By Emily Stifler Explorebigsky.com Managing Editor
BIG SKY – The amount of nitrogen, algae, chloride and sediment in parts of the West Fork of the Gallatin River watershed has increased in recent years, according to data collected by the Blue Water Task Force.
With this in mind, the BWTF has revised its Community Water Quality Monitoring program, in place since the organization’s inception in 2000. It will continue studying stream flow in the west fork and its three main tributaries, and monitor 14 sites, four of which are new.
The new sites include one on the west fork, just downstream of the Big Sky Golf Course at the Community Park, two on the Middle Fork – one just upstream of the confluence with the North Fork and one further upstream below Lake Levinsky¬ – and one on the South Fork upstream of the Meadow Village area. The goal there is to determine if there are differences in nitrogen levels, above and below Meadow Village.
Starting in August 2012, BWTF also added to its sampling program, measuring chloride, sediment and algae in addition to ongoing sampling for nitrate, dissolved oxygen, temperature, conductivity, turbidity, total coliform and E.coli.
Chloride, Gardner said, is a tracer of wastewater influence and road salt. They included it in the sampling program because excessive amounts can kill aquatic animals and vegetation.
BWTF included algae because levels in the West and South Forks are higher than Montana state standards. “It depletes oxygen levels in the stream, which can affect fish,” Gardner said. “Also it’s [not] aesthetic, people don’t really like to look at globs of algae in the river.”
BWTF found excess sediment in the West Fork watershed, which can result from road sand, culvert failure and poorly planned or managed construction sites, or unpaved roads, Gardner said. It’s a concern, “because trout and other aquatic life depend on stream bottoms with [limited] fine sediment, which can clog spawning grounds.”
A previous study conducted from 2005 through 2009, funded by the Montana Department of Environmental Quality, found high levels of nitrogen in the stream in the Mountain Village area, and also below the golf course, Gardner said.
“A lot of the nitrogen was coming from lawns and septic systems not taken care of properly,” Gardner said, adding that it’s also from effluent irrigation applied to the golf course and adjacent pastures.
A new three-year grant awarded by DEQ last spring is dedicated to improving water quality and monitoring any changes.
To address the issues, Gardner plans to work with homeowners associations, businesses and golf courses, studying the amount of nitrogen they’re putting on their properties and developing a plan to reduce it. She’ll also assess riparian areas throughout the watershed to see “which are healthy and which [ones] we might want to improve.”
BWTF also monitored chloride levels in the main Gallatin River this summer, studying seven sites between the Yellowstone National Park boundary and just above the Jack Smith Bridge.
The Montana Department of Transportation recently increased the amount of chloride it uses in traction sand, Gardiner said. BWTF wants to know if that’s impacting the river.
She mentioned a February 2012 article on road salt in Stormwater magazine. “Studies performed by the US Geological Survey (USGS) and private agencies… have begun to show that salt applied to treat icy roads may not disperse as easily as once thought. [They] indicate measurable effects on aquatic life associated with salt concentrations previously considered inconsequential.”
Funding for the Blue Water Task Force’s Community Water Quality Monitoring program was granted by the Big Sky Resort Tax Board in June.