SECCHI DISK CHART : Secchi depth and corresponding light level values are in meters.
Disclaimer: These values were copied off a xeroxed sheet the origin of which is unknown.

Secchi

 

Light Levels

depth

k

50%

30%

15%

5%

1%

0.1%

1

1.700

0.4

0.7

1.1

1.8

2.7

4.1

2

0.850

0.8

1.4

2.2

3.5

5.4

8.1

3

0.567

1.2

2.1

3.3

5.3

8.1

12.2

4

0.425

1.6

2.8

4.5

7.0

10.8

16.3

5

0.340

2.0

3.5

5.6

8.8

13.5

20.3

6

0.283

2.4

4.2

6.7

10.6

16.3

24.4

7

0.243

2.9

5.0

7.8

12.3

19.0

28.4

8

0.231

3.3

5.7

8.9

14.1

21.7

32.5

9

0.189

3.7

6.4

10.0

15.9

24.4

36.6

10

0.170

4.1

7.1

11.2

17.6

27.1

40.6

11

0.155

4.5

7.8

12.3

19.4

29.8

44.7

12

0.142

4.9

8.5

13.4

21.1

32.5

48.8

13

0.131

5.3

9.2

14.5

22.9

35.2

52.8

14

0.121

5.7

9.9

15.6

24.7

37.9

56.9

15

0.113

6.1

10.6

16.7

26.5

40.7

61.1

16

0.106

6.5

11.3

17.8

28.2

43.4

65.2

17

0.100

6.9

12.0

18.9

30.0

46.0

69.1

18

0.094

7.3

12.8

20.1

31.8

48.9

73.5

19

0.090

7.7

13.3

21.0

33.2

51.1

76.8

20

0.085

8.1

14.1

22.2

35.2

54.1

81.3

21

0.081

8.5

14.8

23.3

36.9

56.8

85.3

22

0.077

9.0

15.6

24.5

38.8

59.7

89.7

23

0.074

9.3

16.2

25.5

40.4

62.6

93.4

24

0.071

9.7

16.9

26.6

42.1

64.8

97.3

25

0.068

10.1

17.6

27.8

44.0

67.6

101.6

26

0.065

10.6

18.5

29.1

46.0

70.8

106.3

27

0.063

11.0

19.0

30.0

47.5

73.0

109.6

28

0.061

11.3

19.7

31.0

49.0

75.4

113.2

29

0.059

11.7

20.3

32.0

50.7

78.0

117.1

30

0.057

12.1

21.0

33.2

52.4

80.7

121.2

31

0.055

12.5

21.8

34.4

54.4

83.6

125.6

32

0.053

13.0

22.6

35.7

56.4

86.8

130.3

33

0.051

13.5

23.5

37.0

58.6

90.2

135.4

34

0.050

13.8

24.0

37.8

59.8

92.0

138.2

35

0.048

14.4

25.0

39.4

62.3

95.8

143.9

36

0.047

14.7

25.5

40.2

63.6

97.9

147.0

37

0.046

15.0

26.1

41.1

65.0

100.0

150.2

38

0.045

15.3

26.7

42.0

66.4

102.2

153.5

39

0.043

16.0

28.0

44.0

69.5

107.0

160.6

40

0.042

16.4

28.6

45.0

71.2

109.5

164.5

41

0.042

17.0

29.0

46.0

72.0

111.0

166.0

42

0.040

17.0

30.0

47.0

74.0

114.0

170.0

43

0.040

18.0

30.0

48.0

76.0

116.0

175.0

44

0.039

18.0

31.0

49.0

78.0

119.0

179.0

45

0.038

18.0

32.0

50.0

79.0

120.0

182.0

46

0.037

19.0

33.0

51.0

81.0

125.0

187.0

47

0.036

19.0

33.0

52.0

83.0

127.0

191.0

48

0.035

20.0

34.0

54.0

85.0

130.0

197.0

49

0.035

20.0

35.0

55.0

86.0

133.0

199.0

50

0.034

20.0

35.0

56.0

88.0

135.0

203.0

Last Updated: 03/19/2002