Aquatic Fence

An aquatic fence is a curtain of air bubbles, sometimes many yards long, that stream from a series of holes in an air line submerged and anchored to the bottom of a water way. Gary from Moses Lake Washington sent in this question about compressed air and compressors for an aquatic fence.

"We have a local lake with an outflow spillway in which Fish and Game estimates that nearly 500,000 small fish are swept through each year.

We would like to consider putting in a "bubble fence" at the entrance to the spillway to deter fish from entering.

This would require continuous operation, 24/7, for several months per year.

aquatic fence - bubblers to keep fish in or out
An example of an aquatic fence in operation. Photo:

One Canadian company sells bubble fence tubing that operates at 50 PSI max with an optimal flow of .07 CFM.

What kind of compressor would be best matched to these specs assuming continuous operation?"

My response: Gary... You note that "One Canadian company sells bubble fence tubing that operates at 50 PSI max with an optimal flow of .07 CFM."

What does it mean by optimal flow, and is the air consumption of the tubing .07 CFM at that optimal flow? I can't believe that the "fence" only uses .07 CFM @ 50 PSI. Surely that must be per foot or by the meter?

If you're considering a 24/7 operation, you're going to want to select an industrial compressor for sure. There are many pages on this site about the different types of compressors. May I suggest you look at the different styles, the pages that discuss compressor options, and the location of the compressor installation?

You need to determine what the total flow requirement of the fence will be for the length of aquatic fence you are considering. You'll want to know what the flow requirements are in CFM and at what specific pressure.

Air compressors always deliver higher flows of compressed air from their discharge port at low pressures than at high. That's why the compressed air pressure requirement of the application is so important to know.

When you are talking to various compressor vendors, tell them that you need a unit that will provide that discharge flow at that pressure, to insure that you get sufficient horsepower.

You might want to allow at 10% increase in the compressor size to give you some added capacity down the road.

Don't forget that you'll likely need at least a 220 VAC supply to the compressor, and this has cost ramifications too.

The aquatic fences I've seen have all been using industrial rotary screw compressors.



Comment back from Gary... About the information provided, Bill -

Thanks for your comments. I agree that the flow of .07 CFM must be per foot of tubing although the manufacturer did not state that in their advertisement. The suggestion of a rotary screw compressor is valuable."

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