Common Lake and Pond Problems — and What To Do!
Lakes and ponds are complex ecosystems that require monitoring and care to stay healthy. Whether you use your lake or pond for recreation, as a home for fish or as an attractive addition to your property, there are several issues you probably encounter with its maintenance.
In this article, we look at some common pond problems — some that can be avoided or corrected, others that require professional intervention. Read on to learn how to solve your common lake and pond problems.
Part One: All About Algae
Algae blooms are one of the most common problems encountered by lake and pond owners. More than just aesthetically unappealing, certain forms of algae may harbor toxins. In many cases, algae can be controlled without a dramatic intervention. The first step in determining how to proceed, however, is to correctly identify the problem.
Why Is My Pond Water Green?
Sudden changes in the color of your lake’s water can almost always be attributed to algae blooms. The term algae encompasses a diverse group of organisms, but pond and lake owners typically differentiate between three main types. Each type has distinct physical characteristics:
- Filamentous algae — Filamentous algae is a common occurrence in ponds and lakes. Also known as pond scum, filamentous algae is typically green in color and prone to grow excessively when nutrients such as phosphorous and nitrogen are abundant. Specific types of filamentous algae include Spirogyra, which is easily identified by its bright green color and slimy feel, Cladophora, which is also usually green but cottony to the touch, and Pithophora, which has a coarse texture reminiscent of horsehair. Control methods for each variety of filamentous algae are similar. An experienced aquatic management professional can help you identify which species are present in your lake or pond and suggest an appropriate remediation strategy.
- Planktonic algae — All lakes have some level of planktonic algae under the surface. At normal levels, they will not be visible or harmful to overall aquatic health or water quality. However, when algae levels are elevated, they can quickly cause an unsightly nuisance bloom that disrupts the pond’s ecosystem. These blooms are typically caused by a combination of a certain water temperature and nutrient level. A heavy planktonic bloom will give a pond or lake that “pea soup” appearance or may look similar to a layer of green or greenish-blue paint being spilled on the surface of the water.
- Macrophytic algae — Macrophytic algae are complex, multi-celled organisms with a plant-like appearance. Also known as chara, muskweed and stonewort, macrophytic algae are plant-like in appearance, with clearly identifiable stems and leaves. They grow on the bottom of ponds and can become covered in calcium, giving them a gritty, crusty feeling. At normal levels, macrophytic algae are important components of a pond’s ecosystem, providing food and shelter for a variety of fish. However, excessive growth can cause problems. Because they are so unique from other forms of algae, chara require different types of control. Mechanical removal or treatment with an algaecide are common interventions.
What Are Blue Green Algae?
Blue green algae also know as cyanobacteria are microscopic or planktonic algae. They can contain microcystin and other toxins, which are potentially hazardous and can contaminate lake and pond water. Algal toxins are naturally stored in the algae cells and may or may not be produced by a cell. Effects of exposure to cyanobacteria and their toxins can range from mild skin irritation to potential liver or nervous system damage. Needless to say, cyanobacteria can also be harmful to fish populations and other inhabitants of your pond, as well as any livestock or pets that regularly drink from it.
Despite the name, blue green algae blooms can occur in a number of different colors, including green, grey, red and brown. Heavy algae blooms will often have a strong, unpleasant smell. To determine whether or not toxins are present in a bloom, the water must be sent to a lab for analysis. Once confirmed, fast, professional toxic pond algae control is critical. Several methods of dealing with blooms are available — choosing the right one will depend on the extent of your problem, the size of your lake or pond, and the amount of time and money you’re willing to devote to remediation.
How to Get Rid of Algae
Whether you’re dealing with an outbreak of harmful cyanobacteria or simply want to make your lake or pond a more attractive place to swim, there are multiple methods for handling algae problems. Typically, these can include:
- Mechanical intervention — Mechanical methods of algae control include removing blooms with a rake, seine, screen or other tool. While useful for quickly remediating harmful or invasive growths, mechanical controls do not address the underlying conditions that caused the problem. To address the underlying conditions, they must be used in conjunction with other methods.
- Physical intervention — Some lakes and ponds are more prone to algae growth than others — factors such as aeration, light and nutrient content all affect whether or not algae will bloom. Adding an aerator or making other changes that promote positive physical characteristics is one method of preventing algae outbreaks.
- Biological intervention — Ponds and lakes are complex ecosystems. Under ideal conditions, they will attain a balance in which invasive algae growth is kept to a minimum. In some situations, filter fish such as Tilapia are used to help reduce planktonic algae and maintain such a balance.
- Material intervention — One of the most common methods utilized for controlling noxious algal blooms is with the use of algaecides. When utilized by a professional, algaecides can provide safe and effective management of harmful algae blooms. Out of balance populations of algae can be quickly brought under control when applications are conducted in a timely manner and under appropriate environmental conditions. Fish populations can benefit as well from improved spawning habitat and increased access to forage.
Algae are not the only nuisance plant that can grow in a lake or pond. Methods of control for plants such as fanwort, hydrilla and other pondweeds are similar to that of algae. To determine the best type of intervention for your lake or pond, contact AEC to book a consultation with our team of weed management experts.
Part Two: Managing Fish Populations
A healthy lake or large pond should have a well-stocked, self-sustaining fish population. Fish kills are one of the clearest signs your lake requires intervention. However, it can be difficult to pinpoint exactly what caused the incident and what needs to be remediated. While any pond will experience some natural deaths each year, excessive depletion of the fish population can typically be traced back to one of a few causes.
Low Oxygen Levels
Most fish require dissolved oxygen levels of at least 1 mg/l, though levels should be maintained at 4 mg/l or higher for optimal health (and to avoid stress-related diseases). When levels dip below 1 mg/L, even for a few hours, it can result in rapid population collapse. For this reason, monitoring dissolved oxygen levels is one of the key components of lake and pond maintenance. There are several reasons why oxygen content may drop suddenly, including:
- Planktonic algae blooms — Large, thick blooms of planktonic algae can quickly lead to oxygen loss. Oxygen is high during the daytime hours, but quickly reverses at night and if a bloom is severe enough and suddenly “dies off”, the oxygen can drop to levels that will kill fish.
- Overabundant vegetation — Similarly, an overabundance of aquatic flora can have the same negative effects on lakes or ponds as a large algae bloom. By disrupting the delicate balance of oxygen production, nuisance plants put fish populations at risk.
- Bacterial growth — When plants die, they release nutrients into the water that bacteria use as food. When bacteria populations grow rapidly, they deplete oxygen and put fish at risk. One of the persistent challenges of lake and pond management is ensuring remediation efforts don’t drastically upset the existing balance of an aquatic ecosystem. When it comes to the health of your lake, professional assistance can mean the difference between successfully getting rid of nuisance plants and causing harmful bacterial growth.
- Pond turnover — Pond turnover is common in areas prone to seasonal temperature fluctuation. During the summer, lakes stratify. Colder, dense water stays on the bottom and warmer, less dense water stays on the top. The cooler bottom water is where decomposition processes take place which uses up oxygen. So the bottom waters become void of oxygen. As the temperatures change in Spring and Fall, the water will “turn over” naturally which usually will not cause a problem. With a heavy thunderstorm or natural occurrence, the process can happen faster or sooner and the oxygen depleted bottom water mixes with the upper water causing a fish kill. Installing a diffused aeration system is one way to prevent dangerous conditions from developing.
Other Causes of Fish Kill
Lack of dissolved oxygen isn’t the only reason a fish population can die off suddenly. Bacteria and parasites can cause fish kill. Other culprits may include disease, sewage runoff, high salinity caused by excess rain and more. Remember, a lake is a complex system that must maintain a delicate balance. Introducing any dramatic or rapid change to the environment can have detrimental impacts on the survival and health of the organisms.
Keeping Fish Healthy
If your lake or pond is designated for sport fishing, it’s not enough that your fish are merely surviving. To ensure a healthy fish population, it’s essential to understand your pond’s carrying capacity. A fertile pond can be expected to support a harvest of up to 160 pounds of forage fish (bluegill or redear sunfish) and 40 pounds of predator fish (bass) per surface acre each year.
One commonly cited rule of thumb is that for every pound of bass, 3-5 pounds of forage fish should be present in the pond. At numbers higher than this, fish populations will fail to thrive under increased competition, leading to an unbalanced fishery.
Several methods are available for monitoring the balance and overall health of fish in a lake or pond. Seining can provide important insights when conducted between August and September, after the annual spawning has occurred:
- A healthy population will consist mostly of recently hatched bluegill, with some intermediate bluegill and fingerling bass.
- Bluegill overcrowding is indicated by a catch consisting mostly of intermediate bluegill between 3-5 inches, with some small fingerling bass.
- Bass overcrowding is indicated by a catch of an overabundance of fingerling bass or bass that are all 12-14 inches, along with some intermediate bluegill and little or no young forage fish.
- A lack of game fish along with significant numbers of carp, tadpole, shad or other unwanted populations indicates a serious problem, likely requiring restocking or other drastic intervention.
Lakes or ponds that have been successfully stocked for two years or more can be monitored simply by keeping a record of catch data — including fish weight and length. A healthy pond will produce a mix of bass and bluegill of various sizes. A catch that consists predominantly of smaller bass or small bluegill will likely indicate overcrowding of either species.
If you begin to suspect the fish population of your pond is becoming unbalanced, it may be necessary to stock additional bass or restrict fishing of forage species. To discuss your options with a lake management professional, contact AEC today.
Part Three: Other Water Quality Issues
Of course, there’s more to maintaining a functional lake or pond than algae and fish. Just as there are many reasons for having a pond in the first place, there are other factors that can affect your enjoyment without necessarily compromising its sustainability as an ecosystem. At AEC, clients frequently come to us with a variety of questions, including:
Is my pond safe for swimming, fishing and other recreation?
The most commonly used measure of freshwater quality is its level of the bacteria E. coli. Originating from human and animal waste, E. coli’s presence is not necessarily harmful to humans, though certain strains can cause gastroenteritis and other diseases. More importantly, E. coli levels in excess of 235 colony forming units (cfu) per 100 milliliters of water typically indicate that other disease-causing germs are present.
Other factors that can pose a risk to swimmers include hidden objects, such as under-the-surface rocks and trees. Never dive in an area you’re not familiar with and always have a buddy with you when you swim. Also, as mentioned previously, blue-green algae blooms are of concern to water users.
Why is my pond water muddy or turbid?
Muddy pond water isn’t necessarily bad, though excessive turbidity can disrupt the photosynthesis cycle. For many lake owners, however, muddy water is simply unattractive. Common causes of turbidity can include electrically charged clay particles that become suspended in the water. Excessive winds and carp or koi species can also prevent sediment from settling.
Watershed erosion is another major concern, as runoff can introduce additional dirt and waste into a lake or pond. Each of these different causes demands a different remediation approach. Before attacking the problem, it’s essential to determine its root cause. For assistance, contact a lake and pond professional at AEC today.
How many cattails should I have in my pond?
Cattails, bulrushes and other plants in the typha genus are a common sight in almost any lake or pond. In small amounts, they can provide a useful habitat for fish and other wildlife. However, cattail populations can spread quickly, creating an eyesore many pond owners would rather avoid. As a general rule, cattails should be limited to no more than 10% of the shoreline area. This will provide ample space for fish and fauna while discouraging the plant’s further spread. Excessive cattail growths can be controlled by mechanical intervention or through the use of other products. AEC can help you develop a remediation strategy that’s best-suited to your pond.
Managing a lake or pond is a complex topic and ultimately no single article can sum up everything you need to know to do it properly. That’s why it’s important to have a pond management expert you can trust. At AEC, our team has more than 100 combined years of experience managing lakes and ponds of all sizes. We can assist with algae control, fish population monitoring and more. To find out how we can help you, call today and book your consultation with our team.