MEMORANDUM Comfort Lake-Forest Lake Watershed District

Transcription

1 MEMORANDUM Comfort Lake-Forest Lake Watershed District To: Board of Managers Date: December 7, 2016 From: Mike Kinney Subject: 2016 Watercraft Inspections and AIS Report Summaries Watercraft Inspection Summary Presentation Mike Sorensen will provide a summary presentation of the 2016 watercraft inspection program results. He will cover topics such as: the total number of inspection hours logged at each access, the total number of inspections performed at each access, the total number of drain plug violations, and more. He has already sent detailed lake-specific reports to each of the three local lake associations. Aquatic Invasive Species Report Summaries and Maps Additionally, Blue Water Science maps and summaries of AIS surveys performed in 2016 will be provided at the December meeting. These summaries will include the main takeaways from the surveys which will inform planning for The full reports will be submitted for Board review at the January 26, 2016 regular board meeting. Steve McComas will give a presentation on his findings at the January meeting as well. District and engineering staff have begun planning for 2017 AIS program activities using available information from Blue Water Science, experiences from 2016, and 2017 budget figures. Attached: 2016 Watercraft Inspection Yearend Summary

2 Comfort Lake Forest Lake Watershed District 2016 Watercraft Inspections In 2016, 4 full-time level 1 inspectors and 3 full-time level 2 inspectors operating a decontamination unit spent 3,077.5 hours at landings in the CLFLWD inspecting watercraft and educating boaters. 4,033 inspections were completed this year. This is up from 3,877 inspections completed in Total Inspection Hours Per Season (Forest Lake, Bone Lake, Comfort Lake) 3, , Roughly 1% of boaters entering the water had plants, animals, water, mud etc. on their boat at the time of inspection. This is similar to % of boaters arriving at the launch had their drain plug in. This is down from 2.7% in , , Inspectors averaged 1.3 inspections per hour. This is up from 1.1 inspections per hour in

3 Entrance inspections were performed on: 231 watercraft that had previously been in spiny water flea-infested lakes Of this, 36 were in the infested lake less than 24 hours earlier. Previous Locations of Watercraft Prior to Launching at Bone Lake, Comfort Lake or Forest Lake 83 watercraft that had previously been in starry stonewort-infested lakes Of this, 8 were in the infested lake less than 24 hours earlier. Spiny Water Flea Starry Stonewort *Zebra mussels have been found in Forest Lake, however they have not been found in any other District Lake therefore zebra mussels infested lakes are included in this identification.

4 Bone Lake, July 15, 2016 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Bone Lake, Washington County, Minnesota in 2016 Delineation Treatment Assessment CLP April 15, May 16 No treatment June 2 and 14 EWM May 16, July 15 August 3 (0.69 acres) September 14 Prepared for: Comfort Lake/Forest Lake Watershed District Forest Lake, Minnesota December 2016 Prepared by: Steve McComas Jo Stuckert Blue Water Science

5 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Bone Lake, Washington County, Minnesota in 2016 Summary Curlyleaf Pondweed (CLP) Delineation, Treatment, and Assessment: Bone Lake (MnDNR ID # ) is a 221 acre lake located in Washington County, Minnesota. An initial curlyleaf pondweed delineation was conducted on April 15, 2016 by Blue Water Science to characterize areas that could be treated. Results of the curlyleaf delineation on April 15, 2016 found curlyleaf pondweed present at 3 sample sites. No areas were delineated for treatment. However, a curlyleaf assessment conducted on June 2, 2016, found curlyleaf pondweed had increased to 39 sites at light to heavy densities. A second curlyleaf assessment conducted on June 14, 2016 found curlyleaf at 42 sites with light to heavy growth (Figure S1). It appears curlyleaf had sprouted and grew in a number of areas throughout June. This type of growth for curlyleaf pondweed in June is fairly uncommon. Figure S1. [left] Curlyleaf pondweed was found at 3 sample sites in Bone Lake on April 15, [right] Curlyleaf pondweed was found at 42 sample sites on June 14, Key: green = light growth, yellow = moderate growth, and red = heavy growth. -i-

6 Eurasian Watermilfoil (EWM) Delineation, Treatment, and Assessment: Eurasian watermilfoil (EWM) was verified in Bone Lake in In 2016, an initial EWM delineation was conducted on May 16 and 3 areas totaling 3.2 acres were delineated. However most of the EWM growth was either to close to water lilies or water lilies were growing within the delineated area. Treatment was not conducted and a second delineation was conducted on July 15, EWM was found at 36 sites, mostly on the north and south ends of the lake, with light to heavy growth out to 4 feet of water depth (Figure S2). Two areas totaling 0.6 acres were delineated for treatment. On August 3, 2016, a total of 0.69 acres of EWM was treated in 2 areas (Figure S2). A follow-up assessment was conducted on September 14, 2016 and a several areas of heavy EWM growth mainly in the south end of the lake were observed. In addition, EWM distribution had significantly increased compared to the July 15 survey. EWM was found in patches of light growth around much of the nearshore area of Bone Lake. This widespread EWM distribution had not previously been observed. It is difficult to predict if this widespread growth will be present in 2017 or if it will die back over the winter and not be present in Figure S2. [left] EWM coverage for Bone Lake on July 15, [right] EWM coverage for Bone Lake on September 14, Key: green = light growth, yellow = moderate growth, and red = heavy growth. -ii-

7 Heron Taking Flight off a Trapnet in Little Comfort Lake, September 2016 Fish Survey for Little Comfort Lake, 2016 Fish Survey Conducted: September 14-16, 2016 Minnesota DNR Permit Number: Prepared for: Comfort Lake/Forest Lake Watershed District and Minnesota DNR Prepared by: Steve McComas and Jo Stuckert Blue Water Science St. Paul, MN September 2016

8 Fish Survey for Little Comfort Lake, 2016 Summary Fish Surveys: A total of 12 fish species were sampled using 4 trapnets set over 2-nights in Little Comfort Lake on September 15-16, The fish catch was dominated by bluegill sunfish. The number of bluegills caught per net was high with the average haul of 84.4 bluegills per net (Table S1). This is higher than the normal range of bluegill sunfish per lift for a lake like Little Comfort lake. In the 2016 survey, 2 adult carp were sampled for an average of 0.3 carp/net. This represents a low to moderate carp abundance. Carp have been sampled in previous fish surveys as well also at low numbers (Table S1). Carp likely have a low to moderate impact on water quality in Little Comfort Lake. It is likely that carp can move back and forth from Comfort to Little Comfort through the Highway 8 culvert as well. The abundant bluegill population should limit successful in-lake carp spawning in Little Comfort Lake. Table S1. Little Comfort Lake trapnet results for the fish survey conducted in 1980, 1985, 1990, and 2000 by the MNDNR and in 2016 by Blue Water Science. Fish data are shown as fish/trapnet June 20 (MnDNR) 1985 June 17 (MnDNR) 1990 June 18 (MnDNR) 2000 June 22 (MnDNR) 2016 September 15 and 16 (8 nets) (Blue Water Science) DNR Range Black bullhead Black crappie Bluegill Bowfin (dogfish) Brown bullhead Carp Golden shiner 0.8 Green sunfish Hybrid sunfish NA Largemouth bass Northern pike NA Pumpkinseed Walleye 0.1 White crappie White sucker Yellow bullhead Yellow perch Summary - i

9 Curlyleaf Pondweed in Forest Lake on June 10, 2016 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Forest Lake, Washington County, 2016 Delineation Treatment Assessment CLP April 12, 2016 May 2, 2016 (113.7 acres) June 10, 2016 EWM June 10, 2016 July 18, 2016 (13.9 acres) September 15, 2016 Prepared for: Comfort Lake/Forest Lake Watershed District Forest Lake, Minnesota Prepared by: Steve McComas Blue Water Science St. Paul, MN December 2016

10 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Forest Lake, Washington County, 2016 Summary Curlyleaf Pondweed (CLP) Delineation, Treatment, and Assessment: Curlyleaf pondweed distribution and abundance were evaluated April 12, Later, on May 2, 2016 based on that delineation, a total of 113 acres on the 2,271 acre lake were treated to control excessive growth of curlyleaf. A follow-up curlyleaf assessment was conducted on June 10, 2016 In the delineation survey, curlyleaf was somewhat widespread (Figure S1) and potential future heavy growth was estimated at 113 acres. A total of acres of curlyleaf areas were treated in May 2, The June curlyleaf assessment found curlyleaf growth was light to heavy (Figure S1). Curlyleaf control in the treated areas was below expectations. Several treated areas had poor control. Based on records submitted by the applicator, average water depths used to calculate the quantity of gallons of herbicide to apply were too low and areas were under-dosed with Aquathol, likely producing poor control. This will be corrected in Figure S1. [left] DELINEATION: Map of curlyleaf pondweed distribution from the April 12, 2016 survey. Approximately 114 acres were delineated for CLP treatment. Treatment areas are outlined in red. [right] ASSESSMENT: Map of curlyleaf pondweed assessment sites for June 10, Key: green dots = light growth, yellow dots = moderate growth, red dots = heavy growth, and black dots = no curlyleaf growth. Red outline areas indicates treatment areas. Purple line is the boat track. -i-

11 Forest Lake Curlyleaf Treatment Areas for Figure S2. Curlyleaf treatment areas in 2009 through ii-

12 Eurasian Watermilfoil (EWM) Delineation, Treatment, and Assessment: EWM distribution and abundance were evaluated June 10, Based on that delineation, a total of 13.9 acres on the 2,271 acre lake were treated on July 18 to control heavy growth of Eurasian watermilfoil. About 2 months after the EWM treatment, an EWM assessment on September 15, 2016 found good control in the treated areas with mostly light growth in a few scattered spots. No EWM was observed in Lakes 2 and 3 in 2016 (Figure S3). Figure S3. [left] DELINEATION: Map of EWM distribution from the June 10, 2016 survey. Approximately 13.9 acres were delineated for EWM treatment. [right] ASSESSMENT: Map of EWM assessment on September 15, Key: green dots = light growth, yellow dots = moderate growth, red dots = heavy growth, and black dots = no EWM growth. Forest Lake EWM Treatment Areas for 2015 and 2016 Figure S4. Curlyleaf treatment areas in 2015 and iii-

13 Flowering Rush in Forest Lake, July, 2016 Flowering Rush Delineation, Control, and Assessment for Forest Lake, Washington County, Minnesota, 2016 Delineation: July 14 and 15, 2016 Herbicide Treatments on 36 acres: August 3 and 31, 2016 Assessment: September 21, 2016 Prepared for: Washington County and Comfort Lake/Forest Lake Watershed District Prepared by: Steve McComas Blue Water Science December 2016

14 Flowering Rush Delineation, Control, and Assessment for Forest Lake, Washington County, Minnesota, 2016 Summary In 2016, Forest Lake flowering rush coverage was delineated at 83,189 square feet (1.9 acres) on July 14 and 15, 2016 (Table S1). After controlling flowering rush with herbicide treatments, flowering rush coverage was found to have decreased to 9,183 square feet (0.21 acres) on the assessment survey on September 21, This was a decrease of flowering rush coverage of 89%. Most of the area that decreased was from large flowering rush beds that were treated twice with a diquat herbicide. Only 3 new sites, small in area, appeared from July to September in The third year of the flowering rush program was At the end of 2016, a total of 243 sites of flowering rush had been observed from 2014 to On the September 21, 2016 assessment date, 81 sites of flowering rush were observed. The area of flowering rush decreased from October of 2014 to September of 2016 indicating the flowering rush control program was reducing the distribution and density of flowering rush. Although the estimated total area of flowering rush was around 0.21 acres in September of 2016, a typical flowering rush response is for regrowth from the rhizomes and some regrowth would be expected in Continuing to control areas of flowering rush should reduce abundant regrowth but it appears eradication will be a challenge. The steps for controlling flowering rush in the next few years include the following three methods. 1. Continue treating large areas of flowering rush with diquat. 2. Cut or treat small patches 2 or 3 times/season. 3. Continue to remove flowerheads before seeds are produced which should help reduce areas of flowering rush colonization. Table S1. Summary of flowering rush sites and areas for 2014, 2015, and July 22, 2014 (Delineation) Number of sites with plants 1 st Lake 2 nd Lake 3 rd Lake Total Area Area Area Number of (sf) (sf) (sf) sites with Number of sites with plants Number of sites with plants , ,990 (estimated based on Oct 8 survey) plants 34+ (not including 3 rd lake) Area (sf) 340,740 (estimated) 2 nd Lake was treated with diquat on September 9, 2014 October 8, , , ,125 (Assessment) July 17, 2015 (Delineation) , , ,299 2 nd and 3 rd Lakes were treated by cutting in July and August; 3 rd Lake treated with diquat twice in August, 2015 September 28, 2015 (Assessment) , ,411 (new sites compared to 2014) (11) -- (13) -- (25) -- (49) -- July 14 and 15, 2016 (Delineation) , , ,189 2 nd and 3 rd Lakes were treated with diquat twice in August, 2016 September 21, 2016 (Assessment) , ,183 (new sites compared to 2015) (0) -- (0) -- (3) Summary - i

15 Initial Flowering Rush Delineation - July 14-15, 2016 A flowering rush delineation was conducted on July 14-15, A total of 182 flowering rush sites with areas ranging from 5 square feet to greater than 1,000 square feet were found (Figure S1). A majority of the flowering rush sites were small and somewhat scattered in the nearshore area often in water depths of less than 3 feet. Although 3 areas of continuous flowering rush beds were delineated, many of the small patches could be considered to be continuous as well. A total area of 83,189 square feet of flowering rush was estimated in the July delineation. Figure S1. Flowering rush delineation on July 14-15, Summary - ii

16 Flowering Rush Treatment Map A total of 36 acres of flowering rush was treated with diquat on two occasions on August 3 and August 31. Although the area of flowering rush did not total 36 acres, previous treatment research in the Detroit Lakes area found treating large areas was more effective than treating small, individual patches. The applicator delineated the large areas to be treated. A number of small patches were treated as well. Also an area of about 600 square feet by a public access on Lake 2 was handcut on several dates by CLFLWD staff as an experiment. Figure S2. Flowering rush treatment areas for August 3, and 31, Summary - iii

17 Flowering Rush Assessment About 3 weeks after the August 31 diquat application, flowering rush sites in Forest Lake were assessed. Except for 2 areas in 3 rd Lake, flowering rush control was very good (Figure S3). Flowering rush was found at 81 sites, mostly in small patches of less than 100 square feet. Figure S3. Flowering rush assessment on September 21, Summary - iv

18 Underwater View of Coontail with Attached Filamentous Algae in Comfort Lake on June 14, 2016 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Comfort Lake and Little Comfort Lake, Chisago County, 2016 Delineation Treatment Assessment CLP April 15, 2016 No treatment June 14, 2016 EWM May 6 and 22, 2016 May 11, 2016 (7.5 acres) June 14 and September 14, 2016 Prepared for: Comfort Lake/Forest Lake Watershed District Forest Lake, Minnesota December 2016 Prepared by: Steve McComas Jo Stuckert Blue Water Science

19 Curlyleaf Pondweed and Eurasian Watermilfoil Delineation, Treatment, and Assessment for Comfort Lake and Little Comfort Lake, Chisago County, 2016 Summary Curlyleaf Pondweed Delineation and Assessment Surveys: A curlyleaf pondweed delineation for distribution and abundance was conducted on both Comfort and Little Comfort Lakes on April 15, In the delineation survey, curlyleaf was found at 1 site in Comfort Lake and at 1 site in Little Comfort (Figure S1). No areas were delineated for treatment. About 2 months later, in the June curlyleaf assessment, curlyleaf was found at 5 sites in Comfort and at 2 sites in Little Comfort. Where curlyleaf was present, growth was light in June (Figure S1). Figure S1. [left] DELINEATION: Map of curlyleaf pondweed distribution on the April 15, 2016 survey. TREATMENT: No curlyleaf pondweed treatment was conducted in [right] ASSESSMENT: Map of curlyleaf pondweed assessment sites for June 14, Key: black dot = no curlyleaf, green dot = light growth, yellow dot = moderate growth, and red dot = heavy growth. -i-

20 Eurasian Watermilfoil (EWM) Delineation, Treatment, and Assessment Surveys: An Eurasian watermilfoil delineation for distribution and abundance was conducted on May 6, 2016 and EWM was found at 72 sites. Four treatment areas totaling 7.5 acres were delineated. Treatment of the 7.5 acres in 4 areas occurred on May 11 (Figure S2). A subsequent EWM follow-up survey occurred on May 22 and additional EWM that was missed on the May 6 delineation was observed primarily in the southeast end of Comfort Lake (Figure S2). After the May 11 treatment, which was based on the May 6 delineations, EWM had decreased and was found at 19 sites in the June 14, 2016 assessment. EWM growth was light to moderate with good control in the treated areas (Figure S2). At the end of the summer, another EWM assessment was conducted. EWM was found to have sprouted in a number of new spots including new areas on the western shore in the nearshore area around Comfort Lake. A total of 58 EWM sites were found. It appears EWM is fairly well distributed around much of Comfort Lake in relatively shallow water, generally less than 5 feet. Figure S2. [top-left] DELINEATION: Map of EWM distribution from the May 6 and 22, 2016 survey. [top-right] ASSESSMENT: Map of EWM sites for June 14, [bottom-left] ASSESSMENT: Map of EWM sites for September 14, TREATMENT: EWM treatment occurred on May 11, Key: black dot = no curlyleaf, green dot = light growth, yellow dot = moderate growth, and red dot = heavy growth. -ii-