Windmill Aerators for Ponds and Lakes
We often get the question, “Why use a windmill for pond or lake aeration when there are other aeration options out there?”
The answer is quite simple. Your pond needs aeration to keep it healthy and using a windmill for aeration is one option for doing that. Windmill aerators have been around for 25 or so years. They have proven themselves to be effective in most situations over that time. This article will discuss when windmill aeration works, when it doesn’t and what are viable alternatives.
Q. First, why do I need aeration?
A. All ponds and lakes will benefit from aeration. Pond aeration is just like adding air to an aquarium. With air, the aquarium stays fairly clean. Shut off the air and it starts to turn green. Adding oxygen to a pond helps aerobic bacteria thrive. They are the lifeblood of a healthy pond as aerobic bacteria are much more effective than anaerobic bacteria at breaking down organic matter and excess nutrients. Bottom diffused aeration brings water from the bottom of the pond to the surface where it comes in contact with sunlight and wind, which add viable oxygen. This water then goes back down to the bottom where the aerobic bacteria can start to eat the black organic matter and muck on the bottom. Without aeration, ponds turn eutrophic. They start to accumulate excess muck on the bottom which then feeds algae and other weeds. Aeration has been proven to reduce algae growth, eliminate pond stratification, reduce pond turnover and complete freeze up in the winter. All of this means a cleaner, healthier pond with less fish kills.
Q. When does Windmill Aeration work?
A. Windmill aerators are effective options when:
- Your pond is stocked at normal levels and not severely overstocked. Most farm ponds and small to medium sized fishing ponds are not overstocked. The bass and other fish do a good job of keeping the populations in check.
- You have access to an area where there’s some wind to turn a windmill. Typically, each windmill will need 3-6 mph of wind to turn. We need a little more wind if your diffusers are placed in deeper water (10’ or deeper) because of the added back pressure on the system. For a windmill to be effective, you would need an average of 6-8 hours of wind each day. On some days, there might not be any wind. On others, you might have 24 hours of constant wind. But, if we can average 6-8 hours a day, you can get enough wind to aerate and circulate your pond.
- You don’t want to purchase electricity or want to be as “green” as possible. Wind is free once you have a system set up.
Q. When does Windmill Aeration not work?
- Your pond is heavily stocked and possibly overstocked. In this situation, fish will need supplemental oxygen in the late evening and early morning hours in the hot July, August and September timeframe. Using electric aeration via a top aerator, bottom aerator or an emergency paddle wheel is recommended.
- If your pond is down in a deep ravine or low area where access to wind is not possible. Windmills can be set up to 1,000 feet away from the pond, but sometimes getting access to wind isn’t possible. You might also have tree’s completely surrounding your pond with no open fields or other unobstructed area’s to set up a windmill.
- If you’re in a very low wind area for a majority of the year. 95% of the U.S. gets at least 6-8 hours of a 4-6 mph wind most days. There are some days without wind and some days with tons of wind, but most of the U.S. does get some wind every day – enough to operate a windmill and get some air in your pond to reduce the stratification and get oxygen back down to the bottom.
Q. What are alternatives to Windmill Aerators?
A. Alternatives are really electricity and solar. There are many good electric aerator options out there if you have access to electricity. You can then aerate 24 hours a day or put the aerator on a timer and aerate 12-14 hours if you want. Solar is also a viable option but is about 2-3 times more expensive than using electricity or wind for a given CFM output plus you have the added cost of battery replacement every 4-6 years.
Another option is to integrate a windmill aeration system and an electric aerator into the same system. Both would share the same airlines and diffusers. A control box as sold by Outdoor Water Solutions could be used to manage the two by turning on the electric aerator when the wind isn’t blowing and shutting it back off when the wind starts. This option allows you to aerate 24 hours a day and to do it as cost effective as possible given you’re using wind energy as often as possible.