Is a Windmill Aerator Right for My Dam?

Have a dam in need of aeration and love the idea of having a windmill on your property? In this article we’ll run through everything you need to know to determine whether a windmill is right for you. First, let’s start by looking at how a windmill aerator works.

How does a windmill aerator work? 

Windmill aerators are different to traditional windmills in the sense that traditional windmills typically pump water, whereas windmill aerators pump air. This means you couldn’t use a windmill aerator to fill up your animal troughs with water—windmill aerators do one thing only and that is to aerate water. Here’s how a windmill aerator works: the blade of the windmill spins in the wind, which turns an internal rotor that is connected to a large diaphragm. This diaphragm pumps air down the windmill tower into the dam where air is pumped out of air stations (sometimes called diffusers) which sit on the floor of your dam. The air released from the air stations rises to the surface with the bubbles getting larger and larger, the more distance travelled. This creates a wake which draws water from the bottom of your dam up to the top, like riding a bike behind a bus and not needing to peddle because you are being dragged along by the sucking air. These bottom waters arrive at the surface and gas exchange occurs between the water and the air. Here, nasty gases like carbon monoxide, methane and hydrogen sulphides exit the water while oxygen enters the water. Through this gas exchange, the water cools and gets denser, again sinking. This takes oxygen down to the lower parts of your dam which naturally pushes the bottom waters up, and the cycle repeats itself. 

Above: How windmill aeration works

 

Learn more about the OWS windmill aerator here

How much wind do I need? 

Quality windmill aerators are built to operate even in low wind conditions. Models like the Outdoor Water Solutions Windmill Aerator (which we stock) can continue to run and power an aerator with winds as slow as 8km/hr. This means most elevated properties that don’t have obstructions (e.g. trees, buildings) in the way are suitable for a windmill aerator. Obviously with wind speeds this low, the aerator would be running at a reduced rate so you’ll need to take this into consideration. i.e., if you need a lot of aeration because you’re having a lot of problems with algae, weeds, odour etc, you’ll need more wind (and more aeration) than if you have a fairly healthy dam. The general rule of thumb is the more wind you get, the more suitable a windmill aerator will be for your property.

How big/small does my dam need to be? 

Windmill aerators can aerate waterbodies of all sizes, from small ponds to large dams 2 acres in surface area. Exactly how large of an area you can aerate will depend on the location of your dam, the wind speeds in your area, dam depth, shape etc. We’re happy to provide free, no-obligation advice to ensure your dam is suitable for windmill aeration. 

How deep does my dam need to be? 

Windmill aerators can typically operate in dams from 1.5m to 9m deep. It’s worth noting, the deeper your dam is, the more power you will need to operate your aerator. This is because the air stations (which pump air into your water) sit on the floor of your dam, which means the deeper these air stations are placed, the more pressure is needed to pump the air down to the bottom. That said, a big benefit of having a deep dam is that, although you need more power to run the system, your aerator will be much more efficient at adding oxygen to your water than in a shallow dam. This is because, like we explained above, when the air bubbles rise to the surface, they increase in size relative to the distance travelled. The longer the distance the bubbles travel, the larger they become—increasing the volume of water that is dragged to the surface. So, for instance, if an air station placed at 1.5m is capable of aerating a dam ½ acre in size, this same air station placed at 3.5m might be capable of aerating a dam 2 acres in size. These numbers are plucked out of the air—the exact numbers will depend on many factors, including the operational speed of the windmill blade. The takeaway is the deeper your dam is, the more efficient your aerator will be.

How tall does my windmill need to be? 

The higher you go in height with your windmill tower, the more power you will typically generate because the blades are able to catch higher (less obstructed) winds. Exactly how high you need to go will depend on your location and how far your windmill is from obstructions such as trees, buildings and hills.

Where should I place my windmill? 

The optimal location for your windmill is on an elevated area in open space that receives a lot of wind. You can erect your windmill up to 200m away from your waterbody and still effectively aerate it. You just want to make sure there aren’t any major obstructions between the windmill and aerator that could hinder the capacity of the aerator.  

Is a windmill aerator better than a solar aerator? 

This is obviously dependent on your location and dam specs, but if you’re in a windy area, windmill aerators can often trump solar aerators because they can run at night (not the case with solar aerators) as well as during the day. This means, in the right area, they often do a better job at adding oxygen to water because they can provide more consistent airflow to bodies of water. Windmill aerators also have relatively low maintenance requirements and look great, although this is a matter of personal taste. It’s worth noting, if you don’t have power within 200m of your dam and need more aeration than can be provided by a solar setup on its own, you may want to look at installing both a solar aerator and wind powered aerator. That way your aerator can make use of both the wind and the sun. This of course is a superior setup to a windmill aerator or a solar aerator operating on its own.

Which windmill aerator should I choose? 

We recommend Outdoor Water Solutions’ range of windmill aerators. We stock this range because they are extremely high quality (USA made) and quite a bit smaller and more affordable than their industrial sized counterparts. Still, the towers are built high enough—5m to 7m tall—to catch unobstructed winds. We stock two types of Outdoor Water Solutions windmills: the galvanised windmill and the wooden windmill. Galvanised windmills have a ‘traditional farm’ look with steel legs. Wooden windmills have an even more ‘nostalgic’ old-time look. Both models are super strong and durable.  

All Outdoor Water Solutions windmill kits include a 3 to 4.5 CFM (cubic feet per meter) air compressor which pushes oxygen through a ½ inch weighted air hose which is attached to the outlet. These aerators are capable of aerating dams up to 2 acres in size, depending on the waterbody’s location, depth and shape. Here are some of the specs of the Outdoor Water Solutions Windmill Aerator: 

  • Powers up to 3 air-stations 
  • Suitable from 1.5m to 9m deep 
  • Blade diameter = 1.85m (turns at low wind speeds)
  • Air output: 3.0-4.5 CFM / 30 PSI
  • BalCam II Technology to minimise bearing fatigue 
  • Self-governing head that protects the unit in high winds 
  • Easy to install 
  • 5-year warranty on compressor 

Can I put the windmill together myself? 

Yes, this is very common with the Outdoor Water Solutions windmills. In fact, OWS has produced a series of installation videos to show you how to install your windmill system. Prefer we set it up for you? This is also a possibility depending on your location. Simply let us know this is your preference when you talk to us

Can I add a windmill head to my own windmill stand? 

Yes. Well, at least this is the case with Outdoor Windmill Solutions windmills. We even offer detailed instructions on how to build your own windmill stand from wood. That way, you can use your own wood (saving money) and customise the height, width etc, to match your needs. You would simply purchase the windmill head and aerator and attach these yourself. Ask us about our windmill stand instruction kits. Alternatively, you can install your windmill head to an already erected stand (perhaps an old windmill stand). We recommend filling in the form below and chatting to us first to get advice.