Loch Lomond is a 75-acre, man-made, shallow, hypereutrophic lake constructed in 1955 by damming the southern branch of Bull Creek as part of the development of the 600-home Loch Lomond subdivision in Mundelein, IL. It is the first of a series of lakes that drain into the Upper Des Plaines River.
The lake is owned and maintained by the Loch Lomond Property Owners Association (LLPOA) and is used for aesthetic and recreational purposes – swimming, fishing, canoeing, paddle boating, kayaking and sailing (no motors are allowed on Loch Lomond).
The lake drains a subwatershed of 1439 acres, which in 1955 was largely used for agriculture, but today is a mix of residential, agricultural and commercial. The historical agricultural use and the predominantly clay soil of the area resulted in considerable runoff, siltation and phosphorous contamination of the lake. Subsequent development of the land for residential and commercial purposes caused additional siltation with the phosphorous-laden soil. The lake has lost an average of one foot of depth since 1987.
Historically the lake has experienced impaired water quality and aesthetics caused by frequent blooms of filamentous and planktonic. The blooms occur each year during the summer and early fall. The lake has also experienced cyclic, heavy growth of invasive aquatic plants (Curly-Leaf Pondweed and Eurasian Water Milfoil). While the algae and invasive macrophytes are themselves causes of impaired water quality and aesthetics and must be controlled using best management practices, they are in turn caused by the underlying problem of phosphorous contamination from resuspended silt.
In 2007, the Lake Committee of the LLPOA developed a Loch Lomond Water Quality Improvement Project to address the above issues. The proposed strategy to return Loch Lomond Lake to a state in which NPS (Non-point Source) pollution does not play a significant part in the ecology of the lake is to establish native plants as the determining factor in lake phosphate and oxygen concentrations.
Eliminating competing vegetation, replanting native plants, and maintaining lake turbidity low enough to provide sunlight sufficient for native plants to grow will accomplish this. In addition, an education component consisting of demonstration plantings, a “Lake Education Day”, storm drain labeling, newsletter articles and literature distribution will be employed to educate residents of our 600 homes in methods to stabilize the shoreline, reduce phosphorous loading, and filter run off.
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The project will further commission a study to determine the rate of siltation and the best course of action to deal with the excess phosphate in the existing silt. The first component of this strategy is to eradicate Curly-Leaved Pondweed and Eurasian Water Milfoil by the application of Fluridone at levels toxic to the exotic weeds, but not to most native vegetation nor to lake fauna.
The Lake Management will evaluate the success of the spraying each fall and adjust strategy to create an environment favorable to native plant growth, but hostile to exotic weeds. When the density of exotic weeds has been reduced to less than 10% of the lake surface, the second component of the strategy, the reintroduction of native plants, will begin. The association has determined that the following plants have the highest potential for survival in semi-turbid water: Common Arrowhead (Sagittaria latifolia), Blue Flag Iris (Iris versicolor) and Pickerel Weed (Pontederia cordata) at depths of 0-1.5 feet, and White Water Lily (Nymphaea tuberosa) at depths of 1.5 to 3 feet. Plants that can grow in semi-turbid waters have been chosen for the first planting because eradicating the exotic weeds, while providing a favorable environment for native plants, will also create a phosphate rich environment conducive to algae growth. In addition, the activities of common carp in the lake will add to the turbidity caused by algae.
Association volunteers will plant the native plants (approximately 3,300 Common Arrowhead, Blue Flag Iris, Pickerel Weed and White Water Lily plants), and fence them for protection against waterfowl, herbivores, boaters, and carp. If it is determined that additional Fluridone treatments will be needed to achieve control of the exotic species, water lily planting will be delayed until Fluridone is no longer needed. Most planting will take place within three feet of the shoreline where depths are suitable for the selected plants. Planting will continue each year until 20 to 30 % coverage of the lake bottom (15 acres) has been achieved. As plants take hold and phosphate and turbidity is stabilized, deeper water varieties of submerged native plants will be added to the planting mix.
Contact herbicides will be used where local control of exotics is required. After the eradication of exotic weeds and before native vegetation and buffer strips are sufficient to control phosphate levels, approved copper-based algaecides will be used to control algae growth, reducing turbidity and the possibility of hypoxia, while improving aesthetic quality, reducing odor and improving the environment for site-feeding fauna.
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The Lake Management Committee will evaluate the success of spraying on an ongoing basis. Buffer strips (15 –25 feet wide) will be planted, initially, along at least 230 feet of severely or moderately eroded shoreline and at one 80-foot long storm water inflow. Common Arrowhead (Sagittaria latifolia), Blue Flag Iris (Iris versicolor), and Pickerel Weed (Pontederia cordata) will comprise the in-water plants while the wet edge to dry sections of the strips will be selected from the demonstration buffer strip. Plants that can tolerate intermittent wet and dry will be selected from the demonstration buffer strip for the storm drain inflow. Carp population reduction will be achieved through aggressive fishing. In addition, a carp derby will be held during the spawning season and a bounty will be established for carp. An estimate of the carp population and reproductive capacity will be made during the next fish census, and numbers of carp removed will be tracked in subsequent years.
| Bottom-feeding fish species eradication |
Information/Education:
- Annual Lake Education Day, potentially reaching
600 residences
- Storm drain labeling (~100 drains).
- Ongoing ban of PO4-free fertilizers in subdivision;semiannual reminders to residents
- Annual residents’ meeting on lake management plans
- Monthly newsletter inserts
- Reaching 600 homes |
| Buffer strips: |
- Plant demonstration 10’X40’ buffer strip to educate residents on benefits.
- Assist residents to plant buffer strips, targeting 5% of the shoreline |
| Aquatic vegetation re-establishment: |
|
- Herbicide treatment to remove invasive exotics - Ongoing planting of
native macrophytes (goal is to achieve 20-30% coverage)
- Manage algae to reduce TSS and shading of native macrophytes, and
improve DO and aesthetics
|
| Dredging – evaluate feasibility |
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