Module 4 Stream Invertebrate Survey Interpretation
Coal Creek, Aug 23, 2013 | Survey ID: 19
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 192
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 2
(total # counted 192) / (# of 30cm x 30cm samples x.09m2 2 / (Area: 0.18)) : 1,066.67
B) PREDOMINANT TAXON: Water Mite, (69)
C) WATER QUALITY ASSESSMENTS
POLLUTION TOLERANT INDEX
Good Acceptable Marginal Poor
greater than 22 22 - 17 17 -11 less than 11
3 x (# of category 1) = 12
2 x (# of category 2) = 4
(# of category 3) = 4
Pollution Tolerant Index = 20
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 15
EPT TO TOTAL RATIO
Good Acceptable Marginal Poor
0.75 - 1.00 0.50 - 0.75 0.25 - 0.50 0 - 0.25
# of EPT 58 / total 192 = 0.30
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 23
PREDOMINANT TAXON RATIO
Good Acceptable Marginal Poor
0 - 0.40 0.40 - 0.60 0.60 - 0.80 0.80 - 1.0
PREDOMINANT TAXON RATIO:
69 / 192 = 0.3594
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 3
EPT Index: 4
EPT to Total Ratio: 2
Predominant Taxon Ratio: 4
Total: 3.25

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 9 6 Caddisfly
Dobsonfly
Gilled Snail
36 5 Mayfly
1 1 Riffle Beetle
13 4 Stonefly
Water Penny
Sub Total: 59 16
Category 2 - Somewhat Pollution Tolerant Alderfly larva
3 2 Aquatic Beetle
Aquatic Sowbug
Clam, Mussel
1 1 Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
Scud
Watersnipe Larva
Sub Total: 4 3
Category 3 - Pollution Tolerant Aquatic Worm
39 1 Blackfly Larva
Leech
17 1 Midge Larva (chironomid)
4 1 Planarian
Pouch Snail
Truebug Adult
69 1 Water Mite
Sub Total: 129 4