Aquatic Plant Management for Kirby Lake, Barron County

Background, Goals, Objectives, and Actions

March 2, 2013

Presented again on May 25, 2013

2012-13 Aquatic Plant Management Planning Project

• 2011 – Kirby Lake Management District harvests dead vegetation (reed canary grass) from the lake

– WDNR OK’s the permit, but wants the Lake District to complete an Aquatic Plant Management Plan before any future permits are issued

– Lake District approaches SEH to submit a grant application to support the completion of an APM Plan

• February 2012 - Aquatic Invasive Species Education, Planning, and Prevention Grant Application submitted to the WDNR on behalf of the Lake District

– $11,335.00 Total Project Cost

– $7,348.00 from the State to support aquatic plant management planning

– Was awarded in April 2012

Parts of the Project

• Aquatic plant survey work

• Watercraft inspection

• Aquatic invasive species monitoring

• Public input and education

• Aquatic Plant Management (APM) Plan

Public Input • Lake District Meetings

• Summer 2012 Lake Fair

• Newsletter

• Questionnaire

– Management recommendations summary and two questions about harvesting in the December newsletter

• APM Presentation

• SEH Project Link

Aquatic Plant Management Planning Project

www.sehinc.com/online/kirby-lake

since March 2013 - 23 people visited 59 times

last month - 7 people visited 12 times

What is an Aquatic Plant Management Plan?

• A working document

• A tool for the Lake District

• A valuable planning exercise

• A document required by the WDNR to continue aquatic plant management

Why?

The Threat of Aquatic Invasive Species

Local EWM Infestations

The threat is

very real! 20 mile radius

Native Plants Create Nuisance and Navigation Issues

Benefits of an Approved APM Plan

• Better understanding of lake and watershed characteristics

• Better understanding of existing aquatic plant density, distribution, and diversity

• Documentation of aquatic plant problems

• Protection of desirable aquatic plants

• Pros, cons, and impacts of possible plant management alternatives – Herbicides, harvesting, biological control, physical removal, bio-

manipulation, drawdown, bottom barriers, do nothing, etc. – Timing and target species – Conditions under which management for native or invasive species is

permitted

• Ability to implement management alternatives other than manual removal – Nuisance native plant control for navigation relief – Herbicide use for AIS control (if necessary)

• Easier permitting for approved activities

Lake Characteristics

Trophic Status of Kirby Lake

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

X

X

Trophic Status of Kirby Lake

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

X

X

Aquatic Plant Community

2012 Aquatic Plants • 49 different aquatic plant species

• No Eurasian watermilfoil or curly-leaf pondweed identified

• 2 aquatic plant species of “special concern” in Wisconsin – Robbins spikerush and Snail-seed pondweed

• 17 species (30%) with a high disturbance rating (most sensitive lake surveyed to date by ERS

2012 Aquatic Plants • 49 different aquatic plant species

• No Eurasian watermilfoil or curly-leaf pondweed identified

• 2 aquatic plant species of “special concern” in Wisconsin – Robbins spikerush and Snail-seed pondweed

• 17 species (30%) with a high disturbance rating (most sensitive lake surveyed to date by ERS

2006 vs. 2012 Aquatic Plants

Specific Changes

More watershield, bladderwort, and white-water lily

Less common waterweed and large-leaf pondweed

More Reed Canary Grass

Reasons for the changes?

• Less points sampled in 2006 due to inaccessibility

• Better taxonomy in 2012 survey

• Drought conditions changing lake chemistry (unconfirmed)

• Watershield, bladderworts, Farwell’s water milfoil, white-water lily, small pondweed all benefit from shallow depths and soft, acidic water

– Shallow, soft water, seepage lakes are considered to be a “natural community” of special concern in WI.

• Silver Lining (?)

– Existing conditions “may” not be “ideal” for the growth of CLP and EWM

Aquatic Plant Management Plan (Goals & Objectives)

– Preservation, Protection, and Restoration

• Preserve, protect, and restore the native plant species community in and around the lake to decrease susceptibility to the introduction of new aquatic invasive species

– Prevention

• Prevent the introduction and establishment of new aquatic invasive species through early detection and rapid response

– Management

• Maintain common navigation channels and individual riparian access lanes in areas of nuisance native plant and reed canary grass growth via mechanical and manual control

– Education and Awareness

• Continue public outreach and education programs on aquatic invasive species

– Research and Monitoring

• Develop a better understanding of the lake and the factors affecting lake water quality through continued and expanded monitoring efforts

– Adaptive Management

• Follow an adaptive management approach that measures and analyzes the effectiveness of control activities and modify the management plan as necessary to meet goals and objectives

1) Preservation, Protection, and Restoration

• Provide shoreland improvement/restoration informational materials to property owners

• Sponsor training workshops

• Provide for individual property evaluations

• Recognize property owners who make improvements

X

2) Prevention

• Watercraft inspection

– 4th of July Landing Blitz

• Aquatic invasive species monitoring

– Regularly scheduled time periods

• Educate property owners so they can monitor their own lake frontage for AIS

• Follow AIS Rapid Response Plan if a suspect AIS is identified

Management Alternatives

• Physical removal

– Hand-held rakes, cutters, and diver removal

• Mechanical harvesting

– Large-scale (Harvester Boat)

– Small Scale

• Cutters attached to boats, 4-wheelers, and lawn mowers

• Bottom rollers and surface sweepers

• Suction Dredging

• Aquatic herbicides

• Biological control

– Carp

– Insects

– Trophic status manipulation

• Nutrient management

• Habitat alteration

– Water level manipulation

– Shading (dyes)

– Bottom barriers

– Dredging

• No management

3) Recommended Management

• Manual or Physical Removal

– Near shore in 3-ft of water or less, solid bottom

– Hand pull or cut with weed rakes or razors

• Rakes or razors supplied by the Lake District

– Follow guidelines in NR 109

• Up to 30-ft including docks and swimming areas

• Remove plant material from lake

– Leave coarse woody debris

Management • Mechanical Harvesting

– Establish “common use navigation channels”

• 20-ft wide, 3-ft of water or more

– Establish “individual riparian access lanes”

• 10-ft wide, 3-ft of water or more

• shortest route to open water or common use navigation channel

– Harvested channels and lanes not to exceed 5% of the littoral zone

Why Harvesting?

• Advantages

– Immediate relief

– Most flexible

– Once established, harvested areas can be re-harvested without additional permits

– Site specific

– Vegetation is removed from the lake rather than left to die and decay

– Less impact on DO levels

– Some nutrients are removed with cut plants

– Basic habitat remains intact

– Water can be used immediately following management

– Cut vegetation can be good mulch

– Reed canary grass could be cut

• Disadvantages

– Not species specific

– By-catch of fish and other non-target organisms may be issue

– Cut vegetation can re-grow

– Floating fragments left by the harvester can be a problem

– Off-loading and disposal of cut vegetation can be an issue

• Where to dump it

• Possible odor

• Increased critter issues

– Launching and loading of harvester can be an issue

• Kirby access steep, with loose gravel

– Up front costs can be very high

Why Not Aquatic Herbicides?

• WDNR does not readily support the use of herbicides to control native plants (only for navigation purposes)

• Herbicides generally not effective for channel treatments. Much more effective at large area treatments

• Results are not immediate

• Does not remove vegetation, leaving plants to decay and release nutrients into the lake

• Different herbicides would target different plants, meaning a herbicide cocktail may be needed to provide complete relief, or a higher concentration of a single herbicide used

• Requires a licensed applicator

• Herbicides in the water, they don’t stay where put

• Cost per acre would be greater

Proposed

Harvesting

Plan

7,300 ft of

common use

navigation

channels, 20-ft

wide (3.4 acres)

Riparian access

lanes yet to be

determined

Upwards of 10-

20 tons of wet

vegetation (1/2 to

1 ton of dried

vegetation)

harvested

annually

Proposed

Harvesting

Plan

7,300 ft of

common use

navigation

channels, 20-ft

wide (3.4 acres)

Riparian access

lanes yet to be

determined

Upwards of 10-

20 tons of wet

vegetation (1/2 to

1 ton of dried

vegetation)

harvested

annually

This plan is not set in stone. Each year the

harvesting plan can be modified provided

the WDNR can be convinced that the

modifications are necessary. This requires

documentation. (see Appendix I: Nuisance

and Navigation Guidelines for Native Plant

Management)

Why not open larger

areas of open water

through harvesting?

-Doesn’t solve the

access to open water

issue

- More aquatic plants

removed, greater

chance for non-

natives to get in

- WDNR very

hesitant to issue

permits unless for a

stated need

Acquisition of a Harvester

• Purchase – Initial investment can be

expensive • $45,000 - $65,000 for a new small

harvester (4-6 ft cutting width)

– Requires a “driver/operator”

– Must have storage in the off-season, must provide maintenance

– Must establish off-loading, possible transport, and storage of cut vegetation

– Provides greatest flexibility

– Unlimited access to harvester

– Maybe some grant assistance available to buy a harvester

– No risk of introducing a new species into the lake

• Contract – Difficult to line up contracted

harvesting services

– Contracted services may have limited availability

• Must make arrangements annually

– $500 to $700 per acre harvested, under ideal circumstances

– Likely only one harvest per season

– Risk of introducing undesirable species

– No maintenance or storage required

– Still need to arrange off-loading, possible transport, and storage of cut vegetation

Inland Lake Harvester ILH-5x4 -100 “Mini”

Burlington, WI (5-ft cut, 4-ft deep, 100 cuft

payload) ($58,900.00) (a rebuilt H6-240 is

available at $70,000, $90,000 new)

Aquatic Weed Harvester WH4-75

Spooner, WI (4-ft cut, 4-ft deep, 75 cuft

Payload)

($46,000) *this one is currently being built

in Spooner, and is not completed

Eco-Harvester II, weed

cutter/puller/skimmer , Waupaca , WI (4-ft

cut, 4-ft deep, approx 100 cuft payload)

($45,000)

Cost Comparison: Harvesting vs. Herbicides

• Purchase of a Harvester (over 10 years)

– 3.5 acres x twice annually x 10 yrs. = 70 acres

– $46,000/70 acres = $657.00/acre

• Contracted Harvesting (annually)

– Approx. $180/hr x 12 hrs = $2,160.00

– $2,160/3.5 acres = $617.00/acre

• Herbicide Application (endothall at 4.0 ppm)

– 3.5 acres x 5-ft of water = 17.5 acre-feet

– Aquathol Super K (granular endothall)

• $336.00/acre-ft of water x 17.5 = $5,880 annually

• $5,880/3.5 acres = $1680.00/acre

– Aquathol K (liquid endothall)

• $200.00/acre-ft of water x 17.5 = $3,500 annually

• $3,500/3.5 acres = $1000.00/acre

*herbicide cost estimates are based on2013 price estimates from Lake Management Inc and

are subject to changes annually

4) Education and Awareness

• Aquatic Invasive Species

– Distribute AIS educational materials

– Maintaining signage at the public access

– AIS monitoring and watercraft inspection

• Aquatic plants, animal, and people impacts on the lake

– Sponsor public events including lake fairs, workshops, guest speakers

• Wildlife Monitoring

– Provide educational and informational material related to wildlife

• Loonwatch

• Citizen-based Monitoring Network

• Newsletter and Public Meetings

– Keep the property owners involved in planning and management

5) Research and Monitoring

• Continue participation in the CLMN expanded water quality monitoring program

• Continue and expand water quantity monitoring

– Lake level monitoring (at least weekly)

• Install a staff gage

– Precipitation monitoring

• Install at least one rain gage

• Participate in the Community Collaborative Rain, Hail, and Snow Program (CoCoRaHS)

• Develop a Comprehensive Lake Management Plan for Kirby Lake

6) Adaptive Management

• Annual review of management actions in the lake

– Modify if necessary

• Report annual management results to stakeholders

• 5-year timeline to implement management recommendations in this APM Plan

• Re-evaluate the recommendations in this APM Plan and the management actions therein at least every five years

Questions and Comments?