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.
~ Lake Alva ~
Views from Lake Alva Adopt-a-Lake monitoring, May 2020. Photo by Emily McGuirt.
Figure 1: Location of Lake Alva within the Clearwater Watershed
About Lake Alva
Located in the northern region of the Clearwater Watershed between Rainy Lake and Lake Inez, Lake Alva is 11 miles north of the town of Seeley Lake along Montana Highway 83 (Figure 1). The maximum depth of Lake Alva is approximately 80 feet.
Lake Alva is a popular lake in our watershed to explore by boat. Home to many nesting loons, boaters on Alva must avoid these areas and operate at a “no wake” speed year round to avoid disturbing any fragile habitats. Alva’s shoreline is undeveloped; however, it is an extremely popular camping spot during the summer months, which is likely a contributing factor to some pollution entering this body of water.
Past Monitoring
Secchi and temperature have been measured on Alva since 2009 (Figures 2 and 3). This lake’s transparency is usually well within the “oligotrophic” depth boundary (deeper than 16.5 ft); however, in May of 2020, some of the shallowest Secchi depth measurements ever recorded on this lake were documented.
Figure 2: Secchi depths recorded at Lake Alva from 2009 through 2020.
Figure 3: Secchi depths recorded at 15 sites on 8 lakes in the Clearwater Watershed, 2009 through 2020. The red and green lines represent the bounds for transparencies considered indicative of eutrophic and oligotrophic conditions, respectively. Note that as of 2020, Clearwater and Rainy Lakes were omitted from monitoring.
Dissolved oxygen (DO) was not monitored on Lake Alva until 2020. In 2020 CRC undertook DO monitoring on Lake Alva to give us a better idea of the current conditions and whether water quality was declining. In addition to Lake Alva, DO profiles were taken on 5 other lakes in our watershed (Placid, Inez, Salmon, Seeley, and Big Sky) on a monthly basis throughout 2020 to establish a baseline DO dataset. This was an important step in better understanding the water quality changes that are likely taking place in our watershed.
Figure 4: Dissolved oxygen profiles recorded at Lake Alva in July, August, and September 2020.
Figure 5: Temperature profiles recorded at Lake Alva in July, August, and September 2020.
On Lake Alva, July and August had similar DO levels at the surface, while September saw a jump of about 2 mg/L in DO at the surface (Figure 4). At depth, directly below the thermocline (the depth where dramatic change in temperature occurs), the highest DO was recorded in July, followed by August, then September. This could be due to sub-surface plant growth giving off oxygen. From July-September the thermocline consistently occurred at around 8-9 meters (Figure 5). Below this point in the water column, the water temperature was consistently at about 5 °C. For most of the lakes, including Lake Alva, surface temperatures declined from July-September (highest in July, lowest in September). Figures 4 and 5 show that DO is inversely correlated with temperature, as higher DO is observed in colder temperatures.
DO is an important indicator of water quality because oxygen is essential to many aquatic species. Read more about oxygen in aquatic ecosystems here.
Current and Future Monitoring
Water Quality
Figure 6: Water quality monitoring site on Lake Alva in 2021.
Drawing conclusions based upon the sporadic data that currently exists prior to 2020 is difficult, and 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 Lake Alva (as well as Inez, Big Sky, Placid, Salmon, and Seeley) 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
Figure 7: 11 lakes in the Swan, Clearwater, and Blackfoot drainage basins were monitored for AIS in 2020. In order, as labeled, these lakes include: Holland, Lindbergh, Alva, Inez, Seeley, Placid, Big Sky, Salmon, Upsata, Coopers, and Browns.
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 will continue to monitor for zebra and quagga mussel veligers throughout 2021 on the six major lakes in the Valley.
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.
If you would like to consider getting involved with monitoring Lake Alva or want to learn more about the work being done, please contact CRC’s Dave Torell, (email: dave.torell@crcmt.org ) for more information.
Return to the Clearwater Lakes Alliance main page.
Last updated September 2021