Ponds & Streams
Now that spring is here, it is time to control the weed issues you may have experienced last year. Vegetation is not a bad thing in ponds. Aquatic plants add necessary food and oxygen to the aquatic life that reside in your pond. Some of the good weeds are under the water’s surface and are not a visual issue. It is the vegetation on top of the pond’s water that can cause so much anguish. The first issue to typically appear (and the one that frustrates pond owners the most) is not a weed at all, it is Filamentous algae.
Filamentous algae is a fibrous mat that looks ugly when floating on the pond’s surface and seems to appear overnight. This alga starts its growth cycle on the pond’s bottom. As it grows, it builds oxygen under its fibrous mat. Once buoyant it floats up to the surface. At first, a couple mats will appear and within a few days, the entire pond surface can be covered. It looks bad and if you use your pond for swimming, it is gross to walk/wade through. Fishing can become annoying when the algae snags on the fishing line and hook each time you reel in the line. A little bit of this menace can lead to some major headaches. Left unchecked, it can explode into a real issue that is bad for the pond.
Of course, the next question is, “How do I kill it?” The time to treat for Filamentous algae is when it is growing on the bottom of the pond. Once it floats to the surface, it is too late to treat as it is already dying. Filamentous algae is controllable with some effort. Management needs to be a multi-front approach including mechanical, chemical, biological, and structural control strategies to reduce and rid the pond of this unwelcome guest.
Once the algae floats to the surface there is no sense to treat it with chemical as it is already dying. The best strategy is to mechanically remove it with a rake by pulling it out of the water and away from the pond. You can also drag a rake on the pond bottom, close to shore, to break up the mats making them come to the surface quicker to remove them from the pond. The best time to do mechanical removal is on a windy day as mother nature will help you by blowing the floating algae to one area, making for easier removal. Do not leave the removed mats on the pond bank. As it dies, the nutrients flow back into the pond aiding to the next cycle of growth.
Many copper-based chemicals work very well on filamentous algae. Again, once it comes to the surface it is a waste of money to treat then. Chemical application works best after physical removal of mats, both floating and on the pond bottom. Following this order will require lower volumes of costly chemicals and lessens the potential of killing fish. When treating a pond with any chemical only treat a quarter of the pond at once. If you treat and kill all the plants at the same time, you can create a very low dissolved oxygen zone in the water. It takes large volumes of dissolved oxygen to break down the now dying or dead organic matter. Robbing the water of its dissolved oxygen starves the fish of oxygen and can lead to their death.
Biological and Structural Strategies
This is the hardest one to work on as it often means changing what is happening on the land around the pond. Adding more White Amur fish (biological) is not the answer. They eat bottom rooted pond plants, not algae. If runoff from the landscape runs into the pond this can be a source of nutrient loading. If you do not stop the source of nutrients getting into the pond, then it will be hard to get ahead of the algae. Reducing the pathway (structural) of nutrients getting into the pond will help greatly.
One thing that helps all ponds is the use of an aerator to add oxygen to the water column. Especially in ponds that are trying to breakdown organic material that robs oxygen from fish. Two types exist; the best method is a bottom bubbler (called a diffuser) that forces air from the pond bottom up to the surface with a series of fine bubbles. The other is a fountain. Although they look nice, they do not do as good of a job getting the oxygen back into the water column. Wind and fresh water flowing into the pond will also add a little oxygen, but if the incoming water is laden with nutrients, then it is just adding to the weed and algae growth.
Lastly, keep the Canada Geese off your pond. They are neat to look at, but they are dirty, annoying, and just a couple can really throw off the water quality (especially in small ponds). Their manure, which they deposit at the ponds edge, (where you walk) is very high in phosphorus. Soluble phosphorus is the nutrient that best grows algae. A mature goose at 14 pounds of weight defecates more than 28 times a day, depositing 2 pounds of high nutrient goose droppings. Plus, if you let two geese take up residence, the next year you will have more, as many of the offspring will stay.
Now is the time to start developing your plan of attack or treatment plan for your pond. Be realistic in that if you want no weeds, you will need to build a cement pool, which you will have to treat to keep the algae out of too.
Information found from this article (Spring Pond Management) on the OSU Extension website. Click here for the full article.
Most pond owners would probably agree that having clear water adds to the aesthetics of their pond. The clarity of pond water is primarily influenced by the abundance of microscopic plants (phytoplankton), animals (zooplankton), and suspended soil particles. Phytoplankton and zooplankton abundance will influence the water clarity to varying degrees depending primarily upon the time of year, time of day, and fertility of the pond. Generally, these tiny plants and animals do not influence water clarity as significantly as suspended soil particles.
Muddy water is the result of tiny soil or clay particles suspended in the water. Muddy water can have negative effects other than detracting from the aesthetics of the pond. Muddy water can hinder the feeding ability of largemouth bass, bluegills, and redear sunfish and even reduce their growth. Additionally, phytoplankton growth and abundance is reduced in muddy water. This may compound the problem of poor fish growth in muddy ponds by reducing the amount of food available through the entire food chain.
The first step in correcting a persistent problem with muddy water is to determine the cause. To do this, collect a jar full of pond water, cover it with a lid, and allow it to sit undisturbed for one week. If the water appears clear after one week and sediment is noticed at the bottom of the jar, chances are that something in the pond is stirring up the sediments. However, if the water is still cloudy, then there is a good chance that suspended particles of clay soil are the cause of the muddy water.
The problem may also be a combination of disturbed sediments and the presence of clay soils in the watershed. If disturbed sediments are determined to be the problem, one or more of the following suggestions may help remedy the situation:
Remove undesirable rough fish from your pond. Bullheads and common carp have a habit of rooting around in pond sediment while feeding. Channel catfish may also cause the same problem.
Fence livestock away from the pond and avoid pasturing them on the pond’s watershed. Livestock trample and compact pond banks, causing them to erode.
Establish moderate vegetative growth of rushes, sedges, and cattails to protect pond banks and shoreline areas from wave erosion.
Keep domestic ducks and geese away from the pond. Their feeding activity may destroy shoreline vegetation and resuspend soil particles from the pond bottom.
Maintain good vegetative cover throughout the watershed. If you do not have ownership of the entire watershed, then establish buffer strips of vegetation around the pond.
Plant windbreaks to prevent wind from causing excessive wave action and disturbing sediment in shallow water.
These suggestions offer the best long-term protection against muddy pond water. It is much easier and cost effective to prevent soil particles from eroding into a pond than it is to remove them once they become a problem. If the previous methods prove unsuccessful, it is likely that the muddy water problems are caused by colloidal clay particles that stay in suspension for a long time. Since colloidal clay particles do not settle out easily, other techniques are necessary to improve water clarity. Several techniques are effective at removing colloidal clays from pond water. Each technique requires the addition of various materials to the pond that cause clay particles to settle out. These additives include organic matter (hay), aluminum sulfate (alum), calcium sulfate (agricultural gypsum), and hydrated lime. Each of them work through a chemical reaction that causes suspended clay particles to clump together. These clumps of particles are heavier than individual articles and therefore sink rather than stay suspended. Most of these additives can be purchased from local agricultural supply stores.
ODNR Division of Wildlife - Ohio Pond Management HandbookChapter 6: Page 33