Hello everyone,
so hopefully some of you can help me out and give me some solid advice. I am brand new in every way... to this site and to pond ownership. So I have a few questions and need some help to clarify or expand my extremely limited knowledge. I have a pond now (constructed approximately 10 years ago) on our new property that was put in by the previous owner who hired professionals to build it. It is about 1/2 to 3/4 of an acre and approximately 6-8 ft deep in probably 50% of it or more. Doesn't seem to leak or evaporate too quickly, so that's the good. Now for the bad, at least I think its bad. The pond water is murky/silty and a brownish color all the time now, it's much worse now than when we bought the house a couple of years ago. The original owner claims to never have had to do anything to the pond to keep it clear the majority of the time. I assume from my limited research this is colloidal clay in the water column not settling to the bottom. I also assume that this situation is being made worse by the high number of (75-100) catfish in the pond as the result of the previous owner stocking the pond with them. I am not sure what kind of catfish, but I am thinking they are bullhead due to their color. I read that catfish, and in particular, bullheads root around in the substrate constantly looking for food, making the turbidity in the water worse. There are also large amounts of bluegill and some other smaller (too small to make a good guess) fish in the pond. There is no vegetation in the pond, the pond is completely surrounded by grass and rock embankment which stretches around three sides of the shoreline which sizes from pebble to about 12" across, and several Large (2 Sycamores and 4 Walnuts that are 24-36 inches in diameter or larger and 75'+) trees either at the edge of the pond or within 10 feet of the waterline. No livestock have access to the pond except for the local deer that sometimes graze at the edge. I have been researching Alum and Gypsum to figure out what to do about the current clarity of the water. The more I research, the more questions I seem to have. So now that I have given you a good description, on to the questions.

1. What happens to the clay after it binds and falls out of the water column using one of the recommended methods for clarifying? Does it just stay there? Once bound does it harden or remain bound even with agitation over time or will the catfish eventually just stir it up again, making the whole endeavor of clarifying worthless?

2. If it doesn't bind and turn into something harder or more dense, will I have to drain the pond and dredge the clay out with a backhoe or bulldozer to fix it?

3. Is there a way to fix the problem without removing the catfish or killing them all off? I could be wrong about them being bullheads, how do I tell for sure? I thought I read somewhere that LMB and Channel cats will eat bullheads, would this include larger ones (the majority of the cats in the pond all range in size from about 10-12 inches)? Will any species of catfish in the pond be just as problematic? We have otters that come and occasionally eat the fish and I wouldnt want to chance accidentally poisoning them in the process.

4. Is there a way to filter the suspended clay particles out of the water instead of binding them, or would the cost to do so be exorbitant enough to make it not worthwhile?

5. Can I replace the grass around the pond with something shorter in height that will benefit the pond or the soil surrounding it. Mowing around the pond is problematic since three sides of the berm are too steep to mow without tipping over the mower or sliding into the pond, so that leaves weedeating which of course slings grass and weeds into the water which will just create a new problem (thats the current method being used, and we try to be careful not to get too much in the pond, but, you know what happens). Any recommendations for replacement plants instead of grass to cut down on that maintenance would be a godsend.

6. Should I plant some kind of vegetation in the pond to help with filtration and shade the water to cut down on temps and water loss due to evap? If so, are there any really good, non pervasives that you guys would recommend? I live in the Ozarks of Missouri if that helps with making a rec?

7. Should I aerate the pond, what would be the best method of doing it for a pond this size?

Any other advice or recommendations not already touched upon would also be greatly appreciated. I am a big believer in "knowledge is power", so TIA for any help.

Welcome!

So many things here, I'm not sure where to start. I can't give you specific responses to many of your questions, so I'm not going to go by the numbers, if you don't mind. Maybe if I had a similar type pond and lived closer. (Have you looked for pond and water feature clubs and organizations in your area?)

I would get a glass container, the taller the better, and pull a sample of your cloudy water out to see what it does. If it's truly silt in your water, it should settle out over time (24 hours, plus or minus a great deal depending on what's in the water) in an undisturbed, covered container. You can learn a lot about how long that takes, what the sediment layers look like after it does, and what remains in the water, and what color the water is after settling.

I would also do some water testing before adding or removing anything. You'll want to know pH and hardness for sure, but a full battery wouldn't hurt if you're thinking about investing in this pond. There should be local places that can help, and you can ask your county extension for resources.

It sounds like you've studied up on flocculants a bit, so that's good. I prefer agents that keep working over time, keeping new particles that enter the water column aggregated, to one-time solutions, but there's still some discovery needed to fully understand what is happening. You need to know pH and sediment composition before you know how things like alum and gypsum will work. Changes in pH and mineral composition are fairly permanent fixes, but lots of things can go wrong. In the ponds I've worked with, bacterial action is enough to bind particles together and clear the water, as long as everything is healthy and has enough oxygen. We have a fair bit of silt, but not much true clay, which may make a difference (see settling layers).

Oxygen can help tremendously, and everyone with a large pond around here has some kind of surface agitation. Some people just hook up a pump to a big pipe and let it shoot out over the water--new water surface area exposed to air over time is what matters, so turning over a large section of the water's surface helps. Bacteria and algae both benefit from this, and they make up the bottom of the food chain. A heavily planted pond likely won't need additional aeration.

And I would recommend some plants. Native ones, if you can figure that out (which means I can't help you much from here on the other side of the country) since non-native water vegetation that is vigorous enough to make a difference over a large pond quickly becomes problematic and invasive. Vegetation provides all the things you mentioned, but it also oxygenates and diversifies the ecosystem (for better and worse). Research is needed here, and I wish I knew more about what grows in your part of the country.

You mentioned walnut trees--I've seen trouble when walnut debris falls into the water, but if they're not overreaching they probably won't be a problem.

Really, 100 catfish in 1/2 an acre shouldn't be causing you any water problems. I don't know how accurate that number is, though. Given the size of the pond, I doubt the problem is the fish.

Hopefully some people here can give you more specifics, but I'd really start with finding out more about your sediment and your water chemistry.

Yes, I am currently doing the jar test as we speak. I plan on getting the water chemistry tested soon. So hopefully that will give me a little more insight into whats going on. The water varies in its turbidity and color season by season it seems. Right now the water sample looks about like dark urine or weak tea. I can see about 12-24" from the surface, which is better than it was a couple of weeks ago when visibility was only a few inches deep. The walnut trees are far enough from shore 10-15' that walnuts arent falling directly into the pond, but I dont think they float and some may roll into the pond from time to time. My concern with them would be the toxin that walnuts carry in the rind, and of course leaf litter in the fall.

I am getting good info doing lots of research online, was just hoping more experienced people would help offer insights to speed up the learning curve a bit. Thank you for taking the time to answer me.

I, too inherited a large stock pond. It is fed by a series of springs that created a large swamp. It hasn't been used for livestock for 35 years. It has always been murky, with a muck bottom. It had plenty of fish and a wide variety, due to the river flooding and getting in my pond. My extension agent said it's healthy, leave it alone. I left it alone. THEN, we were infested with Mosquito Fern. It grew and covered the whole pond surface; it was blood red. (stressed) Then ALL the fish in the pond died. P U Then the Fern turned green. (healthy, oh great) After the Mosquito Fern died way back, I put 5 goldfish that my grandson "won" at the fair in the pond. not a good idea. But they seemed to destroy the Fern. Now I have thousands of Goldfish in the pond, some catfish, bluegill, etc. I guess you have to decide what you want to do with your pond. We never swim in ours, so the murk doesn't matter. Fishing is a blast.