upper long lake improvement...

Upper Long Lake Improvement Study

By: Restorative Lake Sciences

November, 2014

Upper Long Lake Depth

Contours

Upper Long Lake Bottom

Hardness

Upper Long Lake Soils

Upper Long Lake Immediate

Watershed

• 900 acres

• Watershed is 7.4X lake

size = small to

moderate watershed =

moderate pollution

Upper Long Lake Invasive

Bi-valves

Upper Long Lake Water

Quality Sampling Locations

Upper Long Lake Water

Quality Data (July, 2014)

Upper Long Lake Sediment

Data (July, 2014)

Upper Long Lake Invasive

Species

Upper Long Lake Invasive

Species

Hybrid Watermilfoil

(Eurasian Watermilfoil + Native

Watermilfoil)

Grows thicker, wider, faster than EWM

and is VERY TOLERANT to herbicides!

EWM Overgrowth in Other Lakes:

Upper Long Lake Milfoil

Distribution

Upper Long Lake Starry

Stonewort Distribution

Upper Long Lake Invasive

Curly-leaf Distribution

Upper Long Lake Emergent

Invasive Distribution

Upper Long Lake Aquatic

Vegetation Biovolume

Upper Long Lake Native

Aquatic Plants

What Happens if We Kill Too Much

Vegetation ?

Toxic Blue-green algae

bloom, Spring Lake,

Ottawa County, MI

Lake may not be able to

break down plant matter

fast enough

What Will Happen If We Do

Nothing?

• EWM will displace native

aquatic plant species

• Fishery will decline in

quantity and quality

• Excessive die-off of

massive EWM beds will

cause major declines in

water quality parameters

• Hydrilla or other species

may invade and further

destroy the lake

Laminar Flow Aeration Components

End-on view:

non-turbulent

flow

Ceramic diffuser

head and anchor

CASE STUDIES OF AERATION ON

MILFOIL REDUCTION AND SEDIMENT

NUTRIENT REDUCTION IN OTHER

MICHIGAN LAKES

EWM Reduction of 80 acres with

LFA

Pickerel Lake, 2013 Pickerel Lake, 2014

Design courtesy of

Clean-Flo, Inc. &

Lake Savers

Changes in South Basin WQ before

and after Inversion Oxygenation

Date Water Column

DO

(mg/l)

Sediment

DO

(mg L-1)

Redox

Potential

(mV)

Nov 11, 2010

Nov 13, 2013

10.9± 1.2

11.9± 0.6

0.33±0.6

6.5±0.9**

-69.8±27

30.2±9.6**

** Statistically significant

Changes in South Basin Sediments before

and after Inversion Oxygenation

Date Sediment

NH3+

(mg/kg)

Sediment

Nitrate + Nitrite

(mg/kg)

Nov 11, 2010

Nov 13, 2013

331±97

192±52**

37.5±59

3.5±0.1**

Conclusions

• No significant differences in water column DO (due to shallow depths)

• Significant differences in water column redox potential (oxidative state post-aeration)

• Significant differences in sediment DO post-aeration (increase)

• Significant differences in both sediment ammonia and nitrate/nitrite (both decreased)

• This data set yields insight into inversion oxygenation mechanism

• Observed changes in sediments may also explain reduction in ammonia-loving aquatic vegetation (i.e. milfoil)

Mechanical Harvesting

Benefits of Harvesting

• Removes some plant

debris and associated

organic nutrient

• Can reduce need for

herbicides but is

generalist

• Should not be used on

species that fragment

Limitations of Harvesting

• Can increase biomass of

fragment-producers

• Does not exclude need

for treatments in “high-

maintenance” lakes

• Can create floating debris

• May need to be repeated

in single season due to

re-growth

Chemical Herbicides

• Applied to both exotic and native aquatic plants

• Most commonly used: 2,4-D, Reward, Triclopyr, Fluridone, Aquathol-K, CuSO4, Glyphosate

• Requires MDEQ permit; residue sampling may be required (i.e. Triclopyr, Fluridone)

• Shallow well restrictions, swimming restrictions, watering restrictions-Notifications required

Biological Control: Weevil

Benefits

• Non-chemical agent

• Self-propagating

• Fast turn over rate on life

cycle within a given

season

• No strong evidence of

fishery predation

Limitations

• Uncertainty exists on

stocking density needs

• Stocking density needs

may be highly site-

specific

• May not be able to keep

up with fast growth rate of

EWM growth

• Response to hybrid

strains of milfoil??

2015-2019

Recommendations

• Treat existing EWM with Triclopyr granular or liquid

with adjuvant (proposed to be mid May-mid June)

in 2015

• Harvest 3-4 weeks post-treatment to remove dead

EWM biomass

• Install LFA aeration system and use

enzymes/bacteria to reduce the muck that is

feeding the EWM (mostly ammonia and nitrate)

• Implement oversight and monitoring program (RLS)

along with community education project

• Restoration instead of stagnant management