Environmental Impacts on Tyler Run 1
Investigation of Environmental Impacts on Tyler Run
Sarah Walsh
York College of Pennsylvania
Environmental Impacts on Tyler Run 2
Abstract
Introduction
There are many factors that impact a stream. Three of the main factors are nutrition
present in the stream, toxins that contaminate the stream and the physical structure surrounding
the area.
Nutrition in a stream environment is necessary for there to be growth and change
among the organisms and plants. Common nutrients in streams are nitrogen, potassium, calcium,
magnesium, sulfur, and silicon. There are also factors that have an impact on the amount of
nutrition that is present; some of these influences are nearby construction sites, agriculture
runoff, pasture run off, and different landscaping from residential areas and athletic fields.
Agriculture, residential and commercial development areas that are upstream can be sources of
nutrients further down the stream. The amount of nutrients in the stream not only affects living
things like algae and plants but it can change pH and dissolved oxygen levels in the system.
Toxins are contaminants that are not natural to the environment and can often be harmful
or throw the community off balance. Different ways that toxins can be put into the stream are
from industrial, commercial, agricultural, or residential land use. Pesticides that are used on
lawns and sports fields can also contribute to the contamination of the stream water. Another
influence on the amount of pollution in the water is the presence of hard surfaces in the
surrounding area. The paved hard surfaces provide a way for the toxins to run off into the
stream. Drainage areas are also a factor that needs to be considered because any variety of toxins
could drain down through a drainage area.
Physical structures have a major impact on the condition of a stream. One prominent
physical structure is the surrounding canopy coverage of the stream. This may not sound
significant but canopy coverage has a profound effect on various things that occur in streams.
The absence of shade over a stream can cause the amount of photosynthesis that occurs to rise
considerably. The reason that photosynthesis levels would increase is because the organisms that
photosynthesize use sunlight to do so and if it is lighter than there would be more photosynthesis.
Temperature is also impacted by the canopy coverage because if there is more light hitting the
stream the temperature of the water will increase. On the other end of the spectrum areas that
have more coverage also change aspects of the stream. Areas that have more coverage are wider
and have a lower average water velocity than in comparison to a sparsely covered area of a
stream. Forested sections of stream have higher ammonium uptake and have a higher bed
roughness. The living organisms in a stream are impacted by the amount of canopy coverage as
well. Macroinvertebrates are found in more significant numbers in the forested areas of streams
compared to that of deforested areas.
These three aspects of a stream are not isolated from each other but can affect one
another. Many times a physical structure change can have an impact on the nutrition that is
Environmental Impacts on Tyler Run 3
present in a stream or even the toxin levels. One reason that a land alteration can change the
amount of nutrients present in a stream is because it changes the water flow of the surrounding
area. This enhanced water flow can often come upon nutrients that it did not beforehand. These
nutrients are then washed into the stream creating a new source of nutrients. Another physical
structure alteration that can affect nutrition is the removal of canopy coverage. Reduction in
canopy coverage makes for less wood input, leaf debris, and organic material into the stream
environment. This affects all levels of the stream because wood, leaf litter, seeds and fruits make
up the food base in a stream. A different physical structure that affects a stream is the amount of
grass buffers along the edge of a stream. Grass buffers act as a filter to pollutants. If there is a
large amount of grass buffer, toxin levels will be lower, but if there is a lack of grass buffer,
toxin levels will be higher.
In the case of Tyler Run, there will be no significant environmental changes as the stream
runs through the York College campus.
Methods
We did a study on a portion of Tyler Run that runs through York College of
Pennsylvania’s campus. Samples were collected from Tyler Run on April 21, 2010. The
weather was cloudy with scattered showers. Samples were collected at three separate locations
on Tyler Run; the three locations are referred to as upstream, midstream, and downstream. The
samples were only taken on York College property. The upstream location of sampling had
partial to full tree coverage, a steep west bank but relatively flat east bank, high bed roughness, a
shore consisting of rocks and dirt, and ankle deep water. The midstream location had minimal
canopy coverage, both banks were slightly sloped, grass grew all the way to the shore of the
stream, the stream bed consisted of small stones and fine sediment, and the water depth was
ankle deep. The midstream location also had large boulders placed along the shore to prevent
erosion. The downstream location had heavy tree canopy, high banks, one which had a wooden
retaining wall, and the bed consisted of course rocks. The deepness of this section of the stream
varied, some parts were ankle deep and other portions were mid-calf deep.
We took data from each of these locations using Vernier (Lab quest) equipment. The
data that we collected consisted of the following: temperature, dissolved oxygen, pH, Nitrate,
and Ammonia. All the previously mentioned data points were taken in a riffle section of the
stream. The other information taken at each location was the width of the stream, the speed at
which the water was flowing, amount of light, chlorophyll and samples of bottom sediment. We
measured the stream’s width with a tape measure and calculated the speed by measuring out a
distance and seeing how long it took a bottle to travel that distance. The amount out light was
determined by direct observation. The chlorophyll was collected by scrubbing off a rock from
each site into a beaker of water and then transferring the water to a plastic container. Dr. Nolan
then measured the chlorophyll levels for us for each site. The collecting of the bottom sediment
was performed by having a group member stand downstream with a net while a person kicked up
Environmental Impacts on Tyler Run 4
sediment that flowed downstream into the net. The sediment was then caught in a net and rinsed
out into a container.
The analysis of the sediment samples took place in lab. These samples were taken in
order to determine the amount of macroinvertebrates present in the stream. A dissecting
microscope was used to view all the specimens that were present in the samples. A count was
taken of the different species of organisms and how many there were at each collection site.
Species Richness, Berger-Parker Index, and the Family Biotic Value were all determined from
this count. Species Richness (S) is the number of different species that are present. BergerParker Index (1/d) is calculated by taking the number that are present in the most abundant
species and dividing that by the total number of individuals in each sample. The Family Biotic
Value is calculated by taking the number of individuals in each species and multiplying that
number by their particular species’ pollution tolerance number. There is a chart of pollution
tolerance given to assign each species a pollution tolerance number. Each species population
multiplied by their pollution tolerance number are then all added together to get the Family
Biotic Index. The Family Biotic Value is determined by dividing the Family Biotic Index by the
total number of individuals present.
Results
Table 1- Environmental Factors and Periphyton from Tyler Run
Width (ft)
Speed (ft/sec)
Temperature (C)
Oxygen (mg/l)
pH
Nitrate (mg/l)
Ammonia (mg/l)
Light
Periphyton
Macroinvertebrates- S
Macroinvertebrates- 1/d
MacroinvertebratesFBI
Upstream
19.4
1.7
13.3
6.5
7.8
27.2
0
Low
95.2
12.4
1.7
8.9
Midstream
18.1
1.7
13.3
6.1
7.8
37.9
0
High
161.6
11.0
1.6
9.5
Downstream
27.3
1.3
13.6
6.5
7.9
33.4
0
Low
71.5
10.8
1.7
8.6
Table 1- This table shows all the data points collected from each site. The above values are all averages
that were calculated from 5 data points for each sample at each site.
Environmental Impacts on Tyler Run 5
The pH, ammonia, and macroinvertebrates (1/d) did not show significant amounts of change from
upstream to downstream. Macroinvertebrates (S) values are not significant because the data has a large
range at each location. The width of the stream decrease from upstream to midstream but then it was
wider at the downstream point than both the up and midstream locations. Water speed was the same at
the up and midstream locations but was slower downstream. Water temperatures were the same for both
the up and midstream locations but increased at the downstream site. Midstream had a lower dissolved
oxygen value than the other two areas. Nitrate levels went up significantly in the midstream location to
37.9 from the upstream nitrate levels which were 27.2. This nitrate value then decreased again to 33.4 in
the downstream location. Light was only high at the midstream location. Periphyton numbers increased
dramatically at the midstream location from 95.2 at the upstream location to 161.6 at the midstream site.
Periphyton numbers then decreased downstream to 71.5. The macroinvertebrates (FBI) value increased at
the midstream site but was lower at both the up and downstream locations.
Discussion
It is evident, given the data results, that the hypothesis that there would be no changes to the
environmental factors in Tyler Run throughout the York College campus is not valid. There were trends
that could be seen throughout the various factors that were studied.
The structure along the stream changed greatly as you moved through campus and this affected
the results of many of the data points. Along the midstream there were retaining rocks that were put there
to keep erosion from happening in order to keep the stream narrow. The retaining walls that were in place
then affected the downstream width because the stream wants to widen out and not be constrained. The
width of the stream also affects the speed of the water because when the stream is not very wide the water
flows faster because it does not have as great of an area to travel through. At the downstream sight the
width was wider and this caused the water to flow much slower because it had more area to travel
through. Another factor that changes the data is the tree coverage; there were high levels of tree coverage
at the up and downstream sights but not at the middle site. This factor can also impact the width of the
stream and the speed of the water. In reference to the study done on “Riparian deforestation, stream
narrowing, and loss of stream ecosystem”, their study showed “that most forested stream channels studied
in the Piedmont region were wider and had lower average water velocity.” This would also appear to be
the same in Tyler Run because the forested areas which were wider also had a lower average water
velocity. The abundance of forest coverage also had an effect on the temperature of the water. The
temperature was the same from the up and midstream locations but was then higher at the downstream
location. The reason for this could be because of lack of canopy coverage at the midstream site. The
water would heat up from the sun hitting the water directly and would then make the water downstream
warmer than the rest of the water.
Literature Cited
1. Closs G., B. Downes, and A. Boulton. 2004. The Tools of Freshwater Ecological Science. Freshwater
Ecology. Blackwell Publishing, Malden, MA.
World Wide Web Document
Environmental Impacts on Tyler Run 6
2. Nutrients. Available from:
http://cfpub.epa.gov/caddis/candidate.cfm?section=135&step=24&parent_section=132.
3. Unspecified Toxic Chemicals. Available from:
http://cfpub.epa.gov/caddis/candidate.cfm?section=135&step=24&parent_section=132.
Research Articles
4. Sweeny, Bernard W., Bott, Thomas L., Jackson, John K., Kaplan, Louis A., Newbold, Denis J.,
Standley, Laurel J., Hession, W.Cully, Horwitz, Richard J. Riparian deforestation, stream narrowing, and
loss of stream ecosystem services. PNAS. 101: 14132-14137