SANDPOINT — The city is firming up its plan to tangle with aquatic noxious weeds at City Beach.

The City Council unanimously approved on Wednesday a three-year contract with Aquatic Weed Solutions to beat back infestations of flowering rush, curly-leaf pondweed and Eurasian milfiol in areas frequented by swimmers and boaters without using herbicides.

“This will be our seventh year of herbicide-free treatments of the beach,” Parks & Recreation Director Kim Woodruff told the council.

The contract with the Sandpoint-based company has a not-to-exceed sum of $90,000. This year’s $30,000 treatment cost is an approved budgeted expense, although treatments in subsequent fiscal years will be dependent on City Council approval, according to the terms of the contract.

The contract requires the use of diver-assisted suction harvesting and the possible use of biodegradable bottom barriers, in addition to other recommended alternative methods which don’t involve the use of herbicides.

The contractor will focus on swim areas first, with a heavy emphasis on flowering rush throughout the entire treatment area.

“Flowering rush is the most concerning,” Matt Lawrence, president of Aquatic Weed Solutions, told the council. “It basically takes over entire bays and channels.”

Flowering rush, which is believed to have migrated from Montana’s Flathead Lake via the Clark Fork River, is known for being stout, forming dense clusters and thriving in deep water.

The density of flowering rush is particularly worrisome at south beach. “It’s a concern,” said Woodruff.

Emphasis will also be placed on combating weeds at the city’s kayak launch on Sand Creek.

“That’s been getting quite cluttered,” Woodruff said.

Aquatic Weeds Solutions is also tasked with ensuring all aquatic invasive species are not within the 3-foot buffer zone of boat propellers and will clear boating lanes of sailboats to a depth of 6 feet due to those vessels’ skegs, according to the contract.

Keith Kinnaird can be reached by email at kkinnaird@bonnercountydailybee.com and follow him on Twitter @KeithDailyBee.