Posts Tagged ‘lake weed control’

Dredging Shallow Lakes | Lake Weed Control

Thursday, October 9th, 2008

Dredging Shallow  Lakes | Lake Weed Control


A little lake weed control pop quiz!

I hope you paid attention in class!

Lake weed control problems occur as a result of?

  • A. The invasion of exotic lake weeds.
  • B. Excessive fertility in ponds and lakes.
  • C. Lack of plankton to color the water.
  • D. Too much light penetrating to the lake bed.

If you answered “D”, you answered correctly. Congratulations! We could have added fifth, for “all of the above”, but it really would not matter. The all inclusive fact is, that without the light penetration to the bottom of a lake, weeds will not grow. No matter how fertile the water, no matter how little algae bloom, no matter what type of lake weed, native or exotic, it can not grow without light!

Water color and depth

Light penetration is determined by two things. The waters color, and depth. If the water is “dark” enough, light can not reach the bottom where weeds, and even algae get their start. If the water is deep enough, light can not reach the bottom. Both issues should be dealt with. There are always areas that will be shallow, and your fish need the food provided by the chain that starts with algae bloom, but some light can penetrate even perfectly colored water and reach the bottom in very shallow areas.

Algae bloom

It is true that algae bloom can go a long way toward decreasing that light, and thereby decreasing the growth of lake weeds, but it can not stop all of them. In shallow areas on sunny days, and in the summers when lakes lose water to evaporation, weeds may exist high enough in the water profile, to get light, and grow faster than the water is replaced. Fluctuating depth can give the weeds a start when the water is low, and then allow them to continue to grow as the water gradually rises.

Water depth

There is really only one way to prevent this problem. Make the lake deeper! This can be done by raising the water level, as in raising the height of the drain outlet or spillway, but that can put your lake at risk. We have all seen water soaked dams fall victim to erosion.

Dredging

There is another way. Dredging. Getting rid of the years of silt that are deposited in the bottom of your lake can decrease your lake weed problems. Most people know that this is an expensive, and messy exercise, but weighing it against constant chemical lake weed control treatment costs for several years may make it look a lot more appealing in the long run. Besides that, new technology is producing new types of equipment that may make it a less costly, and less messy proposition.

You might want to give dredging some consideration during these early days of the “off” season. Getting the dredging done during the late fall and early winter should have you back to normal for the spring and summer fishing fun.

That is your lake weed control test for the day. Class dismissed!

Note:

Chemical controls can be highly effective for dealing with aquatic lake weeds, but will only kill the growth present at the time. If the cause of the underlying problem is not dealt with, the weeds will return. You can count on it. Lake owners should be aware that lake maintenance like any other property maintenance is an ongoing proposition.

Managing Fertility In Ponds And Lakes

Wednesday, August 6th, 2008

Managing fertility in ponds and lakes.


The idea of fertilizing a pond seems strange to many people, but is something that may need to be done.

The reasons for adding fertilizer are pretty simple. Fish eat many types of aquatic invertebrates. These are bugs that exist in pond settings. The bugs need something to eat to get fat for the fish, and that something is algae.

Algae Bloom

The algae that serves this purpose best, is phytoplankton. This is a simple, single cell organism that grows in suspension in the water of ponds and lakes. The nice blue green tint in the water is what you are after. In fact, you want it to be dark enough that you can not see an 8 inch black and white disk at a depth 18 to 24 inches. Algae bloom has the added benefit of reducing weed populations because of the reduction in light penetration.

Fertilizer

The fertilizer you need to use, should be high in phosphorous, and low in the other two main ingredients.
When you look at the analysis of a bag of common fertilizer, you will see 3 numbers, divided by a dash. The middle number is the one you are after. There are several good products on the market for pond and lake fertilizing. and several methods of application. If a powder is used, it can be spread as evenly as possible on the surface of the water, or with an aquatic applicator which will allow it to dissolve gradually. If a liquid is used, it should be mixed with water before application, or it will sink to the bottom and be neutralized. After you have fertilized once, you should check the pond periodically for visual depth. You will need to fertilize regularly at 2 week intervals through the summer, checking the light penetration as you do. Light should not penetrate deeper than 24 inches, and should not penetrate less than 12 to 18 inches. If visibility is less than a foot, suspend fertilizing until it clears to 18 to 24 inches. Fertilizing should begin as soon as the water temperature reaches 60 degrees. I will include more information on how to construct a sechi disk, the type and amount of fertilizer, and the intervals between applications, as time permits.
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