6.7 Water Quality Goals

The HHPLS used an extensive public process to identify water quality goals for the lakes within the watershed, and those goals are incorporated into this Plan.  Where no specific numeric goal was established, then this Plan establishes a goal of no further degradation of water quality.  As discussed in Section 4.2.1 above, the water quality goals in this Plan focus primarily on the Total Phosphorus concentration in the lakes, although for each lake chlorophyll-a (a measure of algal productivity) and Secchi depth (a measure of water clarity) goals are also established.

One of the District’s goals is to manage water quality in lakes to meet state water quality standards to avoid the need to prepare future Total Maximum Daily Load (TMDL) studies.  The Minnesota Pollution Control Agency (MPCA) has established the following standards for lakes:

Table 27.  Minnesota state lake water quality standards

  

Ecoregions

 

North Central Hardwood Forest 

Western Corn Belt Plains

 Parameters

Shallow1

Deep

Shallow1

Deep

Total Phosphorus (mg/L)

60

40

90

65

Chlorophyll-a (mg/L)

20

14

30

22

Secchi transparency (meters)

>1

>1.4

>0.7

>0.9

1 Proposed standards.  Shallow lakes are defined as lakes with a maximum depth of 15 feet or less, or with 80% or more of the lake area shallow enough to support emergent and submerged rooted aquatic plants (littoral zone). 

Source:  Minnesota Pollution Control Agency.

In some cases the HHPLS established a goal for a lake that is less stringent than the state’s goal.  This was often the case where local conditions may make the state goal difficult to achieve.  Where the HHPLS goal as set forth in the table below is less stringent than the state goal, the District will strive to achieve the HHPLS goal as an interim goal.  When the interim goal is achieved, the District will work with the state agencies to determine a plan for Adaptive Management that takes into account appropriate and achievable long-term water quality goals for the lake.

During the life of this Plan the Board may choose to review and amend these goals based on an Adaptive Management Plan or on new information developed through the Hydrologic Data Program or special studies such as the reconstruction of pre-development phosphorus concentrations through diatom studies.  MCWD may also consider revising water quality goals based upon approval of a TMDL by the Minnesota Pollution Control Agency.  Progress toward achieving goals and the continued appropriateness of the goals will be reviewed in the annual Hydrologic Data Report.

Table 28.  MCWD water quality goals and current conditions, Upper Watershed lakes.

 

     

2004 Conditions

Lake

1997 TP Goal (?g/L)

HHPLS TP Goal (?g/L)

1997-2004 Average TP (g/L)

TP (?g/L)

Chl-a (?g/L)

Secchi (m)

TSI

Christmas

18

15

17

29

0.1

4.9

33

Dutch

50

40

67

88

44

1.1

65

Gleason

90

80

90

104

23

1.4

62

Hadley

27

*

N/A

N/A

N/A

1-2**

N/A

Kreatz

N/A

*

N/A

N/A

N/A

<.5**

N/A

Snyder

N/A

*

N/A

N/A

N/A

<.5**

N/A

Minnewashta

25

20

23

25

3

2.6

46

Virginia

49

40

48*

48*

25

1.5

61

Tamarack

50

None

N/A

72***

34

1.3

62

St. Joe

90

None

N/A

22***

N/A

1-2**

N/A

Langdon

50

55-70*

136

138

99

0.4

74

Saunders

N/A

N/A

N/A

N/A

N/A

<0.5**

N/A

Black

N/A

N/A

N/A

N/A

N/A

2-4**

N/A

Long

50

40-50

59

76

40

1.2

64

Mooney

N/A

N/A

143*

N/A

N/A

<0.5**

N/A

Holy Name

N/A

N/A

N/A

N/A

N/A

<0.5**

N/A

Wolsfeld

50

N/A

N/A

N/A

N/A

0.5-1.0**

N/A

Tanager

90

70

95

118

80

1.1

68

Katrina

N/A

N/A

N/A

N/A

N/A

.5-1*

N/A

Thies

50

N/A

N/A

N/A

N/A

1-2*

N/A

Schutz

50

40

36

49

26

1.3

60

Pierson*

27

27

n/a

19

13

n/a

51

Wasserman

50

50

85

88

36

1.0

65

Steiger

50

30

39

41

18

1.5

57

Zumbra

35

25

28

32

12

3.1

51

Stone

90

36

57

47

15

1.9

56

Auburn East

50

50

N/A

N/A

N/A

0.5-1**

N/A

Auburn West

30

27

38

41

14

2.8

53

Lunsten

90

70

N/A

N/A

N/A

0.5-1**

N/A

Parley*

50

50

81

75

70

0.8

61

Carl Krey

90

N/A

N/A

N/A

N/A

2-4

N/A

Church

90

N/A

N/A

N/A

N/A

0.5-1**

N/A

Turbid

N/A

N/A

N/A

N/A

N/A

0.5-1**

N/A

Mud

N/A

N/A

N/A

N/A

N/A

0.5-1**

N/A

Peavy Pond

None

*

66

76

17

2.1

58

Lake Marion

None

*

N/A

N/A

N/A

2-4***

N/A

Shavers Lake

None

*

N/A

N/A

N/A

N/A

N/A

Louise Lake

None

*

N/A

N/A

N/A

N/A

N/A

Libbs Lake

None

30

30

21

2

1.8

46

Forest Lake

None

None

67

71

21

1.7

59

Lake Galpin

None

60

40

30

18

2.1

54

Lost Lake

None

None

N/A

N/A

N/A

N/A

N/A

TP = Total phosphorus concentration

*10% reduction from existing, provided it is greater than 25 ?g/L  ** Clarity as estimated by the University of Minnesota using satellite imagery *** Data from Citizen Assisted Monitoring Program (CAMP)

Source: MCWD.

Table 29.  MCWD water quality goals and current conditions: Lake Minnetonka

       

2004 Conditions

Bay

1997 TP Goal (?g/L)

HHPLS TP Goal (?g/L)

1997-2004 Average TP (?g/L)

TP (?g/L)

Chl-a (?g/L)

Secchi (m)

TSI

Black

50

45

-

40

10

7.7

54

Browns

30

20

22

N/A

N/A

N/A

N/A

Carmens

50

50

-

24

4

2.7

46

Carsons

50

50

-

21

1

3.1

42

Cooks

50

30

33

32

16

1.9

54

Crystal

30

25 - 30

28

26

9

3.0

49

East Upper

none

none

-

29

4

2.7

47

Gideons

none

none

-

22

2

3.3

42

Grays

50

20

-

21

1

3.3

40

Halsteds

50

50 - 60

119

128

41

1.6

65

Harrisons

50

50

63

58

32

1.2

61

Jennings

90

50 - 70

111

110

39

1.4

65

Lafayette

50

20

23

N/A

N/A

N/A

N/A

Lower Lake South

30

20

21

20

6

3.3

46

Maxwell

50

40

33

32

12

2.4

52

North Arm

50

30

32

31

11

2.4

52

Phelps

50

20

-

N/A

N/A

N/A

N/A

Priest

50

30

-

55

28

1.0

62

Robinsons

none

30

-

N/A

N/A

N/A

N/A

Seton

50

100

-

N/A

N/A

N/A

N/A

Smiths

50

50

-

N/A

N/A

N/A

N/A

Smithtown

none

none

-

23

5

2.3

48

Spring Park

50

20

23

20

7

2.9

47

St. Albans

50

20

22

16

4

3.9

43

St. Louis

none

50

-

N/A

N/A

N/A

N/A

Stubbs

50

50 - 55

59

63

30

1.6

60

Wayzata

42

20

20

17

6

3.4

45

West Arm

50

50

71

59

33

1.6

60

West Upper

none

25

28

27

12

2.4

51

*10% reduction of the existing TP concentration provided it is above 25 ?g/L; will require baseline data

**2003 data *** Clarity as estimated by the University of Minnesota using satellite imagery

Table 30.  MCWD water quality goals and current conditions: Lower Watershed lakes
       

2004 Conditions

Lake

1997 TP Goal (?g/L)

HHPLS TP Goal (?g/L)

1997-2004 Average TP (g/L)

TP (?g/L)

Chl-a (?g/L)

Secchi (m)

TSI

Brownie

50

35

38

45

19

1.5

58

Cedar

50

25

22

25

7

3.7

47

Isles

50

40

40

50

28

1.8

58

Calhoun

30

25

24

15

3

5.2

40

Harriet

30

20

23

15

3

5.2

43

Nokomis

50

50

59

80

28

1.0

64

Hiawatha

50

50*

68

68

17

1.3

60

Diamond

-

90

N/A

178

38

0.8

69

Powderhorn

90

120*

N/A

118

37

0.7

68

*Hiawatha’s interim goal in the draft TMDL is 61 and Powderhorn’s is 90.

Source:  MCWD.