You asked, we answered! In our latest webinar, “What the Muck?”, we took a deep dive into organic sediment—how it forms, its impacts, and the best solutions for reducing it. We addressed many of your top questions, but our experts have put together this follow-up to cover the rest.

For your convenience, everything is organized by topic. If you have additional questions, don’t hesitate to CONTACT US or call 330.286.6519 to speak with one of our Lake Therapy experts. And if you missed the webinar, want to share it with a colleague or catch key insights again, you can catch the full recording anytime and get all the valuable takeaways at your convenience.

CATEGORY 1: Sediment and Muck Management 

This category includes questions about managing, reducing, or understanding muck, silt, and organic sediment in waterbodies. 

Q: A lot of residents own their stormwater ponds, but don’t have money to dredge? How can they get storage capacity back?

A: Firstly, watershed management uses indirect measures to reduce nutrient concentrations in the water bodies. To prevent excessive biomass production in the growing season would be the best way to ensure capacity. Ensuring oxygen concentrations at depth are adequate to allow aerobic digestion of the organic material but bacteria is also necessary. SchlixX Plus is a great solution.

Q: Without draining the lake, does mechanical silt removal significant amounts of silt?

A: Silt removal through dredging is the most detrimental to the water body as it can cause increase turbidity, deplete the aquatic plant seedbank and release more phosphorus into the water column, but it may be necessary depending on lake system. There are different types of mechanical silt removal but generally, water can remain in the water body whilst dredging occurs. It will depend on the sediment characteristics how much silt can be removed.

Q: What are some organic options for reducing muck?

A: It depends on your definition of organic. There are less invasive measures than others and some methods can have undesirable side effects. Naturally trying to reduce the amount of nutrients entering the water body is the most organic way to indirectly manage sludge. Products like SchlixX Plus ensure there is enough oxygen to the sediment surface allowing aerobic bacteria to more effectively break down sludge.

Q: Can you liberate detritus from dead/removed reed beds and regain water depth without mechanical extraction?

A: Yes, Oase products, SchlixX or SchlixX Plus, can help with the degradation of organic matter without removing sludge from reed beds to regain water depth. On average, SchlixX Plus has shown to reduce sludge by an average of 15 cm, or 6 in, but maximum reductions have been recorded up to 79 cm, or 31 in, reduction.

Q: How do you deal with thick oily silt?

A: If it is oily in appearance, it could be contaminated. Oase has products to help decompose and break down oil and grease in water bodies.

Q: What is the impact of suspended solids (mud) entering lakes?

A: Inorganic sediment that enters a water body decreases the water volume of a water body over time. This is a natural process but through human activity the delivery of inorganic sediments has increased which means this process happens much more quickly than it would naturally. Organic sediments can also enter our water bodies and contain nutrients which add to the siltation process through organic sludge accumulation. Other indirect solutions to help control nutrients and provide oxygen are available too.

CATEGORY 2: Nutrient Management

This category focuses on questions related to nutrients (e.g., phosphorus, nitrogen) and their management in waterbodies.

Q: How do you decrease nutrients in a pond?

A: There are several ways to reduce nutrients, some of which are discussed in the webinar. External nutrient reduction is the first priority and understanding the source of the nutrients. Regular water quality monitoring can help to determine this and what would be the most appropriate management.

Q: Can you provide some discussion on the use of lime-based products to activate benthic zone and consequent changes is nutrient availability to algae?

A: Lime-based products such as calcium carbonate (CaCO₃) can be useful particularly in acidified system where you want to increase the pH but also reduce phosphorus concentrations. It can be used in water bodies but through its mechanisms, it raises the pH and precipitates orthophosphate out of the water column towards the sediment. However, raising the pH can be detrimental to the system depending on the original pH value. Elevated pH above 8.5 can release phosphorus from aluminum complexes in the sediment and also start to cause problems to aquatic life, but also favor conditions for cyanobacteria. To activate the benthic zone, oxygen is required to promote aerobic bacteria.

Q: Is there another way to reduce phosphates, besides precipitative binding or uptake by algae or plants in fishponds?

A: Reducing external phosphorus from entering the water body should be the first priority. There are some other measures that do not involve precipitation. Alum is primarily a coagulant but also has precipitation qualities. However, alum needs to be applied with a buffer or dosing assessed on phosphate concentrations and the pH of the water body as alum can lower the pH of a water body which can have detrimental impacts. Oase products work through precipitation but also have many other benefits besides phosphate precipitation, unlike other solutions on the market, many of which only target phosphate control. If fish are regularly fed, then the bait also contains nutrients which will be adding to the nutrient load in the system. Benthic fish species will also disturb the sediment and release phosphorus into the water column, fueling algal blooms.

CATEGORY 3: Algae and Aquatic Plant Management

This category covers questions about controlling algae and managing aquatic vegetation.

Q: What is the most effective way to prevent algae?

A: There are direct and indirect solutions available to treat algae. Direct solutions will depend on the algal community present, for example cyanobacteria are more susceptible to peroxide based-solutions than green algae. Indirect solutions involve reducing the nutrients entering the water body through catchment management and controlling and preventing nutrient release from sediments. Regular water quality monitoring helps to understand what is happening in the water body and where the nutrients are most likely coming from. Appropriate management measures can then be deployed to improve the symptoms of nutrient pollution such as algal blooms.

CATEGORY 4: Water Quality and Chemistry

This category includes questions about maintaining or correcting water quality and understanding chemical interactions in waterbodies.

Q: How should you to maintain/correct water quality?

A: Regular water quality monitoring will determine changes in the water body and will give a good indication of what is causing poor water quality and to be proactive with management, if required. Best practices include preventing nutrient run-off, having a diverse aquatic plant community and a balanced trophic structure, e.g. no high amounts of benthic fish species or zooplanktivorous fish species.

Q: How great is the influence of sludge on the Gh and Kh value of the water?

A: Yes, GH can be lowered if there is a lot of sludge/organic matter in the system as organic matter can bind with Ca and Mg, lowering the Gh of the water. The decomposition of organic matter/sludge produces carbon dioxide which can lead to acidity, but CO₂ reacts with water to form carbonic acids (H₂CO₃). These carbonic acid species can dissociate into bicarbonate and hydrogen ions which can increase the Kh levels and subsequently pH can increase it but can form a bit of a buffer system and the influence of Kh is also dependent on pH.

CATEGORY 5: Ecosystem and Biodiversity

This category focuses on questions about enhancing biodiversity or supporting specific aquatic life.

Q: How do you improve copepods?

A: To improve copepods, you need to improve the water quality and promote the occurrence and biodiversity of aquatic macrophytes which provide refuge for copepods from zooplanktivorous fish. Perhaps reducing the zooplanktivorous population would help regeneration of copepods to your waterbody, if they are present. Understanding the water chemistry and fish population would help to identify what management measures would be most suitable to benefit the copepod community in your water body.

Q: How can I improve the diversity of insect life in a clay lake?

A: Understanding the water quality of the lake would help with management. Ensuring there is adequate shallower areas to allow aquatic macrophytes to establish will help with macroinvertebrate diversity. Having a mixture of submerged, emergent, marginal and floating species will encourage macroinvertebrate diversity.

Q: How can I improve the water for fish life?

A: Regular water quality monitoring will determine changes in the water body and will give a good indication of what is causing poor water quality and to be proactive with management, if required. Best practices include preventing nutrient run-off, having a diverse aquatic plant community and a balanced trophic structure, e.g. no high amounts of benthic fish species or zooplanktivorous fish species.