Last Summer I rearranged my diffusers. When I went to pull up the weighted lines some of them were hard as heck to pull up because they were entangled in some kind of submerged vegetation that was still growing. I SHOULD have gotten pics to identify, but I did not. These lines were in 8' to 12' of water. I did not think plants could grow in water that deep with ~18-24" of visibility or less. The water was no where near that deep in the past. We raised it a total of 7'. 4.5' one year and then an additional 2.5' a year or two later.

Here is my question. Could those plants that grew around the airlines survive in 10' of water or was it their "last hoorah" from all the years they were established there when water was much shallower? I know it would help to know what type of plants. If they are there this Summer I will get pics for identification.

If it's milfoil, I'm pretty sure it can grow as deep as 12 feet. I think hydrilla is capable of growing near that depth as well. Google both and see if either resemble what you pulled up. Both are considered invasive, and can overtake a pond if not managed. Before you raised your water, was it blanketing the surface?

Some of the best fishing I've ever done has been on BOWs where either was prevalent. Lots of O2, cover and cooler water in the summer, warmer water in the winter. LMB as well as SMB love to hang out in it because that's where the forage wants to be too. It's got both good and bad traits. When either mat on top, you'd think it was just solid grass, but there's tunnels all thru it underneath.

How big and deep is your Pond? Did the grass you pulled up look green and healthy or was it turning brown? There are some chemicals that will kill it but if you're restricted on how to combat it, you may need to look into a few grass carp if they're legal where you live. Chemicals will deplete the oxygen as the grass dies back so there is a measure of how big an area you can kill at one time without endangering your fish.

If I had a BOW with enough depth and surface acreage, I wouldn't mind having either but it can be a bear to control.

I can't remember it ever covering the surface, but we raised the water the first time 5 years ago so it's been a while. I was totally uneducated then and was completely focused on repairing the dam and not so much on the water.

I will say that for the last few years there is absolutely zero sign of any vegetation. If I had not pulled that stuff up with the airline I would have never even known it was there.

My place is 7-8 acres at 10,000' in the mountains. Long hard Winters and I have waged a war against fish kills every year. Excess vegetation is certainly not helping my cause. Going to be interesting to see if it is there again this year.

If you've never seen it on the surface then it probably isn't either of those. They are both very aggressive and usually start shallower from my understanding and grow VERY fast.You should have noticed them before now (unless it's somehow just getting started). I did some refreshing on both last night. Hydrilla actually can grow even deeper.

Only way to be sure is to try to pull up some more and post a pic so we can see it.