Aquatic invasive species such as Eurasian water milfoil and zebra mussels are among the biggest environmental threats facing Whitefish Lake, a local water monitor told the Whitefish Chamber of Commerce on Wednesday.

The Chamber hosted its annual “State of the Lake” program to look at areas of concern about the quality of Whitefish Lake.

Mike Koopal, director of Whitefish Lake Institute, said he’d give the lake a B grade when asked by an audience member to rank water quality. The lake is clean and “very pristine,” he said, but compared to its historical past, there’s evidence of some degradation.

A study completed last March by the Institute, which monitors water quality in Whitefish Lake, showed three confirmed areas of septic leachate contamination, including City Beach Bay, Viking Creek and the Lazy Bay area. Two areas with a high potential for such contamination included Lazy Channel and the Dog Bay area.

Septic leachate is the liquid that remains after wastewater drains through septic solids.

“Septic systems aren’t intended to last forever,” Koopal said, pointing to the need for a program to create incentives for property owners around the lake to tie into the municipal sewer system wherever possible.

Results of the study prompted the Whitefish City Council to establish the Whitefish Community Wastewater Committee last July to make recommendations to the council on wastewater management, septic systems and wastewater conveyance issues.

Pharmaceuticals in the water is another “emerging” issue, Koopal said.

The cumulative effect of sediment and nutrient loading in Whitefish Lake is clearly evident along the shoreline, he said. Rocks that used to be free of any residue now are covered with slimy muck.

Aquatic invasive species are high up on the Institute’s watch list.

Zebra mussels have the ability to colonize shore areas such as Whitefish’s beloved City Beach, and their sharp shells would make it difficult to walk in the water without water shoes. Koopal said zebra mussels, if introduced to Whitefish Lake, also would have the potential to clog the city’s water intake pipe — and that could be an expensive fix.

Eurasian water milfoil is a problem in Beaver Lake, and its proximity to Whitefish Lake is a concern for the Institute.

“Milfoil can sluff off and repopulate,” Koopal said, noting that all it would take is a postage-stamp-sized piece of milfoil to stick to a duck’s leg and it could be transferred from Beaver to other lakes.

A work group of various local and state government agencies and water-quality organizations took steps last summer to prevent the spread of the invasive, noxious weed in Beaver Lake. The lake was closed to the public in October 2011 after a 12-foot-by-12-foot patch of milfoil was discovered during a state field trip.

A diver was sent in to pull out the weeds; then barriers purchased by Flathead County were placed in the water.

Flathead County Weed Superintendent Jed Fisher said more monitoring will commence this summer. A diver will go in again and use of the barriers will be assessed.

“We felt we had a good reduction of the milfoil after the mats were pulled last fall,” Fisher said, “but that could all change this spring. All options are on the table, depending on the size of the infestation.”

The “State of the Lake” presentation also included information about Les Mason and Whitefish Lake state parks. Whitefish Lake State Park attracted 63,000 visitors last year, while Les Mason had 10,000 users, park manager Dave Bennetts said. The economic impact of state parks across Montana is $289 million, with a $122 million impact here in the Flathead Valley.

The ongoing cleanup of the Whitefish River was noted. BNSF Railway Co. representative Bill Reed said a third season of removing contaminated soil from the river bed will start in April and be completed by mid- to late summer.

Last summer BNSF contractors removed about 450 cubic yards of petroleum-contaminated sediment from Whitefish Lake that remained from a 1989 train derailment that caused diesel fuel to spill into Mackinaw Bay.

There were questions from the audience about what the railroad is doing to prevent future trail derailments and where containment equipment now is stored.

Rico Montini, BNSF’s Whitefish trainmaster, said containment equipment is kept in a trailer at the Whitefish rail yard and the company is working with Flathead’s hazardous materials team to purchase more equipment.

Production from the Bakken oil fields in Western North Dakota and Eastern Montana will mean more oil tankers on the rail line, Montini said, but a tunnel on the line limits the number of trains that can pass through. A maximum of 45 trains can travel through Whitefish in a 24-hour period, he said.

Trains are longer, however, up to 112 cars, Montini said.

Features editor Lynnette Hintze may be reached at 758-4421 or by email at lhintze@dailyinterlake.com.