Part 3:
HOW PRISTINE ARE THE FLATHEAD VALLEY’S LAKES?
by Cassidy Mantor
Flathead Lake flushes all of its water every 2.2 years. Compared to Lake Tahoe, which takes about 650 years to fully flush and replenish, Flathead’s flushing time is very short for a lake of its size and contributes towards water quality resilience.
When one thinks of Montana, pristine glacial lakes, rivers, and mountains most likely come to mind. Our lakes aren’t only spiritually and ecologically meaningful; in addition to being valuable natural resources, they are economic assets that need protection too. It may come as a shock then that federal and state agencies have classified many waters in northwest Montana, including Flathead Lake, as impaired. According to the Clean Water Act, “Waters are assessed as impaired when an applicable water quality standard is not being attained. Impaired waters require a total maximum daily load (TMDL) or alternative restoration plan to reduce pollutant loadings and restore the waterbody.” Impaired water negatively impacts the health and wellbeing of people and the environment. It may also have a major economic cost.
But how can this be? Flathead Lake is beautiful and clear. It’s the 79th largest freshwater lake in the world and is formed by runoff from pristine wildlands including Glacier National Park, the Bob Marshall Wilderness complex, and the Mission Mountains. The water should be clean. Unfortunately, the federal government designated it as impaired in 1996. According to records from the U.S. Environmental Protection Agency and Montana Department of Environmental Quality (MTDEQ), human activities have caused an impairment due to inputs of the nutrients nitrogen and phosphorus, sediments, and other pollutants.
Flathead Lake flushes all of its water every 2.2 years. Compared to Lake Tahoe, which takes about 650 years to fully flush and replenish, Flathead’s flushing time is very short for a lake of its size and contributes towards water quality resilience. However, the lake’s water quality has deviated substantially enough from historic conditions to land it on the impaired list in the 1990s, and now it requires attention and regulation to keep it from getting worse. The lake’s water quality relies on the buffering of a functioning ecosystem upstream in the Flathead Watershed, an area larger than the developed area of the Flathead Valley. With the population doubling over the past 30 years and increased development of the valley bottom and the lake shoreline, that natural buffer is under a legitimate threat.
The Flathead Lake Biological Station (FLBS), the country’s second-oldest ecological research station founded in 1899 and part of the University of Montana, serves as “Sentinel of the Lake,” and since 1977, has conducted a rigorous monitoring program that helps shape policies that have slowed the decline of water quality for the lake and its tributaries. Mitigating efforts have included implementing one of the country’s first bans on phosphorous detergents, issuing upstream mining bans, and upgrading municipal wastewater treatment systems. The efforts have worked and phosphorus levels have not increased over the past 40 years, but with the population continuing to expand and more development and erosion, the aquatic environments in the valley can only handle so much.
The Bottom Line
In 2021, FLBS and the Whitefish Lake Institute conducted a natural resource economic study to estimate the financial benefits of Flathead and Whitefish Lakes on the Flathead Valley. Their data set consisted of over 7,000 real estate sales transactions from 2004 to 2018 – before the COVID boom in population and property values. By the numbers, they found the following results:
Lakefront homes on Whitefish Lake commanded a premium of 254% or $1.3M on average compared to the same home located over 2km from the lake.
Lakefront homes on Flathead Lake commanded a 114% or $0.5M average price premium compared to the same home over 2km from the lake.
Each meter of Flathead Lake shoreline was worth an additional $3,087. For an average shoreline of 40m this equated to roughly 28% increase of mean sale price. Shoreline length on Whitefish Lake was more uniform and therefore did not contribute additional value.
Water access for non-lakefront homes held a premium of 30% increase in price.
The report estimated that Flathead Lake boosted shoreline and nearby property values by $1.6 – $2.2 billion. That also equated to $12 to $17 million in property tax revenue. In Whitefish, the lake increased property values $0.6 to $1.1B, contributing $5 to $8M in property taxes. With schools and local government almost exclusively funded by property taxes, Flathead and Whitefish Lakes add $3B in property value to the Flathead Valley and generate $25M in annual property tax, which is very important for government services in the local communities.
Degradation to the water quality of these lakes and environmental impact would result in decreases in property values and associated decreases in tax revenue for local communities. It is in our economic best interest to protect our water quality.
Why Impaired Water is a Bigger Problem
Beyond the dollar, harmful algae blooms (HAB) of cyanobacteria, or blue-green algae, are another threat of declining water quality. HABs are caused by an imbalance in nutrients in the water and resemble pea soup, grass, or a paint spill. They’re toxic to humans and animals, and all it can take to get sick is swimming in an affected area. According to MTDEQ, HABs are triggered by human influences from land-based sources (think fertilizer, ground disruption and shoreline erosion from construction, and waste) as well as high water temperatures. They are most common in fall and spring. Due to low nutrient conditions, HABs are very uncommon in the Flathead Watershed, but FLBS and other partners vigilantly watch for them as a warning sign of deterioration and changes in conditions. Luckily, neither Flathead Lake nor Whitefish Lake have HABs.
However, there are many threats to water quality that are present and have manifested in the watershed. The DEQ reported that at the mouth of the Flathead River, discharges from municipal storm sewers, a loss of riparian habitat, temperature changes, and upstream sources of pollutants contributed to nitrogen, oxygen, phosphorus, chlorophyll, and other sediment imbalances. Flathead Lake went on the impaired list in 1996 and remains on the list after a more recent assessment in 2020 for its levels of mercury, nitrogen, phosphorous, and chlorophyll.
North of the City of Whitefish, the Stillwater River has experienced alterations to streamside vegetative cover from agriculture and land development. The Whitefish River, a tributary of the Stillwater that flows out of Whitefish Lake, landed on MTDEQ’s impaired list due to PCBs – polychlorinated biphenyls aka “forever chemicals” – as well as oil and grease from spills and site clearing for land development or redevelopment.
As of the MTDEQ’s 2020 data, Whitefish Lake is listed as impaired because of PCBs and mercury. According to the state’s 2020 Environmental Assessment, which includes the MTDEQ’s 2020 Clean Water Act Information Center Water Quality Assessment, aquatic life in the Whitefish Lake is “threatened” with PCBs and mercury being the probable cause. The City of Whitefish gets its drinking water from this lake.
What Can We Do To Stop It?
Tom Bansak, Associate Director of the Flathead Lake Biological Station, says that although Flathead Lake and Whitefish Lake are both classified as impaired and have seen degradation from their original historic conditions, they’re still cleaner than most freshwater bodies around the globe. Optimistic about the future of Montana’s lakes, Bansak notes that in order to get off the impaired list, the state has to take action and create targets for conditions it wants the water to meet. “These nutrient limitations remind people that we can’t let things get worse here,” he shares.
The largest stressors to the ecosystem are development in the watershed, specifically bringing green grass right up to the shoreline, paving over farmland, aging or improperly functioning septic systems, and the strain on the overall wastewater treatment due to the population expansion. Bansak views the impairment classification as cautionary but not a death sentence: “This impairment reminds us that at some point in time the buffering and filtration capacity of the Flathead Valley may be taxed and maxed out, and nutrients and pollutants from human activities could change the lake forever.”
Bansak offers several action items that are manageable for anyone calling the Flathead Valley home:
Create a buffer strip of native vegetation along all waters whether it’s lakefront, river bank, or a small tributary stream.
Practice careful application of fertilizer along shorelines, particularly before rain.
For homes on septic systems, schedule proper maintenance, pumping, and inspection.
The reasons are straightforward and are designed to minimize the effect that human activities have on our waters. Native vegetation has deeper roots that strip out nutrients more thoroughly than non-native grass lawns. Fertilizer will wash directly into lakes and streams when it rains, and phosphorus is a limiting nutrient, meaning too much could cause permanent, irreversible damage. Finally, properly functioning septic and wastewater treatment systems will protect water quality and ensure better public health for society at large.
Whitefish Lake has more protective measures in place compared to Flathead. Bansak notes that the City of Whitefish has more lakeshore regulations in part because the city’s drinking water comes from it. He calls the combined efforts on both lakes a success story in terms of people caring and investing in stewardship fixes.
As Bansak points out, the Flathead Valley has an amazing, intact ecosystem and it is in all our best interests to do the right thing to sustain it.
