CLEARLAKE OAKS >> The Keys cleanup of algae, primrose, azolla and other problematic plant life clogging Clear Lake and its channels, all the while blocking sunlight from penetrating the lake surface, is gaining some ground yet has a way to go.
Donna Mackiewicz, treasurer of the Clearlake Oaks Property Owners Association offered her testimony of initiatives under way to make progress on other vegetation mitigation. Mackiewicz noted the POA has 832 parcels with access to the waters of Clear Lake. She is also a frequent contributor to the municipal advisory council East Region Town Hall at Moose Lodge each month and invites input to POA activities on their webpage at: www.keyspoa.com.
Clear Lake is a naturally eutrophic lake, informs Mackiewicz. "Eutrophic lakes are nutrient rich and very productive, supporting the growth of algae and aquatic plants (macrophytes)," she said. "Being a highly eutrophic lake it is very alive, so we have vegetation (native and invasive) and all the science that goes along with the water column." Big Valley Band of Pomo Indians has a great webpage, she notes. They monitor water quality around the lake and their data on Cyanotoxins is a very valuable resource.
Mackwiewicz also cautions that in warmer months all those around the lake experience harmful algal blooms with high cyanobacteria concentrations. "Cyanobacteria or blue-green algae are bacteria capable of photosynthesis - creating their own energy from the sun," Mackiewicz said. "These organisms occur naturally in surface water such as lakes, ponds, rivers and streams; and when conditions are right (excess nutrients, warm temperatures, and sunshine) they can rapidly form blooms of harmful algal blooms characterized by the presence of toxins produced by the bacteria."
Angela DePalma Dow, County of Lake Water Resources Invasive Species Coordinator takes monthly grab samples as part of Clear Lake Ambient Sampling, in which she grabs water from surface and the bottom – she sends this for testing for algae and cyanotoxins.
There are beneficial aquatic plants that help combat the harmful elements including: tules which play a crucial role in freshwater marsh ecosystems, Coontail and Sago Pondweed, Mackiewicz also noted. "But as temperatures rise so does our plant life, such as we are seeing in the Marina Village channel at Highway 20/Keys," she said. "Azolla spreads really fast in the warming temperatures and can be a problem for boaters, clogging engines. The plant covers the surface area blocking out sunlight just as the invasive creeping water primrose does."
Yet she cautions a homeowner that wants to remove aquatic vegetation should apply for a Lake County Water Resources permit. A permit can be for hand pulling, mechanical, like a harvester or herbicide treatments by the State approved, license applicators only. If residents intend to have aquatic herbicides/algaecides applied to Clear Lake for aquatic plant management in 2024, the State Water Resources Control Board is permitting this activity through Water Quality Order No. 2013-0002-DWQ General Permit No. CAG990005, Mackiewicz advised.
The Board of Supervisors approved a contract with Clean Lake, Inc. for aquatic vegetation management around the lake for $262,500 earlier this month, on the consent agenda Item 3.16.
During the 2022-2023 season, the nuisance aquatic plants most commonly found and controlled in Clear Lake include but are not limited to: native sago pondweed, invasive curly leaf pondweed, invasive creeping water primrose, native coontail , native pacific and mosquito fern.
"The bottom line is, for Keys homeowners right now is the harvester can't be used to remove the azolla (through harvesting), but it can be used to push it around, create a path," she added. "Also, individuals can scoop it with nets, from shore, docks, boats, or the harvester. It's native, so drying it out and using it as compost is just fine, as long as it's not moved around to other water bodies."
Another problem in the Keys is the invasive Mute Swans. "They pull out large swaths of tules as they feed on plants. They consume up to 8 pounds a day and we have 3 adults and 4 cygnets," Machiewicz said. "The Blue Ribbon Committee for the Rehabilitation of Clear Lake awarded a grant that will hopefully get the swans and other invasive species like carp and goldfish under control. This year we have spent $17K and the year before when the primrose was really out of control, we hired a company and paid close to $5,000 in county fees."
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