Northwest Montana Lakes Volunteer Monitoring Network 2016 Program Summary 5.8 MEDIUM LAKES. (Surface Area Acres)

Transcription

1 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary 5.8 MEDIUM LAKES (Surface Area 1 Acres) Beaver Blaine Blanchard Five Foys Glen Holland Lower Stillwater Murphy Rogers Sophie 66 Whitefish Lake Institute

2 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Beaver Lake Trophic Status: Oligo-mesotrophic Surface Area: 144 acres Maximum Depth: 96 feet (29.3 meters) Beaver Lake has a catchment area of 2,43 acres composed of the Piegan group belt series (46%) and alluvium (38%) (Ellis & Craft, 28). Beaver Lake is located in Flathead County northwest of Whitefish on the northern edge of Lion Mountain. The lake s elevation is 993 meters. Fish distribution records indicate a presence of brook trout, flathead minnow, rainbow trout and kokanee. The lake has one motorized public access site on the south side of the lake. Temperature and oxygen profiles show that Beaver Lake was stratified during the summer sampling dates, and has been within the avoidance threshold range for salmonids at depths of up to 7 meters during July and August. Oxygen profiles show that the lake has been between avoidance and anoxic thresholds for salmonids at depths greater than 1 meters. Anoxia has been observed at depths greater than 15 meters. When anoxic conditions occur at the benthic interface an oxidation reduction potential exists and nutrients stored in the sediment can be liberated back into the water column given the right conditions. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 6-12 meters. Beaver Lake often ranks highest among medium lakes for total phosphorus, total nitrogen and chlorophyll (a). Beaver Lake s 21, 211 and 216 average calcium concentration was 39.9mg/L classifying it as a high risk for zebra mussel colonization. The 212 alkalinity level was reported at 82mg/L. In 211, Eurasian watermilfoil was discovered on Beaver Lake in mid-october. The relatively small patch was found by DNRC near the boat ramp during a training retreat. This is the first lake in the Flathead basin to have a positive DNA for EWM. A multi-agency workgroup was established and addressed the issue by hiring a diver to evaluate the size of the infestation, and deploy bottom barriers until the spring when the best management techniques were evaluated. In 212, the bottom barriers were removed, and a suction dredge was used to remove as much EWM as possible. Prior to dredging, the Whitefish Lake Institute installed a sediment curtain near the outflow of Beaver Lake to help prevent EWM fragments from entering Beaver Creek which flows into Whitefish Lake. In 214 and 215, only isolated plants were found and in 215 a little more than a pound of EWM was removed. WLI removes and reinstalls the curtain seasonally. Additionally, WLI maintains a monitoring station on Beaver Creek as a part of their baseline monitoring program. In 216, a few individual plants were found under a submerged log. Turbidity curtain on Beaver Lake. Photo courtesy WLI. 67 Whitefish Lake Institute

3 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Beaver Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Beaver Lake Summer Temperature (F) Beaver Lake Fall Temperature (F) ritical Thermal Maximum Incipient Lethal Temperature /17/1998 8/24/21 5 8/29/22 7/28/21 8/15/211 7/4/212 7/15/213 7/14/214 8/25/ /1/21 1/31/211 1/17/212 1/31/213 1/17/214 11/16/215 8/15/216 Beaver Lake Beaver Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic /7/1998 8/24/21 8/29/22 7/3/29 7/28/21 8/15/211 1/1/21 7/4/212 1/31/211 7/15/213 1/17/ /15/214 8/25/ /31/213 1/17/214 8/15/216 11/6/ Whitefish Lake Institute

4 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lake Blaine Trophic Status: Oligotrophic Surface Area: 382 acres Maximum Depth: 141 feet (43 meters) Lake Blaine has a catchment area of 18,963 acres composed of glacial till (53%), Appekunney argillite belt series (36%) and glacial lake deposits (2%) (Ellis & Craft, 28). The lake is located in Flathead County at an elevation of 914 meters. Surrounding land ownership is entirely private. Fish distribution records indicate a presence of brook trout, kokanee, lake trout, largemouth bass, largescale sucker, longnose sucker, northern pike, northern pike minnow, rainbow trout, sunfish, westslope cutthroat trout, and yellow perch. No formal public access exists on Lake Blaine; however volunteers reported that a lakefront landowner allows informal public access on their property at the north end of the lake. Temperature and oxygen profiles show that Lake Blaine was stratified during all summer sampling dates. Temperature profiles show that Lake Blaine has been within the avoidance threshold range for salmonids at depths of up to 6 meters during July and August. Oxygen profiles show that the lake has been between avoidance and anoxic concentration thresholds for salmonids at depths greater than 14 meters. Hydrolab profiles show that the lake was mixed during fall sampling dates with the exception of the 21 sampling date where the lake was stratified. Anoxia has been observed at depths greater than 15 meters. When anoxic conditions occur at the benthic interface an oxidation reduction potential exists, and nutrients stored in the sediment can be liberated back into the water column, given the right conditions. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 7-14 meters. Lake Blaine s 211/216 average calcium concentration was reported at 33.2mg/L classifying it as a high risk for zebra mussel colonization. The 212 alkalinity level was reported at 13mg/L. In 211, volunteers reported higher than normal water elevations, and more vegetation than ever observed. Two AIS reports were submitted to the website database for EWM in 211. Montana Department of Agriculture (MDA) was contacted after the report was filed, and confirmed that the plant in question was not EWM. In 212 and 213, volunteers reported increased shore erosion from recreational boat use. Lake Blaine panoramic. Photo courtesy Gayle Chaffey. 69 Whitefish Lake Institute

5 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lake Blaine Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Lake Blaine Summer Temperature (F) Lake Blaine Fall Temperature (F) Incipient Lethal Temperature tical Thermal Maximum /14/ /3/ /13/213 12/2/211 8/12/214 11/2/212 9/1/215 11/13/213 8/17/216 11/16/215 Lake Blaine Lake Blaine Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance -1 Hypoxic -1 8/14/ /3/ /13/213 12/2/211 8/12/214 11/2/212 9/1/215 11/13/213 8/17/216 11/16/215 7 Whitefish Lake Institute

6 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Blanchard Lake Trophic Status: Meso-oligotrophic Surface Area: 143 acres Maximum Depth: 3 feet (9.1 meters) Blanchard Lake has a catchment area of 2,649 acres. The geologic formations in the watershed are dominated by glacial till (54%) with the remaining area in the Piegan group belt series (Ellis & Craft, 28). The lake is located in Flathead County three miles west of Whitefish at an elevation of 969 meters. Fish stocking and population survey records indicate a presence of largemouth bass, northern pike, yellow perch and pumpkinseed. Blanchard Lake has one motorized public access on the far north end of the lake. WLI maintains two monitoring locations on the lake. Temperature and oxygen profiles show that Blanchard Lake was either stratified or weakly stratified during summer sampling dates. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 6 meters during August. Oxygen profiles show that Blanchard Lake has been between avoidance and anoxic concentration thresholds for salmonids at depths greater than 6 meters. Hydrolab profiles show that the lake was mixed during fall sampling dates. Blanchard Lake is considered a warm water fishery. Blanchard Lake often ranks among the highest of medium lakes for total persulfate nitrogen. The lake s 211/216 average calcium concentration was 39.5mg/L classifying it as a high risk for zebra mussel colonization. The 212 alkalinity level was reported at 82mg/L. An EWM survey was conducted near the public access site after the discovery in Beaver Lake. No EWM was found, however, northern milfoil was found throughout the lake. In 212, what is believed to have been whorled milfoil was found. More surveying is recommended to confirm the types of milfoil species present in the lake. A Macrophyte survey was conducted in 214 where fragrant water lily was found along much of the south west shore. Former WLI Intern Megan Powell and volunteer Carol Treadwell-Steitz monitor Blanchard Lake. Photo courtesy WLI. 71 Whitefish Lake Institute

7 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Blanchard Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Blanchard Lake Summer Temperature (F) Blanchard Lake Fall Temperature (F) Incipient Lethal Temperature cal Thermal Maximum 8/31/1998 9/4/21 9/4/22 8/19/25 8/21/26 8/9/21 8/28/211 1/13/21 8/23/212 1/27/ /14/213 7/29/ /23/212 1/9/213 8/7/215 1/28/214 8/15/216 11/9/215 Blanchard Lake Blanchard Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic 8/31/1998 9/4/21 9/4/22 8/19/25 8/21/26 8/9/21 8/28/211 1/13/21 8/23/212 1/27/ /14/213 7/29/ /23/212 1/9/213 8/17/215 1/28/214 8/15/216 11/9/ Whitefish Lake Institute

8 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary A macrophyte survey was conducted on Blanchard Lake on September 3, 214. A total of 222 sites were surveyed for plants/algae. Dense macrophyte beds exist in Blanchard Lake and several plant species were found during the survey. Blanchard is considered a warm water fishery, and oxygen levels drop substantially during summer months after the lake becomes stratified. Blanchard Lake Although northern milfoil was not a dominate plant, it exists throughout much of the lake. The pink teardrop icons on the map represent fragrant water lily, an invasive plant that was intentionally planted in Blanchard and other nearby lakes as an ornamental. Dominant Plant Distribution September, 214 Chara Co-dominance >2 ft Deep 7% 3% 25% 9% 11% Bladderwart 24% 17% Water Shield Yellow Water Liliy Yellow water lily and water shield are emergent plants that have floating leaves. During the summer months, these plants blanket the surface of Blanchard Lake. Photo courtesy Kim Schierl. Co-dominant Plant Species Composition Co-dominant % Yellow Water Lily /Bladderwart 2.75 Water Shield / Bladderwart Yellow Water Lily / Bladderwart / Chara 9.43 Yellow Water Lily / White Stem Pondweed 7.55 Yellow Water Lily / Chara 5.66 Bladderwart / Chara 5.66 Northern Milfoil / Chara 3.77 Yellow Water Lily / Bladderwart / Illinois Pondweed 3.77 Other Whitefish Lake Institute

9 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Fragrant water lily. Photo courtesy WLI. Fragrant water lily (left) is a non-native aquatic plant with large symmetrical white or pink blooms and heart-shaped glossy green floating leaves with a purple underside. The leafstalk is submerged and grows out of large rhizomes which serve as a common food source for muskrats. The flowers range from 3 inches wide with several broad, curved petals that narrow toward the center. They are found in still, relatively shallow water (1.5 meters) lakes and ponds with silty beds. Native to the eastern portion of North America, its commercial popularity has caused its extensive dispersal throughout North America. The plant is now considered a secondary invader that can achieve extraordinary population growth and destabilize ecosystems. Illinois pondweed (right) is a submerged plant that is native to Montana. Illinois has both submerged and floating leaves up to eight inches in length. Green flowers extend three inches from the water s surface and are organized in whorls. Illinois pondweed is often confused with Richardson s pondweed (native), and non-native curly leaf pondweed. Illinois pondweed. Photo courtesy WLI. Curly-leaf pondweed. Photo courtesy WLI. Curly-leaf pondweed (left) is an invasive aquatic perennial that is native to Eurasia, Africa, and Australia. It was accidentally introduced to United States waters in the mid-188s by hobbyists who used it as an aquarium plant. The leaves are reddish-green, oblong, and about 3 inches long, with distinct wavy edges that are finely toothed. The stem of the plant is flat, reddish-brown and grows from.2-1 meter long. The plant usually drops to the lake bottom by early July. CLP leaves resemble lasagna noodles. CLP infestations discovered in several isolated patches in Flathead Lake and the Flathead River. 74 Whitefish Lake Institute

10 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lake Five Trophic Status: Oligotrophic Surface Area: 152 acres Maximum Depth: 62 feet (18.9 meters) Lake Five s drainage basin is dominated by glacial till (68%) with the remainder lying in the Grinnel argillite belt series (Ellis & Craft, 28). Lake Five is located in Flathead County in the Hungry Horse Ranger District at an elevation of 993 meters. Fish distribution records indicate a presence of brook trout, kokanee, largemouth bass, longnose sucker, northern pike minnow, pumpkinseed, rainbow trout, walleye, westslope cutthroat trout and yellow perch. A new motorized public access site was constructed in the fall of 211 on the southeast end of the lake. Temperature and oxygen profiles show that Lake Five was stratified during summer sampling dates. Temperature profiles show that Lake Five has been within the avoidance threshold range for salmonids at depths of up to 9 meters during August. Oxygen profiles show that Lake Five has been between avoidance and anoxic concentration thresholds for salmonids at depths greater than 13 meters. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 9-13 meters. Hydrolab profiles show that the lake was mixed during fall sampling dates. Lake Five ranked highest among medium lakes for calcium. Lake Five s 21, 211 and 216 average calcium concentration was 42.4mg/L classifying it as a high risk for zebra mussel colonization. The 212 alkalinity level was reported at 15mg/L. In 215, Lake Five ranked highest among medium lakes for chlorophyll (a). A visual survey for EWM was conducted in 211 and 212 along the shoreline yielding no suspect results. Additional surveying is recommended based on new ease of access, and recreational use. Photo: Volunteer Ron Ridenour and his dog Cody cruising on Lake Five. 75 Whitefish Lake Institute

11 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lake Five Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, Year Lake Five Summer Temperature (F) Lake Five Fall Temperature (F) Incipient Lethal Temperature tical Thermal Maximum /31/1998 8/22/21 8/29/22 8/25/25 8/1/212 7/3/213 8/19/214 9/9/215 8/17/216 11/28/211 1/26/212 11/4/213 1/29/214 11/1/215 Lake Five Lake Five Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic /31/1998 8/22/21 8/29/22 8/25/25 8/1/212 11/28/211 7/3/213 1/26/212 8/19/214 11/4/213 9/9/215 1/29/214 8/17/216 11/1/ Whitefish Lake Institute

12 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Foys Lake Trophic Status: Mesotrophic Surface Area: 241 acres Maximum Depth: 134 feet (4.9 meters) Foys Lake has a drainage basin of 1,836 meters. The basin area is dominated by the Piegan group belt series (86%) of the Salish Mountains with the remainder composed of glacial till (Ellis & Craft, 28). Foys Lake is located three miles southwest of Kalispell in Flathead County at an elevation of 16 meters. The lake is surrounded entirely by private land ownership. Fish distribution records indicate a presence of arctic grayling, kokanee, rainbow trout and redside shiner. Foys Lake has one motorized public access site located on the southeast end of the lake. Temperature and oxygen profiles show that Foys Lake was stratified during summer sampling. The temperature profile shows that Foys Lake was within the avoidance threshold range for salmonids at a depth of 7 meters during August. Oxygen profiles shows that the lake was between avoidance and anoxic concentration thresholds for salmonids at a depth greater than 17 meters. When anoxic conditions occur at the benthic interface an oxidation reduction potential exists and nutrients stored in the sediment can be liberated back into the water column given the right conditions. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 8 meters. Hydrolab profiles show that the lake was mixed during fall sampling dates. Foys Lake consistently ranks among the highest of Medium lakes for total phosphorus, total nitrogen and chlorophyll (a). The lake s 21, 211 and 216 average calcium concentration was 3.8mg/L classifying it as a very low risk for zebra mussel colonization. The 212 alkalinity level was reported at 7mg/L. In 211, 212 and 214 an EWM survey was conducted near the public access site yielding no suspect results. Very few macrophytes (aquatic plants) were found in the littoral zone during the surveys. Volunteer Allen Gustafson prepares to collect a winter hydrolab profile blow the ice on Foys Lake. Photo courtesy WLI. 77 Whitefish Lake Institute

13 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Foys Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, Year Foys Lake Summer Temperature (F) Foys Lake Fall Temperature (F) Incipient Lethal Temperature tical Thermal Maximum /8/211 8/22/212 11/19/212 8/11/213 11/12/ /5/214 8/16/ /28/214 11/5/215 Foys Lake Foys Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic /8/211 8/22/212 11/19/212 8/11/213 11/12/ /5/214 8/16/ /28/214 11/5/ Whitefish Lake Institute

14 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Glen Lake Trophic Status: Oligotrophic Surface Area: 31 Acres Maximum Depth: 4 feet (12.2 meters) Glen Lake has a basin area of 4,839 acres composed of alluvium (65%) and the Piegan group belt series (Ellis and Craft, 28). Glen Lake is located in Lincoln County at an elevation of 914 meters. It has a surface area of 31 acres and a maximum depth of 4 feet. Surrounding land ownership is 1% private. Fish stocking records indicate a presence of kokanee and rainbow trout. There is also a population of yellow perch. There is one motorized public access site located on the northeast side of the lake. Temperature and oxygen profiles show that Glen Lake was either evenly mixed or weakly stratified during summer sampling dates. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 6 meters during July and August. Hydrolab profiles show that the lake was mixed during fall sampling dates. Glen Lake s 21, 211and 216 average calcium concentration was 28.3mg/L classifying it as a moderate to high risk for zebra mussel colonization. The 212 alkalinity level was reported at 15mg/L. Photo: Volunteer Guenter Heinz en route to the Glen Lake monitoring location. Photo courtesy WLI. 79 Whitefish Lake Institute

15 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Glen Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, Year Glen Lake Summer Temperature (F) Glen Lake Fall Temperature (F) Incipient Lethal Temperature tical Thermal Maximum -8 7/28/28-8 8/5/29 7/28/21 9/5/211 11/7/211 7/22/212 1/22/ /16/213 7/15/ /6/213 1/22/214 7/18/216 11/2/215 Glen Lake Glen Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic -8 7/28/28-8 8/5/29 7/28/21 9/5/211 11/7/211 7/22/212 1/22/ /16/213 7/15/ /6/213 1/22/214 7/18/216 11/2/215 8 Whitefish Lake Institute

16 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Holland Lake Trophic Status: Oligotrophic Surface Area: 414 acres Maximum Depth: 156 feet (47.5 meters) Holland Lake has a basin area of 423 acres which is composed of both the Piegan group (39%) and Missoula group (32%) belt series and alluvium (2%) (Ellis & Craft, 28). Holland Lake is located fifteen miles north of Seeley Lake in Missoula County at an elevation of 1,28 meters. Surrounding land ownership is entirely USFS. Fish distribution records indicate a presence of bull trout, kokanee, largescale sucker, longnose sucker, mountain whitefish, northern pike minnow, peamouth chub, rainbow trout, westslope cutthroat trout and yellow perch. Holland Lake has one motorized public access on the east end of the lake. The lake can also be accessed from the campground on the northern side of the lake. Temperature and oxygen profiles show that Holland Lake was stratified during summer sampling. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 6 meters during July and August. Hydrolab profiles show that the lake was mixed during fall sampling dates. Holland Lake s 211/216 average calcium concentration was 21.2mg/L classifying it as a moderate risk for zebra mussel colonization. The 212 alkalinity level was reported at 77mg/L. No EWM was found during a survey conducted in 212. Holland Lake and Mission mountains. Photo courtesy Gravity Shots. 81 Whitefish Lake Institute

17 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Holland Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic Location: N, W 4 3 Oligotrophic Year Holland Lake Summer Temperature (F) Holland Lake Fall Temperature (F) Incipient Lethal Temperature ical Thermal Maximum /6/1998 8/11/25 11/15/211 8/26/212 11/2/212 7/31/213 1/17/213 8/7/214 1/21/214 9/8/215 1/29/215 Holland Lake Holland Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic /6/1998 8/11/25 11/15/211 8/26/212 11/2/212 7/31/213 1/17/213 8/7/214 1/21/214 9/8/215 1/29/ Whitefish Lake Institute

18 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lower Stillwater Lake Trophic Status: Oligo-mesotrophic Surface Area: 25 acres Maximum Depth: 53 feet (16.2 meters) Lower Stillwater Lake has a drainage area of 13,49 acres. Lower Stillwater Lake has the largest drainage area by far of all the medium sized lakes. The geology of the drainage area is composed of alluvium (37%) and the Piegan group (19%), Ravalli group (19%) and the Wallace formation (23%) of the belt series (Ellis & Craft, 28). Lower Stillwater is located in Flathead County 12 miles northwest of Whitefish on Highway 93 at an elevation of 975 meters. Surrounding land ownership are State Trust Lands and private. Fish distribution includes lake trout, mountain whitefish, northern pike, pumpkinseed sunfish, rainbow trout, westslope cutthroat trout, and yellow perch. There is one motorized public access site on the south end of the lake. Temperature and oxygen profiles show that the lake was stratified or weakly stratified during summer sampling. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 3 meters during July and August. Oxygen profiles show that Lower Stillwater Lake has been between avoidance and anoxic concentration thresholds for salmonids at depths greater than 6 meters. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 5-8 meters. Hydrolab profiles show that the lake was mixed during fall sampling dates. Lower Stillwater Lake s 21, 211 and 216 average calcium concentration was 36.4mg/L classifying it as a high risk for zebra mussel colonization. The 212 alkalinity level was reported at 13mg/L. The lake was surveyed for EWM in 212 and 213. No EWM was found. A 212 report of curly leaf pondweed was investigated and identified as Richardson s pondweed. Linda and Eric Sawtelle on Lower Stillwater Lake. Photo courtesy WLI. 83 Whitefish Lake Institute

19 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lower Stillwater Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Lower Stillwater Lake Summer Temperature (F) Lower Stillwater Lake Fall Temperature (F) Incipient Lethal Temperature tical Thermal Maximum -1 8/23/21-8 7/24/28 7/23/29 11/7/211 7/18/212 1/23/212 7/18/213 1/9/213 7/14/214 8/6/ /28/214 11/2/215 8/27/216 11/16/215 Lower Stillwater Lake Lower Stillwater Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic -1 8/23/21-8 7/24/28 7/23/29 1/2/21 7/18/212 11/7/211 7/18/213 1/23/212 7/14/214 8/6/ /9/213 1/28/214 8/27/216 11/2/ Whitefish Lake Institute

20 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Lower Stillwater Lake A macrophyte survey was conducted on Lower Stillwater Lake on August 27, 216. A total of 56 sites were surveyed for plants/algae. No EWM was found in the survey, but because northern milfoil is the most dominate plant, it indicates that Lower Stillwater has favorable habitat for EWM. There was more plant diversity found on Lower Stillwater than any of the other lakes monitored in 216. Dense mats of marigold, chara and pondweed on the north end of the lake were observed. There were also large quantities of filamentous algae observed on the east side of the islands. Lower Stillwater Lake Dominant Plant Distribution September 216 Water Moss Sago Pondweed Yellow Waterlily Bladderwort Pondweed (Undistinguishable) Marigold Elodea 4% 2% 2% 2% 2% 2% American Pondweed Northern Milfoil 4% 5% 38% 7% Filamentous Algae 13% 2% No Plants Present Chara Panoramic of Lower Stillwater Lake. Photo courtesy WLI. 85 Whitefish Lake Institute

21 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary 86 Whitefish Lake Institute

22 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Murphy Lake Trophic Status: Oligotrophic Surface Area: 141 acres Maximum Depth: 71 feet (21.6 meters) Murphy Lake has a drainage area of 3.66 acres. The geology of the drainage basin is a composite of alluvium (52%), Ravalli group belt series (26%) and the Piegan group belt series Ellis & Craft, 28). Murphy Lake is located in Lincoln County in the Kootenai National Forest of the Fortine Ranger District at an elevation of 96 meters. Surrounding land ownership is 1% USFS. Fish distribution includes largemouth bass and northern pike. There is one primitive motorized access located on the north end of the lake. Temperature and oxygen profiles show that Murphy Lake was evenly mixed or weakly stratified during summer sampling. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 7 meters during July and August. Hydrolab profiles show that Murphy Lake was mixed during fall sampling dates. Murphy Lake s 21, 211 and 216 average calcium concentration was 28.5mg/L classifying it as a high risk for zebra mussel colonization. In EWM surveys were conducted near the public access site yielding no suspect results, however, northern milfoil were found throughout the lake. Additional visual surveying is recommended based on ease of access, recreational use and number of macrophytes present. Murphy Lake boat ramp with informational signage on AIS. Photo courtesy WLI. 87 Whitefish Lake Institute

23 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Murphy Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Murphy Lake Summer Temperature (F) Murphy Lake Fall Temperature (F) Incipient Lethal Temperature cal Thermal Maximum 7/31/28 8/5/29 9/5/211 7/18/212 11/7/ /2/213 7/15/ /22/212 1/9/213 9/2/215 1/24/214 7/19/216 11/2/215 Murphy Lake Murphy Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic 7/31/28 8/5/29 9/5/211 7/18/212 11/7/ /2/213 7/15/ /22/212 1/9/213 9/2/215 1/24/214 7/19/216 11/2/ Whitefish Lake Institute

24 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Rogers Lake Trophic Status: Meso-oligotrophic Surface Area: 239 acres Maximum Depth: 19 feet (5.8 meters) Rogers Lake has a drainage area of 3,66 acres. The catchment is dominated by the Wallace formation belt series (75%) with the rest as glacial till (Ellis & Craft, 28). Rogers Lake is located in Flathead County at an elevation of 1,219 meters. This is the shallowest of the medium sized lakes included in the program. Surrounding land ownership is primarily private and Forest Service. Fish distribution records indicate a presence of arctic grayling, redside shiner, and westslope cutthroat trout. There is one primitive motorized public access located on the north end of the lake. Temperature and oxygen profiles show that Rogers Lake was evenly mixed during summer sampling. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 5 meters during August. Oxygen profiles vary considerably from year to year. Hydrolab profiles show that Rogers Lake was mixed during summer and fall sampling dates. Rogers Lake often ranks among the highest of medium lakes for total phosphorus and chlorophyll (a). The lake s 21, 211 and 216 average calcium concentration was 2.8mg/L classifying it as a moderate risk for zebra mussel colonization. The 212 alkalinity level was reported at 81mg/L. An EWM survey was conducted in 212 and 213 near the public access site yielding no suspect results, however, northern milfoil was found throughout the lake. Additional visual surveying is recommended based on ease of access, recreational use and number of macrophytes present. In 215, Rogers Lake ranked highest among medium lakes for total phosphorus. 89 Whitefish Lake Institute

25 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Rogers Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic 2 1 Location: N, W Year Rogers Lake Summer Temperature (F) Critical Thermal Maximum Rogers Lake Fall Temperature (F) Incipient Lethal Temperature 8/2/1998 8/9/22 8/2/25 8/29/26 8/14/212 8/19/213 8/5/214 8/18/215 8/16/216 1/22/21 11/8/211 11/1/212 11/5/213 11/5/215 Rogers Lake Fall Dissolved Oxygen (mg/l) /22/21 11/8/211 11/1/212 11/5/213 11/5/215 9 Whitefish Lake Institute

26 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Sophie Lake Trophic Status: Oligotrophic Surface Area: 221 acres Maximum Depth: 7 feet (21.3 meters) Sophie Lake is located in Lincoln County four miles northwest of Eureka on Highway 37 at an elevation of 792 meters. Surrounding land ownership are State Trust Lands, MFWP and private. Fish stocking records indicate a presence of rainbow trout and kokanee. Population surveys also found bluegill, bull trout, largescale suckers, northern pike and northern pike minnow. There is one motorized public access site located on the south end of the lake. Due to high water, the public access, dock, and campground were flooded in the spring/summer of 211and 212. Temperature and oxygen profiles show that Sophie Lake was stratified or weakly stratified during summer sampling. Temperature profiles show that the lake has been within the avoidance threshold range for salmonids at depths of up to 5 meters during July. Oxygen profiles show that Sophie Lake has been between avoidance and anoxic concentration thresholds for salmonids at depths greater than 13 meters. Depth profiles suggest that the ideal depth for salmonid habitation during summer months is between 6-12 meters. Hydrolab profiles show that Sophie Lake was mixed or weakly stratified during fall sampling dates. Sophie Lake s 21, 211 and 216 average calcium concentration was 23.1mg/L classifying it as a moderate risk for zebra mussel colonization. The 212 alkalinity level was reported at 11mg/L. An EWM survey was conducted in 212 near the public access site yielding no suspect results, however, northern milfoil was found throughout the lake. Additional visual surveying is recommended based on ease of access, recreational use and number of macrophytes present. Photos taken on June 22, 212 depicting Sophie Lake flooding. Photos courtesy Barb Hvizdak. 91 Whitefish Lake Institute

27 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary Sophie Lake Carlson's Trophic State Index (TSI) 1 9 Hypereutrophic Carlson's TSI (Total) Chlorophyll (a) Secchi Depth Total Persulfate Nitrogen Total Phosphorus 8 7 Eutrophic 6 5 Mesotrophic 4 3 Oligotrophic Location: N, W Year Sophie Lake Summer Temperature (F) Sophie Lake Fall Temperature (F) Incipient Lethal Temperature itical Thermal Maximum /31/28 7/3/29 7/28/21 8/13/211 7/16/212 7/16/213 7/22/214 8/1/215 7/18/216 11/4/211 1/22/212 1/8/213 1/22/214 11/2/215 Sophie Lake Sophie Lake Summer Dissolved Oxygen (mg/l) Fall Dissolved Oxygen (mg/l) Avoidance Hypoxic /31/28 7/3/29 7/28/21 8/13/211 7/16/212 11/4/211 7/16/213 1/22/212 7/17/214 1/8/213 8/1/215 1/22/214 7/18/216 11/2/ Whitefish Lake Institute

28 Northwest Montana Lakes Volunteer Monitoring Network 216 Program Summary 93 Whitefish Lake Institute