The recent growth of aquatic vegetation has generated many questions from affected residents and a lot of social media chatter. The Moss Committee was created at the June Board meeting as a special committee to research our water quality and vegetation issue we could see developing in several coves. Building on previously gathered professional and expert advice and counsel, as well as ongoing evaluation, the committee has developed this communication to provide additional information on the issue and an overview of action steps and plans to address it in the short and long term.
Below are answers to the most common questions and concerns expressed by the community on this topic.
- Is what we are experiencing normal?
Answer: Longtime residents say vegetation has never been this extensive, which is based on individual experience, but not necessarily accurate over time. These observations depend on how far back you go in history and where you reside on the lake. Similar overgrowth was common in the early parts of the lake’s existence and in more recent times occurred in 2016. The response was the release of 2,000 grass carp and the purchase of the weed harvester. This caused an abnormal elimination of almost all vegetation. Several coves saw overgrowth in 2025; this year, many more are affected and to a greater extent. This year’s growth remains minimal or what should be typical along about 70% of the shoreline, but eight coves have unusually dense, unexpected growth.
While seasonal aquatic plant growth is expected each summer, what is atypical is the concentration and intensity of growth in certain coves. Factors that contribute include 1) increased water clarity associated with zebra mussels, 2) elevated nutrient levels (phosphates), 3) warm and rainy weather patterns, 4) shallow waters (lack of dredging contributes), and 5) sun exposure.
Since last year’s experience, the Association has researched with professionals means for addressing vegetation with a goal of a more seasonal experience. This fix includes many tactics; however, there is no immediate fix for this season. As the plan is implemented, we will continue to monitor conditions, leverage professional guidance, and evaluate adjustments to the plan based on effectiveness and environmental considerations.
- What exactly are we seeing?
Answer: Current observations indicate the vegetation includes: Southern Naiad (native submerged aquatic plant), Coon tail (a floating bushy plant), Duckweed (floating plant with tiny leaves), and Filamentous Green Algae (floating green mats), but current observations do not indicate Blue-green algae blooms (Cyanobacteria).
- Is the water safe? Has the association had professional engineers or biological advisors evaluate or test the water?
Answer: None of the vegetation observed qualitatively by the biologists from Allstate Consultants, DNR, and the Missouri Extension Office is harmful; however, irritation can always occur for those with sensitivities. Lakes are not pools and conditions can always change. We have tested nutrient levels (which are 3-4x the normal for phosphorus) but have not had cause to test for blue-green algae. We are working to develop a policy to test for blue-green algae should it be observed (appears like blue-green oil-paint, but can be easily confused with harmless duckweed).
- What caused this?
Answer: Several contributing factors include:
- Heavy spring and summer rainfall causing nutrient-rich runoff from upstream watersheds and farmland, elevating nutrient levels 3-4x normal for phosphorus levels
- Embedded phosphates in our silt accumulated over long periods with no dredging activity.
- Shallower water in coves (10’ or less)
- Warm air and water temperatures and sunlight.
- Zebra mussels increasing water clarity allows for more sunlight to reach the lake bottom.
- Waterfowl that bring in native aquatic plants from other lakes
A complex combination of these factors all contributed to the problem. Most experts agree that overgrowth of aquatic vegetation typically results from multiple environmental factors occurring together. This is well documented in US lakes.
- Are zebra mussels making this worse?
Answer: Yes, because zebra mussels filter suspended particles from the water, they can increase water clarity. Increased sunlight penetration may allow aquatic plants to grow in deeper water than previously possible. Red ear perch have been added in the last two years to eat the larvae of the zebra mussels and decrease the population.
- Can anything be done immediately?
Answer: Mechanical and manual removal are options, but temporary as the vegetation grows quickly in these conditions. Removal can also make the problem worse as Naiad reseeds from fragments caused by raking and boat activity.
- We are deploying a mechanical weed harvester owned by the HOA. This is a temporary fix and has limited impact. The harvester is operational, but experiencing mechanical issues because of age and design. A plan is in place to improve for this year and future year use.
- Efforts to pilot a third-party option for augmenting our own operations when we have excessive vegetation is underway over the next few weeks. Since mechanical and manual removal options are temporary with minimal impact, the pilot program will evaluate effectiveness and costs. Removal between docks will not be an option at this point. Any weeds removed with contracted or HOA-owned machines will be removed from the Parkway by the HOA.
- Removing vegetation around individual docks by raking or with raking services offered by local providers is an option for homeowners. However, manual removal of the vegetation can propagate plant growth.
- Can anything be done to prevent this in the long-term?
Answer: A long-term plan is being implemented to bring the lake back to an environmental balance, as well as look at short-term, temporary options to support the recreational use of the lake in our shallower water areas.
- A fish stocking program including Grass Carp and Red Ear Sunfish has been developed; stocking typically takes place in the fall.
- Execute the current dredging plan to reduce silt buildup, including adding funding to speed up the projects.
- Execute our evolving watershed plan to manage water runoff, including adding funding to speed up the projects.
- Providing supplemental weed harvesting in limited areas as needed
- Monitoring water quality and nutrients as part of dredging operations to guide decisions around options like Phosphate Bonding techniques; a pilot will be done this year.
Sterile Grass Carp are an effective non‑chemical vegetation management tool. Fish stocking must be carefully monitored to avoid overstocking. Maintaining an appropriate number is essential for long‑term control, which requires adding fish in stages so younger carp replace those aging out. The lake shifted from being overstocked in 2016 to understocked over the past decade. With 450 carp added this past year, additional stocking is planned for fall and spring, followed by an annual stocking program based on observed lake conditions. Why Sterile? Grass Carp are an invasive species that, if able to reproduce, would wipe out our fishery and create imbalance, especially with the Redear Sunfish key to managing Zebra Mussels.
Dredging is an important part of the plan. Over the last 3 years, we have been developing and executing a long-term dredging plan (this includes the design and preparation of silt basins for silt removal). Dredging takes nutrient-heavy silt out of the lake with the added benefit of deeper water. The deeper water doesn’t allow sun to get to the bottom and improves overall recreational use of the lake.
Watershed Management is a critical part of the long-term plan. The Association recently completed a full engineering study of the watershed that supports planning for silt mitigation and addressing nutrient-rich runoff. Areas like lake drainage inlets are being overhauled to slow water flow and allow silt to drop out before the lake. Not a 100% solution, but every piece of the puzzle is needed.
A lot of the watershed we do not own or control, so our plan includes working with owners/managers to build catch basins and ditch checks to improve all aspects of the watershed.
Education is key, especially when it comes to homeowners fertilizing their properties. There are non-phosphate alternatives that we would like members to consider switching to.
Also, chemical herbicides on lawns and sprayed directly into the lake are harmful to the fishery and make it hard to keep the ecosystem balanced. Limiting the use and never applying in the lake itself are key to a successful long-term plan.
- Why are some coves much worse than others?
Answer: Current observations indicate that several coves have experienced significantly heavier vegetation than most of the lake, including Waterfall, Quantrill’s, Union, Big Rock, Sunrise, Sunset (not an exhaustive list), and other shallow areas in coves and around docks. Why? Sunlight penetrates deeper water to the bottom of the lake, allowing vegetation to grow in nutrient-rich sediment/silt. Runoff from farm fields contributes a significant amount of nutrients into the lake. Yard fertilization may also contribute, but it is unknown how much. Shallow water and silty bottoms provide the seeding ground for vegetation. Commonalities of these coves? Shallow with less traffic and water current outside of rain events, more runoff than the main body of the lake, full sun exposure. Conditions also change, and the situation is dynamic.
In contrast, deeper, rocky, east- and north-facing lakeshore areas are experiencing very limited weed growth. Some areas of the main channel that are exposed to extended sunlight (south and west facing) and prevailing winds are experiencing growth between docks and float-in issues. Any shallow area with little water movement will be the heaviest impacted.
- Are there treatments that won’t harm fish?
Answer: We have looked at all options and are biased toward non-chemical options. Local or individual use of any chemicals in the lake is strictly prohibited. Why? Treatment of the lake with any chemicals or herbicides requires professional management by environmental specialists and has limited success in big bodies of water. An option suggested by the Allstate Consultants biologist for future years (not this year) is the use of professionally managed spot-treatment combined with mechanical removal as a contingency plan for addressing overgrowth in the worst areas. Adding more grass carp is still recommended as the preferred solution by everyone, including other area lake operators.
- Can residents install weed barriers around docks?
Answer: Currently, weed barriers around docks are not permitted. The Association, over the off-season, will investigate whether this could be a manageable option. The anticipated challenge is placing large underwater foreign objects in the water where docks are close together, and the fact that leaving materials in the lake over time can degrade or be forgotten, which can cause significant issues for dredging operations.
- Should we look at what other lakes are doing?
Answer: Members of the Executive Team and Staff have established regular meetings with other lake associations. While the experience in discussing common challenges is interesting and informational, Lotawana is unique in size and issues. At this point, we are not aware of other lakes in the area experiencing the same issue. Some are using Grass Carp or spent millions of dollars in aeration projects. Lakes not yet contaminated with Zebra Mussels have established robust controls over boats coming and going from their lakes. Zebra mussels are probably the one differential that makes our lake unique compared to others.
Also, a lot of the lakes are in watersheds primarily composed of residential vs. farmland or have different drainage structures like retention basins (Winnebago). We will continue to connect with other lake associations and lake management professionals to ensure we are optimizing our plan and minimizing future vegetation blooms.
Summary
This year’s vegetation explosion was difficult to predict. Last year there were issues in a few coves, but this year we have experienced the “Perfect Storm” of warm, wet weather, clear water, nutrient-rich runoff, sun, and an aging grass carp population. The HOA Board (all residents) and other resident volunteers are committed to addressing the problem, leveraging expert opinions, as we are all homeowners and all affected by this issue.
Since the lake is the most important community asset and resource for recreational use, we want to be transparent through communication tools we have, but need your support in spreading the word to all members.
The board is developing an Environmental Policy and associated process and planning tools that can be leveraged long-term by future leadership and staff to protect our lake and individual investments. Key tenets being discussed as we create the policy:
- Balance the overall lake environment.
- Water quality defined and managed.
- Safe recreational and sporting access
- Long-term management strategies
- Contingency plans for short-term issues
- Financial planning for capital projects and yearly operations
The Association will provide updates to keep you informed through the Association Communication avenues. We highly recommend regular reading of the Lotawana News as the primary source, along with future documentation to be posted on the website.