Clearwater Lakes Alliance Information

Disclaimer: For a general intro to lake ecology and a list of terms used below, check out the CLA home page.

~ SEELEY LAKE ~

About Seeley Lake

Seeley Lake is a 1,047-acre glacially formed lake with a maximum depth of 125 feet. This lake is located centrally in our watershed, north of Placid Lake and south of Lake Inez (Figure 1). Of the lakes in our watershed, Seeley is the least remote and easiest to access from town, with some of the highest amount of development along its shoreline.

Seeley Lake supports a variety of fish, much like Salmon Lake, including the following species:

Past Monitoring

Seeley and Salmon have been a focus of water quality concerns in the past. In 1996, both lakes were listed for water quality impairment, but removed from listing by MTDEQ in 2006, citing a general improvement in nutrients, dissolved oxygen, and Secchi transparency.

These lakes' water qualities were also of concern in the 1970s when heavy logging and other industrial activities heavily influenced our watershed. Following this period of heavy pollution and lacking environmental oversight, the EPA concluded that nutrient loading in Seeley Lake was consistent with a mesotrophic system, somewhere between “acceptable” and “dangerous”. Seeley Lake serves as the primary water source for the town of Seeley Lake, and is centrally located to town, making it one of the most important water sources for the residents of the Clearwater Valley.

Although water quality has improved in the decades following the EPA listings, continual monitoring is an important step in understanding the lake conditions and how they continue to change. Secchi depths and temperature have been monitored on Seeley Lake every summer since 2009 (Figure 2). Based on CRC’s monitoring work, we know that Seeley Lake has moderate levels of algae and plant growth, similar to Salmon Lake. Seeley consistently has Secchi depth measurements between 10 and 20 feet, often between the eutrophic and oligotrophic depth boundaries, leaning more towards oligotrophic depths (Figure 3).

Dissolved oxygen (DO) data has been collected on Seeley Lake sporadically over the past few decades (Figure 4). These data are extremely important in giving us an idea of the influence that humans are having on our lakes.

An analysis was previously completed for Seeley and Salmon Lakes in 2012 by Vicki Watson of the University of Montana in her report, titled “Lake Water Quality, Trophic Status, and Potential Loading Sources for Clearwater Lakes”. In the report, Watson explains that temperature and DO depth profiles from the summer of 2010 were used to assess patterns of thermal stratification in these two lakes. Seeley was well stratified by mid-June, but DO levels did not drop much with depth until August except at one site, that which was furthest south in the lake, where waters below 10 meters dropped in oxygen by mid-June. Seeley’s thermocline (the depth where dramatic change in temperature occurs) was around 4-6 meters deep, while Salmon’s thermocline first formed at about that same depth, but later in the summer migrated down to about 6-8 meters. Both lakes were still well stratified in early September but had turned over by the end of October.

State water quality standards for dissolved oxygen to protect freshwater aquatic life in most Montana waters is 5 parts-per-million (ppm) as a 7-day-mean minimum. If early life stages are present, the 7-day-mean standard is 9.5 ppm. Two of the sites monitored on Seeley Lake in 2010 were above 5 ppm throughout the water column for the entire summer; but at site 3, waters around and below 7 or 8 meters dropped below 5 ppm.

In 2020, CRC undertook DO monitoring on Seeley Lake to give us a better idea of current conditions and whether water quality is declining. In addition to Seeley, DO profiles were taken on 5 other lakes in our watershed (Salmon, Placid, Big Sky, Alva, and Inez) on a monthly basis in 2020 to establish a baseline DO dataset.

Profiles on Seeley Lake were only taken at the mid site and south site (sites 2 and 3, respectively), as the northern site has a maximum depth of approximately 37 meters, exceeding our DO meter’s 30-meter cord (Figures 5 and 6). From July through September, DO was consistently low at the surface on Seeley, ranging from approximately 7-8 mg/L at both of the sites. Seeley and Inez are the only lakes that did not exhibit DO levels above 10 mg/L at any point in the summer. At the mid-lake site (site 2), DO often increased below the thermocline before suddenly dropping to 0 mg/L at about 20-23 meters. At site 3, DO decreased more steadily through the water column. The thermocline was consistently at around 6-7 meters at both sites on Seeley Lake.

Current and Future Monitoring

Water Quality

Drawing further conclusions based upon the sporadic data that currently exists prior to 2020 is difficult, but as Watson’s reporting shows, monitoring is necessary, especially in these waterbodies that have been affected by anthropogenic pollution in the past. More consistent measurements are needed to better assess the status of each lake in the valley. 

In 2021, CRC is collecting data on DO, conductivity, algae, nutrient, and pH conditions on Seeley Lake (as well as Alva, Inez, Big Sky, Placid, and Salmon) in order to continue establishing baseline data to aid in future water quality analyses. We will also be analyzing data to evaluate the health of our aquatic ecosystems in the Valley. This includes looking for trends in Nitrogen and Phosphorous levels, presence of E. coli bacteria, evidence of oxygen depletion, growth of potentially toxic algae, and other changes to the waterbodies in the Clearwater Watershed.

A new addition to the monitoring process this year is a multiparameter water quality monitoring instrument. This new piece of equipment was recently purchased thanks to a Bureau of Reclamation WaterSMART grant. It uses sensors to accurately read and record levels of conductivity, algae, and pH as deep as 30 meters (~100 feet) in our lakes. Such data is integral to determining the health of our lakes here in the Clearwater Watershed and can aid in detecting harmful algal blooms and habitat degradation.

Check back in the winter for results and findings from our monitoring season!

Aquatic Invasive Species (AIS)

Zebra and Quagga Mussels

CRC has been monitoring for invasive species in the Clearwater Watershed throughout the summers since 2009 on each of the major lakes in the Valley (Alva, Inez, Seeley, Salmon, Placid and Big Sky). One of the biggest threats to Montana’s waterways is the introduction of zebra and quagga mussels, collectively referred to as dreissenid mussels. The purpose of our AIS program is to monitor for the presence of veligers in the lakes by straining large volumes of lake water through a fine mesh net to collect planktonic and microscopic materials in the lake water, including mussel veligers, if present. Veligers are the free-swimming, microscopic juveniles of zebra and quagga mussels. Over the course of the 2020 field season, 62 total sites, spread out over 11 lakes (Figure 7), were sampled each round, totaling 310 samples.

We are happy to report that zebra and quagga mussel veligers were undetected in all of the samples collected and analyzed in 2020. We are continuing to monitor for zebra and quagga mussel veligers throughout 2021 on the six major lakes in the Valley.

Fragrant Waterlilies

Another problematic invasive species in the Clearwater Watershed is the non-native Fragrant Waterlily. The Fragrant Waterlily was likely introduced to the region as an ornamental plant, but has since experienced exponential population growth. The mats of these waterlilies are detrimental to aquatic habitat and outcompete native plant species. Fragrant waterlilies can also cause oxygen depletion, which negatively affects native fish and amphibian species. In 2020, the Missoula County Weed District mapped the waterlilies on the major lakes in the Clearwater, recording a total of 72 acres of the species on Seeley Lake.

In 2021, CRC held lily digging and cutting events at two different locations on Seeley Lake in an effort to remove the invasive species. In early July 2021, CRC’s first Do-the-Dig event was debuted at a pilot demonstration site on Seeley Lake. For this event, CRC staff and Montana Conservation Corps members from across the state worked together to dig up invasive waterlily rhizomes (clonal root systems). A total of nine volunteers dug and removed an entire truckload of lily rhizomes that were taken to Missoula Garden City Compost. This demonstration site will continue to be used in the upcoming years as a test site to explore the most effective and environmentally friendly ways to combat invasive waterlily infestation.

In late July 2021 CRC held its second annual Make-The-Cut invasive lily removal event. Participants competed to cut and collect as many waterlilies as they could at Big Larch Campground and Beach Area.  At the conclusion of the event, 37 bags of waterlilies, weighing over 850 pounds (300 pounds more than what was collected last year!), were removed and collected. Digging and cutting lilies, in combination, have been shown to reduce waterlily populations. However, these efforts need to be consistent and, ideally, community-wide.  This work was made possible with sponsorships and in-kind contributions from Citizens Alliance Bank, Missoula Textiles, Garden City Compost, Rovero’s Ace Hardware, Cory’s Valley Market, Heritage Outdoors, Stageline Pizza, Ice Cream Place, Grizzly Claw, and Trail Creek Merc.

We hope to hold events such as these at more lakes in the Clearwater Valley in upcoming years.

Through CLA, we hope to involve more residents in our citizen science Adopt-a-Lake program to expand the parameters we monitor and increase our monitoring frequency.  CLA will also help us to take steps to actively improve the water quality of the lakes, which over time will hopefully be evident through the monitoring data we collect.

Establishing baseline monitoring data through our Adopt-a-Lake program is only the start.  Contact CRC’s Jon Haufler ( jon@crcmt.org) to learn more about current efforts and/or how you can get involved.

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