Short answer: A turkeys nest dam suits a flat site where earth can be borrowed from inside or beside the basin, while a ringtank is a circular raised reservoir built from imported or excavated fill. Choosing between them depends on available clay, topography, rainfall, pumping, cost and the water use planned for your property.
When a landowner asks me about a turkey’s nest dam, they are usually trying to solve a practical problem: the block is too flat for a conventional valley dam, but there is still a good reason to store water. A raised ring of compacted earth can make that possible, provided the foundation, liner material and overflow arrangements are treated as seriously as the wall itself.
The names are often used interchangeably, which creates confusion. In everyday farm language, a turkey’s nest is a raised earth dam that holds water in a shallow, usually round or oval basin. A ringtank is the more deliberately circular version, often designed around irrigation, stock water or a pumped supply. The shape is not the deciding factor; the site and the construction method are.
I have seen owners focus on the excavation volume and miss the bigger questions: where will the wall get competent foundation contact, how will clean water enter, and what happens when a storm arrives with the tank full? A well-planned raised dam can be very useful. A rushed one can become an expensive ring of wet soil.
What is a turkeys nest dam, and how is it different from a ringtank?
A turkey’s nest dam is primarily a raised embankment built above relatively flat ground. The contractor excavates or imports suitable soil, forms a circular or curved wall, and creates a basin inside it. Water may arrive from runoff, a diversion drain, a bore, a creek pump or a combination of these sources, subject to local rules.
A ringtank is generally a purpose-designed circular storage tank made from a continuous earth ring. It is common on irrigation and cropping properties because its footprint can be chosen independently of a natural gully. That can make the water level, pump intake and internal access easier to manage, but it also means the wall may be exposed to water pressure all the way around.
| Consideration | Turkey’s nest dam | Ringtank |
|---|---|---|
| Best setting | Flat to gently sloping land | Flat land with planned circular storage |
| Typical water source | Runoff, diversion or pumping | Usually pumped or diverted supply |
| Main design challenge | Foundation and safe overflow | Uniform wall, sealing and full-ring stability |
| Good fit for | Stock water and general farm storage | Irrigation, tanks and controlled supply |
When does a raised dam make sense?
Start with the water job, not the earthmoving quote. If the aim is to catch a reliable overland flow in a natural depression, a conventional valley dam may store more water for less wall. If the land is broad and flat, a turkey’s nest or ringtank can provide storage where a gully dam cannot.
Raised storage is also useful when you want gravity pressure to a trough, a protected pump intake, or separation between clean irrigation water and a muddy drainage line. A ringtank can be built near the point of use, but that convenience only works if the ground can support the load and the fill is suitable.
As a rule of thumb, every extra metre of water depth increases the force the wall must contain and the consequence of a defect. A 3 m deep ringtank is not just a 3 m hole with a circular pile of dirt around it; it is a continuous engineered embankment holding water on every side.
For an early sense of the planning sequence, compare your idea with Big Ditch’s farm dam construction guide and farm dam location checklist before machinery arrives.
The soil and foundation questions that decide the project
Water storage needs a low-permeability barrier, not simply a large quantity of dirt. The best borrow material is usually a well-graded clay or clay loam that can be placed in thin layers and compacted while it is close to the right moisture. Topsoil, roots, organic matter and loose sand belong outside the sealing zone.
On flat sites, the wall may look uniform while the foundation changes dramatically around the circle. One section can sit on firm clay and the next on old drainage gravel, fill, cracking soil or a buried root zone. Strip, key and prepare the foundation consistently; do not assume that a circular plan makes the ground consistent.
A 150 mm compacted lift is a useful construction benchmark for earthwork, but the correct lift thickness depends on the material and the compaction plant. The important point is that each layer is tested or carefully controlled, rather than burying loose windrows beneath the next load.
Clay content, dispersive behaviour and salinity can change the outcome. If the material crumbles when dry, pumps under a roller or stays slick and plastic when wet, pause the build and test it. Spending $500 on a basic soil assessment can be cheaper than trying to seal a failed embankment after it fills.
How much freeboard and batter does a ringtank need?
Freeboard is the vertical distance between the design water level and the crest. It provides room for wind setup, wave run-up, settlement and rainfall arriving before the spillway can carry it away. A raised dam should never be planned so the normal full level sits right at the top of the wall.
Allowing 600 mm of freeboard is a common starting point for a small farm storage conversation, but it is not a universal safety value. Catchment, fetch, wall height, settlement, storm intensity and the consequence of a breach all matter. The spillway must be lower than the crest and able to pass the design flow without cutting into the earth wall.
The water-side and outside slopes are called batters. A 3:1 batter rises 1 m for every 3 m horizontally, giving a gentler face than a 2:1 batter. Gentler slopes use more earth but are easier to mow, inspect and maintain, while steep faces demand better material, compaction and erosion control.
Plan for settlement as well as construction height. If a crest settles by 10% of its built-up height, a wall that was finished too close to the target level can lose important freeboard before the first dry season ends. The final profile needs enough width for safe access and inspection.
Big Ditch’s explanation of freeboard on a farm dam covers the measurement in plain language, while the guide to dam batter slopes shows why the profile affects both safety and cost.
Water supply, spillways and everyday operation
A ringtank is often filled by a pump, which makes water accounting and operation important. Work out the pump rate, delivery pipe, intake position and backup plan before choosing capacity. If a pump can deliver 30 L/s, it moves 108,000 L, or 0.108 ML, in one hour; that inflow still needs a safe destination if the tank is full.
Keep the emergency spillway away from the most vulnerable part of the wall where possible, protect its entry from erosion, and make sure the discharge path does not send water onto a neighbour, road or septic area. A pipe is not automatically a spillway: blocked screens, power loss and a storm larger than the pump system still need to be considered.
Fence stock away from the crest and water-side face if practical. Cattle tracks can loosen the surface, muddy the storage and create a maintenance problem just where the wall needs regular inspection. Check for wet spots, animal holes, cracking, slumping, blocked drains and new erosion after heavy rain.
For a useful operating routine, follow this farm dam maintenance checklist. It is easier to spend 20 minutes looking over a wall after rain than to discover a developing leak when the tank is already low.
Here is a Queensland example of why the site matters more than the name. In 2022, Lindsey Hughson inspected a cattle property near Toowoomba, Queensland, where the owner called the proposed storage a turkey’s nest. The useful decision was not whether the sign should say “ringtank”. Lindsey walked the proposed circle, checked the clay borrow area and traced the overflow route. The first layout crossed a shallow gravel seam, so the wall was shifted and the foundation work was adjusted before construction.
That example is worth remembering because a neat circle on a plan can hide an awkward section of ground. The final storage volume, wall length and pump position all changed slightly, but the project gained a more dependable foundation and a discharge path that did not run toward the yards. Good dam building is often about making a small change early.
Queensland owners should check current advice and approvals with the Queensland Department of Agriculture and Fisheries farm dam guidance. Owners in New South Wales can also review the NSW Department of Primary Industries farm dam information. Watercourse works, extraction, earthworks and safety obligations can vary by location and project scale.
Which option should you choose?
- Define the use. Separate stock water, irrigation, fire protection and domestic supply because each has different quality, reliability and access needs.
- Confirm the source. Map runoff, pumping distance, electricity, bore yield and any legal limits before counting on a full tank.
- Test the ground. Locate clay borrow, inspect the foundation and identify gravel, rock, fill, dispersive soil or buried drainage.
- Sketch the safety profile. Set the water level, freeboard, crest width, batters, spillway and downstream flow path together.
- Price the whole job. Include stripping, excavation, haulage, compaction, pipes, fencing, revegetation, testing and maintenance, not just the dirt moved.
Choose a turkey’s nest when a raised earth basin is the simplest way to create storage on your block and the site has suitable fill. Choose a ringtank when circular, controlled storage near a pump or irrigation system is the priority. If the ground is poor or the overflow consequence is serious, redesigning the location may be wiser than forcing either option.
ANCOLD’s dam safety resources are a useful reminder that risk should be considered alongside capacity. A farm dam may be small, but the right inspection, maintenance and emergency planning still protect people, stock, neighbours and the investment in the earthworks.
Frequently Asked Questions
Is a ringtank the same as a turkey’s nest dam?
They are closely related raised-earth storage designs, and people often use the terms in the same conversation. A ringtank usually emphasises a circular, purpose-designed storage embankment, while turkey’s nest is the broader farm term for a raised dam on flatter ground. The construction quality and site conditions matter more than the label.
Can a turkey’s nest dam be built without a natural creek?
Yes, it can be filled by runoff diversion, a bore, a creek pump or another lawful supply. The design still needs a stable foundation, suitable compacted fill, a safe spillway and a clear discharge route. Confirm water and earthworks requirements with the relevant state authority before starting.
How do I know whether my site has enough clay?
Look for consistent, workable clay below the topsoil and test it rather than judging by colour alone. A borrow pit may contain enough material in one corner but not enough for the complete wall and basin. A site inspection can identify seams, gravel and moisture problems before they become expensive construction changes.
Plan reliable raised storage for your property Book a site inspection with Big Ditch before the next earthworks season.