Water Quality in Mark Twain LakeNovember 17, 2015

Dan Obrecht

Senior Research Associate

obrechtd@missouri.edu

University of Missouri-Columbia

The Missouri Department of Natural Resources

Region VII, US Environmental Protection Agency, through

the Missouri Department of Natural Resources, has

provided partial funding for this project under Section 319

of the Clean Water Act

OutlineWater Quality Parameters

What, Where, How & Why?

Variability

Space & Time

Mark Twain vs. other Missouri reservoirs

WATER QUALTY PARAMETERS

Phosphorus

& Nitrogen

Nutrients = Fertilizer

Nutrient sources:runoff from farm fields

animal waste

excess fertilizer application

urban runoff

failing septic systems

sewage treatment plants

Algae

Diverse group of organisms

Mostly microscopic

Have photosynthetic pigment

Require sunlight, water, CO2 & nutrients

Chlorophyll is our measure of the

amount of algae in a water sample

Suspended Sediment

Sources of Sediment:

Farm fields

Development/

construction

Bank

and

Shoreline

erosion

Urban

Runoff

Secchi Transparency

Clarity determined

by amount of

algae and

suspended

sediment

Readings in Missouri

range 3” to 360” (30

feet!) with an

average ≈ 39”

How do the

parameters relate

to each other?

10 100

10

1

Missouri

Mark Twain Lake100

20 40 605 200

2

4

6

20

4060

Total Phosphorus (µµµµg/L)

Alg

al

Ch

loro

ph

yll

(µµ µµ

g/L

)

10 100

10

1

Missouri

Mark Twain Lake100

20 40 605 200

2

4

6

20

4060

Total Phosphorus (µµµµg/L)

Alg

al

Ch

loro

ph

yll

(µµ µµ

g/L

)

Average Suspended Sediment 5.9 mg/L

Rest of the years averaged 2.9 mg/L

1000100

10

1

Missouri

Mark Twain Lake100

2000400 600

2

4

6

20

4060

Total Nitrogen (µµµµg/L)

Alg

al

Ch

loro

ph

yll

(µµ µµ

g/L

)

10 100

4

39

Missouri

Mark Twain Lake

401 2 200

78

156

234

8

16

23

Algal Chlorophyll (µµµµg/L)

Se

cc

hi

Tra

ns

pa

ren

cy (

inc

he

s)

10.6

4

39

Missouri

Mark Twain Lake

401 2.3

78

156

234

8

16

23

Suspended Sediment (mg/L)

Se

cc

hi

Tra

ns

pa

ren

cy (

inc

he

s)

Why do we care?

Water clarity is how general

public gauges water quality

THE BADReduce aesthetics

Impact recreation

Oxygen imbalances

Increased treatment cost

Toxins

Algae

THE GOODBase of the food web

Source of dissolved oxygen

And THE UGLY!

Suspended Sediment

Reduce aesthetics

Impact aquatic habitats

Increase treatment costs

Often accompanied by nutrients,

especially phosphorus

Water Quality Variations in Mark Twain Lake

Space & Time

SPACE

13

4

2

Site 4 Site 3 Site 2 Site 1

Phosphorus (µg/L) 60 58 46 48

Nitrogen (µg/L) 1141 1036 983 1054

Chlorophyll (µg/L) 15.9 14.2 17.3 15.4

Sus. Sediment (mg/L) 3.7 4.7 3.4 0.9

Secchi (inches) 24 24 30 36

Lakes of Missouri

Volunteer Program

Average values

from 2002 season

15

2

Site 5 Site 2 Site 1

Phosphorus (µg/L) 60 52 55

Nitrogen (µg/L) 1283 1182 1209

Chlorophyll (µg/L) 12.8 13.4 13.1

Sus. Sediment (mg/L) 3.6 3.3 2.7

Secchi (inches) 34 35 38

Lakes of Missouri

Volunteer Program

Long-term average

values from 2002 -

2014

64

42

33

27

20

Long-Term Average

Phosphorus Values (µg/L)

Lake Ozark = 59 miles between sites

Mark Twain = 8 miles

Lake of the Ozarks

TIME

0

20

40

60

80

100

120

140

Co

nc

en

tra

tio

n in

µµ µµg

/L

April May June July Aug Sept

Phosphorus

Chlorophyll

Site 1 - 2011

0

2

4

6

8

Su

sp

en

de

d S

ed

ime

nt

(mg

/L)

50

40

30

20

10

0

Sec

ch

i (i

nc

he

s)

April May June July Aug Sept

Secchi

Transparency

Suspended Sediment

Site 1 - 2011

Overall

Average

Range of

Annual Means

Difference

(max/min)

Phosphorus (µg/L) 49 21 – 159 7.6

Nitrogen (µg/L) 1232 708 – 1818 2.6

Chlorophyll (µg/L) 12.2 6.8 – 20.8 3.1

Suspended Sediment (mg/L) 2.8 0.8 – 8.8 11.0

Secchi Transparency (inches) 32 17 - 62 3.6

Year to Year Variations in Water Quality12 years of monitoring from Site 5

20032004

20052006

20072008

20092010

20112012

20132014

60

50

40

30

20

10

Se

cch

i D

ep

th (

inch

es

)Site 5

Average 32 inches

20032004

20052006

20072008

20092010

20112012

20132014

0

20

40

60

80

100

120

140

160

To

tal P

ho

sp

ho

rus (µµ µµ

g/L

)

Average 49 µµµµg/L

Site 5

Mark Twain compared to other MO Reservoirs

0 40 80 120 160 200 240 280 320 360 400

Average Total Phosphorus (µµµµg/L)

0

20

40

60

Nu

mb

er

of

Re

serv

oir

s Mark Twain = 56 µµµµg/L

Higher than 66% of MO reservoirs

Range 6 – 397 µg/L

n = 229

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Average Total Nitrogen (µµµµg/L)

0

5

10

15

20

25

30

Nu

mb

er

of

Re

serv

oir

s

Mark Twain = 1276 µµµµg/L

Higher than 90% of MO reservoirs

Range 110 - 2010µg/L

n = 229

0 10 20 30 40 50 60 70 80 90 100 110 120

Average Chlorophyll (µµµµg/L)

0

10

20

30

40

Nu

mb

er

of

Re

serv

oir

s

Mark Twain = 15.4 µµµµg/L

Higher than 50% of MO reservoirs

Range 0.7 – 119.4µg/L

n = 229

0 4 8 12 16 20 24 28 32

Suspended Sediment (mg/L)

0

10

20

30

40

50

Nu

mb

er

of

Re

serv

oir

s

Mark Twain = 3.1 mg/L

Higher than 57% of MO reservoirs

Range 0.3 – 33.2mg/L

n = 229

Summary

-Suspended sediment levels

can be high enough to affect

the chlorophyll-phosphorus

relationship.

10 100

10

1

Missouri

Mark Twain Lake100

20 40 605 200

2

4

6

20

4060

Total Phosphorus (µµµµg/L)

Alg

al C

hlo

rop

hyll

(µµ µµ

g/L

)

1000100

10

1

Missouri

Mark Twain Lake100

2000400 600

2

4

6

20

4060

Total Nitrogen (µµµµg/L)

Alg

al C

hlo

rop

hyll (µµ µµ

g/L

)

-Most years nitrogen is

>1000µg/L and Mark Twain

Lake does not fit the MO

chlorophyll-nitrogen

relationship.

-Secchi transparency is

influenced more by

suspended sediment then

algal concentrations.

- Limited longitudinal

gradient for phosphorus and

suspended sediment (only 3

sites with 8 miles distance).

10.6

4

39

Missouri

Mark Twain Lake

401 2.3

78

156

234

8

16

23

Suspended Sediment (mg/L)

Sec

ch

i T

ran

sp

are

nc

y (

inch

es

)

Site 5 Site 2 Site 1

Phosphorus (µg/L) 60 52 55

Nitrogen (µg/L) 1283 1182 1209

Chlorophyll (µg/L) 12.8 13.4 13.1

Sus. Sediment (mg/L) 3.6 3.3 2.7

Secchi (inches) 34 35 38

- Water quality is highly

variable both within

and among years.

- Mark Twain Lake has high

nitrogen concentrations

compared to most Missouri

reservoirs.

20032004

20052006

20072008

20092010

20112012

20132014

0

20

40

60

80

100

120

140

160

To

tal P

ho

sp

ho

rus

(µµ µµ

g/L

)

Average 49 µµµµg/L

Site 5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Average Total Nitrogen (µµµµg/L)

0

5

10

15

20

25

30

Nu

mb

er

of

Re

se

rvo

irs

Mark Twain = 1276 µµµµg/L

Higher than 90% of MO reservoirs

12

5

New Lakes of Missouri Volunteer Sites?

A thing is right when it tends to preserve the

integrity, stability and beauty of the biotic

community. It is wrong when it tends otherwise.

Aldo Leopold

20032004

20052006

20072008

20092010

20112012

20132014

0

20

40

60

80

100

120

140

160

To

tal P

ho

sp

ho

rus

(µµ µµ

g/L

)

Average 49 µµµµg/L

Site 5

20032004

20052006

20072008

20092010

20112012

20132014

0

200

400

600

800

1000

1200

1400

1600

1800

2000

To

tal N

itro

ge

n (µµ µµ

g/L

)Site 5

Average 1240 µµµµg/L

20032004

20052006

20072008

20092010

20112012

20132014

0

1

2

3

4

5

6

7

8

9

Ino

rgan

ic S

ed

ime

nt

(mg

/L) Average 2.9 mg/L

Site 5

20032004

20052006

20072008

20092010

20112012

20132014

0

3

6

9

12

15

18

21

Alg

al C

hlo

rop

hy

ll (µµ µµ

g/L

)

Average 12.2 µµµµg/L

Site 5