Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Old Lake Coontail Help

Its my first post and I'm needing help with one of our lakes, The lake was dammed off in about 1925 and its about 11 acres. Some old notes at the time it was built say that it was 30ft deep at the dam. Now the deepest I can find with my depth finder is 12ft. There was a valve installed that hasn't been opened in about 8 years. We used to draw the lake down in the winter for weed control, but haven't since the valve quit working, though we are in the process of replacing the valve. Also, the lake drains about 2-3 times the watershead that a like its size should and heavy rains send water rushing over the spillway for days.

The water is very clear and we have a big problem with coontail and milfoil with some FA also. We had a biologist out to shock the lake to see what kind of fish populations we had. The vegetation made it difficult to get good results. They said our coverage was close to 80% and perscribed Grass Carp at 10 per acre and spot treatment with Navigate 2-4D granular.
He said it would take 2-3yrs before we notice a dfifference and maybe 5 yrs before it cleans up from the grass carp.

There are about 70 members in my club and they are very anxious to see results. Years ago we dumped bags of fertilizer in spots where the current could wash it throughout the lake with varying results. The biologist doesn't recommend this. The Navigate works where we spread it, but at $450 per acre, and only one year per treatment, we don't feel its cost effective.

I am considering either stocking more grass carp, using lake dye, or adding an aeration system (the water that is trickling out of the old valve has a sewage smell to it which tells me the DO level must be low near the bottom).

Any advice would be appreciated

I would try pond dye at ice out in the spring or this fall, try to get your water clarity down to less than 36" if you can. Apply the dye conservatively, you do want some light penetration to feed an algae bloom. Add dye as needed later on.

Vegetation needs these three things to grow well:

1. light
2. nutrients
3. the right temperature

Take away any one of those three things and aquatic vegetation won't grow well. Reducing the amount of light the vegetation receives is a simple remedy.

Navigate does work well but it is expensive and has to be done every year, at least that is my experience. My dad's old pond also had issues with milfoil and coontail. I like clear water but it can really let the aquatic vegetation get out of control.

Are the any oak trees around the lake?

Shorty, there are a few oak trees, but mostly sycamores and maples. I also forgot to mention that some of our downstream neighbors have found grass carp in the creek after heavy rains and we've removed 3 otters from the lake in the last year and a half since we stocked the grass carp. Just wondering how many of our original 110 we lost? Thanks.

With grass carp (GC) you either too many or not enough, it is really hard to find a happy medium using grass carp for vegetation control. My dad an I added some several times but never saw the reduction in the aquatic vegetation that we thought we would. GC do like current so if you have frequent heavy overflows you are likely to lose some of them downstream if your overflow is not screened off to prevent them from escaping.

Old pond typically mean high nutrient loading. Dye will work to some extent depending on your water clarity. What is it during the early spring/summer?

Thanks esshup. The water is very clear pretty much all year. What brand or type of dye is best?

When you say that you put fertilizer where the current could carry it through the pond, does that mean that you have water flowing in and out of the pond?

Typically, the "best" dye is the one that does what you want it to do, AND fits into your budget.

Essup, yes there is a creek that feeds into the lake and the current kind of circulates around the lake. We would dump 50lb bags of fertilizer 4 or 5 at once onto a spot on a point or tip of an island that had the slight current going past it. In the summer, during dry periods there is no flow to the creek. The fertilizer turned the water a pea green color, if I remember right, to keep sunlight from penetrating to the coontail and milfoil. Thanks again for the help.

If there is inflow and outflow, then you will have to be constantly adding dye to get enough of a concentration to block sunlight. If you buy or make a secchi disk, and keep the visibility to 18"-24" you will minimize weed growth without dye if the bloom is dense enough. If you haven't done so, also check alkalinity and hardness of the water.