Madison
Period 4
October 4, 2011
Water Quality of the West Branch of the Susquehanna
Statement of the Problem:
Find the water quality of the West Branch of the Susquehanna based on land use and the
presence of certain macro invertebrates.
Research:
The water quality of a stream is a very important indicator of the treatment of the land
around the stream. To identify water quality of a stream, the first thing that must be taken into
consideration is the land use around the stream. Streams that run through cities usually have
very poor quality water because of thermal pollution, trash, and no trees to provide oxygen,
food, and habitats for macro invertebrates. Farms on the other hand, have fair water quality.
Farms have very little trees to provide shade, food, and habitats for macro invertebrates. Also,
fertilizers and chemicals from the fields wash into the streams and harm wildlife. The best
water quality that can be found is in forests because of the plentiful amount of trees and plants
provide a good habitat for macro invertebrates.
The quality of water in a stream can also be determined by the species of macro invertebrates
that live in the stream. By identifying the sensitivity of the macro invertebrates living in the
stream, pollution can be detected in a stream. So, to find the water quality of any given
stream, both the land use and the type of macro invertebrates must be taken into
consideration before drawing conclusions.
Hypothesis:
The water quality of the West Branch of the Susquehanna in Curwensville, PA will be
fair.
Materials:

Shoulder length gloves

Waders

Hand lens

Tweezers and spoons

One gallon dishpans

Ice cube trays
Madison
Period 4
October 4, 2011

Taxonomic key to aquatic organisms

Kick net

Calculator
Procedure:
Pick an accessible stream with a gradual slope or beach like area. The stream site should be
about 91 meters long and 41 meters upstream of any manmade objects. Begin at the most downstream
of the three sites you will be sampling at. First, select a square meter of riffle area to sample at. Next,
have the holder of the kick net place the net firmly against the bottom of the stream at a forty-five
degree angle and facing upstream. The kicker then kicks up the sampling area working his or hers way
downstream. The kicker should kick the first few inches of the sample area. After a few minutes, the
kicker and holder will remove the net with a forward scooping motion and carry it to shore. Once on
shore, they will lay the net out on the ground, sort the macro invertebrates collected using spoons and
tweezers, and place them in containers for identification later. Then they will repeat the same
procedure at the other two sites while working their way downstream. Once finished collecting
samples, the macro invertebrates will be identified and recorded. The macro invertebrates will be
gently released upstream from where they were taken. Then, the data should be analyzed and
conclusions based on the water quality of the stream should be drawn.
Results:
Date: September 26, 2011
Time: 11:30 AM
Location: West Branch of the Susquehanna in Curwensville, PA
Weather: Mostly Cloudy
Air Temperature: 26 Degrees Celsius/79 Degrees Fahrenheit
Water Temperature: 19 Degrees Celsius/66 Degrees Fahrenheit
PH Level: 6
Number of Participants: 19 People
Madison
Period 4
October 4, 2011
Sensitivity of the Macro Invertebrates in the West
Branch of the Susquehanna
Very Sensitive
Somewhat Sensiive
Macro Invertebrates in the West Branch of the Susquehanna
Species
Number Found
Relative Abundance
Dobsonfly Larva
8
Rare
Caddisfly Larva
51
Common
Other Mayfly Larva
20
Common
Fingernail Clam
6
Rare
Analysis:
After testing the water quality in the West Branch of the Susquehanna by the macro
invertebrates found and the land use, the quality of the water was found to be poor. The water
quality was found by calculating the pollution tolerance index for each type of macro
invertebrate found in the stream and grouping the sensitive, somewhat sensitive or tolerant
macro invertebrates together. Each type of macro invertebrate was then given a relative
abundance weighting factor based on the number found and was rare, common or dominant.
Next, the relative abundance was multiplied by the given weighting factor in each pollution
tolerance group. These group index values were added together to get the total index value for
Madison
Period 4
October 4, 2011
the site. Then the final number was used to find if the water quality rating was good, fair or
poor.
Most of the macro invertebrates were very sensitive and the remaining was somewhat
sensitive. No non sensitive macro invertebrates were collected. Equal amounts of the macro
invertebrates were rare and common, but none were dominant.
Conclusion:
In conclusion, the water quality in the West Branch of the Susquehanna was not fair as
stated, but instead poor.
By using a macro invertebrate stream assessment, the water quality of the stream was
found. The macro invertebrate stream assessment used information such as the species found,
pollution tolerance, number found, and relative abundance weighting factors to calculate the
water quality. The water quality was found to be poor because the number found and the
weighting factor of each macro invertebrate multiplied together and added was not high
enough to be considered fair or good quality.
Some errors may have occurred during the experiment at the stream. First, the kicker
and net holder may have not properly collected the macro invertebrates and either kicked up
sediment in more or less than one square meter or accidentally released some of the macro
invertebrates during the removal process. Another error that could have happened could be
that some of the macro invertebrates were not counted when being sorted. This could have
been because the person identifying the macro invertebrates was not able to identify the type
of macro invertebrates.
Finding the water quality of a stream is very important because many environmental
and recreational activities rely on having a healthy stream. For instance, to find out if a stream
is good for fishing, it would be necessary to know the water quality to determine whether or
not fish would choose the stream as their habitats.
Self-Grade: 100/100