Dilution is Not the Solution to Pollution

A recent Montana Bureau of Mines and Geology (MBMG) study recognized a simple, if alarming, fact: some areas of Southwest Montana are losing water.

Read the Bozeman Daily Chronicle’s publishing of our Op-Ed on this issue here.

The MBMG study looked at evolving land use and groundwater flow patterns in the Four Corners region of the Gallatin Valley to evaluate ground and surface water flows on lands that have been converted from agricultural use to residential and commercial uses.  Although the study’s scope was geographically limited to the Four Corners area and to water quantity, its results should be read as a cautionary tale for Southwest Montana and water quality management.

No one can argue that the character of the Four Corners area, much less the greater Gallatin Valley, has dramatically changed in the last 20 years. As the MBMG study notes, there has been a 560% increase in urban and commercial land use, and a 150% increase in well density over just the last 12 years!

Unfortunately, there’s been scant discussion of the insidious, dare we say unpopular, reality that lesser ground and surface water flows also bring – less water quantity often leads to impaired water quality. Put another way, the best available science is telling us we need to do more to protect water resources, with less.

Decreasing ground and surface water trends should be a call to action for communities and decisionmakers throughout Southwest Montana. Let’s consider the potential negative qualitative, legal, and economic repercussions of decreasing water quantity and, in turn, how communities and decisionmakers need to respond.

As the Bozeman Daily Chronicle previously reported, trends shown in the MBMG study unequivocally point to a likely future where the Gallatin River – and its upstream tributaries and groundwater aquifer – contain less water. Less water places increased stress on our natural environment – places like our remaining wetlands, lowlands, and riparian areas – to do what they do naturally: filter pollution. As every 5th grade science student learns, our local watersheds have a carrying capacity – an ability to naturally handle whatever comes down the proverbial pipe. Once that capacity has been met, a tipping point is reached; when tipping points are exceeded, watersheds typically experience cascading, multi-dimensional negative ecological impacts.

Unfettered agricultural land use conversion, a lack of development restrictions, and little to no water pollution infrastructure means the Four Corners area, much less the greater Gallatin Valley, appears to be headed towards an ecological tipping point, if not a path of ecological decline.

Legally speaking, water quantity depletion means previously unrecognized or insignificant water quality problems may rise to the level of scientific significance, and require action. The Federal Clean Water Act requires our State Dept. of Environmental Quality (DEQ) to triennially assess whether state waters are meeting their designated and existing uses. E.g. whether a waterway that typically supports cold water fisheries, drinking water, recreational contact etc., is scientifically and practically doing so.

Decreasing water quantity alongside increasing pollutant loading in the Gallatin means that we rely on our surface and groundwater’s dilution capacities at the risk of not meeting waterways’ designated uses, and in so doing bring down the federal, legal hammer in terms of new, or increasingly stringent, water quality related regulation. Practically speaking, such increased regulation could take the shape of limitations on land use, such as a requirement that every new subdivision in the Lower Gallatin Valley possess or, at the minimum, be connected to waste water treatment facilities. Thus decreasing water quantity can incite potential water quality ramifications with have heavy economic consequences.

If our current land use trends (and related water pollution impacts) continue and in fact grow, yet water quantity decreases, we will face certain economic realities in terms of land use, wastewater infrastructure, and building and development limitations. To be clear, these types of regulation are good things; science-based land use limitations will be an essential, future component that helps us keep the Gallatin Valley a clean, healthy place to live, work, and play. Indeed, failing to recognize and act upon the nexus between water quantity and quality threatens Gallatin County’s critical outdoor economy. A recent Business for Montana’s Outdoors poll found that 70% of businesses say that Montana’s outdoor lifestyle is a key factor in deciding to locate or expand in our state. Clean, readily available water is likewise a key building block of our local outdoor economy!

State and local decisionmakers need to be proactive and transparent in engaging local stakeholders and citizens in discussing water quantity trends, as well as in taking necessary steps to protect water quality. This means, at the state level, taking the readily available science about local water quantity and quality and requiring more stringent limitations in pollution permits. Conversely, it also means local government needs to not only track, but restrict, development and/or proposed land use when it would negatively affect water resources. Lastly, decreased water quantity means that individuals, local communities, business, and our decisionmakers need to elevate our water quality dialogue and focus on implementing needed water efficiency measures and pollution controls.


Southwest Montana’s vibrant outdoor culture is predicated in large part on clean, readily available water. Let’s listen to science and common sense and take the necessary steps to proactively manage our growth, water resources, and pollution so that Montana’s future generations grow up with clean, readily available water.