By Marne Hayes EBS COLUMNIST
Monitoring water quality is an important part of helping reveal the health and composition of our rivers in a snapshot in time, as well as over weeks, months, and years. It is crucial for ensuring the sustained health of the rivers we enjoy, telling us not only what’s going on at a single point in a stream, but also what is happening upstream, and holistically throughout a watershed.
In the Gallatin River watershed, the Gallatin River Task Force monitors for both quality and quantity. Monitoring provides the basic information needed to characterize and identify trends or changes in water quality over time, and address water quality concerns that arise as a result of activities on, around, or near the river and its tributaries.
Water quality monitoring gives us an indication of a number of aspects of river health, and can identify the effects of environmental changes and community land-use practices that may be affecting the quality of our river and its tributaries, ranging from runoff, to erosion, to irrigation, development, and more.
Currently, there are studies being conducted with the Montana Department of Environmental Quality to better understand changes in algae conditions along the Gallatin. For this specific study, there are 13 water collection sites along the main stem, the West Fork, Taylor Fork, Middle Fork, and South Fork. At each site, vials of water are collected, and sent to a lab in Helena for testing.
The data collected at these sites gives information on nitrogen and phosphorous levels, as well as the hardness of the water. Additional testing done at these sites provides information about water temperature, conductivity, turbidity, pH, and dissolved oxygen; all indicators of the overall health of the river.
Algae monitoring and sampling is a much lengthier process. Depending on the section of the river, a range of anywhere from 11 to 20 samples of algae are taken at a single site. This involves being in the river, physically scraping algae from the rocks on the riverbed, and sending those samples to the lab to inform the DEQ and other agencies about the health of the Gallatin.
The collection at each site may take up to 4 hours, making involvement and help from volunteers critical to the success of the sampling. In addition to collecting samples, experiments are deployed at various locations in the river for multiple weeks to understand which nutrients—nitrogen or phosphorus or a combination of both—are causing the excess algae growth.
Data collected at these sites also helps inform management decisions on the local, state and even national level, providing the critical information needed to make decisions about management and mitigation of current or potential concerns with water quality, including algal growth.
The Gallatin River Task Force has been collecting water quality data for 22 years, adding to baseline information collected in previous years, and analyzed further through a more targeted, algae-centric lens to give comprehensive information about the river’s health and trends over time. The analysis of the information helps to assess why there have been changes in algae growth in past years, and what the extenuating factors may be that are causing growth in some years, and not in others. This information helps to pinpoint what nutrient levels the Gallatin can support, known as TMDLs, Total Maximum Daily Loads, without promoting excess algae growth.
The data is analyzed with technical assistance from the DEQ and used by the task force and other organizations for specific initiatives or to make regulatory decisions. For example, the DEQ uses data collected by the Gallatin River Task Force for decisions such as creating TMDLs, which potentially develop more stringent nutrient criteria for the Gallatin.
Other agencies like the Bureau of Mines and Geology, Big Sky County Water and Sewer District, or various consultants may also use the information for restoration planning, conservation initiatives, or community planning like that going into the annexation of a Gallatin Canyon Water and Sewer District.
Water quality monitoring identifies sources of pollution or impacts to the watershed ecosystem, and directs ongoing work focused on finding solutions to restore or improve water quality, raising the viability of the river.
The information aids in making decisions that involve the river, including how to mitigate nutrient load from land-use practices, and how to tailor restoration projects to best serve the Gallatin’s response to environmental circumstances.
Over time, and through numerous years of sample collection, the data provides a bank of information that has been used to formulate the Upper Gallatin Nutrient Reduction Plan, the guiding document that outlines targeted mitigation strategies and projects that aim to reduce nutrient loading and mitigate future algae blooms in the Gallatin River.
Marne Hayes is the communications manager for the Gallatin River Task Force.