Development Pressure & the Gallatin River

What starts as trickle in Yellowstone National Park becomes a vital ecological, economic, and social cornerstone some 50 miles downstream at the confluence of the West Fork Gallatin below Big Sky, Montana.  Sadly, the world-class Gallatin River and the trophy blue-ribbon trout fishery and world-class recreational opportunities it supports are more at risk than ever before.

Since 2018 the mainstem Gallatin has suffered three consecutive years of noxious green algae blooms for 10+ miles downstream of the confluence with the West Fork Gallatin, which itself experiences recurring seasonal algal blooms along most of its breadth.  The West Fork collects the majority of stream flows in Big Sky, a booming mountain resort community where unsustainable, irresponsible development has exploded and pollution control has taken a backseat to investment portfolios and unprecedented building pressure.

The Gallatin’s seasonal, widespread algal blooms are reason for concern because enough noxious algal growth can not only be a nuisance for recreation, but if prolonged and widespread they negatively affect macroinvertebrate life, decrease oxygen concentrations in the river, and create unnaturally warm temperatures, which in turn adversely affects fish populations and aquatic communities.

During the summers of 2018, 2019, and 2020 Waterkeeper performed monitoring and river surveys on the Gallatin River and West Fork, measuring common river health parameters and documented the size, scope, and severity of algal blooms.  Three years investigating these algal blooms and reviews of best available scientific research indicate unnatural nutrient pollutant loading traceable to man-made sources is causing or contributing to the Gallatin’s algae bloom troubles.  Despite most stakeholders’ awareness that development pressure has undeniable negative effects on local landscape and waterway health, meaningful solutions have remained elusive as laissez-faire regulators and politics and profits continue to dominate decisionmaking.

Making matters worse is the ongoing housing boom and massive increase in development pressure in both the Canyon and Resort regions of Big Sky, fueled to even larger heights by the CV-19 pandemic.  Overwhelming development pressure continues apace yet the community still lacks a long-term, science-based plan to deal with wastewater disposal without compromising the health of local waterways, nor does it possess infinitely sustainable sources of potable water.  Failure to deal with these basic water resource infrastructure and planning issues threatens substantial, new water pollution problems that will, at minimum, exacerbate ongoing summer pollution problems in the Gallatin.

Waterkeeper’s long investigation into Big Sky’s unprecedented development, infrastructure, and water quality science has revealed that a lynchpin to protecting the mainstem Gallatin and ensuring algal blooms are the exception – not the rule – is finally address the landscape’s carrying capacity.  At present, science indicates that the Gallatin is receiving too much nutrient pollution that, in conjunction with warm summer temperatures and water clarity, is creating noxious algal blooms.  While we can’t control the weather, we certainly can control our landscape activities that contribute harmful pollutants to our waterways.

Now is the time to be proactive in addressing the threat of nutrient pollution to the Gallatin River by ensuring a science-based pollution diet is created and enforced.  Until the Gallatin has a science-based pollution diet we should be pumping the brakes, not pumping more money into new development.  Every continued year of algal blooms creates worse river health that jeopardizes bug life, our trophy trout populations, recreational use, and the countless businesses and jobs that depend on a clean and healthy Gallatin.