Creek Water Quality
Lab Report
Nigel Pasman
Danny Stapleton
Gabby Bojorquez
Nick Kubo
Nick Meyer
Mr. Yang
AP Environmental Science
Period 5
March 20, 2013
Abstract:
This experiment was established over the course of six (6) different visits to a singular location
within the creek near Westmont High School. The particular goal of these observational visits
were to establish an educated value for the quality of the water within this creek; that value is
determined through a variety of variables, from surrounding flora and fauna to more empirical
units such as dissolved oxygen contents, flow rates, and concentration of particular chemical
compounds. Through a series of calculations, both these empirical and ab-initio observations can
be used to calculate the overall water quality of the tested location. Each observation of the
immediate water quality took place approximately one month after the previous, and one month
before the next receptively. Throughout the observations the variables fluctuated with the current
weather conditions and circumstances in recent occurrence. For some time, construction was
being done juxtaposed to the testing site, and a marked decline in water quality can be noticed
from this. Similarly, periods of high or low rainfall or drastically different temperatures also
impacted the tested variables in the location. The impacts of these particular circumstances were
not short lasted, the site often needed a reasonable time to recover from the shock change.
Problem Statement
What changes in water quality will occur after observing a designated creek area in San Jose
within a 7-month time frame?
Hypothesis:
The scientists expect to find a decrease/decreasing trend in dissolved oxygen levels from their
designated creek area due to the following factors: the presence of animals and bacteria, the
changing environment, and human interference.
Background:
The Water Quality Index (WQI) was developed in the early 1970s in an effort to compare the
quality of water from all parts of the country. Over one hundred water-quality experts were
called together to create this standard means of using one number to represent nine criteria for
calculating the degree of water quality for a given body of water. The results are used to decide
whether the water may be considered healthy, to monitor it over time, and to assess it relative it
to any other body of water on Earth.
Human beings depend on a clean, healthy water supply. Public health officials and
environmental biologists have developed tests that can help monitor the quality of surface waters
and locate potential sources of pollution. In this laboratory activity, the scientists will test water
samples for nine basic characteristics that aquatic scientist use to rate the overall health of a body
of water. The nine tests to determine the WQI, Temperature, pH, Dissolved Oxygen, Turbidity,
Fecal Coliform, Biochemical Oxygen, Total Phosphates, Nitrates, and Total Suspended Solids
will be looked at over a 7-month time frame. The scientists will try to see if there are changes in
water quality throughout the time-frame. Usually these tests are repeated several times to get a
full picture of how an ecosystem may change over a period of time. The scientists will anecdote,
record, and observe the various factors that contribute to these changes over time.
Materials/Equipment Used:
•
•
•
•
•
•
•
•
•
•
•
GPS
Conductivity Probe
Nitrate, phosphate, oxygen, coliform pill & bottle
Flow rate sensor
pH sensor
D.O. probe
Basket
Ruler
Test tubes/vials
Measuring tape
Lab notebook to record data
Variables:
Every object recorded in the experiment is an independent variable. The only dependent variable
is the water temperature which is dependent on the air temperature, and the humidity which is
also dependent on the air temperature.
Procedures:
Water Quality Field Procedure
From Sep. 2012-Feb. 2013
This is performed on a monthly basis, where the group of five scientists will go down to their
designated creek location near Westmont High School.
1. Perform the following tasks in any order (but start with bacteria, since it must sit for 20
minutes). If you find yourself waiting for a piece of equipment, try to start on one of the
other tasks
1. Prepare filtered split, to be used for nitrate measurement. Follow filtering
procedure
2. Measure pH (follow pH-meter procedure)
3. Measure D.O., electrical conductivity, and salinity (follow D.O. meter procedure)
4. Measure Turbidity, follow the turbidity measurement procedure
5. Measure Nitrate Content, follow measurement procedure
6. Measure basic water quality, follow measurement procedure
7. Measure Water Temperature, follow measurement procedure
8. Measure Total Dissolved Solid, follow measurement procedure
9. Measure flow rate, wind speed, and humidity
10. Fill up 2 test tubes with creek water.
Results:
Westmont
Stream Study
GPS Location:
Lat.: 37.27' Long.: 121.99"
T-Values
Mo
nth
Sept
.
Oct.
Nov
.
Dec.
Jan.
Feb.
p
H
6
6.
6
6.
4
Turbi
dity
(NTU)
123.
2
138.
2
123.
5
Wat
er
Tem
p
(oC)
18
°C
19
°C
19.5
°C
6. no
15.3
1 tube °C
6. 144. 9.8
4
1 °C
6. 130. 9.2
3
4 °C
DO(mg
/L)
O2
Saturati
on(%)
Nitrate (ppm)
no
probe
4.9m
g/L
8.9m
g/L
20ppm
clear less than
1 ppm
clear less than
1 ppm
4.65
mg/L
6.7m
g/L
8.2m
g/L
somewhat
clear less than
5ppm
less than 1
ppm
less than 1
ppm
Phosp
hate
Total
Disolve
d
Solid(uS
/cm)
No
1ppm Probe
1ppm
249.9
4ppm
249.6
3ppm
249
4ppm
248.3
4ppm
248.2
Colif
orm
(Yes
or
No)
yes
yes
yes
Weather observations: Sept.
Cloud Cover:
Clear (<20%)
Wind (circle
one)
Partly Cloudy (20- Cloudy
50%)
(50-90%)
Very windy
Wind Speed: light
Windy
Overcast
>90%
Breezy
Rain
ing
Still
Humidity: fairly hot/humid
Air Temperature: 85°F
Has it Rained in the past 24 Hours?
_____no___________________
If Yes How Much (in
cm)
Unusual water conditions (e.g.
color, odor):
lots of
trash
No
Date of last test:
______N/A_______________
Weather observations: Oct.
Cloud Cover:
Clear (<20%)
Wind (circle
one)
Partly Cloudy (20- Cloudy
50%)
(50-90%)
Very windy
Wind Speed:1.2 m/s
Windy
Overcast
>90%
Breezy
Rain
ing
Still
Humidity: __________54.3______
Air Temperature: _____22.9 C______________
Has it Rained in the past 24 Hours?
________________no________
If Yes How Much (in
cm)
Unusual water conditions (e.g. color,
odor):
Different smell than previous time
Date of last test:
____________9/5/12_________
Weather observations: Nov.
Cloud Cover:
Clear (<20%)
Wind (circle
one)
Wind Speed:.4 m/s
Partly Cloudy (20- Cloudy
50%)
(50-90%)
Very windy
Windy
Overcast
>90%
Breezy
Rain
ing
Still
Humidity: 95.42%
Air Temperature: 15.3 °C
Has it Rained in the past 24 Hours?
______________2cm__________
If Yes How Much (in
cm)
Unusual water conditions (e.g. color,
odor):
foul smelll; much less
water
yes
Date of last test:
10/6/12
Weather observations: Dec.
Cloud Cover:
Clear (<20%)
Wind (circle one)
Wind Speed:.1 m/s
Partly
50%)
Cloudy
Very windy
(20-
Cloudy (5090%)
Windy
Overcast
>90%
Breezy
Raini
ng
Still
Humidity: 69%
Air Temperature:15°C
Has it Rained in the past 24 Hours?
__________yes______________
If Yes How Much (in
cm)
Unusual water conditions (e.g. color, odor):
Water project going on. They were trying to purify
the water.
yes
Date of last test:
11/2/12
Weather observations: Jan.
Cloud Cover:
Clear (<20%)
Wind (circle
one)
Wind Speed:.7 m/s
Partly Cloudy (20- Cloudy (50- Overcast
50%)
90%)
>90%
Very windy
Windy
Breezy
Raini
ng
Still
Humidity: 58.2
%
Air Temperature: 13.7 °C
Has it Rained in the past 24 Hours?
____________yes____________
If Yes How Much (in cm)
Unusual water conditions (e.g. color,
odor):
no terrestrial life; completely rocks and
water
yes
Date of last
test:12/6/12
Weather observations: Feb.
Cloud Cover:
Clear (<20%)
Wind:(choose
one)
Partly Cloudy (20- Cloudy (50- Overcast
50%)
90%)
>90%
Very windy
Wind Speed: .45 m/s
Windy
Breezy
Raini
ng
Still
Humidity: 58.2%
Air Temperature:7.8°C
Has it Rained in the past 24 Hours?
___________yes_____________
If Yes How Much (in cm)
Unusual water conditions (e.g. color,
odor):
a lot of algae/moss in water and it has a dark
murky color
yes
Date of last
test:1/10/13
Conclusion:
The purpose of the experiment was to investigate the change and monitor a specific location in
the creek passing through Westmont High School. The experiment was carried out through
monthly examinations of the creek. The creek was evaluated consistently through the
measurements of specific variables. These factors included measuring pH, dissolved oxygen,
conductivity, salinity, turbidity, nitrate content, temperature, flow rate, wind speed, and
humidity. These were measured in the same way, in the same location, for seven months. The
hypothesis stated that the scientists expect to find a decrease/decreasing trend in dissolved
oxygen levels from their designated creek area due to the following factors: the presence of
animals and bacteria, the changing environment, and human interference. Though the data did
display that the presence of animals and bacteria, the changing environment, and human
interference did reduce the dissolved oxygen, this was not exponential and the levels fluctuated
rather than purely decrease over the time period. The dissolved oxygen levels would rise and fall
due to other factors rather than just decrease due to the increase of exposure to life presented
above. There is countless room for error in this experiment. Any measurement could have been
off, thus ruining the data which in turn would ruin the entire lab. The scientists group could have
measured outside their designated area one day and measured water that was inconsistent with
the other data. Rainfall destroyed certain plants and manmade structures which allowed
more/less water to flow changing the data. One example of this would be a manmade dam which
was actually taken out which changed the course of the lab groups creek. The experiment could
have been improved by having step-by-step hands-on tutorials on how to conduct the research.
Another would be the physical marking of lab group’s territory so that the measurements were
always within the same area. Lab groups could have periodically compared notes with other
period’s data in order to prevent outliers and or incorrect data. If that were to happen the group
could then re-measure it and correct it in order to keep the data consistent and relevant. Future
experiments could benefit from these changes. What real world information can be gathered
from this is that humans are a part of the natural environment. Unfortunately they have not yet
learned to moderate their activities in such a way as to help the environment. Human activities
often lead to degradation of the environment (which caused the loss of dissolved oxygen).
Impacts of humans include pollution in land, freshwater creeks and rivers, destruction of
habitats, and endangerment and extinction of flora and fauna species like in our experiment.
Humans have a great impact on ecosystems and biodiversity. Sometimes humans can have a
positive impact on ecosystems, but often human actions can have detrimental ecological
consequences. Changes in the environment that cause changes in creak’s function can be
described as disturbances such as damming, channelizing, dumping, recreation, littering,
domestic animals, and invasive species.