Building a pond from scratch involves a lot of steps that you need to take. These include clearing out the soil, building a dam, and then filling the pond with fish. What if the water remains muddy and turbid, though?
A muddy pond isn’t the most aesthetically pleasing thing. Aside from that, it has the downside of not allowing enough sunlight to filter through the water. This can affect the plant life in your pond, which also adversely affects the fish population.
Many reasons could cause the water in your pond to be muddy. We’ll go over them as well as how to clear up a muddy pond in a fast and effective manner.
Water turbidity in artificial ponds could be the result of different factors. They have to do with the nature of the clay forming the bed, the environment around it, or the creatures living inside the pond.
Here are some of the reasons your pond gets muddy in detail:
Silt or clay soil makes up the beds of most ponds. Clay is made of microscopical soil particles that make it an ideal building material for dams and similar structures. That said, it also has a massive downside.
Some clay particles are so tiny that they’re lighter than water particles. As such, clay is an ideal candidate for creating a suspension with pond water.
Most clay particles clump together and sink to the bottom of the pond. However, if the ionic charge of those tiny clay particles is the same, they’ll repel each other. They’ll then remain suspended in the water, causing turbidity.
Sometimes, rainfall or high winds create waves in the pond. When waves come around, they cause the soil in the watershed around the pond to erode and fall into the body of water.
This tends to happen in ponds where there’s not enough grass to hold down the soil. Grassroots extend horizontally, making the top layer of soil more stable.
Examples of sod-forming grasses include smooth bromegrass, Kentucky bluegrass, and redtop.
Erosion can also happen in ponds dug inside a crop field, where plant material can decompose and cause heavy sedimentation.
If your pond started clear but developed a murkiness after you introduced aquatic animals, they could be causing the turbidity.
Bottom-feeding behavior can cause the clay on the pond bed to get introduced to the water, turning it muddy. Certain types of animals pose this problem, such as crawfish, aquatic insect larvae, and some fish species like buffalo fish, bullhead, and carp.
If you use your pond as a watering hole for livestock, animals wading into the water can cause muddiness. Cattle movement can also collapse some of the surrounding structures, like dams, into the pond.
Even if you don’t keep livestock, there’s a chance wild animals from nearby woods could be using your pond as a watering hole. Ducks, geese, feral pigs, and deer often wander to places with water and cause mechanical disturbance of the shoreline.
Muddy ponds aren’t only aesthetically unpleasant, they also carry some dangers that their clear counterparts don’t have, such as:
- It hides trash, broken glass, or plant material that can cause injuries to swimmers.
- It reduces sunlight penetration into the water, which compromises plant life at the bottom. This issue takes away a huge food source for marine life.
- It makes the fish in the pond taste/smell unpleasant.
- It encourages the overgrowth of toxic blue-green algae and harmful bacteria.
Clearing up a muddy pond requires you to know what the reason for the murkiness is. You can do the following test to know whether you’re contending with mechanical agitation or clay turbidity:
- Get a clear gallon jug and fill it up with the pond water.
- Let the jug sit out in an area, undisturbed, for at least a week.
- If the turbidity clears up within the week, then you’re dealing with mechanical agitation.
- In case the muddiness doesn’t clear up, then you have an issue with the clay composition that you need to take care of.
- Seed the watershed area with sod-forming grasses, like smooth bromegrass, Kentucky bluegrass, or redtop.
- Introduce predator fish, like bluegill or largemouth bass, to control the population of crawfish or other nuisance fish.
- Fence the pond area to avoid animals wading in and disturbing the water. If used as a watering hole, open a small area for the livestock to use.
- Plant trees on the upwind side of your pond for their wind-breaking action.
- Rip-rap the shoreline to maintain the watershed area.
These measures should take care of the mechanical agitators that can cause your pond to turn murky. If you do this and it doesn’t fix the problem, then you might need a chemical solution to this issue.
As we mentioned earlier, clay particles cause turbidity due to their ionic charge that repels other clay particles and keeps them suspended. If this issue is fixed, then the clay particles will coalesce and sink to the bottom under their weight.
Several chemical compounds are used for this specific purpose. Garden-grade gypsum (calcium sulfate dihydrate), or alum (a type of aluminum sulfate) are the two most common options.
Here’s how to test how much your pond needs from either compound:
- In the gallon jug full of clear water, preferably from a nearby stream or rainwater, dissolve two level teaspoons of gypsum or one teaspoon of alum.
- Fill several clear jars of equal size with turbid water from the pond, and mark each one to differentiate it.
- Take one tablespoon of the treated clear water and add it to the first jar of pond water.
- Add two tablespoons of the treated clear water to the second.
- Repeat with an increasing number of tablespoons in the other pond water jars.
- Determine the minimum amount of treated water solution you need to clear the pond water.
- Do your calculations to determine the water volume in your pond and multiply the amount of gypsum or alum slurry you need to clear the entire thing.
There’s one thing to keep in mind, though, which is the fact that some ponds will clear up and only get turbid after several years. Meanwhile, others will require the treatment to be done every rainfall season or regularly.
One indication you can use to know whether your pond will remain clear or not is to look at nearby ponds, whether natural or artificial. If they’re clear, you’re in luck! If not, then you should be prepared for repeating the process.
Learning how to clear up a muddy pond can prevent your pond from looking subpar and harboring some unknown dangers beneath the surface.
If there’s a mechanical agitator that causes turbidity, you should know how to eliminate it. In case the soil composition isn’t on your side, you should know how to treat your pond to maintain a healthy environment for your fish.
Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.
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