January 2023 - Treating Our Community Lake
After years of study, the Lake Committee recommended that the Board initiate treatment of our community lake to mitigate the risks to humans, pets, and wildlife imposed by the potentially toxic algae blooms.
These harmful blooms are caused by cyanobacteria. Here is how AquaTechnex, the company that is treating blooms across the West, explains the problem:
Harmful algal blooms (known as HABs) in a lake can be a threat to wildlife, pets and human health. These forms of algae can produce both acute and chronic toxins. The acute toxins like microcystin and anatoxin are dangerous and fast-acting. There are a number of pet deaths attributed to animals drinking from an impacted lake each year. There are also compounds that are known to cause ALS [often called Lou Gehrig’s disease] and other longer term diseases produced by these algae species. Recently researchers at the University of Florida documented microcystin toxins airborne 10 miles downwind of an infested lake under light breeze conditions.
So the potential threat is not trivial and not only water contact-based, but also airborne. Risks aside, there are aesthetic benefits to treating the lake. At Kitsap Lake, a lake Aquatechnex recently treated, water clarity increased to 14 feet. Our water clarity is about 4 inches in summer to about 15 inches in winter, so we have one very sick lake.
These cyanobacteria blooms occur because the lake has become “over-enriched” with too much phosphorous—exactly what these algae need to thrive. The phosphorous comes primarily from septic system drainage throughout the hillside and around the lake. Runoff from lawn fertilizer and pet waste, if not picked up, add to the problem.
For years the lake has captured all that phosphorus and cycled it from the water into algae and then into the bottom sediments after the algae die. After decomposing on the bottom the phosphorus is released back into the water during periods of low oxygen. That phosphorous then joins new incoming phosphorous from runoff and the cyanobacteria go crazy with warming summer waters.
Treatment of the lake will commence in the spring with a product called Phoslock, which is approved by the Department of Ecology, and has been used extensively from California to Washington to improve the aesthetics and health of big to small lakes. The active ingredient in Phoslock is bentonite, which is not toxic to humans or wildlife. It simply bonds chemically to the phosphorous and then takes it to the bottom where it remains locked up, unable to re-enter the water and feed the algae.
The treatment costs are as follows: Permitting (~$1450), then in the spring 2023: nontoxic algacide initial treatment ($2900), then two Phoslock treatments spring and fall ($23,500 x 2 = $47,000). Subtotal = $51,350 + sales 8.5% tax ($4,365) = $55,715. Perc lots will be assessed $110; non-perc lots, $55. You will have an option of paying half in March and half in July, or in one lump sum in March.
We will be able to judge how long the benefits will last once we treat the lake. The Board will then be able to plan effectively for any future treatments and be better prepared to seek alternative funding. Duration depends on how much and how quickly new phosphorous is entering the lake, but re-treatment should be expected in within 2 to 5 years, perhaps longer. To extend the effectiveness of the treatment, we can all do our part by properly maintaining our septic system, reducing fertilizer use, and picking up and disposing of pet waste.
We all have unintentionally and inadvertently shared in creating this problem. So let’s reduce health risks, revitalize the lake’s aesthetic appeal, re-enable its safe use and enjoyment, perhaps stock it with game fish fishing, like we did years ago, and keep it safe for wildlife. But first we need to lock away the high levels of phosphorous that have added up over time.
Learn more about AquaTechnex and Toxic Algae Removal at https://aquatechnex.com/toxic-algae-removal/