While Solana Bay residents deal with the aftermath of this spring’s flooding, the Okanagan Basin Water Board’s harvester will begin cleaning up the bay itself.

The harvesting machine is currently being assembled at the Osoyoos Marina, and will be launched today, immediately moving to Solana Bay as a priority area,” said OBWB’s James Littey.

“We will begin by cutting a navigation channel around the perimeter of the bay and down the center of Solana Key.”

The work, he said, will occur “over the next few days,” and will require some patience from Solana Bay residents.

“I’d ask that residents not try to flag down the operator, as it will only make the whole process longer, and less will get done by disturbing him.”

He’s also asking boaters to slow down whenever they are around the harvester.

“We have flat-bottomed hulls, and [they] are very susceptible to wake and waves.”

Environmental permits allow rototilling in Solana Bay between April 1 and October 1, which is outside of the optimal time. This year, OBWB intended to rototill the bay after April 1, but because of the flooding, had to remove the machine before the operator could get into the bay.

He instead volunteered to help sandbag.

The OBWB’s three full-time harvester operators work throughout the year to control milfoil in all the major valley lakes, including Okanagan, Kalamalka, Wood, Skaha and Osoyoos.

During the winter, between October and April, OBWB rototills the lake bottom to remove the milfoil roots while the plant is dormant. Those weeds float to the surface, and die in the cold temperatures.

Rototilling reduces the overall volume of weeds in an area, and if done in consecutive years, it can temporarily eliminate milfoil. However, it also provides room for native weeds to grow back, so it only targets the invasive plants, and does not always mean a plant-free area.

OBWB is not allowed to target native plants which are beneficial to water quality and the ecosystem.

During the summer, OBWB harvests the weeds, which involves cutting the plant about 5-6 feet below the surface, and conveying it onto the machine. The load is then dumped on shore, and a truck collects the weeds and takes them to farms, gardens or orchards if requested, and in the worst case, to the landfill.

There are only two harvesting machines for all the lakes in the valley, meaning no lake gets cut more than once per summer.

Milfoil grows up to five cm per day, so if it is cut six feet down on June 20, it could reach the surface again by the end of July.

The harvester’s access to Osoyoos Lake is restricted by other factors, including:

  • when the lake freezes in the winter, OBWB has to pull the machines out before they get stuck in the ice;
  • when the lake is too high, the harvesters cannot physically fit under the highway bridge;
  • when the lake is too low, OBWB cannot physically launch or remove the machines at the marina launch;
  • any hazards in the water, such as mooring buoys, anchors, docks, barges, boats, airplanes, swimmers, etc. make the harvesters less efficient, or can even completely exclude them from an area;
  • there is a lack of feasible weed transfer sites for harvesting operations in the summer, and the nearest to Solana Bay that accommodates both the machine from the water, and the truck from land is at Legion Beach, which adds hours of transport time each day.

“As a policy we treat public beaches, parks, and boat launches as a priority,” said Mr. Littey. “The service is provided to all residents at public parks and beaches, not only to those who own lake front property, or a private dock.

“We also treat areas of the lakes that are adjacent to private property once the public areas are treated, and as time allows.”

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