Bio-mapping of Rivers
- Case study Assam State

 

4.0 COMPARISION OF BIOLOGICAL STATUS OF RIVERS IN MEGHALAYA AND ASSAM STATE

Although, Assam and Meghalaya are the sister states of North-Eastern India, their rivers differ from each other with respect to Taxonomical composition of biota (Table 13 & 14) and Biological Water Quality Criteria evolved from the saprobic score and diversity score of water quality (Table 15). Diptera and Megaloptera Taxonomic group of benthic macro-invertebrate families, were totally absent in clean water quality class `A’ Rivers of Assam. Plecoptera group was absent in Class `B’ water quality and Ephemeroptera and Megaloptera were absent in Class `C’ Water Quality Rivers of Assam compared to taxonomic groups of water quality classes of Meghalaya State.

Taxonomic groups of Crustacea, Hemiptera and Ephemeroptera were the additional Taxa existed in the water quality class `D’ of highly polluted rivers of Assam. Taxonomic groups of benthic macro-invertebrates of `E’ Class water quality were not observed in Rivers of Assam and Meghalaya.

 

Table 13: Comparison of Taxonomic composition of Benthic Macro-invertebrates in Assam & Meghalaya

 

S. No.

 

Group/Taxa

% Taxonomic composition of Benthic Macro-invertebrates

BWQC Class `A’

BWQC Class `B’

BWQC Class `C’

BWQC Class `D’

BWQC Class `E’

Meghalaya

Assam

Meghalaya

Assam

Meghalaya

Assam

Meghalaya

Assam

Meghalaya

Assam

1.

Arthropoda

86.95

80.0

87.5

73.68

77.14

58.33

57.14

41.66

0.0

0.0

Insecta

97.5

93.75

89.28

63.45

96.29

85.71

100.0

33.33

0.0

0.0

Crustacea

2.5

6.25

7.15

14.28

3.7

14.28

-

20.0

0.0

0.0

2.

Mollusca

10.86

15.0

9.37

26.31

11.428

33.33

14.28

33.33

0.0

0.0

3.

Platyhelminthes

2.17

5.0

3.12

0.0

-

0.0

-

0.0

0.0

0.0

4.

Annelida

-

0.0

-

0.0

11.42

8.33

28.57

25.0

0.0

0.0

Table 14: Comparison of Biological Status of Rivers of Meghalaya and Assam

S. No.

Taxonomic Group

Range of Saprobic

score

Range of Diversity Score

 

Water

quality

Water Quality Class

Indicator Colour

Meghalaya

Assam

Meghalaya

Assam

Meghalaya

Assam

1.

EPHEMEROPTERA

PLECOPTERA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

DIPTERA

PLANARIA

MEGALOPTERA

EPHEMEROPTERA

PLECOPTERA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

PLANARIA

-

-

 

 

7.0-8.6

 

 

7.0-9.3

 

 

0.2-0.8

 

 

0.26-0.57

 

 

Clean

 

 

A

 

 

Blue

2.

EPHEMEROPTERA

PLECOPTERA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

DIPTERA

PLANARIA

EPHEMEROPTERA

PLECOPTERA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

DIPTERA

-

 

 

6.0-6.7

 

 

6.0-6.8

 

 

0.47-0.72

 

 

0.5-0.6

 

 

Slight pollution

 

 

B

 

 

Light Blue

3.

EPHEMEROPTERA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

DIPTERA

MEGALOPTERA

HIRUDINEA

OLIGOCHAETA

TRICHOPTERA

ODONATA

MOLLUSCA

CRUSTACEA

HEMIPTERA

COLEOPTERA

DIPTERA

HIRUDINEA

OLIGOCHAETA

-

-

 

 

3.4-6.2

 

 

4.2-6.16

 

 

0.2-0.8

 

 

0.2-0.7

 

 

Moderate pollution

 

 

C

 

 

Green

4.

MOLLUSCA

DIPTERA

HIRUDINEA

COLEOPTERA

OLIGOCHAETA

-

-

-

MOLLUSCA

DIPTERA

HIRUDINEA

COLEOPTERA

OLIGOCHAETA

CRUSTACEA

HEMIPTERA

EPHEMEROPTERA

 

 

2.6-6.0

 

 

2.2-5.0

 

 

0.2-0.3

 

 

0.3-0.37

 

 

Heavy pollution

 

 

D

 

 

Orange

5.

No benthic macro-invertebrates

 

0.0

0.0

0.0

0.0

Severe pollution

E

Red