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Dams – Private Property

What is a private dam?

Private dams are dams on private property.

They are usually built from earth, and vary in their size and shape.

Section 3 of the Water Act 1989 defines a dam as being: “anything in which by means of an excavation, a bank, a barrier or other works water is collected, stored or concentrated.”

There are several common designs or types of private dams including:

  • Gully dams; usually consist of an earth embankment constructed across a gully, valley, natural depression or fold in the land.
  • Hillside dams; usually consist of a 3 sided or single crescent / curved embankment and, as the name suggests, situated on the side of a hill or slope.
  • Excavated tank dams; can consist of an excavation below the natural surface level or may also include above-ground engineered earth embankments surrounding an excavation, allowing for increased water storage above and below the natural surface level. Excavated tank dams are usually used to store water that is diverted from rivers, creeks or groundwater bores and are common in flat areas where it is not possible to construct a gully or hillside dam.
  • On-stream dams; are similar in design to gully dams and usually consist of an earth embankment situated on a waterway.
What licences do I need?

The licences that you may need for your private dam include:

Anyone who wants to construct, alter, repair or decommission a dam on a waterway must obtain a Private Dam Construction Licence before starting any works.

You may also need a licence to build and operate a dam that is not on a waterway if you are proposing to build a large dam, or potentially hazardous dam.

This will depend on the size, location and potential hazard of the dam.

A large or potentially hazardous dam is a dam that:

  • Has a wall that is 5 metres or more high above ground level at the downstream end of the dam and a capacity of 50 megalitres or more; or
  • Has a wall that is 10 metres or more high above ground level at the downstream end of the dam and a capacity of 20 megalitres or more; or
  • Has a wall that is 15 metres or more high above ground level at the downstream end of the dam, regardless of the capacity; or
  • Is a dam belonging to a prescribed class of dams (at the moment, there are no prescribed class of dams)

It is your responsibility to ensure that you comply with the Water Act 1989. We advise that you contact us on 1300 139 510 to discuss licensing requirements before starting any works.

Please note that as well as a works licence, most local Shire Councils require a planning permit. You should contact your Shire Council to discuss.

 

If you have any enquiry about other works on waterways (eg bridges, culverts), contact your nearest Catchment Management Authority.

Your Dam Your Responsibility

How do I obtain a works licence?

How do I obtain a works licence?

You need to apply to us with an application form and fee. We strongly recommend you talk to us first, as not all applications are approved.

If you intend to take and use water from a dam for any purpose other than domestic and stock use, you must obtain a Surface Water Licence.

Do I need a dam operating licence

By law, many farm dams require an operating licence.
They include dams that are:

  • Situated on a waterway, regardless of size
  • 5 metres high at the wall with a capacity of 50 megalitres or more
  • 10 metres high at the wall with a capacity of 20 megalitres or more
  • 15 metres high at the wall, regardless of capacity.
  • These dams are regarded as potentially hazardous, and require special operating conditions.

We strongly recommend that before you begin, you make an appointment to have a chat with one of our staff.

To obtain an operating licence, you need to submit:

Surveillance and Emergency Management Plan (SEMP)

The SEMP must be prepared by an experienced consulting engineer. It should include as a minimum:

  • A summary of the dam properties, current dimensions and other features
  • An appropriate dam surveillance program and check list
  • A Dam Safety Emergency Plan (see our website)
  • Inspection photographs
  • Spillway capacity computations
  • Locality and catchment plan
  • Any recommendations regarding works needed to bring the dam to acceptable standards

Licence conditions

Your licence may include conditions such as:

  • Submitting monitoring when required by Southern Rural Water
  • Remedial works to correect any faults identified by the SEMP

Your Dam Operating Licence is valid for 5 years, and has an annual fee. When your licence is due for renewal, we will send you an application, and you will need to submit an updated SEMP.

 

Dam maintenance and repairs

A dam is a valuable asset on any property, providing essential water supplies.

If your dam fails, it can lead to:

  • Expensive repair bills
  • Lost productin whilst your dam is fixed
  • Legal liability for any damage caused to people, property or the environment

It makes sense to keep your dam in good repair!

Dam owners often seek advice from Southern Rural Water about their obligations when undertaking works to dams – particularly when a works licence is needed.

This Fact Sheet provides some guidance on when a works licence is required. Remember, it is always best to check with us before you start work.

Spillway

Your dam spillway must be designed to take a 1 in 100 year flood (technically known as an Australian Rainfall Index rain event). Storms can hit without warning, and a correctly sized spillway is essential protection for your dam. The spillway must never be reduced in size without approval from Southern Rural Water.

Compensation pipe and valve

The valve must be operated regularly to avoid seizure due to rust and other build-up. Regular operation will also reduce the amount of silt and other debris that can build up in the compensation pipe. You should maintain safe and simple access to the valve at all times.

Dam wall

Keep your downstream wall clear of trees, shrubs and weeds. The slope should have an even cover of deep-rooted grass, regularly maintained to allow a visual assessment of the wall.

Dam crest

You can use the crest of the dam for vehicle or stock crossings. However, it should be kept level to avoid pot holes and uneven areas forming. You should also keep your crest fenced to exclude stock from both the upstream and downstream walls. Allowing stock access to the walls will cause damaging erosion.

Dam crest

You should install a straight line of fence posts across the crest and check them regularly. Any movement should be immediately reported to Southern Rural Water and your dam engineer.

You should also regularly check for leaks, wet spots, slumping or any signs that the dam may be at risk. Regular inspections and prompt maintenance will help you get the maximum life span from your dam.

This advice is general in nature, and you should seek expert advice about the best way to keep your dam safe and operating properly.

What is maintenance?

Basic maintenance of a dam does not require a licence from Southern Rural Water. This includes:

  • Cleaning out of weeds
  • Minor works to repair erosion damage on the crest, embankment or spillway
  • Removal of vegetation from the dam wall
  • Maintenance of the compensation pipe or trickle pipe

What maintenance will require a licence?

Any modification to the structure of the dam will need a licence!
It is always best to check with us before you start work.

You need a licence to construct, alter, operate, remove or decommission any dam that:

  • Is located on a waterway
  • Has a wall height of 5 metres or higher and a capacity of 50 megalitres or more
  • Has a wall height of 10 metres or higher and a capacity of 20 megalitres or more
  • Has a wall height of 15 metres or higher, regardless of the capacity.

Maintenance includes:

  • Any alteration to the dams holding capacity or wall height
  • Modification of the crest, spillway, compensation pipe or trickle pipe
  • Reconstruction of the dam wall due to damage – such as damage sustained during a flood
  • Repairs that result in disturbance to the embankment – such as removing a section of the embankment to replace or repair a compensation pipe or trickle pipe.1

Getting a licence?

We strongly recommend that before you begin, you make an appointment to have a chat with one of our staff.

To obtain a works licence, you must submit:

  • An application form (see our website)
  • A site plan or location plan
  • Appropriate fees (see our website)

Engineering requirements?

Typically, a condition of a works licence will require the dam works to be designed and the construction supervised by a suitably qualified engineer.

Our website has a list of consulting engineers.

Note: a ‘suitably qualified engineer’ means a person eligible for membership of the Institution of Engineers Australia who is able to demonstrate competence in the design, construction supervision and surveillance of dams.

Dam Safety Emergency Plan

Don’t drink the water

The quality of water from private dams can vary widely.
Dam water is untreated and should not be considered safe for human consumption without proper treatment.

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