Stroubles Creek Practice

Stroubles Creek Practice

Stroubles Creek Sample VA SOS Multimetric Score Calculation

Remember - This is fictional data created solely for this exercise and does not necessarily represent the true condition of the stream.

Volunteers in Blacksburg sampled Stroubles Creek at Smithfield and Plantation Roads on June 8, 2001 and found the following organisms:

Macroinvertebrates	Counts
Worms	16
Flat Worms	36
Leeches	13
Crayfishes	1
Sowbugs	5
Scuds	11
Stoneflies	0
Mayflies	32
Dragonflies and Damselflies	1
Hellgrammites, Fishflies, and Alderflies	0
Common Netspinners	29
Most Caddisflies	0
Beetles	0
Midges	25
Blackflies	15
Most True Flies	6
Gilled Snails	0
Lunged Snails	11
Clams	0
TOTAL

Calculate the total number of organisms they collected, then use the numbers from the above table to calculate these individual metrics:

Metric Name	Number of Metric Organisms		Total Number of Organisms in the Sample		Metric Score (Percent)
% Mayflies + Stoneflies + Most Caddisfly		Divide By		=
% Common Netspinners		Divide By		=
% Lunged Snails		Divide By		=
% Beetles		Divide By		=

% Tolerant		% Non-Insects
Taxon	Number of Organisms in Taxon	Taxon	Number of Organisms in Taxon
Worms		Worms
Flatworms		Flatworms
Leeches		Leeches
Sowbugs		Crayfish
Scuds		Sowbugs
Dragonflies and Damselflies		Scuds
Midges		Gilled Snails
Blackflies		Lunged Snails
Lunged Snails		Clams
Clams
Total Tolerant Organisms		Total Non-Insect Organisms
Total Tolerant Organisms Divided by the Total Number of Organisms in the Sample		Total Non-Insect Organisms Divided by the Total Number of Organisms in the Sample
Multiply by 100 to get your Metric Score		Multiply by 100 to get your Metric Score

Now use your individual metric scores to calculate the final ecological condition score:

Determine whether each metric should get a score of 2,1, or 0. Write your metric value from the previous page in the 2nd column (Your Metric Value). Put a check in the appropriate boxes for 2,1, or 0. Then calculate the subtotals and Save Our Streams Multimetric Index score and determine whether the site has acceptable or unacceptable ecological condition.

Metric	Your Metric Score	2	1	0
% Mayflies, Stoneflies, and Most Caddisfly		Greater than 32.2	Between 16.1 - 32.2	Less than 16.1
% Common Netspinner		Less than 19.7	Between 19.7 - 34.5	Greater than 34.5
% Lunged Snail		Less than 0.3	Between 0.3 - 1.5	Greater than 1.5
% Beetle		Greater than 6.4	Between 3.2 - 6.4	Less than 3.2
% Tolerant Organisms		Less than 46.7	Between 46.7 - 61.5	Greater than 61.5
% Non-Insect Organisms		Less than 5.4	Between 5.4 - 20.8	Greater than 20.8
		Total # of 2s:	Total # of 1s:	Total # of 0s:
	Subtotals:	Multiply by 2:	Multiply by 1:	Multiply by 0:

Now add the 3 subtotals to get the Save Our Streams Multimetric Index Score:__________

_____ Acceptable Conditions (7 to 12)

_____ Conditions cannot be Determined - Gray Area (8)

_____ Unacceptable Conditions (0 to 6)

Are you done with your calculations? If so click here to go to the answers!