Floating Islands International
A diagram from Floating Islands International shows how floating islands work. They are perforated with dozens of holes that are planted with a variety of native wetland species. The plants’ roots will reach into lake as they grow, where they will take up excess nutrients, according to King County DNRP. The agency plans to install four floating islands at Hicklin Lake in White Center.

Hicklin Lake will get four “Floating Islands” to aid cleanup effort

Hicklin Lake, the polluted body of water anchoring Lakewood Park in White Center, finally received good news on Feb. 25 with King County announcing they have secured funding to bring in four “floating islands” that will be used to capture “excess nutrients in the water that lead to Hicklin Lakes’s water quality problems.”

King County’s Department of Natural Resources and Parks (DNRP) said a $50,000 grant from the Washington Department of Ecology Algae Control Program will cover the majority of an $86,000 project.

The islands will be “250 square feet in size, built of a durable polycarbonate, and anchored in place,” according to a press release.
DNRP goes on to explain:

The islands are perforated with dozens of holes that are planted with a variety of native wetland species. The plants’ roots will reach into lake as they grow, where they will take up excess nutrients.

A bio-film of microscopic organisms that forms along the bottom of the floating islands and the plant roots will also take up nutrients from the water.

King County staff will take monthly water quality samples from locations throughout the lake to test the islands’ effectiveness at absorbing pollutants for three summers.

The project is expected to start this spring and will be completed by June 2015 at a total cost of more than $86,000.

Hicklin Lake water quality has been a concern for years, with elevated levels of fecal coliform bacteria and phosphorus, as well as a history of harmful algae blooms that have posed potential health threats to people, pets and wildlife.

The lake has been treated twice with alum to reduce phosphorus levels – first in 2005 and again in 2011. It is hoped that the floating islands will prove to be effective and will help to reduce the need for alum application or types of in-lake nutrient controls.

One becomes four
Before White Center and the rest of North Highline went to the polls in November to soundly reject Burien’s annexation bid, DNRP announced plans in August to pilot a single floating island. The plan came together in great part due to pressure from Friends of Hicklin Lake and their found, Dick Thurnau, who researched the floating island concept and presented it to the county.

The single island’s future was in question before the annexation vote as it was likely the lake and park would come under Burien jurisdiction with a “yes” vote. A resounding “no” was the result, putting Hicklin back in King County’s court.

Sally Bartley Abella, a freshwater ecologist and senior engineer for DNRP, explained how the program expanded to four islands:

“The short story about how the islands grew from one to four is that I was able to procure a grant from the Washington Department of Ecology Algae Control Program using the King County funds I had available as a match for the dollars I requested in the proposal,” she said. “Ecology is also very interested in how well these islands might work, and they appreciated our proposal to do some independent monitoring both near and far from the islands over several years to check for nutrient reduction in Hicklin Lake.”

Friends of Hicklin Lake had expressed concern that a single island in the original plan would not produce clear results on the technology's effectiveness. Abella agreed that having four instead of one will provide more robust results.

“Being able to install four islands and monitor for multiple years are a big advantages in testing these systems,” she explained. “It was not clear if one island could make a difference in a short amount of time, either in water nearby or farther away. Based on the suggestion of a company who makes the structures, four should make an impact on nutrients throughout the lake. So, having four islands equally spaced around the shoreline of the lake not only gives us good replication for effectiveness near the islands, but it also gives us a reasonable chance to see if they are effective on a whole lake basis.

“It makes for a much better study, of course. But even more important, it greatly improves the odds for their being effective in dealing with the pollutant problems in Hicklin Lake,” Abella added.

Abella said DNRP is currently in the process of soliciting bids from floating island manufacturers. From there, “Our current plan is to complete the permit process with the Washington Department of Fish and Wildlife by the end of April, finalize location and design plans with KC Parks by the end of May, and have planting and installation completed by the end of July.”

Thurnau, the 86-year-old watchdog of Hicklin Lake who taught his children how to swim there back when people dared enter the water, said the recent development is “wonderful news,” although he still harbors lingering concerns over the budget for, and size of the islands based on his own conversations with Floating Island International. Thurnau said FII told him 1,000 sq. foot islands would be needed at an estimated cost of around $175,000 in total.

Abella said DNRP’s budget of $86,000 “comes down to available dollars to carry out the project,” and that the quote given to Thurnau was for islands with aerators, a more expensive model than the “passive” model DNRP will implement.

“We can afford passive islands, which the company says are also effective,” she said, also adding that the 250 sq. foot islands are consistent with King County’s plans from the beginning.

Thurnau said he is looking forward to the possibility of TAF students at the nearby Bethaday Learning Space working with DNRP scientists for school projects, and hopes the floating island technology will eventually lead to a clean Hicklin Lake the community will once again use to congregate and swim.

“That’s what we would like to see,” he said.

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