Amnicon & Dowling Lakes Aquatic Plant Management

Planning Project

Project Background

• Aquatic Invasive Species Education, Prevention and Planning Grant Application

– Submitted to WDNR in August 2011

– Awarded in October 2011

• $33,374.00 Total Project Cost

– State Share = $25,030.00

– Amnicon-Dowling Lake Management District Share = $8,344.00

• Original End Date – June 30, 2013

– Extended End Date – December 31, 2013

Objective of the Project

• What is an Aquatic Plant Management (APM) Plan?

– A working document used to guide appropriate aquatic plant management

– A tool for the Lake District to use to educate and inform property owners and lake users

– A valuable exercise in planning to help understand the complexities in dealing with aquatic plants

– DNR required document to complete aquatic plant management including non-native invasive species and native plants

Complete an Aquatic Plant

Management (APM) Plan for both

lakes

•Approved by both the ADLMD

and the WDNR

Parts of the Project

• Aquatic plant survey on both lakes

– Early season curly-leaf pondweed and Eurasian water milfoil

– Mid season all aquatic plants

• Water quality review

– Current

– historical paleocore

• Gather public input

– Lake Use Survey

– Draft APM Plan comment

• Aquatic Invasive Species (AIS)

– Watercraft inspection, AIS monitoring, AIS education and outreach, purple loosestrife beetle assessment

Aquatic Plant Surveys - 2012

• Completed by Endangered Resource Services, LLC

– Matt Berg, Proprietor

• Final Aquatic Plant Survey reports completed in late 2012 and distributed to the Lake District

Highlights of the Plant Survey Work

Curly-leaf Pondweed (CLP) Eurasian water milfoil (EWM)

Curly-leaf Pondweed in Amnicon • 5.4 acres in 2012

• 1.4% of total lake surface area

• Found in 4-9 ft of water

• Monotypic at 6-ft

• Exploits disturbed areas

• Fills in where other plants begin to thin

• Likely impacting wild rice growth

More AIS

Purple

Loosestrife

Reed

Canary

Grass

Chinese

Mystery

Snails

Native Plants – Amnicon The Good!

501 points sampled, Maximum depth of plant growth = 11-ft,

(43.5%) of total surface area

-Littoral Zone =

56% of the lake

-60 different plant

species

-3.66 species/site

-7 extremely high

value or sensitive

species

-Ave CC value =

6.8 out of 10

Wild Rice

Widely scattered in south and

southwest bays, none dense or

harvestable

23 survey points with wild rice

Native Plants – Amnicon Not so Great…

Average Density

2.21 out of 3

Native Plants – Dowling The Good…but not so great

253 points sampled, Maximum depth of plant growth = 7-ft,

11.5% of total surface area, only 30% of littoral zone

-Littoral Zone =

38% of the lake

-33 different plant

species

-1.79 species/site

-Only 3 high value

or sensitive species

-Ave CC value =

6.3 out of 10

-No wild rice

Native Plants – Dowling Not so great…

• Not much vegetation in the lake

Nitella sp.

Watershield

Current Water Quality – Amnicon & Dowling

• Amnicon

– Plant dominated

– Ave. water clarity = 6-ft

– Ave. Total Phosphorus = 24.6 ug/l

– Ave. Chlorophyll a = 8.3 ug/l

• Dowling

– Algae dominated

– Ave. water clarity = 3.6 ft

– Ave. Total Phosphorus = 35.5 ug/l

– Ave. Chlorophyll a = 18.7 ug/l

Amnicon

Dowling

Trophic Status

http://www.hillsborough.wateratlas.usf.edu/shared/learnmore.asp?toolsection=lm_tsi

X

X

Amnicon

Dowling

Historic Water Quality – Amnicon & Dowling Top-Bottom Paleocore

• Amnicon – Top (current) TP: 26 ug/L

– Bottom (historic) TP: 25 ug/L

– Top: > aquatic vegetation

– Bottom: < aquatic vegetation

• Dowling – Top (current) TP: 80 ug/L

– Bottom (historic) TP: 26 ug/L

– Top: < aquatic vegetation

– Bottom: > aquatic vegetation

Public Use Survey 300 surveys mailed out, 95 returned (31.6%)

• Amnicon

– 59 surveys returned

– Residency

• Permanent – 29

• Undeveloped Land – 1

• 2nd Home – 7

• Cabin – 23

– Ave. Time on Lake

• 26.4 years

– Minimum – 1 year

– Maximum – 90 years

• Dowling

– 36 surveys returned

– Residency

• Permanent – 10

• Undeveloped Land – 4

• 2nd Home – 3

• Cabin – 19

• Mobile Home – 1

– Ave. Time on Lake

• 21.3 years

– Minimum – 1 year

– Maximum – 84 years

Top Lake Uses

• Amnicon

– Swimming

– Rest/Relaxation

– Fishing

– Wildlife viewing

– Quiet Sports

• Changes

– Split between “no changes” and “worsened”

– Greatest Changes

• Game fishing, pan fishing, motorized sports, and swimming

• Dowling

– Swimming

– Fishing

– Rest/Relaxation

– Quiet Sports

– Wildlife viewing

• Changes

– Slightly “worsened”

– Greatest Changes

• Game fishing, pan fishing, and swimming

Lake Characteristics

• Amnicon

– Rooted vegetation, green scum, motorized boats, and use of jetskis increased

– Wild rice decreased

• Septic System Check

– 55.9% would support

– 18.6% would oppose

• Water Quality

– 61% Fair, 15% Good, 20% Poor

• Dowling

– Green scum, use of jetskis, and noise pollution increased

– Public use and garbage in the lake decreased

• Septic System Check

– 44.4% would support

– 11.1% would oppose

• Water Quality

– 28% Fair, 14% Good, 47% Poor

What Most Affects Water Quality?

• Amnicon

– Faulty septic systems

– Dead and dying vegetation

– Lawn runoff and shoreland erosion

– Others

• Water level, road next to lake, AIS, flooding

• Dowling

– Faulty septic systems

– Dead and dying vegetation

– Others

• Water level

The Lake Community generally supports removing

AIS from the system, providing property improvement

incentives, dredging, and update of septic systems.

Knowledge of Aquatic Invasive Species

LOW

LOW

LOW LOW

LOW

LOW

SOME

SOME At least 55.8% would attend an

AIS Training Session!

Support for Aquatic Plant Management Alternatives

• Amnicon

– Most Support

• Mechanical harvesting

• Physical removal

– Least Support

• No management

• Chemical herbicides

– Who Should Be Responsible?

• ADLMD

• WDNR

• Dowling

– Most Support

• Physical removal

• Mechanical harvesting

– Least Support

• Chemical herbicides

• Biological control

– Who Should Be Responsible?

• ADLMD

• WDNR

Wild Rice 2010 Ceded

Territory Manoomin

Inventory

ERS, August 2012

SEH, August 2012

Conclusions • Property owners on both lakes support

implementing aquatic plant management actions

• Management of CLP is necessary on Amnicon

• Management of nuisance native aquatic vegetation is necessary on Amnicon

• Protection of existing beds of aquatic plants and possible reestablishment of aquatic plants is necessary on Dowling

• Greater AIS education effort on both lakes is needed to help protect the lakes from future introductions

• Wild rice protection will impact all aquatic plant management options; at least on Amnicon

Preliminary Aquatic Plant Management Recommendations

• Continue AIS prevention and monitoring efforts on both lakes

• Provide greater AIS Education efforts for property owners on both lakes

• Continue water quality monitoring on both lakes

• Protect and enhance wild rice waters in Amnicon

– Possibly reestablish/introduce wild rice on Dowling

• Continue purple loosestrife and other AIS management efforts

• Implement aquatic plant management actions that will maintain or improve water quality in both lakes

Aquatic Plant Management Actions

• Encourage/support physical removal of nuisance aquatic plants and aquatic invasive species

– NR 107 – It is legal to remove aquatic vegetation from the lake in an area up to 30-ft wide without a permit provided all plant material is removed from the lake

– Physical removal of AIS is not restricted provided it is removed from the lake

• Mechanical harvesting

– Of CLP in areas where wild rice will not be impacted

– Of nuisance aquatic vegetation in designated navigation channels

– Of access corridors between docks and open water or navigation channels

Management Actions continued:

• Work with Tribal Resources to determine a wild rice restoration plan in Amnicon

– Re-seeding in CLP harvesting areas

• Consider dredging of navigation corridors if aquatic plant harvesting does not provide adequate relief

– Will require a separate “dredging” plan to be devised

• Implement a more complete water level monitoring and management program

– Lake level monitoring

– Stream flow between lakes

Management Actions continued:

• Provide education materials related to shoreland improvements and best management practices

• Design and implement a shoreland improvement incentives program

– Design and installation of rain gardens, buffer zones, shoreland restoration, and runoff diversion projects

• Individual property owners

• Roadway right-of-ways

• Consider comprehensive lake management planning for water quality

– Near shore and watershed runoff

– Septic system survey

– Internal loading

The End

Questions?