Impacts of Channel
Modification on Adirondack
Streams and Land Use
(Agriculture) on Champlain
Valley Streams
Kinsey Irvin
10/28/13
ENV 433
River Ecology
Introduction:
Streams can easily be affected by disturbances in the environment which can have an effect on
the flow regime, discharge, sediment, biota communities and fish, the breakdown microbial and algae
growth, and many others. These all can be tested in these affected streams to see how the disturbance
changed the function of the stream and those organisms living within it. The study objectives were to
look at ecosystem impacts on streams that are infected by land use and streams that are channelized for
flooding purposes. The study area we used was two Champlain Valley streams to assess the damage
agriculture would have on the watershed and we used two reach sections of the Ausable River to look at
channelization destruction to the flow of the stream.
Runoff is known to be one of the largest reasons for water quality to be degraded in a small river
system. This runoff has become such a problem because of urbanization, which can be described as the
constant increase growth in cities and more people living within one area. This causes for more roads to
be built, which are very poor at absorbing precipitation. Poor absorption of roads and sidewalks lead to
more intense flood waters and an increase in pollutants into stream flow systems (Hatt et. al 2004).
Runoffs from urban areas are very hard to measure and regulate because this is not point-source
pollution. Runoff involves a variety of human activities, so pointing the blame on one source can be a
difficult (Hatt et. al 2004).
One of the largest sources of pollution is agriculture near a stream bed, due to the chemicals, or
fertilizers, that are used on fields that eventually drains into the flow regime. North America contains
over 150 major river basins that show agricultural use of land that can be up to zero percent in northern
rivers to 66% in Mississippi Basins. Agriculture can be the cause for many runoff problems in small to
large stream systems (Allan 2004). Agriculture can deplete a large percentage of nitrates and dissolved
organic nitrogen from the top soil, normally rich in these minerals, which causes the river to be at a loss
when the soil become wet and leaches into the river. This nitrogen and nitrate are important to streams
because the microbial and algae populations depend on these useful minerals for growth (Wohlfart et al
2012). Land use can have other effects on the river system like a drastic change in habitat, a decrease in
water quality, and the range of biota found within the stream to be lacking (Allan 2004).
The first part of the study was to compare the differences between an agricultural watershed
and a reference site that was forested. Two streams in the Champlain Valley were picked for this study;
they were Rae Brook and Farrell Brook. Farrell Brook is a forested stream that has tree cover blocking
out most of the sun. Farrell Brook's major food source is allochthonous from the deciduous trees when
they drop their leaves. Rae Brook was our agriculture stream that was surrounded by land use, having
the major source of food being autochthonous and the stream could have less diversity. Our hypothesis
for this part of the study is that our data will show that Farrell Brook has a high biodiversity of biota, a
higher percentage of algae species, a larger fish community and an overall healthy environment. Rae
Brook is going to be sicklier because the runoff will make it less diverse in both biota and algae species
and the fish are going to be less diverse and not as healthy.
Channelization is a devastating man-made disturbance that can affect a stream way of motion
and all the life within the stream. Channelization is done mostly for flooding control, it can also be done
for navigation, improvement to draining from the river, and to try and control migration of the stream
bed. Channelization can be done by straightening the stream flow, widening the channel width,
deepening the stream, or relocating the stream entirely (USEPA 2007). This can cause a problem in
downstream flooding, a change in channel topography, a change in velocity, and displacement of biota
and microbial in the stream. These changes to the stream seem to be all interconnected, meaning that
affecting one ultimately affects the others as well (USEPA 2007). The United States Environmental
Protection Agency (2007) believes that with planning channelization, precautions have to be taken into
account for the disturbance affecting the stream pattern and damage done to the stream will most likely
be long term. The USEPA (2007) states that engineers and ecologists should work together in designing a
channel modification project to decrease human impacts on the stream flow and help rehabilitate the
systems that might be affected with the modification.
The channelization in the Adirondack streams was due to reactions of the highway department
caused by the mass destruction of Hurricane Irene that hit New York in August of 2011. The storm
caused major landslides and flooding in the Adirondack area. This stream was entered by a front loader
and the bottom large sediment was moved and placed on both sides of the stream making the stream
straighter, thinner and in a “V” formation. We wanted to look at the differences between a reach
impacted by channel modification and a reach of the same stream, to shows how the stream acts
normally. We also got to go and test after a restoration attempt was conducted to fix most of the
channel modification. This was done to take a look at how this stream was going to coming back from
the disturbance.
The affected stream we chose for this study is called John's Brook, a stream in the Ausable River,
where the affected reach was made to be a straight, thin and “V” stream. The other reach was very
rocky with pools and steps, like a normal river system. The sediment in the unaffected stream was from
little gravel size to large boulders. The sediment layout was made very differently in the affect reach
because the rocks were all relatively the same size, giving no variety in sediment or changes in the
stream bed. The channel modification may result in a faster flow regime within that river reach. Our
hypothesis for this part of the study was that the reach affected with modification will show little biota
diversity, a faster and not changing flow regime, a relatively similar sediment size throughout, less fish
and fewer algae species. The reach that was our reference point with show a change in flow regimes,
more fish, more algae, more variety of sediment sizes, a high biodiversity of biota in the stream, and
more pools and riffles.
Methods:
General field and lab methods for this project follow Hauer and Lamberti (2007). At each study
site physical-chemical variables, benthic invertebrate abundance, periphyton biomass, and fish
abundance were measured. General methods are outlined below.
Physical-chemical variables measured in each study stream included stream conductivity,
temperature, mean width, mean depth, mean substrate size, mean point velocity and selected hydraulic
variables. Variable means were determined from random points selected in a 50-100 m study reach on
each stream. In addition organic matter content (CPOM and FPOM) was determined from drift samples
and benthic samples. Organic matter biomass was determined after drying each sample at 55C for 24h.
For each study site watershed area, link number and stream order were also determined using GIS
methods.
Benthic macroinvertebrates were sampled using Surber (or Hess) samples at 5-7 randomly
selected locations within sample reach area. Samples were taken to 10 cm depth in the substrate.
Organisms were then preserved using formalin or a 70% ETOH solution and placed in labeled container
for later identification. Benthic organic matter from each sample was partitioned in to CPOM (>1mm)
and FPOM (<1mm) and samples were sorted for invertebrates followed by laboratory identification of
macroinvertebrates to lowest possible taxon.
Primary producer biomass was measured using periphyton-epilithon scrapings as in Hauer and
Lamberti (2007). Mean size, randomly selected stones were gathered adjacent to each Surber or Hess
sample location. Each rock was removed from stream bed and an area with a diameter of one inch was
isolated using a one inch diameter cylinder with rubber seal. Isolated area was then scraped with
vertically inverted modified toothbrush and rinsed with stream water. The resulting solution was then
filtered onto a pre-weighed whatman GF/A paper filter. Biomass was determined after drying each
sample at 55C for 24h.
Fish sampling was conducted at each stream utilizing the removal/depletion 3-pass
electrofishing method. Each fish sampling reach was approximately 50m in length. Three passes were
made up each reach with the same effort. Following each pass the fish were identified, lengthed, and
weighed. After the measurements were taken and recorded for all three passes the fish were released
into the stream. A cumulative catch vs. catch per unit effort (CPUE) curve was used to estimate total
abundance as in Hauer and Lamberti (2007).
I. Physical Features:
A. Stream size:
Rae brook and Farrell brook are 2nd order streams and both John’s brook sites are a 3rd order stream
(Table 1).
Rae brook and Farrell brook streams a small streams that are show a small channel through tree
covered areas and are 2nd order streams because two 1st order streams come together to create to make
both brooks.
Table 1: Comparison of stream size among the study sites.
B. Mean depth:
Rae brook showed the lowest flow of all sites surveyed having an average of fewer than 13 cm,
Farrell brook showed an increase in flow of 6.5 cm compared to Rae brook. John’s brook bridge sites
were much smaller in depth having the channelization being slightly smaller, by 6 cm, than the
restoration stream which was 26 cm in depth. The John’s brook reference stream measured the largest
depth with an average of 46 cm (Fig 1).
Figure 1: Mean Depth
C. Mean velocity:
Rae brook, just like depth, showed the lowest velocity of all the sites with an average of only .17 m/s.
Farrell brook showed a small change in faster flow from Rae brook with only a difference of .10 m/s.
John’s brook reference site showed the opposite effect then depth having a slower flow of .33 m/s
then both the channeled stream, which was .43 m/s, and the restoration stream, which showed the
fastest flow of .68 (Fig. 2).
Figure 2: Mean velocity (m/s)
D. Discharge:
Discharge was only able to be calculated for Rae and Farrell brook streams and the results show that
Farrell brook had a discharge of .07 m3s-1 and Rae brook was only .03m3s-1, which is a difference of
.04m3s-1 (Fig. 3).
Figure 3: Discharge (m3s-1)
E. Mean substrate:
Rae brook had the smallest sediment by far of only 5.6 cm and Farrell brook showed a difference of
22 cm compared to Rae brook. John’s brook reference site showed the greatest substrate size with an
average of 46 cm. The channelization caused the substrate to be 24 cm in size and the restoration
increased the size by 11 cm (Fig. 4).
Figure 4: Mean Substrate (cm)
F. Percent embeddedness:
Embeddedness of substrate could not be calculated for John’s brook stream sites but the results at Rae
and Farrell brook showed that Rae brook had little embeddedness of substrate which only 17%.
Farrell brook’s sediment showed to be 29% deeper into the ground (Fig 5).
Figure 5: Embeddedness (%)
G. Mean Reynolds number:
The mean Reynolds number was calculated for all four streams, Rae brook showed to have the lowest
number of 14,314 and Farrell brook was 20,000 higher than that. John’s brook restoration showed the
highest value over 110,000 and both John’s brook reference and the John’s brook channelization
were smaller by around 90,000 (Fig 6).
Figure 6: Mean Reynolds Number
H. Froude’s Number:
Froude’s number was calculated for all four streams as well, the data showed that Rae brook and
Farrell brook were close in value with only a difference of 0.3. John’s brook reference site showed
the highest value of .43 and the reference tied for the smallest with a value of .15 (Fig 7).
Figure 7: Mean Froude Number
II. Invertebrates:
A. Total invertebrate density:
The greatest number of invertebrates was seen in Rae brook with over 3,000 per m2. Farrell brook
showed only 430 invertebrates per m2 and the John’s brook sites showed the lowest numbers for both
John’s brook bridge sites. John’s brook reference showed the second highest value of 921 per m2 but still
over 2,000 less than Rae brook.
Figure 8: Invertebrate density (#/m2) in the study sites
B. Identified Taxa:
The largest amount of organisms we found within the four streams was the Heptageniidae mayfly,
Chironomidae, and Simuliidae. The smallest amount of organisms found were Diptera pupae, Tipula,
Antocha, and Oigochaeta (Fig. 9).
Figure 9: Percentage of each identified taxa at each site.
C. Ephmeroptera:
The composition of Ephemeroptera showed that Rae brook had a large percentage of mayflies,
Paraleptophiebia and Ephemerellidae were both very common within these samples. Farrell brook had the
smallest amount of mayflies and contained two types, Baetidae and Ephemerellidae. John’s brook
reference site showed a larger number of mayflies counted than the channelization and restoration sites,
and the most common mayfly was Baetidae (Fig. 10).
Figure 10: Ephemeroptera family composition
D. Plecoptera:
Rae brook showed a higher number of Plecoptera just like Ephemeroptera, with Leuctriae being the most
common. John’s brook reference site showed a large percentage of Leuctriae as well, and showed a higher
density than both bridge sites. The smallest amounts of Plecoptera were found in both disturbance
effected John’s brook sites (Fig. 11).
Figure 11: Densities of species in the Plecoptera family at sites.
E. Trichoptera:
Rae brook had the largest amount of Trichoptera and had the greatest diversity mostly made up of
Hydropsychidae larva. Farrell and both John’s brook bridge sites were also made up of Hydropsychidae
larva but at much lower amounts. The second highest amount of Trichoptera was found in John’s brook
reference and showed a large proportion of Philopotamidae Chimarra and Hydropsychidae larva (Fig. 12).
Figure 12: Trichoptera family densities of species per location. (#/m square)
F. EPT density:
The EPT density showed that Rae brook had a more EPT taxa then all other sites combined, the data also
showed that Farrell was over 1,500 smaller EPT than Rae brook. John’s brook reference was the second
highest with John’s brook bridge sites being about 600 and 800 smaller in EPT (Fig. 13).
Figure 13: Ephemeroptera, Plecoptera, and Trichoptera density (#/m2) in the study sites.
G. Percent EPT:
Percent EPT showed that Rae brook and Farrell brook had relatively low percentages of EPT taxa out of
total individuals and all three John’s brook sites showed over 90% of all the invertebrates found in sample
were EPT taxa (Fig. 14).
Figure 14: Percent of the total number of individuals that were Ephemeroptera, Plecoptera, and
Trichoptera in the study sites.
H. Density of filter feeding taxa:
Filter feeders were the most prevalent in Rae brook stream samples and Farrell brook samples showed to
be less dense by over 110 individuals. John’s brook reference was the second highest while both John’s
brook bridge sites having less than 5 individuals per m2 (Fig. 15).
Figure 15: Density of the Filter feeding taxa at 4 sites per square meter. (10/7 John’s bridge site was
sampled directly after a disturbance.)
I. Percent filter feeders:
Rae brook and Farrell brook are similar in amount of filter feeders out of total invertebrates, showing only
a 1% difference. John’s brook reference has the highest percentage of filter feeders out of total
organisms, with John’s brook bridge sites being less than 2%.
Figure 16: Percent of the total density that was filter feeding taxa at 4 sites. (10/7 John’s bridge site was
sampled directly after a disturbance.)
J. Percent sediment taxa:
Rae brook was the highest between the four streams for sediment taxa, samples showed that over 50% of
the organisms found in total organisms were sediment dwellers. Farrell brook samples showed low
percent of sediment taxa along with all John’s brook sites. The second largest percentage was seen in the
John’s brook restoration site with only 9% of total (Fig. 17).
Figure 17: Proportion of sediment taxa in each study site.
K. Richness:
The highest richness of 27 numbers of species was seen in Rae brook, Farrell brook richness was just 8
less than Rae brook. John’s brook reference is the second highest by having 18 numbers of species, with
both John’s brook bridge sites being only 3 and 8 species less (Fig. 18).
Figure 18: Invertebrate richness in the study sites
L. Sorensen similarity index:
The strength of similarity is the highest between Rae and Farrell brook but only .03 more than John’s
brook sites. Johns brook reference and the channelization stream are just about at a strength of .6, and the
least strong streams are the reference site and the restoration site, with only a strength of .4 (Fig. 19).
Figure 19: Sorensen Similarity Index, Similarity of the species composition.
M. Simpson Index:
Rae brook and Farrell brook show only a .07 difference in Simpson index, but both are still above 70%.
John’s brook reference is the tied for the lowest percentage with John’s brook restoration having the
highest percentage of over 80% (Fig. 20).
Figure 20: Simpson’s Diversity Index.
III. Drift Invertebrates:
A. Mean drift invertebrates:
Rae brook drift samples showed more diversity of invertebrates than Farrell brook, with the largest values
for terrestrial and Paraleptophlebia. Farrell brook showed only a few species, the most individuals found
were Chironomidae in small amounts (Fig. 21). John’s brook reference site showed a large variety of
species, with the highest values for Baetidae and terrestrials. John’s brook channeled stream showed only
two types of invertebrates in the drift and John’s brook restoration saw an increase to seven different
types and with larger amounts.
Figure 21: Mean values of invertebrates found in drift samples in Rae and Farrell brook sites.
Figure 22: Mean values of invertebrates found in drift samples in John’s brook bridge and reference sites.
B. Mean benthic and terrestrial:
Rae brook results showed terrestrial organisms dominated the drift and benthic organisms were less than
half of the terrestrials amount. Farrell brook had very little benthic and only one terristrial organism in the
drift net (Fig. 23). John’s brook showed a large amount of benthic organisms and terrestrial organisms
were less than half of the benthic amount. After the restoration, John’s brook bridge had the same amount
of benthic and terrestrials and John’s brook after channelization, showed more benthic organisms then
terrestrials (Fig. 24).
Figure 23: The total mean benthic and terrestrial organisms in the drift sample at Rae and Farrell brook.
Figure 24: The total mean benthic and terrestrial organisms in the drift sample at John’s Brook Bridge and
reference site.
IV. Fish
A. Total Fish:
The most fish were caught in Rae brook and the amount of fish caught was greater than Farrell brook by
over 100 fish. The smallest amount caught was John’s brook Reference site and John’s brook bridge sites
had over 40 more fish caught (Fig. 25).
Figure 25: Fish abundance across all 4 sample sites
B: Fish Species:
In Rae brook, the highest percent caught were Eastern Black nose Dace and these fish made up over 60%
of all the fish caught. In Farrell Brook, both Brook Trout and Eastern Black nose Dace were the highest
caught fish making up about 85% of the total. John’s brook reference stream showed a 90% of the total to
be Red Horse and Brown Trout. John’s brook bridge sites showed 80% of the total fish caught to be
Catostomidae (Fig. 26).
Figure 26: Percent composition of fish taxa for each site
V. Organic Matter
A. Organic CPOM:
Rae brook has the highest percentage of CPOM mass; it has 3.3g more CPOM than Farrell brook. John’s
brook reference site showed the second highest amount of CPOM and both John’s brook bridge sites were
less than half the amount found in reference site (Fig. 27).
6
Organic Matter: CPOM
Mass (g)
5
4
3
2
1
0
-1
Rae
Brook
Farrell
Brook
Johns Johns
9/9
9/16
Location
Johns
10/7
Figure 27: Mean Benthic Particulate Organic Matter (CPOM) at each study site.
B. Organic FPOM:
Results of organic FPOM showed that Rae brook had more particulates in the water than Farrell brook,
the difference in mass was .35g. John’s brook restoration site showed the highest amount of FPOM and a
drastic change in mass from the channeled stream, a difference of .7g. The reference site showed very
little FPOM in the samples but was still higher than the channeled site (Fig. 28).
Figure 28: Mean Benthic Particulate Organic Matter (FPOM) at each study site.
C. Drift CPOM:
Rae brook showed the lowest amount of CPOM in the drift samples and Farrell showed an increase of
.5g. John’s brook channelization stream and the reference stream showed very little drift CPOM but
John’s brook restoration site showed almost triple the amount (Fig. 29).
Figure 29: Drift organic matter (CPOM) at each study site.
D. Drift FPOM:
Rae brook showed to have the highest amount of FPOM found in the drift samples, it is almost triple the
amount found in Farrell brook. John’s brook reference showed to be the second highest mass of FPOM,
and John’s brook channelization had an amount very close to zero (Fig. 30).
Figure 30: Mean Drift Particulate Organic Matter (FPOM) at each study site.
E. Peri and Moss:
Rae brook showed the largest mass of peri from samples and the largest amount of moss. Moss was only
able to be calculated in Rae and Farrell brook and results showed there was .55g more moss in Rae brook.
Farrell brook was the second largest mass of peri which was .15 grams. John’s brook sites were all under
.1g for the channelization, reference and restoration streams (Fig. 31, 32).
Figure x. Mean periphyton biomass (g per filter) at each study site.
Figure 32: Mean moss biomass at each study site.
Discussion:
I.
Rae and Farrell brook:
Our hypothesis was that our data will show that Farrell Brook has a high biodiversity of biota, a
higher percentage of algae species, a larger fish community and an overall healthy environment. Rae
Brook is going to be sicklier because the runoff will make it less diverse in both biota and algae
species and the fish are going to be less diverse and not as healthy. This hypothesis was not supported
by the data because Rae brook was the more diverse stream with over 3,000 invertebrates and 198
fish recorded.
Rae brook showed a lower depth and a slower velocity because it is a smaller stream than Farrell
brook. Discharge showed that a greater volume of water went through Farrell Brook per unit time
than Rae brook. The sediment found in Rae brook was seen to be small pebbles to cobbles in a
uniform pattern where Farrell brook showed a larger range of sediment that were more embedded into
the benthic sediment. Reynolds and Froude numbers showed that both Farrell and Rae brook are
turbulent and erratic streams that can have eddies as part of the flow.
Rae brook showed overall to have a larger percentage of invertebrates, while Farrell brook had
low numbers. This can be seen because Rae brook has higher nutrients, especially phosphorus, which
changes the biodiversity of the area, and Rae brook has ten times the ions in the water which causes
for high productivity. This high productivity can be seen due to land use and run off which brings
larger percentages of ions and nutrients into the water then an overhanging forest would. Rae brook
showed to have the highest amount of midges and this can be because Rae brook sediment is soft and
little pebbles that allow midges, sediment adapted mayflies, and filter feeders to live there. With this
high productivity, Rae brook had the largest amount of Philopotamidae Chimarra because it feeds on
sediment dwelling organism and has a vast array of food sources.
EPT was the highest in Rae brook but the percentage of EPT out of the total invertebrates
identified was low because the samples were filled with midges and others not EPT organisms, which
makes the health of the stream decrease. Rae brook had the highest richness of species, this can be
hypothesized that recently an intermediate disturbance happened allowing new species to repopulate
the area. Rae and Farrell brook showed to be the highest similarity between all the streams, this can
be found because most of the invertebrates were found in both streams, just in different amounts. The
Simpson’s index, which is the probability if two organisms were pulled randomly that they would be
different, was over 70% for both Rae and Farrell brook, which means both streams, had a high
biodiversity.
The invertebrates found in the drift samples showed a higher biodiversity of species in Rae brook
than Farrell brook, supporting the idea that Rae brook has a higher productivity rate. Farrell brook
shows a normal tread of a drift dominated by benthic organisms, but Rae brook shows a drift that is
terrestrial dominated and this can be evidence that intermediate disturbance has occurred recently in
the streams past. Rae brook showed a much larger percentage of fish than Farrell brook, but the Dace
found at Rae brook showed a parasite on the outside of the fish that is normally found in stream with
unhealthy water conditions. In Farrell brook, cold water stream fish, like Dace and Trout, were found
in abundant numbers where warm stream fish, like minnows, were abundant in Rae brook.
Benthic CPOM was very high in Rae brook and this can be seen due to increase in moss and
leaves that were in the stream. FROM was seen to dominate the benthic samples of Rae brook
because of the very fine and loose sediment that makes up the benthic layer of the stream. Drift
CPOM was higher in Farrell brook and this can be seen because of the seasonality of when we
collected samples and the tree cover adding allochthonous material to the stream. The highest
biomass of Peri and moss were found in Rae brook, this can be seen because of the uniform flow
conditions, and can be connected to invertebrate’s abundance in this stream because peri and moss are
food and habitat for many organisms.
II. John’s brook reference and bridge sites:
Our hypothesis for this part of the study was that the reach affected with modification will show
little biota diversity, a faster and not changing flow regime, a relatively similar sediment size
throughout, less fish and fewer algae species. The reach that was our reference point would show a
change in flow regimes, more fish, more algae, more variety of sediment sizes, and a high
biodiversity of biota in the stream, and more pools and riffles. Our hypothesis was supported with the
data showing the reference site was a more productive system with slower flow regimes and John’s
brook bridge sites showed the effects of a disturbance causing for less productivity and a faster flow.
John’s brook reference site showed a larger depth than both John’s brook bridge sites and this is
because the stream was able to erode and cut the V shaped valley by normal water flow. The velocity
was higher in the bridge sites due the channeling or the stream causing for a steeper gradient and less
rocks in the way to slow the flow. The restoration stream showed effects of seasonality when it came
to velocity because rain added more to the flow. The substrate was found to the very uniform at the
channelized stream because the machines that came into the stream took out all the larger boulders.
The restoration efforts showed a change in sediment size and a less uniform stream but it was still not
as high a range as the reference site, which the stream will eventually get closer to. The Reynolds and
Froude numbers showed that John’s brook bridge sites were the most turbulent streams but the
reference site was erratic and high in turbulence as well.
The invertebrate density was the highest in the reference site; this is because it is a normal
flowing stream not affected by a disturbance. Both John’s brook streams site showed a decline in
density, richness, EPT taxa. This was the largest problem in the restoration site since we sampled only
a week after the stream was worked in. All the John’s brook sites showed out of total organisms
sampled, they were mostly EPT taxa, which showed that the streams were at much healthier than the
Rae brook stream. The similarity of between the reference and the channelized stream was the highest
because the disturbance was longer in the past allowing the effected invertebrates to start to come
back and recolonize the channel. The lowest similarity was both bridge sites because the restoration
showed little re-colonization at the time we sampled, and seasonality could have played a role as well.
The drift invertebrates supports the disturbance effect as well, there was little biomass of
invertebrates in the drift in the channelization site but a higher amount was seen in the restoration site
due to disturbance to the flow regime. The highest biomass in the drift was seen in the reference site
and this can be due to seasonality changes in the stream. John’s brook bridge sites showed a relative
even amount of benthic to terrestrial organisms and the reference showed a larger number of each in
the drift samples. Fish in bridge sites showed that the stream was dominated by benthic suckers and
this showed that the water was for warm for trout to live. The reference stream was dominated by
trout and this showed that the water was cold and a good environment for trout.
Benthic CPOM was seen in high percentages in the reference site due to the tree cover and the
seasonality change. The benthic CPOM was low in both bridge sites due to the higher flow regimes
and the disturbance that could have moved most of the CPOM downstream or into drift. The benthic
FPOM was the highest in the restoration site due to the disturbance that caused for sediment to be
moved and be deposited downstream. The drift CPOM showed to be highest in the restoration site
due to the disturbances that caused sediment to be picked up and to be drifted downstream and there
was a seasonal pulse of allochthonous material. Drift FPOM was less in the restoration site than the
reference site can be seen because the fast flow condition of the restoration stream could have taken
the FPOM in the drift downstream of where the disturbance was. Peri levels were relatively low in all
three samples sites, this can be seen because the flow regimes for John’s brook are much higher than
Rae and Farrell brook and the stream order is larger.
Conclusion:
I. Rae and Farrell Brook:
Farrell Brook is a forested stream that has tree cover blocking out most of the sun. Farrell Brook's
major food source is allochthonous seasonally from the deciduous trees. Rae Brook was our
agriculture stream that was surrounded by land use, having the major source of nutrients being
autochthonous from moss and peri and the stream showed more productivity due to run-off. Rae
brook stream was a more productive stream than Farrell brook, this can be seen because of run-off
coming from the agriculture land added to the ion and nutrients making it rich for biomass and
production. This data did not support the hypothesis showing that a change in nutrients, especially
phosphorus, showed a different community of biota. The sediment was uniform and fine allowing
production of sediment taxa and filter feeders to be higher than EPT. This makes the stream less
healthy and the fish showed a parasite that is common when water conditions are not good. Rae brook
data showed that an intermediate disturbance has allowed for colonization of the area by new
organisms and an increase in terrestrials in the drift. Farrell brook was less productive stream but
showed a healthier stream due to high amounts of EPT taxa and fish that were sick. Farrell brook also
had more CPOM because of seasonally of tree cover and cold water fish, like Dace and Trout. The
effects can be seen of agriculture land near a stream causes run-off of nutrients and ions causing for a
higher biomass for a little stream which might cause a problem in competition for food sources.
II. John’s brook bridge and reference sites:
The affected stream we chose for this study is called John's Brook, a stream in the Ausable River,
where the affected reach was made to be a straight, thin and “V” stream. The reference reach was
very rocky with pools and steps, like a normal river system. Our hypothesis was supported by the data
that showed that the reference river was a normal river system and the disturbance of channelization
caused an increase in flow and less colonization in the river. The John’s brook bridge site where
channelization was done by humans, this showed a disturbance of the stream that effected the
downstream flooding, the channel topography, velocity, and displacement of biota and microbial in
the stream. This can be due to the disturbance and the most effected stream was the restoration site,
this is because we sampled this stream only seven days after the restoration and didn’t allow for recolonization to take place. The largest change from the reference site to the bridge sites was the
disturbance which causes drastic effects to the stream function and the biotic organisms living in it.
Channelization, from my perspective, caused a change in the flow of the stream and with flood events
doesn’t help with over land flow because the flow of the system causes a larger flood disturbance
downstream. Channelization efforts, if needed, should go with a more natural system of changing the
stream due to the drastic effects of the biota and fish that live in the stream and the time it takes to
recolonize to a healthy diverse stream system.
References:
Allan J. 2004. Landscapes and Riverscapes: The Influence of Land Use on Stream Ecosystems. Annual
Review of Ecology, Evolution, and Systematics. [Internet]. 35(2004): 257-284. Available from:
http://www.jstor.org/stable/30034117.
F. R. Hauer and G.A. Lamberti. 2007. Methods in Stream Ecology. Academic Press. Hatt B., Fletcher
T., Walsh C. J., Taylor S. 2004. The Influence of Urban Density and Drainage Infrastructure on the
Concentrations and Loads of Pollutants in Small Streams. Environmental Management. [Internet].
34(1):112-124.
United States Environmental Protection Agency. 2007. National Management Measures to Control
Nonpoint Source Pollution from Hydromodification; Chapter 3: Channelization and Channel
Modification. Available from: http://www.epa.gov/owow/nps/hydromod/index.htm.
Wohlfart T., Exbrayat J.-F., Schelde K., Christen B., Dalgaard T., Frede H.-G., and Breuer L. 2012. The
importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated
landscape. Biogeosciences Discussions. [Internet]. 9: 7465–7497. Available from: www.biogeosciencesdiscuss.net/9/7465/2012/