compaction. Cows do not – they tend to be more destructive than supportive. Wind is a major cause of water evaporation. An island in the dam will assist in “breaking” the wind action. Anything to stop wave action and evaporation is important.

 

  • Trees too close to a dam are not good as their roots can break the seal. Once they die the impact can be even worse.​​

Afternoon Session – Tanks and Irrigation
Presenter 2: Peter Quinby ‘The Right Stuff for Landholders’
(Irrigation Consultant and Contractor)

info@rightstuff4landholders.com.au

  • If a sand pad is required for a water tank, it will cost about $1,500. A pad is required for all steel tanks.

  • Have separate tanks for different uses eg: Potable Consumption, Gardens, Animals.

  • Consider the dam pump intake area. Yabbies can be an issue if they take up residence in the
    suction filter when young and grow too big to get out. When the pump is activated they are sucked into the pump and can clog it and cause the motor to burn out.

  • Irrigation relies on a set of conditions, relating to pressure and flow. So, it is important to get the optimum pressure and flow.

  • Check the pressure needed to close a solenoid valve. This is usually measured in metres of head.

  • DC pumps are better than AC pumps but are more costly.

  • Solar pumping systems apparently do not have a regular supplier that has been around a long time. There have been people who bring in a ‘container load’, sell them and close the business.

  • Solar-powered pumps should be considered to be live unless there is an isolator switch.

  • Evenness of water volume can be an issue. Drippers with pressure compensators means that watering does not begin until there is an even water pressure. This is ideal for a sloping site.

  • There are many types of irrigation heads. One should not mix up different types of heads
    requiring different water pressures and delivering different flow rates otherwise evenness of watering is affected.

  • Specific local rainfall data can be obtained from the Bureau of Meteorology.

List of Useful Contacts:
Dam builders
Peter Brown 
Draglines Dam-it Contracting
0407 389 092,
pete.jan@westnet.com.au
Bridgetown Bulldozing 
9761 2116
0428 851 869


Water Diviners
Greg Giblett
0428 612 522

Irrigation Suppliers
Peter Quinby
The Right Stuff for Landholders
12 Rose St, Bridgetown
(08) 9761 4725
info@rightstuff4landholders.com.au
www.rightstuff4landholders.com.au
Rick and Tania Evans 
Richfeeds and Rural Suppliers
170 Hampton Street
9761 1520
Paul Doust Bridgetown
Mitre 10
9761 1067


Local Water Tank Suppliers
Rick and Tania Evans 
Richfeeds and Rural Suppliers
170 Hampton Street
9761 1520
Peter Quinby
The Right Stuff for Landholders
12 Rose St, Bridgetown
(08) 9761 4725
info@rightstuff4landholders.com.au
www.rightstuff4landholders.com.au