Lake Restoration Basics
Most people don't have the luxury of having a lake in perfect condition. In fact, most folks buy a property with an existing lake, and have to figure out how to manage it afterward. Most are not even aware that a lake needs management, but they soon learn that lakes, like lawns and landscapes do not manage themselves, and will require attention similar in financial scope to maintaining an equivalent size lawn. In other words, an acre of water costs about as much to maintain as an acre of lawn.
The similarities don't end there. If you purchase a home with a lawn that has not been adequately cared for, you will probably have to do some lawn restoration. If you purchase a property that has a lake which has not been properly maintained you will need to perform some basic lake restoration. These are only the basic elements that can be handled without major work.
There are several areas you will need to give proper attention.
The depth of the lake is very important. If the lake is too shallow lake weeds and pond algae may be a serious problem, boating and other recreational activities may also be difficult. To determine the average depth, and map out the most shallow and deepest parts, you can use a standard depth finder, and cross the lake several times from both directions to map it out. If you don't have a depth finder, you can do this the old fashioned way with a plumb line. This method involves a string with a weight on one end and knots tied every foot. Draw out a grid pattern of the lake, and follow this using the string line to "sound" the bottom, marking the depth on your map as you go. The more times you cross, the more soundings you take, the more accurate your map and depth information. Not only will this allow you to know the overall depth of the lake, it will also give you an account of how much water it holds, (important if you need to do an aquatic herbicide treatment based on parts per million) but it will show shallow spots to avoid when boating, and deeper spots which some fish prefer at certain times of the year. You can then use this information for any dredging operations you might want to do, and to improve fishing.
Increasing lake depth
There are only two ways to make a lake deeper. You can remove soil from the bottom, or you can add water. Dredging can be difficult and expensive, and raising the water level should be approached with caution. To raise the water level, you will need to make sure that the dam is adequate to handle the rising water level. If the lake is equipped with an overflow pipe to drain excess water, this pipe can be extended by the amount you want to reach. If it uses a spillway, the spillway will need to be increased in height to reach the depth you desire. This type of change borders on serious lake restoration , and may require professional assistance. Before doing anything of this nature, the dam should be inspected, and there are a few other things that should be done.
- Any bottom cleanup, like removing obstructions and rubble should be done while the water is shallow, or when the lake is drained.
- Weed problems may be easier to solve when the water is at a lower level.
- If you plan to do a fish audit, it will probably be easier to do at lower water depths.
If the lake is at the water level you desire, you should check the water for several factors.
If the pH is between 6.8 and 8.6 it should be fine. If it is below 6.8 the water is to acidic, and pH should be raised by liming.
Turbidity is the problem of soil particles suspended in the lakes water. If this is an issue, then something should be done to reduce the flow of soil particles into the lake. The most common source of this problem is bare ground in the watershed. The watershed should have vegetation, if it doesn't, you should supply it. If the problem is on someone else s property, you may need to plant a vegetative barrier between your lake and neighboring property, especially if the offending property is adjacent to the lake intake.
When light penetrates to the bottom of a lake, all sorts of undesirable characteristics can develop. Pond algae and lake weeds start at the bottom. Even if your lake is pretty deep, sunlight can reach the bottom in the shallow areas. The best means of preventing these problems is algae bloom. Algae bloom, or phytoplankton suspended in the water profile can prevent the sunlight from reaching the bottom of the lake, thereby preventing weeds an pond scum from becoming a nuisance. Phytoplankton has added benefits, it is the start of the lakes food chain, produces usable oxygen in the water, and keeps the water cooler. Algae bloom is produced by fertilization.
To know whether or not your lake should be fertilized, you should take a secchi reading. A secchi disk is an 8 inc black and white disk. If the disk is visible deeper than 24 inches, you need fertilizer. If it disappears before it reaches 18 inches, you probably have another problem, excessive fertility.
Excessive vegetation in lakes is the most common problem facing lake owners in my neck of the woods. Any serious lake restoration will involve dealing with undesirable and excessive vegetation. This can be done by mechanical means, or by the use of herbicides at the earliest possible stages as mentioned above. To prevent future infestations, the issues of water depth and fertility should be used.