Annual Bolton Lakes Watershed Community Forum

Newhoca Lodge October 14, 2014

Northeast Aquatic Research George Knoecklein

Bolton Lakes

Watershed Lower Bolton Lake = 2,379 acres Middle Bolton Lake = 1,946 acres Upper Bolton Lake = 1,293 acres

Specific drainage basins: Lower Bolton = 258 acres Middle Bolton = 532 acres Upper Bolton = 1,243 acres

Percentage upstream basin: Lower Bolton = 88 % Middle Bolton = 71 % Upper Bolton = 100 %

Upper Bolton Lake

Surface area = 50.3 acres Maximum depth = 7 feet Total volume = 350 acre-feet ? Drainage area = 1,242.7 acres Residence time / Flushing rate

0.27 years / 3.7 times per year

Middle Bolton Lake

Surface area = 121 acres Maximum depth = 18 feet Total volume =1,126 acre-feet Drainage area = 1,825 acres Mean depth 9.8 feet Residence time / Flushing rate

0.89 years / 1.1 times per year

Lower Bolton Lake Surface area = 175 acres Maximum depth = 18 feet Total volume =1,668 acre-feet Drainage area = 2,204 acres Mean depth 9.5 feet Residence time/Flushing rate

0.72 years /1.4 times per year

Summary of Morphometric Characteristics

Lake Area -acres-

Volume -acre-feet-

Basin -acres-

% direct

% upstream Retention -years-

Flushing Rate

Upper 50 (50) 350 1,293 ~ 100 0.27 3.7

Middle 121 (60) 1,126 1,946 29 71 0.89 1.1

Lower 175 (151) 1,668 2,379 11 88 0.72 1.4

Monitored Inlets

26 inlets to Middle and Lower Bolton Lakes monitored for storm event phosphorus inputs

Phosphorus concentrations at three dams

0

5

10

15

20

25

30

35

Mar Apr May Jun Jul Aug Sep

Tota

l Pho

spho

rus

Months 2014

Upper Bolton

Middle Bolton

Lower Bolton

Total phosphorus concentrations in Lower Bolton Lake

0

10

20

30

40

50

60

70

80

90

Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Tota

l Pho

spho

rus

-ppb

Months 2013 - 2014

TopMiddleBottom

Phosphorus concentrations MBL outlet and LBL surface

0

5

10

15

20

25

30

35

40

45

50

Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Tota

l Pho

spho

rus

-ppb

Months 2013 - 2014

Middle Bolton Dam

Lower Bolton Surface

Water Clarity in Lower and Middle Bolton

0

0.5

1

1.5

2

2.5

3

3.5

Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov

Wat

er C

larit

y -m

eter

s

2013-14

Solid blue = Mid. Bolton

Water Clarity and Phosphorus in LBL

0

5

10

15

20

25

30

35

40

45

500.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov

Tot

al P

hosp

horu

s

-ppb

Wat

er C

larit

y -m

eter

s

2012 - 2013 - 2014

Water Clarity

Phosphorus

Winter Water Level Drawdown of Middle Bolton Lake

-80

-70

-60

-50

-40

-30

-20

-10

0

Wat

er L

evel

Dow

n (i

n)

Middle Bolton Lake Levels During Deep Drawdowns 2006 - 2010

Bathymetric Map of Middle

Bolton Lake

Approx. location of drain pipe from Middle to Lower Bolton Lake

Approximately 50 acres of shoreline (40%) is exposed

during 6 foot drawdown About 20 acres (16%) during a 3

foot drawdown and 10 acres (8%) during an 1.5 foot

drawdown

Cross-section of Middle Bolton Lake

0

2

4

6

8

10

12

14

16

18

20

0 200 400 600 800 1000 1200 1400 1600 1800

Wat

er D

epth

in fee

t

Distance in feet

Lake level during deep drawdown

Outlet pipe to Lower Bolton Lake -9feet below surface

Watershed Management

Plan

Management of the watershed for what purpose? Lake Water Quality? Control Bluegreen algae blooms? Other ?

17

Creeping Normalcy “Perhaps the commonest circumstance under which

societies fail to perceive a problem is when it takes the form of a slow trend concealed by wide up-and-

down fluctuations” - Jared Diamond

Collapse

Bolton LakesBolton Lakes WatershedUpper Bolton LakeMiddle Bolton LakeLower Bolton LakeSummary of Morphometric CharacteristicsMonitored InletsPhosphorus concentrations at three damsTotal phosphorus concentrations in Lower Bolton LakePhosphorus concentrations MBL outlet and LBL surface Water Clarity in Lower and �Middle BoltonWater Clarity and Phosphorus in LBLWinter Water Level Drawdown of Middle Bolton LakeBathymetric Map of Middle Bolton LakeCross-section of Middle Bolton LakeWatershed Management PlanCreeping Normalcy