Pond Boss
Posted By: jsames Antivortex Baffles - 04/29/11 01:57 AM
I am new to the forum and I am also the owner of my very first pond. I am overjoyed to find this website and forum. I am certain to be using it quite frequently and hope to be able to share what I learn with my pond.

I have searched and searched the forums and haven't found much about baffles. I did find the USDA guide in the archives and also searched it. Very good to have.

I recently discovered a small hole running parallel to the face of the dam of this pond. I wanted to make sure that it wasn't something bigger and check the construction of the dam. I had someone from the NRCS come out to take a look as the previous owners had much of the work done on the land that I purchased by the USDA. It also has a cattle waterer at the bottom that looks like it is fed from the dam also. So, I figured they may have participated in the construction of the dam.

The NRCS said that the dam was safe, that they had not built it because it did not have a baffle and that the overflow drain pipe needed a baffle to prevent a vortex.

That was less than a month ago and I have not installed a baffle yet. It has rained, well, like everyone knows and we have had consecutive days of flood warnings. I checked the dam the other day.

Here is the situation:
1. a 2.5 acre pond
2. an 8 inch pvc overflow pipe that runs through the dam, no baffle or screen
3. the pipe was covered by at least 3 feet of water
4. no vortex and only a few small bubbles at the water's surface above the pipe
5. A steep backslope and about a 25 foot dam on the back side.

Problem: Only about 1/3 of the pipe on the exiting side is full of water. Shouldn't that pipe be nearly full?

Also, the NRCS said that I should construct the baffle to be placed at the top of the overflow pipe, parallel to the pond surface. The USDA manual has baffles on the side, perpendicular to the pond surface, not the top. Where does the baffle go? And is it the solution?

Thanks - let me know if more info is needed.
Posted By: Brettski Re: Antivortex Baffles - 04/29/11 02:13 AM
Hey jsames...welcome to the show.
Hooded inlet might yield a few more hits with the forum. The link is my effort at creating the same. I have a smaller drainage area, so I don't believe I have yet put it to use.
Posted By: zhkent Re: Antivortex Baffles - 04/30/11 01:59 AM
Here we use what is called a canopy inlet.
The "canopy" is is made cutting about 1/3 off of an 8" cap. That 1/3 is glued and/screwed to the top of the pipe covering a little less than 1/3 of the hole in the pipe.
Now from the bottom of each side of this canopy cut the bottom of the pipe off at about 45 degrees.
The larger hole now in the pipe lets water enter the pipe faster and the canopy should stop cavitation at about 4" of water over the top of the pipe.
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