Teacher’s Guide
Introduction to the Biotic Water Quality of a Stream
Lesson Description
This lesson allows students to learn the Biotic Water Quality Score (BWQS) method for collecting
macroinvertebrates. Organisms with a high sensitivity to reduced oxygen levels are given a high
numerical value. Organisms that can thrive in low oxygen levels are given a low numerical value.
Factors that promote high oxygen content will also promote a diversity of macroinvertebrates. The
central idea behind quantification is that macroinvertebrates have a wide range of oxygen
requirements.
Following student research on assigned benthic, aquatic organisms, the preliminary activity will allow
students to perform a “dry run” to practice the skills needed for the actual BWQS field study. Skills
included are: collecting procedures, proper identification of aquatic organisms, using a taxonomic
key, data recording and evaluation. The preliminary activity in the classroom consists of showing the
students the kick seine net and demonstrating how to use it. A key idea is to put down four meter
sticks to show students the size of the area they should be disturbing. Students will learn that
“kicking” is turning over rocks and mixing up the sediment with their feet as well as rubbing the
benthic organisms to dislodge them from the bottom of the rocks. After these skills are demonstrated,
students in small groups use the sheets from their student packets to identify the various groups of
aquatic organisms. Students use a picture and/or taxonomic key to identify each organism and then
tally all organisms on the BWQS data sheet. Using MS Excel, students create a spreadsheet with the
appropriate biotic values for each organism. Using this spreadsheet they then calculate the BWQS.
See www.projectwatershed.org for details.
Following the procedure, three samples are collected from the stream study site. Each kick seine
collection must be scanned carefully to find all the organisms. Usually an attempt is made to collect
100 organisms for the purpose of having a representative sample. Be aware that the larger more
motile organisms will be collected first. Teachers will demonstrate how to carefully move debris and
search for the less motile macroinvertebrates. Give students the opportunity to use the same
techniques to continue the search. With continued supervision and patience the smaller, less motile
organisms will be collected.
Sometimes students collect far fewer aquatic macroinvertebrates than the expected numbers. In this
case, it is easy to express the number of organisms collected as a percentage of 100. In a small
population, each organism must be represented in the final BWQS. Find the spreadsheet from the
Project Watershed website, with all formulas included, under teacher resources. If you are unable to
download the spreadsheet from the website, the BWQS sheet included in this packet will have to be
calculated by students.
Science Concepts Introduced
• Sampling procedures
• Macroinvertebrate identification
• Determination of species diversity
• Observation of macroinvertebrates life cycles
1
Process Skills Emphasized
• Collecting benthic organisms
• Using a taxonomic key
• Organizing
• Analyzing data into a spreadsheet using MS Excel to determine the BWQS.
• Use an MS-Excel spreadsheet to analyze and graph data.
Technology Used
• Internet
• Word and Excel programs
• Project Watershed database
• Aquatic macroinvertebrate picture keys: www.iwla.org
• www.dec.state.ny.us/website/dow/stream/index.htm
MST Standards
• Standard 1 – key idea 1 and 3
• Standard 4 – key idea 6 and 7
• Standard 7 – key idea 1
Learning Outcomes
Students will be able to:
• Properly use a taxonomic and/or picture key to identify benthic organisms
• Collect aquatic macroinvertebrates using a kick seine net
• Enumerate all organisms collected
• Compute a BWQS based on a collection of macroinvertebrates
• Graphically represent each group of the organisms that make up the BWQS
• Use the Project Watershed database to compare BWQS to the chemical and physical properties of
a stream.
Time Requirements
• Preparation activity - two class periods (60 – 80 minutes)
• Data collection – 30 - 40 minutes (approximately) at a stream site.
• Data Analysis - two-class period (60 – 80 minutes) in the computer lab
Instructional Strategies
• Collection and identification of macroinvertebrates
• Enumeration of macroinvertebrate on a spreadsheet.
• Group research, followed by presentations
Background
Research on Macroinvertebrates
Nerbonne (2003) found a possible bias and error in sorting and identifying aquatic insects
(macroinvertebrates). In a masters thesis she described students, when sorting insects from debris
(kick seine,) selected mostly larger (rather than smaller) insects and insects that moved slowly
(compared to insects that moved too fast or not at all). Proper insect identification was also a
problem. Nerbonne’s study shows the need for adequate training and preparation. She also
suggests that sampling groups work in teams for sorting and identifying aquatic macroinvertebrates to verify students sorting and identification efforts.
Prior to the field trip, knowledge of the stream site and weather conditions is a necessity for the
safety of the students. Even smaller streams can be dangerous with fast, high waters.
2
Project Watershed has a permit, and all schools involved are collecting under the Project
Watershed umbrella. Project Watershed has a collection license that will support your activities
only while collecting with them.
The handouts of macroinvertebrates from the Project Watershed site (see teacher resources) that
represent the collections for the classroom simulation are in the student packet. The
macroinvertebrate collection key is in the teacher packet. This preliminary activity will allow
students to become familiar with the collecting equipment, collecting procedures, identification of
macroinvertebrates, data recording and the calculation of the BWQS.
Preliminary Activity
Teachers should have a basic understanding of the aquatic macroinvertebrate life cycles and also
be able to identify (or use a key to identify) most of the aquatic insects on the data table.
Chemical and physical needs of aquatic organisms are important to know because of the
relationship between those parameters and the number and types of aquatic organisms.
Students will perform a classroom simulation of the stream collection process before going to the
stream for the actual field collection process. Each time they will follow the same procedure as
seen in the SUNY ESF Lesson #5 Biological Stream Monitoring: How to Calculate the Biotic
Water Quality Score. Collect aquatic macroinvertebrates, properly identify them and input the
values into a spreadsheet to determine the BWQS.
Stream Data Collection
Students must be supervised while in or near the stream performing the collection procedures.
Assume that at least 10 different groups of benthic organisms could be identified. Then from their
simulation they will be able to separate all similar organisms into separate containers. Once they
have scanned the kick seine after three different collections a final tally of each container will be
conducted. The students then record the final number of each different type of organism and
record the data on the tally sheet. Carefully release all organisms back into the stream. Collect all
equipment and prepare to exit the stream site leaving it as clean as when you arrived.
Assessment
Assessment of this lesson is two fold. First, the preliminary student activity can be assessed by which
stream site each group is performing. Teachers have the data answer sheet to check student’s results.
Each group will receive stream site sheets numbered 1 thru 5. The results should be the same from
group to group when using the sample stream site. Second, after data is collected in the field it must
be analyzed. Students will analyze each set of data collected to input the BWQS. Students will use the
Project Watershed spreadsheet from the teacher resource section on the website to analyze their data.
Extensions/Options
• This same activity can be done using one stream site and comparing the BWQS from season to
season.
• Research the life cycles of aquatic organisms; this will promote understanding of how aquatic
ecosystems can change from season to season. Groups of 2 or 3 can research specific organisms
and present to the class pictures of juveniles and adults and their ecological role at various stages
of their metamorphosis.
• Project Watershed’s database can be used to download the data for graphing the water chemistry
at the site where students have collected invertebrates. Compare the chemical and physical
properties of all highly sensitive (a high BWQS value) stream collection sites to the same
properties of low sensitivity sites (a low BWQS value). Report the similarities and differences in
your findings to the class.
• Analyze the similarities or differences in the BWQS in fall, winter, spring and summer
collections.
• Draw relationships between abiotic (chemical and physical) properties and biotic properties.
3
Key Terms
abiotic, aquatic organisms, benthic, biotic, chemical and physical parameters , cobbles, diversity,
nymph, larva, macroinvertebrates, life cycles, runoff, stream ecosystems, riffles, pools.
Prerequisite Knowledge
• basic understanding of stream ecology
• use of taxonomic dichotomous keys of macroinvertebrates
• use of taxonomic dichotomous picture keys of macroinvertebrates
• Microsoft Word and Excel
• aquatic life cycles
• pollution ecology of runoff in streams
• runoff
• nonpoint source pollution
• point source pollution
Equipment Needed
• aquatic kick seine net
• white board or white background
• light colored collecting pans and jars (10 – 12)
• forceps and plastic spoons (6 – 8 of each)
• boots or waders (2 or 3 pairs)
• taxonomic and picture keys (4 or 5 laminated)
References
Biological Stream Monitoring: How To Calculate the Biotic Water Quality Score, Lesson 5 on
invertebrates monitoring can be downloaded from the SUNY ESF website. Follow these links:
1. www.esf.edu/outreach/
2. K-12 teachers & students
3. K-12 programs and resources
4. Supplemental curriculum materials and other resources
5. Environmental analysis of watersheds
See Key from Project Watershed for identification of macroinvertebrates.
M.K. Mitchell and W.B. Stapp 1997 Field Manual for Water Quality Monitoring, GREEN/Earth
Force, Alexandria, VA.
Websites
• Project Watershed Database: www.projectwatershed.org
• Aquatic Macroinvertebrate picture keys: www.iwla.org
• www.dec.state.ny.us/website/dow/stream/index.htm
Work Cited:
Caduto, Michael J., 2003 Canaries of the Waters, Sanctuary, Massachusetts Audubon Society, p.
11 – 13.
Nerbonne, Julia Frost and Bruce Vondracek. 2003. Volunteer Macroinvertebrates Monitoring:
Assessing Training Needs Through Examining Error And Biases In Untrained Volunteers,
Journal of the North American Benthological Society 22 (1): 152 – 163.
Handouts
1. Data collection sheets from the Project Watershed website. www.projectwatershed.org
2. Each Stream Study (1-5) is based on material found on the Project Watershed web site.
3. Spreadsheets for sample collections of the BWQS.
4
Sample 1 BWQS Answer Page
Total points = 372/40 = 93 Biotic Water Quality Score = Excellent
10 Stonefly nymph x 10 points =100 10 Mayfly nymph x 10 points = 100
4 Caddisfly larva x 10 points = 40
6 Dobsonfly larva x10 points = 60
4 Crayfish x 6 points = 24
2 Water Penny larva x 10 points = 20
2 Riffle Beetle larva x 10 points= 20
2 Gilled Snail x 4 points = 8
5
Sample 2 BWQS Answer Page
Total points = 174/32 = 54 Biotic Water Quality Score = Good
2 Stonefly nymph x 10 points = 20 3 Fishfly larva x 6 points = 18
1 Caddisfly larva x 10 points= 10 1 Water Penny larva x 10 points = 10
2 Cranefly larva x 8 points = 16
14 Midgefly larva x 5 points = 70
2 Crayfish x 6 points = 12
4 Aquatic worm x 0 points = 0
6
Sample 3 BWQS Answer Page
Total points = 108/19 = 56 Biotic Water Quality Score = FAIR
2 Dobsonfly larva x 10 points x 20 2 Stonefly nymph x 10 points = 20
4 Midgefly larva x 5 points = 20
5 Crayfish x 6 points = 30
3 Aquatic worm x 0 points = 0
3 Damselfly nymph x 6 points = 18
7
Sample 4 BWQS Answer Page
Total points = 129/28 =46 Biotic Water Quality Score = POOR
2 Leech x 2 points = 4
2 Cranefly larva x 8 points = 16
4 Aquatic worm x 4 points = 0
5 Midgefly larva x 5 points = 25
3 Lunged snail x 4 points = 12
12 Blackfly larva x 6 points = 72
8
Sample 5 BWQS Answer Page
Total points = 166/47 = 35 Biotic Water Quality Score = POOR
15 Aquatic worm x 0 points = 0
3 Lunged snail x 4 points = 12
9 Blackfly larva x 6 points = 54
20 Midgefly larva x 5 points = 100
9
Sample 6 BWQS Answer Page
Total points =322/36 = 89 Biotic Water Quality Score = EXCELLENT
7 Mayfly nymph x 10 points =70
2 Cranefly larva x 8 points = 16
8 Caddisfly larva x 10 points = 80 1 Planarian x 0 points = 0
4 Gilled snail x 4 points =16
10 Stonefly nymph x 10 points = 100
2 Dobsonfly larva x 10 points = 20 2 Water Penny larva x 10 points = 20
10
Student’s Guide
Introduction to the Biotic Water Quality of a Stream
Introduction
Aquatic insects are like canaries in the coal mine. They indicate the health of the water. Each aquatic
species has certain tolerances to pollution levels. Insects can be affected by changing water chemistry,
temperature, dissolved oxygen, substrate and water flow. A clean environment has a diversity and
richness of aquatic insects (Caduto, 2003).
Pollution of a stream can come from many different sources. Water that passes through a heavily
residential area faces runoff from lawn chemicals and fertilizers, sewage treatments outflows, and
leaching of septic systems. In a rural area, most of the contamination comes from runoff from farms
containing high amounts of nitrogen and phosphorus (Caduto, 2003). All types of runoff have the
potential to harm an aquatic ecosystem. If runoff kills algae on rocks, then mayflies that feed on the algae
die off. The stoneflies and others that feed on the mayflies soon die off and eventually affect the top
predators such as trout.
In a coal mine when a canary died, the miners got out of the mine quickly. If the insects and other
macroinvertebrates die in our streams, what can we do? Where can we go? Our job is to use
macroinvertebrates as indicators of stream health to tell us if there are pollution problems in the stream or
watershed. A wide diversity of oxygen sensitive macroinvertebrates in a stream equates to a healthy
canary in a coal mine.
Learning Outcomes
Students will be able to:
•
Properly use a taxonomic and picture key for aquatic macroinvertebrates.
•
Collect aquatic macroinvertebrates using a kick seine net.
•
Graphically represent the Biotic Water Quality Score (BWQS) and compare water quality
conditions at the site at various seasons of the year.
Skills Required
•
Group work in a cooperative manner
•
Using a taxonomic key (proper macroinvertebrate identification)
•
Proper sampling procedures
•
Data collection and analysis
•
Spreadsheet composition (data entry and analysis)
New Terms
abiotic, aquatic organisms, benthic, biotic, chemical and physical parameters , cobbles, diversity, nymph,
larva, macroinvertebrates, life cycles, runoff, stream ecosystems, riffles, pools.
11
Quest
We are making a transition from our current biotic monitoring method to a more quantified method for
Biotic Water Quality Score (BWQS). Your quest is to find a way to improve the biotic method by using
the BWQS.
You will include a section in your final report offering suggestions for improvement. All aspects of biotic
monitoring are open for suggestions. If something about the process described in the lesson is unclear to
you, define the problem and suggest a possible improvement. Suggestions will go to your teacher and to
the Project Watershed host site. If you are uncertain what the suggestion for improvement should be, at
the very least explain what you are having difficulty understanding. We will make every attempt to help
you in your quest.
Materials
• aquatic kick seine net
• white board or plastic about the size of a kick seine (2’ x 3’)
• light colored collecting pans and jars (10 – 12)
• forceps and plastic spoons (6 – 8 of each)
• boots or waders (2 or 3 pairs)
• taxonomic and picture keys (4 or 5 laminated)
• data tables
Procedure
Research on macroinvertebrates
1. Students work in pairs or small groups.
2. Each group will be given a specific aquatic organism.
3. Each group will be responsible for gathering as much information on that organism and presenting it.
This can be done using poster board or power point.
4. Presentations should include information for each stage of nymph, larva and the adult. Include: a
picture, physical descriptions, changing habitats, scientific name, role in the food web, use as an
indicator species and any human uses.
Preliminary Lesson
1. In small groups you will each receive a packet containing pictures of benthic organisms from an
actual stream sample.
2. Your group task is to correctly identify all presorted organisms.
3. Make sure everyone in the group agrees. Identification is a team effort, not the job of one student
(group checks and balances).
4. Record the numbers for each macroinvertebrate next to its name in the spreadsheet.
5. The last step is to calculate the BWQS for that stream site using the values in the spreadsheet.
Stream Data Collection
You will be collecting macroinvertebrates from a specific section of a stream and determining the BWQS
for that section. The BWQS may not be indicative of the entire stream because of many other factors.
Discuss with your group why and how these numbers can change from section to section of the stream.
1. In groups, pick a shallow area (1’– 2’) in a riffle near the study site. The sample area should have
plenty of cobbles (rocks).
2. Samples should be taken as demonstrated by your teacher in class. It is very important samples are
gathered as carefully as possible to obtain a representative sample of the macroinvertebrates living in
the stream.
3. The collecting group will split into 2 sub-groups. The kickers (2 students) and the collectors (4 or 5
students). Students can switch from time to time.
4. A 3’ by 3’ area should be sampled (kicked) for 1 minute.
12
5. The kick seine should be carefully brought to the stream bank and placed on a white background (for
better visibility).
6. Three or four students should check the net for macroinvertebrates. Students should be thorough and
take their time.
7. Carefully remove these organisms and place all similar organisms in a container with water.
8. After all macroinvertebrates have been collected, they need to be identified accurately. Every member
of the collecting team needs to help. All decisions need to be verified by another member of the team
(a system of checks and balances).
9. Record your data on the data sheet. The BWQS can be calculated from the data sheet.
Extensions/Options
Prepare a presentation of your stream study data at a public forum. Using either poster board or power
point, present your sampling methods, data collected and analysis of the water quality. You may
hypothesize on why the stream supports this type of diversity and describe why projects like this have an
important place in environmental monitoring.
Assessment
1. Perform the previous method of sampling using the same organisms in this sample. Compare and
contrast the previous method to the BWQS.
2. Explain the importance of Indicator Species.
3. How do the abiotic factors such as temperature and dissolved oxygen (DO) affect the abundance or
presence of certain aquatic organisms?
4. How are aquatic organisms that are sensitive to pollution like the canary in a coal mine?
5. Besides temperature and dissolved oxygen, what other (a) chemical factors and (b) physical factors
can affect the diversity of aquatic macroinvertebrates?
6. Why might the BWQS change from section to section of the same stream?
Handouts
• Data collection sheets from the Project Watershed website. www.projectwatershed.org
• Packet with spreadsheets and sample collections.
13
Investigating a Watershed Using BWQS:
Sample 1
(1) 10 collected
(1) 10 collected
(1) 4 collected
(1) 2 collected
(1) 6 collected
(1) 2 collected
(1) 4 collected
(1) 2 collected
(1)
14
Sample 2
(2) 2 collected
(2) 3 collected
(2) 1 collected
(2) 1 collected
(2) 2 collected
(2) 14 collected
(2) 2 collected
(2)
4 collected
15
Sample 3
(3) 2 collected
(3) 2 collected
(3) 5 collected
(3) 4 collected
(3) 3 collected
(3) 3 collected
16
Sample 4
(4) 2 collected
(4) 2 collected
(4) 4 collected
(4) 5 collected
(4) 3 collected
(4) 12 collected
17
Sample 5
(5) 15 collected
(5) 3 collected
(5) 9 collected
(5) 20 collected
18
Sample 6
(6) 7 collected
(6) 2 collected
(6) 8 collected
(6) 1 collected
(6) 4 collected
(6) 10 collected
(6) 2 collected
(6) 2 collected
19
BIOLOGICAL WATER QUALITY MEASUREMENT
A biotic score is based on the tolerance of different benthic organisms to pollutants; some
organisms are tolerant and some are sensitive. According to the biotic score method,
sensitive organisms are assigned high values and tolerant organisms are assigned low
values. The computer average value for a collected sample yields the Biotic Water Quality
Score.
Procedure:
(1) Collect close to 100 organisms.
(2) Identify all the organisms using a macroinvertebrate identification key;
record the number of each organism identified.
(3) Enter the number in the yellow number column. Excel will multiply
the number of each organism identified by its BWQS
and then divide the product by 10.
(4) Excel will calculate the individual organism scores to obtain the percentage of the total = BWQS.
Suggested ranges of Biotic Water Quality Scores for streams in New York State:
80-100
60-80
40-60
0-40
AQUATIC
ORGANISMS
non-impacted (excellent water quality )
slightly impacted (good water quality )
moderately impacted (fair water quality)
Severely impacted (poor water quality)
BIOTIC WATER QUALITY SCORE WORKSHEET
NUMBER
BIOTIC
COLLECTED
VALUE
PRODUCT
(A)
(B)
AXB
Aquatic worm
Beetle Larva (not riffle)
Black fly
Caddisfly
Clam
Cranefly
Crayfish
Damselfly
Dobsonfly
Dragonfly
Fishfly
Leech
Mayfly
Midge
Riffle Beetle
Scud
Snail
Sowbug
Stonefly
Water penny larva
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TOTAL
0
0
8
6
10
6
8
6
6
10
6
6
2
10
5
10
6
4
2
10
10
Product/10
A X B / 10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BWQ SCORE =
Source: Robert Bode, NYS DEC
Nov-99
NAME OF STREAM:
LOCATION:
DATE:
20
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
#DIV/0!
Teacher’s Guide
Comparing Current Chemical Water Quality Measurements with
Past Measurements At A Stream Site
Lesson Description
In this lesson, students will compare their most recent water quality measurements with their past
measurements at the same stream site. Samples are usually taken during the spring and fall seasons of
the year, and to avoid seasonal variations, the spring measurements should be compared only to spring
measurements from the past. The same protocol should be followed when comparing the fall
measurements to those from the past.
Samples collected from the most recent stream surveys can be measured and converted to Q values.
(Mitchell and Stapp). The averaged measurements from the same site collected for the same season of
the year should also be converted to Q values. The Q values, as illustrated in the aforementioned
reference, assign a value between zero and one hundred for each measurement conducted.
By using a Q value, the amount of a substance present can be compared to the ideal amount of that
substance. The Q value allows us to compare the measured levels of phosphates, nitrates, turbidity and
all the other measurements to the ideal values for the stream sample. The use of Q values provides a
level playing field, and instead of comparing apples to oranges we can compare, for instance, the
ripeness of apples to the ripeness of oranges. The measurement of ripeness for apples and oranges can
be assessed by Q values, and this analogy can be applied to any of the water quality measurements for
comparison.
There are several other methods to evaluate and analyze the water quality data, but they require the
use of statistics that may be outside the scope of this investigation or beyond the expertise of the
students. Keeping with the data conversion to Q values, our comparisons will be simply how far is our
sample or our database average below the ideal amount for each measurement. Any difference in
value that is greater than 10 Q values is considered worthy of closer inspection and further
investigation.
Science Concepts Introduced
•
•
Compare current data collected from a stream site to accumulated data at that stream site.
Evaluation of recently collected data to an on-line database.
Process Skills Emphasized
•
•
•
•
Accessing web based information.
Downloading data to a spreadsheet.
Comparing recently collected data to the database average
Preparing a class presentation
Technology Used:
•
•
•
Computer
Analytical software such as MS Excel
Internet
MST Standards
Standard 1: Key idea 1 - Performance indicators 1, 2, 3
Standard 2: Key idea 2 - Performance indicators 1, 2, 3
Standard 3: Key idea 1 - Performance indicator 2
Key idea 6 - Performance indicator 1
Standard 7: Key idea 1 - Performance indicators 1 and 4
Key idea 2 - Performance indicators 1, 2, 3, 4, 5, 6
Learning Outcomes
Students will be able to:
1. Use a spreadsheet to find the averages for a set of chemical values.
2. Manipulate data in MS Excel.
3. Convert data into graphs in MS Excel
4. Compare and evaluate a recent collection with past collections of data.
5. Communicate group results in a class presentation
Time Requirement
4 Class periods or 2 double periods (block)
Collection and analysis
Comparisons and class presentations
Instructional Strategies
Learning and communicating through group work
Background
•
•
•
•
•
Input a new column (monthly) in the downloaded database, allowing students to cancel out
seasonal differences.
Assist groups on the spreadsheet manipulation. If possible, arrange to have a technophile in each
group capable of performing, or better yet, teaching the spreadsheet functions to the other group
members.
If students do not have computer access, the teachers may have to sort the database to obtain
average values for comparison.
Use the Q values to make the comparisons. Values usually deviate from the number (+ or –) by
two or three Q values.
A good estimation for a significant number will be a difference of ten or more Q values between
chemical measurements.
Assessment
•
•
•
Q value results will be quantified and compared in a group presentation.
A written report will be submitted following the oral report.
Both reports will be evaluated to see how students determined the Q values.
Extensions/Options
1.
2.
3.
Students plot spring/fall variation for each chemical test.
Each group graphically displays seasonal variations.
Compare two samples from different stream sites from the same stream (collected on the same
day). These comparisons should be relatively simple because the same weather and precipitation
conditions will be present at both sites.
Key Terms
Q values, upstream site, downstream site, database, chemical v non-chemical measurements
Prerequisite Knowledge
1.
2.
3.
All participants will understand how to find optimum results for water chemistry tests using the Q
values tables from the references. (Mitchell and Stapp).
The water quality chemistry tests include: dissolved oxygen (DO), pH, nitrates, phosphates, total
dissolved solids, chlorides, biochemical oxygen demand (BOD).
The non-chemical water quality tests include: turbidity, and fecal Coliform
Equipment Needed
Computer with MS Excel and MS Word
Printer
Internet Access
References
M.K. Mitchell and W.B. Stapp 1997 Field Manual for Water Quality Monitoring, GREEN/Earth
Force, Alexandria, VA
Web sites:
http://wow.nrri.umn.edu/wow/data/pplotter/index_ice.html
http://wow.nrri.umn.edu/wow/overview.html
Handouts
Conversion Graphs for water quality measurements to Q values from Mitchell and Stapp
Student’s Guide
Comparing Current Chemical Water Quality Measurements with
Past Measurements At A Stream Site
Introduction
Once water quality measurements obtained from a stream study are available, there must be an investigation to see
if those measurements are accurate. The most recent stream study will be compared to the averaged test results
from the database. If these results are similar in Q value to the samples collected in the past, they will tell us no
significant pollution has occurred recently (the last several days) upstream from the collection site.
Pollution can enter the watershed in many forms. Project Watershed’s nine tests are specific to the most probable
types of pollution. If differences between your sample and the average from the database are found in significant
numbers, it would signal pollution is entering the watershed somewhere upstream. The water quality chemistry tests
include: dissolved oxygen (DO), pH, nitrates, phosphates, total dissolved solids, chlorides, biochemical oxygen
demand (BOD). The non-chemical water quality tests include: turbidity, and fecal coliform. Your instructor will
present a simple method for comparing test results using Q values (Mitchell and Stapp).
Learning Outcomes
Students will be able to:
• Use a spreadsheet to find the averages for a set of chemical values.
• Manipulate data in MS Excel.
• Convert data into graphs in MS Excel
• Compare and evaluate a recent collection with past collections of data.
• Communicate group results in a class presentation
Skills Required
• Use of computers and software
• Sort information from the database
• Compare data from various sites and times
• Public speaking
New Terms
Q values, chemical physical and biological parameters.
Quest
You are an investigator searching for traveling midnight polluter (s) who has been releasing illegal chemicals into
our local streams. We know that there have been large amounts of certain chemicals released at various times of the
year. The problem is that we only monitor the stream twice a year. Realizing that once the chemicals are released,
they can be washed away by the stream flow. We have to almost catch the polluter(s) in the act. Your task is to
compare recently collected samples to the Project Watershed database and determine if the polluter(s) has made an
illegal release into your stream.
Materials
A set of data from your most recent stream study
Computer with MS Excel and a word processing program
Access to the Internet
Procedure
1.
2.
3.
4.
5.
Download all the water chemistry data at the selected stream site.
Sort the data by month to avoid seasonal influences.
Compute and evaluate the mean for each of the nine parameters of water quality from the database.
Convert each mean to a Q value from the established reference.
Convert the current data collected from the recently measured stream site into Q values using the reference
(Mitchell and Stapp).
6.
Compare the Q values for each of the chemical parameters to see if there are what you would consider to be
significant differences.
7. Find any deviation between current and past values. Explain the differences and why they would be considered
highly significant.
8. Develop an Excel bar graph to show the current and past Q values for visual comparison of the investigation
results.
9. Present the results of your investigation to the class.
Extension/Options
1.
2.
3.
4.
5.
Students plot the monthly values for each of their chemical tests.
Identify variations in the spring/fall period. Expect wide variations.
Graphically display any seasonal variation.
If your stream fails to show expected variations, choose another stream (available on the website) with a larger
database.
Compare two samples from different stream sites from the same stream collected on the same day. These
comparisons should be relatively simple because the same weather and precipitation conditions were present at
both sites. Expect minimal variations.
References
M.K. Mitchell and W.B. Stapp 1997 Field Manual for Water Quality Monitoring, GREEN/Earth Force, Alexandria,
VA.
Websites:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
http://www.projectwatershed.org
http://wow.nrri.umn.edu/wow/under/parameters/turbidity.html
http://wow.nrri.umn.edu/wow/under/parameters/oxygen.html
http://h2osparc.wq.ncsu.edu/info/do.html
http://bcn.boulder.co.us/basin/data/NUTRIENTS/info/TP.html
http://www.epa.gov/volunteer/stream/vms56.html
http://oregonstate.edu/instruction/bi301/eutrophi.htm
http://bcn.boulder.co.us/basin/data/NUTRIENTS/info/NO3+NO2.html
http://www.campbellsci.ca/CampbellScientific/Catalogue/Hydrolab_Chloride.pdf
http://wilkes.edu/~eqc/tds.htm
http://bcn.boulder.co.us/basin/data/NUTRIENTS/info/TDS.html
http://www.ncsu.edu/~ajclevel/pHeffects.htm
http://www.dec.state.ny.us/website/dow/stream/orderpageone.htm
http://www.people.virginia.edu/~sosiwla/Stream-Study/Key/MacroKeyIntro.HTML
http://bcn.boulder.co.us/basin/data/NUTRIENTS/info/index.html
http://www4.ncsu.edu/~ajclevel/macroinvert.html
See websites (above) to research why the Q values vary by a significant amount.
Assessment
Rubric
•
•
•
•
•
•
•
Work effectively by following directions for analysis of water quality parameters using Q values.
Demonstrate the ability to gather and process information by downloading the appropriate data.
Demonstrate the ability to calculate all parameters into seasonal averages using a spreadsheet for comparison.
Generate Q values from the processed data.
Demonstrate ability to analyze Q values (present to past).
Demonstrate significant differences in Q values and offers a hypothesis for the variations.
Present results and interpretation in a clear, concise and informative manner.
Handouts
OPTION: BIOLOGICAL WATER QUALITY MEASUREMENT
THE BIOTIC WATER QUALITY SCORE METHOD
A biotic score is based on the tolerance of different benthic organisms to pollutants ; som
organisms are tolerant and some are sensitive. According to the biotic score metho
sensitive oranisms are assigned high values and tolerant organisms are assigned lo
values. The computer average value for a collected sample yields the Biotic Water Qua
Score.
Procedure:
(1) Collect close to 100 organisms
(2) Identify all the organisms using a macro-invertebrate identification ke
record the number of each organism identified
(3) Enter the number in the yellow number column. Excel will multip
the number of each organism identified by its BWQS
and then divide the product by 10
(4) Excel willl calculate the individual organism scores to obtain the percentage of the total = BWQ
Suggested ranges of Biotic Water Quality Scores for streams in New York State
80-100
60-80
40-60
0-40
AQUATIC
ORGANISMS
non-impacted (excellent water quality
slightly impacted (good water quality
moderately impacted (fair water quality
Severely impacted (poor water quality
BIOTIC WATER QUALITY SCORE WORKSHEET
NUMBER
BIOTIC
COLLECTED VALUE
PRODUCT
(A)
(B)
AXB
Aquatic worm
Beetle Larva (not riffle
Black fly
Caddisfly
Clam
Cranefly
Crayfish
Damselfly
Dobsonfly
Dragonfly
Fishfly
Leech
Mayfly
Midge
Riffle Beetle
Scud
Snail
Sowbug
Stonefly
Water penny larva
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TOTAL
0
0
8
6
10
6
8
6
6
10
6
6
2
10
5
10
6
4
2
10
10
Source: Robert Bode, NYS DEC
Nov-99
NAME OF STREAM:
LOCATION:
DATE:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BWQ SCORE =
Product/10
A X B / 10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
#DIV/0!
Teacher’s Guide
Using A Volunteer Acquired Database Constructed On The Internet,
Examine the Relationship between Dissolved Oxygen and Water Temperature
Lesson Description
The relationship between dissolved oxygen and water temperature is critical for aquatic
life in a stream, river or lake. More dissolved oxygen is present in water with a lower
temperature compared to water with a higher temperature.
The reason for this inverse relationship between dissolved oxygen and temperature is that
the solubility of a gas in a liquid is an equilibrium phenomenon. According to La
Chatelier's Principle, any reaction reaching equilibrium will seek a new equilibrium when
a variable (temperature) influencing that equilibrium is altered.
This gas solubility in a liquid relationship can be further clarified if you think about what
happens to a cold carbonated beverage; as it is opened and stands around for a while at
room temperature. Once warmed to ambient temperature the taste is very “flat”; since
more of the “tangy”; carbon dioxide bubbles have escaped. Boiled water also tastes “flat”
because all of the oxygen gas has been removed by heating. More dissolved oxygen is
present in water with a lower temperature compared to water with a higher temperature.
Given the two variables of dissolved oxygen and temperature with a possible linear
relationship, an analysis of the relationship is possible by plotting both variables on a
graph as part of an XY scatter plot. Using MS Excel spreadsheets, it is very easy to do
this. Using either Excel or a graphing calculator, calculate the correlation coefficient,
conduct a linear regression on the data, and find the given r-squared value along with the
"best-fit-line" equation.
The correlation coefficient = r is a value between negative 1 and positive 1. The closer
the value is to -1 and +1, the better the predictability of the relationship. If r =-1, there is
a negative slope and if r = +1 the r-value represents a positive slope or positive
relationship. Variables with r-values close to 0 represent no relationship.
R squared represents the % change in the dependant variable that can be contributed to
the independent variable. If r-squared is 0.88, then 88% of the change in the dependant
variable is attributed to a change in the independent variable. Most of the time, multiple
variables will affect the given variable as is the case of water temperature and dissolved
oxygen. In brief, r squared is the relative predictive power of a model. The value of r
squared (r2) is a descriptive measure between 0 and 1. The closer it is to one, the better
your model. By "better" we mean a greater ability to predict. A value of r squared equal
to one (which only occurs in fairy tales and textbook exercises), would imply that the
linear regression provides perfect predictions, and the more the two variables are related.
As the r-squared value gets closer to zero, the less the two variables are related and the
less reliable the regression equation will be for purpose of making predictions
Science Concepts Introduced
Making predictions from data previously collected and analyzed for their correlation.
Process Skills Emphasized
• Internet retrieval of a specific database
• Interpreting data
• Applying statistics
• Computer analysis
Technology Used
• Internet
• MS Excel using the correlation function.
MST Standards
Standard 2 Key idea 1
Standard 3 Key Idea 6
Standard 4 The Living Environment Key Idea 5
• Living Environment 5
• Physical Setting/Earth Science 2 & 7
Learning Outcomes
Students will be able to:
• Access the Project Watershed database at <www.projectwatershed.org>.
• Open a spreadsheet, copy and paste (download) the values to be investigated.
• Save the original database and make a backup copy.
• Sort the data by stream, by date, or by location.
• Find the correlation between water temperature and dissolved oxygen.
• Generate scatter plot graphs.
• Prepare a report describing their findings for the dissolved oxygen/water temperature
correlation.
Time Requirement
2-4 class periods or 2 blocks (dependant upon student skill level using the Internet,
spreadsheets and graphing programs).
• Class period one: accessing and exploring the database at <www.projectwatershed.org>
• Class period two: downloading selected data, placing it in a MS Excel spreadsheet, and
manipulating the data using the MS Excel correlation, formula and chart functions.
• Class period three: preparation of a statistical report by student groups with class
discussion on the understandings formed and/or anomalies observed.
Instructional Strategies
• Cooperative learning groups
• Individual learning
• Statistical inquiry
Background
When downloading information from the website, it is necessary to select for MS Excel format.
Students will need to enter the correlation formula and highlight two columns of variables to
determine if a relationship exists. Students will also highlight two columns in order to use the
Chart functions to produce a graph of the selected variables. The primary focus of this exercise
is to have students examine the variables, dissolved oxygen and water temperature. Once they
have learned how to use MS Excel to examine these selected variables, they will be able to use
the same procedures to examine any pair of selected variables.
The reference section of this lesson contains a number of links to web pages that provide
computer directed instruction in the use of spreadsheets, graphing, and finding correlations.
Since instruction in spreadsheet use is primarily procedural, it is recommended that a strategy of
demonstration followed by guided practice be employed.
Because the process of data collection is inherently flawed, students will find that the observed
results of their investigation may differ strikingly from their expected results. This provides an
excellent opportunity to stress the importance of accuracy and precision whenever data is
collected. In addition, it should be emphasized that there are many variables other than water
temperature that can affect dissolved oxygen concentration. Because the expected relationship is
based upon controlled laboratory measurements, interfering variables such as those found in field
collected data are not present. This provides an excellent opportunity for students to consider
what other factors could be altering dissolved oxygen concentrations from their expected levels.
Assessment
1. Students demonstrate their competence for the learning outcomes as follows:
• Access the Project Watershed database and download selected data by copying and
pasting selected data into a spreadsheet.
• Prepare a graph(s) from teacher designated sets of data using default formatting.
• Derive the correlation coefficient of data by using the statistical formula functions for
correlation in a spreadsheet.
• Perform a self-directed search of the Project Watershed data and report on the findings.
(Findings must include copies of the data selected, graphs and statistical findings applied
to the data.)
• Put forth conclusions based on their findings and provide possible explanations and/or
suggestions for further data collection or analysis to satisfy their search.
2. Student groups will be responsible for developing a report on their findings for presentation
to the class.
3. Students take part in a class discussion of their data as well as their interpretations, and
conclusions relative to the database and the statistical and graphic tools they used.
Rubric for statistical correlation and graphic applications:
100 points with suggested point distribution as follows:
• 10 points for successfully accessing the online database
• 10 points for successfully copying and pasting data in a spread sheet
• 15 points for entering and using the correlation formula in the spread sheet
• 15 points for producing a scatter plot graph of the variables using the chart menu
• 20 points for interpreting the statistical correlation in a written report
• 20 points for interpreting the graph produced in a written report
• 10 points for the presentation of findings to the class.
Extensions/Options
• Use graphic and statistical techniques to perform additional self-directed searches of the
Project Watershed database to examine other sets of paired variables for possible
correlation.
• Student groups use the paired variables for analysis of different streams or seasons. Find
variables with the highest correlation. Ultimately, students will gain confidence in using
MS Excel spreadsheets as a way to prospect for potential relationships between other
paired variables.
• After investigating the database in this lesson, students should be encouraged to
participate in a stream sampling experience.
Key Terms
Dissolved oxygen, correlation, variable, database, coefficient, r-value, linear regression,
best-fit-line and scatter plot.
Pre-Requisite Knowledge
• Skill in computer use is desirable but could be taught by assigning more time for this
lesson.
• Knowledge of the relationship between gas solubility and solvent temperature, presented
formally in previous classes, or informally by using a simulation or an analogy.
Equipment Needed
A computer connected to the Internet.
References/Websites
Interpretation of graphs and statistical findings:
1. Scatter plot, line graph and/or correlation information:
http://www.mste.uiuc.edu/courses/ci330ms/youtsey/scatterinfo.html
http://www.itl.nist.gov/div898/handbook/eda/section3/scatterp.htm
http://noppa5.pc.helsinki.fi/koe/corr/cor7.html
2. Scatter plot and line graph with excel instructions:
http://www.ncsu.edu/labwrite/res/gh/gh-linegraph.html
3. Line graphing
http://www.mste.uiuc.edu/courses/ci330ms/youtsey/lineinfo.html
4. Correlation
Using Excel spreadsheets to find statistical correlation between two sets of data.
a. Choose a cell where you want to display the results.
b. Enter an equal sign, then “correl”, and a left parenthesis. ex. =correl(
c. Describe the range of values for the first variable: ex. =correl (b2:b85
(This describes the series of values for the first variable in column b from cell
number 2 to cell number 85.)
d. Next type a comma (,) and then the range for the second value P.
ex. = correl (b2:b 85,d2:d85)
In this example, you are looking for the correlation between the values for first variable
listed in column b, rows 2 through 85 and the values for the second variable listed in
column d, rows 2 through 85. When you complete entering the formula, hit return and the
numerical value for the correlation should appear.
Correlation describes how much one variable is affected by another variable. If the
dependent variable increases in proportion to the increase of an independent variable, the
relationship is described as a positive correlation. If the dependent variable increases in
proportion to the decrease of an independent variable, the relationship is described as a
negative relationship. The formula for correlation produces a number from -1 to +1. The
number 1 indicates a perfect correlation and sign indicates whether the relationship is
positive or negative. To see graphic representations of this, visit the following website
<http://www.mste.uiuc.edu/courses/ci330ms/youtsey/scatterinfo.html>
Handouts
Project Watershed
Correlation Of Two Variables
Dissolved Oxygen vs. Water Temperature
A. Importing Data:
1.Go to<http://www.projectwatershed.org>
2. Click on the database icon
3. Click on Browse Data By Stream.
4. Select the parameters you wish to view in this lesson; they will be dissolved
oxygen and water temperature.
5. Click on the stream you would like to study.
6. Finally Click on Submit
7. Copy and paste this information into an Excel Spreadsheet. (You may have to reformat your row and column dimensions to make it look good. Do this by
highlighting all columns used, and go to the format menu.)
8. Save and print out this sheet. Highlight all data and make sure you “set print
area”.
B. Graphing Your Data:
1.) Highlight all your numerical data. (Make Dissolved Oxygen the X-Variable and
water temperature the Y Variable.)
2.) Click on the Chart Wizard in the menu bar.
3.) Choose the XY Scatter Plot as your graph.
4.) Go through the process making sure you have a key, label both axis and also
include a title.
5.) Format your graph any other way you wish and create it as a “New Sheet”
6.) Save and print out this graph. (All you need to do is click on the graph and hit
print.)
C. Getting the Best-Fit-Line:
1.) While looking at the chart, go to the Chart Wizard drop down menu and choose
“Add trend line”.
2.) Choose Linear (Should be the default).
3.) Click the options tab in this window and select “To display the equation and the r2
value on the chart”.
4.) Save the graph and print a copy.
Complete the following questions, staple all copies to this sheet and hand in. Make sure
your name is on all copies!
Directions: Answer the following for your graphs concerning the relationship between
dissolved oxygen and water temperature.
1)
Best-fit-line equation:
__________________________
2)
What is your r2 value?
____________________
3)
What is your r-value (Correlation Coefficient)?
____________________
4)
Explain in words what the correlation coefficient (r) says about the relationship
between these two variables. What is/are “good” r-value(s)?
5)
Knowing that the equation of all lines in the form Y = mx+b has a slope of m and
a Y-Intercept of b, what is the slope and the Y-Intercept of your best-fit line?
6) Interpret these values. What does the slope say about the rate each changes? What
can you say about the Y-Intercept?
7) Knowing an equation that represents a pattern of data allows us to make
predictions about one variable when we know the value of the other. Assuming
the temperature in your stream is 20 degrees Celsius, what would you predict the
dissolved oxygen level to be?
Data for Hand held Graphing Calculators If No Internet is Available
Dissolved
Water
O2 (mg/L) Temp (C)
Date
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Mill Run Park
Limestone Creek, Mill Run Park
Limestone Creek, Mill Run Park
Limestone Creek, Minoa Shepps
Corners Rd--Smith's Market
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
5/22/1995
2449860
10/23/1997 2450745
4.7
18
8
7.7
1/29/1998
2450843
12.5
4.2
5/20/1998
2450954
7.1
23.3
10/9/1998
2451096
8.6
14.4
6/8/1999
2451338
6.5
22.1
10/8/1999
2451460
4.7
11.2
2/24/2001
2451965
9.4
2
10/19/2001 2452202
9.7
12.3
2452370
10.5
5.8
10/24/2002 2452572
10.2
8.8
10/17/2003 2452930
8.9
11.6
10/21/2004 2453300
9.6
10.8
2450605
8.9
20.1
10/28/1998 2451115
9.5
12.4
10.6
14.2
10
7.3
4/5/2002
6/5/1997
5/3/1999
2451302
10/23/1997 2450745
7/9/2002
2452465
9.2
19
8/20/2002
2452507
7.9
20.3
10/10/2002 2452558
10.4
14.2
6/7/2003
2452798
8
14
7/8/2003
2452829
7.8
21.5
6/15/1995
2449884
10
18
10/23/1997 2450745
9.6
7.7
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
1/29/1998
2450843
11
3.3
5/20/1998
2450954
8.8
21.7
5/29/1998
2450963
11
3.3
10/9/1998
2451096
9.5
14.1
6/8/1999
2451338
7.4
23.5
10/8/1999
2451460
10.5
9.5
10/23/2000 2451841
10.8
9.1
2/24/2001
2451965
13.2
1.7
10/19/2001 2452202
10.9
10.1
2452370
12.5
3.9
10/24/2002 2452572
11.2
7.2
10/17/2003 2452930
10.5
9.5
10/21/2004 2453300
10.3
9.6
4/5/2002
Student’s Guide
Using A Volunteer Acquired Database Constructed On The Internet,
Examine the Relationship between Dissolved Oxygen and Water Temperature
Lesson Introduction
The relationship between dissolved oxygen and water temperature is critical for aquatic
life in a stream, river or lake. More dissolved oxygen is present in water with a lower
temperature compared to water with a higher temperature.
The reason for this inverse relationship between dissolved oxygen and temperature is that
the solubility of a gas in a liquid is an equilibrium phenomenon. According to La
Chatelier's Principle, any reaction reaching equilibrium will seek a new equilibrium when
a variable (temperature) influencing that equilibrium is altered.
This gas solubility in a liquid relationship can be further clarified if you think about what
happens to a cold carbonated beverage as it is opened and stands around for a while at
room temperature. Once warmed to ambient temperature the taste is very “flat”; since
more of the “tangy”; carbon dioxide bubbles have escaped. Boiled water also tastes “flat”
because all of the oxygen gas has been removed by heating. More dissolved oxygen is
present in water with a lower temperature compared to water with a higher temperature.
You will be investigating the co-relation of two sets of values given in the Project
Watershed database. By using a statistical application of a computer spreadsheet, you can
determine the effect of temperature on the ability of water to capture and retain dissolved
oxygen.
You will download dissolved oxygen and temperature data into a MS Excel spreadsheet.
There are two MS Excel tools you will be using.
Tool 1: Statistical Correlation
Correlation indicates positive or negative association between variables. Two variables are
positively associated when the largest values of one are accompanied by largest values of
the other. Two variables are negatively associated when the largest values of one are
accompanied by the smallest values of the other. Correlation tests describe how strongly
the two scores are associated or correlated with each other. In this lesson, you will
examine the variables of dissolved oxygen and water temperature to determine if a
correlation exists between these two variables. Correlation is measured between negative
1.0 and positive 1.0. Correlations approaching 0.0 (middle of the range) indicate little or
no relationship. Correlations close to +1.0 indicate strong positive relationships.
Correlations close to -1.0 indicate strong negative relationships.
With a vast amount of laboratory testing and measurement showing a strong negative
correlation between dissolved oxygen and water temperature, you will have the opportunity
to examine this relationship on field collected data. By examining how well the real field
data demonstrates the ideal laboratory relationship between dissolved oxygen and water
temperature you will be able to identify the strength of the correlation. .
Tool 2: Graphing
Using the chart menu in an Excel spreadsheet, you will make graphs of the two variables
- dissolved oxygen and water temperature. You will be looking for patterns of plotted
points such as a straight line or a scatter of points that appear to slope upward or
downward.
A grouping of points which seem to slope from left to right indicates a positive correlation,
and one which slopes from right to left indicates a negative correlation. Once the best-fitline is produced it will be possible to predict the ideal levels of dissolved oxygen at any
temperature between zero and one hundred.
Learning Outcomes
Students will be able to:
• Access the Project Watershed database at <www.projectwatershed.org>.
• Open a spreadsheet, copy and paste (download) the values to be investigated.
• Save the original database and make a backup copy.
• Sort the data by stream, by date, or by location.
• Find the correlation between water temperature and dissolved oxygen.
• Generate scatter plot graphs.
• Prepare a report describing their findings for dissolved oxygen/water temperature
correlation.
Skills Required
• Basic knowledge of spreadsheet statistical functions
• Interpreting data
• Graphing using spreadsheets or graphing calculators
New Terms
Dissolved oxygen, correlation, variable, database, coefficient, value, linear regression, best-fitline, and scatter plot.
Quest
You are a forensic ecologist studying stream water quality data included in the Project
Watershed database. From past experience, you have learned that an increasing water
temperature during the summer can adversely affect the fish population in a stream,
causing them to surface and "gasp for air."
After deducing that a lack of dissolved oxygen is the most likely cause of their distress,
you implement a study of the dissolved oxygen and water temperature in Limestone
Creek to seek a statistical correlation between the two parameters, and the possibility of a
potential "fish kill." If a correlation is found between dissolved oxygen and water
temperature, your next task will be to determine what water quality factors (positive or
negative) that caused the changes in the dissolved oxygen concentration in the creek. And
you will finally predict the temperature that will induce stress in the general fish
population (gulping for air) and what temperature you would then expect the death of fish
to occur.
Materials:
• A computer with Microsoft Excel
• Internet connection
• MS Excel
Procedure
1. Divide into groups of three to five students. The students will use dissolved oxygen
and water temperature data collected at Limestone Creek.
2. Access the Project Watershed database website and select the dissolved oxygen and
water temperature for all years. Copy the data and paste it in an Excel Spreadsheet.
3. In an empty cell next to the two columns of data, type “= correl (This informs the
program of what formula you intend to use).
4. Then, holding the mouse button down, highlight the first column of data. (This will
appear as “array 1” in the formula cell).
5. Next, holding the control key down, use the mouse to highlight the second column
of data. To finish, return to the formula cell and type a “)” to finish the formula. It
should look like the following: =CORREL(H2:H326,G2:G326).
a.“correl” directs the program to find the correlation.
b. Brackets “( )” enclose the data to be used in the calculation.
c. “H2:H326” describes the range of the first variable starting with cell H2 and
going to cell H326, including all data cells between.
d. “G2:G326” describes the range of the first variable starting with cell G2 and
going to cell G326, including all data cells between.
6. When you type in the last “)”, hit “Enter”, and the value for the correlation will
appear.
7. To create a graph of the two variables, highlight the entire column for one variable by
clicking on the capital letter at the top of the spreadsheet column. This designates
that the numerical data entries in that column will be used. While holding down the
control key, click the letter at the top of the second column. For this procedure, the
two columns selected should be water temperature and dissolved oxygen.
8. Go to the control bar at the top of the page and select Chart Wizard. (It looks like a
small, multicolored bar graph with 4 vertical bars). Select the “XY (Scatter)”.
Follow the instructions at the bottom of the Chart Wizard window by clicking on
“Next”. The third window allows you to label the X and Y-axes of your graph.
9. When the graph is finished, go to the control bar and the top and select “Chart” to
view the pull down menu. Next select “add Trend line”. When the new window
appears, select the “Linear” and push enter. A trend line appears which is the “bestfit” line for the points on the graph. In effect, it averages all the data to find the best
possible, single line to represent all the points, regardless of how scattered they are.
10. Repeat the action in step 7. When you have the window, click on the tab, which
says “Options”. This will cause a new window to appear. At the bottom of the
window are three boxes you can select. Select “Display equation in chart”. This
will give the formula of the line drawn in the form, Y = mx + b. The slope of the
line will indicate a possible relationship even if the correlation formula did not.
Select “Display r-squared value on chart” and you will get a value for r2. For
example, an r2 value of .65 is interpreted as, “changes in the first variable are
responsible for 65% of the changes in the second variable”.
11.
12.
Print your graph. Be sure to include the correlation value, the formula for the trend
line, and the value of r2.
When you have completed investigating the water temperature and dissolved
relationship, select two other variables for study, and follow the same procedure for
these new variables as you did above.
Extension/Options
• Use graphic and statistical techniques to perform additional self-directed searches of the
Project Watershed database to examine other sets of paired variables for possible
correlation.
• Student groups use the paired variables for analysis of different streams or seasons. Find
variables with the highest correlation. Ultimately, students will gain confidence in using
MS Excel spreadsheets as a way to prospect for potential relationships between other
paired variables.
• After investigating the database in this lesson, students should be encouraged to
participate in a stream sampling experience.
References/Websites
Interpretation of graphs and statistical findings:
1. Scatter plot, line graph and/or correlation information:
http://www.mste.uiuc.edu/courses/ci330ms/youtsey/scatterinfo.html
http://www.itl.nist.gov/div898/handbook/eda/section3/scatterp.htm
http://noppa5.pc.helsinki.fi/koe/corr/cor7.html
2. Scatter plot and line graph with excel instructions:
http://www.ncsu.edu/labwrite/res/gh/gh-linegraph.html
3. Line graphing
http://www.mste.uiuc.edu/courses/ci330ms/youtsey/lineinfo.html
4. Correlation
Using Excel spreadsheets to find statistical correlation between two sets of data.
a. Choose a cell where you want to display the results.
b. Enter an equal sign, then “correl”, and a left parenthesis. ex. =correl(
c. Describe the range of values for the first variable: ex. =correl (b2:b85
(This describes the series of values for the first variable in column b from cell
number 2 to cell number 85.)
d. Next type a comma (,) and then the range for the second value P
ex. = correl (b2:b 85,d2:d85)
In this example, you are looking for the correlation between the values for first variable
listed in column b, rows 2 through 85 and the values for the second variable listed in
column d, rows 2 through 85. When you complete entering the formula, hit return and the
numerical value for the correlation should appear.
Teacher’s Guide
How Do Geology and Physical Streambed Characteristics Affect Water Quality?
Lesson Description
In this lesson, the students research a dynamic, vertical dimension of a watershed - the
geological bedrock. Landscape regions, such as the Erie-Ontario Plains and the Allegany
Plateau of Central New York, result from the interaction of erosional action upon various
types of underlying bedrock. These rocks differ in their resistance to erosional conditions.
The great variety of landscape regions in New York State is due to the diversity in and
the resistance of the bedrock found throughout the State.
The Devonian and Silurian geological bedrock of Central New York are important factors
affecting the conditions and physical, chemical and biological processes occurring in a
watershed’s streams, and in regions where climate is similar, this bedrock may be the
most significant factor determining a watershed’s condition. Water in its natural state is
never pure, absorbing minerals and salts from the land over which it passes. Since the
physical, chemical and biological conditions in a watershed are often directly or
indirectly related to bedrock and underlying geologic formations, the bedrock can often
provide an explanation why a stream has certain characteristics, especially the
composition of the streambed.
Geological bedrock also determines the slope of a basin and its drainage patterns. The
difference between the highest elevation in a region and the lowest elevation in that
region is defined as topographic relief. Topographic relief of a landscape region and
gravity influence: stream velocity and discharge, stream flow direction, watershed
drainage, and creation of watershed divides, streambed composition; and ultimately, the
water quality parameters in a stream.
A major challenge for the students in the lesson is locating Project Watershed stream sites
that have not been impacted by point and nonpoint source pollution and cultural
eutrophication runoff.
Science Concepts Introduced
•
•
Geological bedrock, landscape regions and topographic relief
Data retrieval, interpretation and analysis
Process Skills Emphasized
•
•
•
Retrieval of data on the Internet
Collecting, graphing and interpreting data
Interpreting geological, topographic and watershed maps
Technology Used
•
•
Internet
MS Excel
MST Standards
•
•
•
•
•
Standard 1 Key Ideas 1, 2, 3 Scientific Inquiry Performance Indicators A, K
Standard 2 Key Idea 1, 2
Standard 3 Key Idea 3
Standard 4 Key Idea 1, 2 Performance Indicator 2.1
Standard 7 Key Idea 1, 2
Learning Outcomes
Students well be able to:
• Identify and describe the geological bedrock and landscape region(s) of Central
New York.
• Locate and delineate the major watersheds in Central New York and correlate
them with the underlying bedrock and landscape regions.
• Select stream sites that clearly exhibit bedrock and landscape characteristics and
show a low probability of human activity; and then select stream sites that are
obviously impacted by human activity.
• Illustrate how topographic relief influences each of these stream sites with regard
to direction of flow, velocity and discharge.
• Develop a database profile of the physical, chemical and biological water quality
parameters at each natural site.
• Develop a database profile of the physical, chemical and biological water quality
parameters at each human impacted site
• Compare the database profiles of the natural and human impacted stream sites.
• Identify those water quality parameters most likely generated by the underlying
geological bedrock, landscape region and topographic relief at the natural stream
sites.
Time Requirement
Four class periods or two double (block) periods
Instructional Strategies
•
•
•
•
Interacting and learning through group work
Using scientific inquiry
Applying basic mathematics skills
Direct instruction
Background
This is a challenging lesson for the students because they are expected to be concerned
with several earth science concepts - geological bedrock, landscape region, topographic
relief and hydrologic elements - stream flow, stream velocity, discharge and watershed.
The teacher should assess early on the students’ knowledge of earth science; some
instruction by the teacher prior to the lesson may be necessary. They may need help with
bedrock and topographic maps and how these can be correlated with watershed maps.
The downloading, interpretation and analysis of stream water quality data from the
Project Watershed database by the students and then applying this data to their selected
stream sites may be a new dimension of learning, and inquiry, for them. There are a lot of
data to deal with, but the sub-watershed approach should facilitate the students¹ work.
The most difficult part of this lesson will be locating stream sites in their selected subwatersheds that have been minimally impacted by human activity. Since chloride testing
had not been established until 1999, students have been advised to download
<www.projectwatershed.org> water quality data from 1999 through the present.
With the exception of the topographic and watershed maps, five handouts are available to
facilitate the students’ work. These maps can be obtained from your County Soil and
Water Conservation District, New York State Department of Environmental
Conservation or the United States Geological Service.
Assessment
1. Each of the four groups submits:
• a comprehensive poster depicting their research on the selected sub-watershed
stream sites.
• a log of all collected data in Excel form
• a list of parameters resulting from geological bedrock and landscape region with
supportive library research.
2. Teacher’s appraisal of individual student participation in group work and
interpretations and conclusions made by each group
Rubric
•
•
•
•
Participates productively with members of his/her group (30%)
Demonstrates facility for reading and interpreting maps (10%)
Demonstrates ability to download, manipulate and graph data (20%)
Writes and presents observations, interpretations and conclusions in a clear and
concise manner (40%)
Extensions/Options
•
If available, find a water quality database for a watershed in a different bedrock
region than Central New York and compare that collected data to Project
Watershed data.
•
Describe the water quality parameter changes that might occur as a stream flows
from one landscape region to another.
•
Conduct a field trip to a stream site where bedrock is evident, perform water
quality testing and estimate how the bedrock may have affected the test results.
•
Identify sources other than bedrock for variations in water quality parameters in a
stream or watershed.
Key Terms
watershed, basin, delineate, streambed, corridor, geology, geological bedrock,
landscape region, cross section, relief, slope, parameter, discharge, water quality,
nonpoint source, point source, cultural eutrophication
Prerequisite Knowledge
•
•
•
•
Basic mathematics competency
Use of topographic and geological maps
Watershed concept
Basic knowledge of earth science and geology
Materials
•
Computer with Microsoft Excel
•
Computer access to Internet
•
Earth Science Reference Tables: Generalized Landscape Regions of NYS and
Generalized Bedrock Geology of NYS
•
Topographic maps of Central New York region
•
Maps of Oneida - Seneca - Oswego and Tioughnioga River watersheds
References/Web Sites for Teachers/Students
Bedrock Studies
http://water.usgs.gov/pubs/fs/fs-003-02/
Earth Science Reference Tables
http://www.nysedregents.org/testing/reftable/ESRTpg1and2C2.pdf
Geography of NYS
http://www.netstate.comstates/geography/ny_geography.htm
Landforms Depicted on Topographic Maps
http://www.csus.edu/indiv/s/slaymaker/Archives/Geol10L/landforms.htm#Undergrou
nd%20Water
NYS Geologic Map/Legend (cross section)
http://www.albany.net/~go/newyorker/
http://geology.about.com/library/bl/maps/newyorkmapmid.jpg
http://geology.about.com/library/bl/maps/nylegend.jpg
Topographic Maps
http://www.nh.nrcs.usda.gov/technical/Publications/Topowatershed.pdf
http://ngmdb.usgs.gov/Other_Resources/rdb_topo.html
Water Quality
http://www.pacd.org/resources/downstream/downstream_sinkholes.htm
http://www.leo.lehigh.edu/projects/hydroprobe/wqdef.html
http://www.pwea.org/Images/2004StudentReseachPapers/joseph_goodwill_research_
paper.pdf
Water Quality Database
http://projectwatershed.org
Watersheds
http://web.cnyrpdb.org/extranet/cnyrpdb/oneidalake/SOLWFinal/ch2-3.pdf
http://water.usgs.gov/
http://ga.water.usgs.gov/edu/dictionary.html
United States Geologic Service
http://www.usgs.gov/
Handouts
Topographic Map(s) of Oneida - Seneca - Oswego Rivers Basin
Topographic Map(s) of Onondaga - Otisco Lakes, Oneida Lake, Seneca River and
Tioughnioga River sub-watersheds
Regents Earth Science Reference Tables
Generalized Landscape Regions of NYS
Generalized Bedrock Geology of NYS
How to Delineate a Watershed
How To Locate a Watershed in a Landscape Region
How To Locate a Watershed Over Geological Bedrock
How Does Topographic Relief Affect a Watershed?
Identifying Water Quality Parameters Generated By Geological Bedrock
How to Delineate a Watershed
The following procedure will help you locate and connect all of the high points
around a watershed on a topographic map.
1. Draw a circle at the outlet or downstream point of the watershed in question.
2. Put small "X's" at the high points along both sides (contour lines) of the
watershed, working your way upstream toward its headwaters.
3. Starting at the circle that was made in step one, draw a line connecting the
"Xs" along one side of the watershed. This line should always cross the
contours at right angles (i.e. it should be perpendicular to each contour line it
crosses).
4. Continue the line until it passes around the head of the watershed and down
the opposite side of the watercourse. Eventually it will connect with the circle
from which you started. At this point you have delineated the watershed. The
delineation appears as a solid line around the watershed.
Source: NRCS Method for the Comparative Evaluation of Nontidal Wetlands in
New Hampshire, 1991. Alan Ammann, PhD and Amanda Lindley Stone.
How To Locate a Watershed in a Landscape Region
Name of Sub-watershed Group _________________________________
1. Define a watershed and a landscape region.
2. Prepare a transparency of the watershed delineated on a topographic map. After
adjusting for scale, apply the transparency to the Generalized Landscape Regions of
NYS and identify the landscape region in which the watershed is located. Is the
watershed located in the Erie-Ontario Lowlands or the Allegany Plateau?
3. Refer to the Geography of NYS reference
<http://www.netstate.com/states/geography/ny_geography.htm>. Describe the terrain
in which the watershed is situated.
4. Compare the topographic relief in the two landscape regions. How does the relief
affect the direction of flow, velocity and the discharge of streams in the watershed?
How To Locate a Watershed Over Geological Bedrock
Name of Sub-watershed Group __________________________
1. Prepare a transparency of the watershed delineated on a topographic map.
2. After adjusting for scale, apply the transparency to the Generalized Bedrock Geology
of NYS and identify the type of bedrock over which the watershed is located.
• Is the watershed located over the Silurian or Devonian bedrock? Describe the
composition of the Silurian or Devonian bedrock that underlies the watershed. Be
specific (limestone, shale, etc).
• If a stream is flowing close to the bedrock, what effect does the bedrock have on
the streambed and on the quality of the water in the stream, the watershed?
• What effect does the stream have on the bedrock?
3. For a more vivid, detailed view of Central New York bedrock, download the NYS
Geological Bedrock Map reference <http://www.albany.net/~go/newyorker/>. Repeat
Steps 1 and 2 using this geological map.
How Does Topographic Relief Affect a Watershed?
Name of Sub-watershed Group ____________________________________
1. If relief is the difference between the highest elevation in a region and the lowest
region in a region, which Landscape Region in Central New York has the higher
relief? Which has the lower relief?
2. After delineating the watershed on the topographic map, describe how relief
(elevation and slope) in the watershed determines each stream¹s direction of flow,
velocity and discharge.
3. If a stream is swiftly flowing over bedrock in steep terrain, describe the erosional
effect of the water. How is the stream¹s water quality changed by erosion? If a stream
is flowing slowly over the land, how is the stream¹s water quality changed by
erosion? What happens over time to the particle size of rock material in a streambed
as the stream¹s velocity increases?
4. In consideration of the Bedrock Region that underlies the watershed, propose some
chemical parameters that can be found in the water.
5. . In a fast flowing stream, are the rocks more or less embedded in the silt, sand or
mud than in a slow flowing stream?
6. How does relief affect aquatic organisms in a stream?
Identifying Water Quality Parameters Generated By Geological Bedrock
Name of Sub-watershed Group_________________________________
1. View and compare the MS Excel Bar Graph Profiles of the averaged physical,
chemical and biological parameters for the selected bedrock impacted stream sites and
human impacted stream sites researched in the sub-watershed.
2. Use the following format to compare the bedrock impacted stream sites and human
impacted stream sites.
3. Identify the water quality parameters that most probably were generated by the
geological bedrock at the selected bedrock site (s), and not by human cultural activities.
Bedrock Impacted Stream Site(s)
Human Impacted Stream Site(s)
Stream Name
Stream Name
Site Location
Site Location
Observable Data: Streambed Composition
Physical Data
Stream velocity
Stream velocity
Discharge
Discharge
Chemical Data
Suggested parameters in Project Watershed Database: pH, water temperature, dissolved
oxygen, biochemical oxygen demand, phosphate, nitrate, chloride, total dissolved solids
and turbidity
Biological Data
Macroinvertebrate abundance
Macroinvertebrate abundance
Diversity index
Diversity index
Student¹s Guide
How Do Geology and Physical Streambed Characteristics Affect Water Quality?
Lesson Introduction
A watershed, also called a drainage basin, is the area in which all water, sediments, and
dissolved materials drain from the land into a common body of water, such as a stream,
river, lake or ocean. A watershed encompasses not only the water, but also the
surrounding land from which the water drains. A watershed may be either a large or small
area, and its physical characteristics can greatly affect how the water flows. These
characteristics affect stream flow and can be a key to evaluating the quality of water in
the watershed.
Geological bedrock is an important factor affecting the conditions and physical, chemical
and biological processes occurring in a watershed, and in regions where climate is
similar, this bedrock may be the most significant factor determining a watershed¹s
condition. Water in its natural state is never pure, absorbing minerals and salts from the
land over which it passes. Since the physical and ecological conditions of a watershed are
often directly or indirectly related to bedrock and underlying geologic formations, the
bedrock can often provide an explanation why a stream has certain characteristics,
especially the composition of the streambed. The slope of a basin and its drainage
patterns are also influenced or determined by geology.
Landscape regions result from the interaction of erosional action upon various types of
underlying bedrock. These rocks differ in their resistance to erosional conditions. The
great variety of landscape regions in New York State is due to the diversity in and the
resistance of the bedrock found throughout the State.
Streams with beds above the water table are ephemeral streams; those with beds below
the water table are permanent streams. Not only are streams affected by their geologic
environment, streams in turn affect their geologic environment. The nature and
magnitude of the effect are influenced by the amount of water (discharge) and character
of flow (turbulence).
Geological bedrock also influences the topographic relief and landscape regions in
Central New York. Relief is the difference between the highest elevation in a region and
the lowest elevation in that region. A landscape region is a geographic description of the
land: lowlands, plateau, mountains, etc. The topographic relief of a landscape region
determines: stream velocity and discharge, stream flow direction, watershed drainage,
creation of watershed divides, stream bed composition; and ultimately, water quality
parameters in a stream.
The main purpose of this lesson is to assess the impact of geological bedrock, landscape
regions and topographic relief on the water quality of selected Central New York
watershed streams. Students face a challenge in this lesson: In addition to the impact of
these aforementioned natural sources, human activities leading to point and nonpoint
source pollution and runoff from cultural eutrophication may also substantially impact
the water quality of these streams.
Learning Outcomes
Students well be able to:
• Identify and describe the geological bedrock and landscape region(s) of Central
New York.
• Locate and delineate the major watersheds in Central New York and correlate
them with the underlying bedrock and landscape regions.
• Select stream sites that clearly exhibit bedrock and landscape characteristics and
show a low probability of human activity; and then select stream sites that are
obviously impacted by human activity.
• Illustrate how topographic relief influences each of these stream sites with regard
to direction of flow, velocity and discharge.
• Develop a database profile of the physical, chemical and biological water quality
parameters at each natural site.
• Develop a database profile of the physical, chemical and biological water quality
parameters at each human impacted site
• Compare the database profiles of the natural and human impacted stream sites.
• Identify those water quality parameters most likely generated by the underlying
geological bedrock, landscape region and topographic relief at the natural stream
sites.
Skills Required
• Accessing a database on the Internet
• Collecting, graphing and interpreting data
• Interpreting topographic maps
• Delineating a watershed
• Working cooperatively
New Terms
watershed, basin, delineate, streambed, corridor, geology, geological bedrock, landscape
region, cross section, relief, slope, parameter, discharge, water quality, nonpoint source,
point source, cultural eutrophication
Quest
A geological hydrologist, you are asked to search for and investigate stream sites in
Central New York watersheds that have not been affected by point and nonpoint
source pollution and cultural eutrophication. Since these streams are relatively rare,
you must employ: top of the line mapping skills, competent water quality data, and
most of all, qualified and responsible personnel to conduct the research.
Materials
• Computer with Microsoft Excel
• Computer access to Internet
• Earth Science Reference Tables: Generalized Landscape Regions of NYS and
Generalized Bedrock Geology of NYS
• Topographic maps of Central New York region
• Maps of Oneida - Seneca - Oswego and Tioughnioga River watersheds
Procedure
1. Using watershed and topographic maps, students identify and delineate the Oneida Seneca - Oswego Rivers basin. Next, students locate and delineate the Onondaga Otisco Lakes, Oneida Lake and Seneca River sub-watersheds in the Oneida - Seneca Oswego Rivers basin. Finally, students locate and delineate the Upper Tioughnioga
River sub-watershed.
2. Working in groups of four, each group selects one of the sub-watersheds for study.
What streams or rivers flow in the selected sub-watershed? (Since the Seneca and
Upper Tioughnioga sub-watersheds are smaller in area, and the Project Watershed
collected water quality data is considerably less, it is suggested that smaller student
groups work on these selections and larger groups work on the Onondaga - Otisco and
Oneida sub-watersheds.)
3. Referring to the Regents Earth Science Reference Tables, overlay (transparency) the
Generalized Landscape Regions of NYS map on the selected sub-watershed and
identify the region(s) in which it is located.
4. Referring to the Regents Earth Science Reference Tables, overlay (transparency) the
Generalized Bedrock Geology of NYS on the selected sub-watershed and name and
describe in detail the subsurface bedrock material (limestone, shale, sandstone, etc)
under the sub-watershed.
5. Using a topographic map(s), observe the relief that determines the elevation and slope
of the streams in the selected sub-watershed, indicated by contour lines. Describe how
relief determines the streams direction of flow, stream velocity and the sub-watershed’s
drainage. Explain the possible effects of relief on the chemical and biological
conditions and processes in the sub-watershed¹s streams.
6. Referring to a topographic map depicting the selected sub-watershed and after viewing
the Project Watershed database at <www.projectwatershed.org>, identify Project
Watershed stream sites that exhibit bedrock and landscape characteristics, and show a
low probability of point source and nonpoint source pollution and cultural
eutrophication resulting from runoff. These stream sites will most likely be flowing
over steep terrain and a distance from housing and development. Streambed
composition descriptions in the database may be helpful.
7. Repeating Step 6, identify Project Watershed stream sites that are clearly impacted by
point source and nonpoint source pollution and cultural eutrophication resulting from
runoff. These stream sites will most likely be found on low terrain and flowing near or
through housing and development. The contrasting sites in Steps 7 and 8 may belong to
the same identified stream(s).
8. Using the Browse Data by Stream option at <www.projectwatershed.org> and
Microsoft Excel, develop a bar graph profile of the averaged physical, chemical and
biological water quality parameters for each bedrock impacted site. Also, develop a
Microsoft Excel bar graph profile of the averaged physical, chemical and biological
water quality parameters for each human impacted site. (It is suggested that each profile
be based on data from 1999 through the present.)
9. Organize the data into four categories: observable (streambed composition, etc),
physical (stream velocity and discharge), chemical (pH, water temperature, dissolved
oxygen, biochemical oxygen demand, phosphate, nitrate, chloride, total dissolved solids
and turbidity) and biological (macroinvertebrate abundance and diversity index).
10. Compare the database profiles of the natural bedrock impacted and human impacted
stream sites.
11. Identify those water quality parameters most likely generated by the underlying
geological bedrock and landscape region in each sub-watershed. Students should
support their identifications with library and Internet research.
12. Each student group presents their sub-watershed research to the class. The teacher
and the class compare all the sub-watersheds with regard to geological bedrock and
landscape region generated water quality parameters.
Extensions/Options
• If available, find a water quality database for a watershed in a different bedrock
region than Central New York and compare that collected data to Project
Watershed data.
• Describe the water quality parameter changes that might occur as a stream flows
from one landscape region to another.
• Conduct a field trip to a stream site where bedrock is evident, perform water
quality testing and estimate how the bedrock may have affected the test results.
• Identify sources other than bedrock for variations in water quality parameters in a
stream or watershed.
Assessment
1. Each of the four groups submits:
• a comprehensive poster depicting their research on the selected sub-watershed
stream sites.
• a log of all collected data in Excel form
•
a list of parameters resulting from geological bedrock and landscape region with
supportive library research.
2. Teacher¹s appraisal of individual student participation in group work and
interpretations and conclusions made by each group
Rubric
• Participates productively with members of his/her group (30%)
• Demonstrates facility for reading and interpreting maps (10%)
• Demonstrates ability to download, manipulate and graph data (20%)
• Writes and presents observations, interpretations and conclusions in a clear and
concise manner (40%)
Teacher’s Guide
Using a Statistical Procedure To Search A Database
For Out of the Ordinary Values (Outliers)
Lesson Description
This lesson will allow your students to perform a yearly peer review of a viable Internet database. The
data in the Project Watershed database www.projectwatershed.org, like most Internet material, is not
subject to rigid testing to be sure it is absolutely 100% correct. While the chemical testing has a
rigorous quality assurance/quality control maintained and performed by adult supervisors, as with any
protocol, there may be some problems in the process from the collection to the reporting of data.
In this procedure, we will investigate the values given in the database and using a statistical application
we will identify outliers. Outliers by definition appear to be outside of the range of the data. Outliers
may be the result of possible input errors or for some good scientific reason they may require further
investigation. The outliers may, however, be the product of some interesting event or phenomenon
that is worth investigating in another study. The ozone hole at the South Pole was so far outside of the
expected values that it was ignored for several years because it was thought to be an outlier. For these
reasons, all reported outliers should be investigated.
By applying the statistical formula that locates values outside of the probable range of the collected
data, we can determine if the extremes of the ranges are unrealistic
Science Concepts Introduced
We will be performing a peer review of a database collected by our fellow teachers and students. Our
task will be to identify values (outliers) for further investigation. This lesson will be posted on the
website and be made available to math classes for practice using box plots and 5# summaries to locate
outliers. Their peer review will perform quality assurance for the site that is the largest volunteer
stream study publicly accessible on the Internet. Stress to students that the values change from year to
year and that they perform a service of peer review as they monitor the data in this website.
Process Skills Emphasized
• Internet retrieval of a specific database
• Interpreting data
• Applying statistics
• Quality Assurance
• Computer analysis or other technology
• Cooperative learning
• Oral class reports
• Peer review
• Composing letters to public officials
Technology Used
• Internet
• MS Excel
MS Word
Mini Tab Calculator
TI-80 series calculator
MST Standards
Standard 6: A and B
Standard 7: A and B
1
Learning Outcomes
Students will be able to:
• Access the www.projectwatershed.org site on the Internet.
• Open a spreadsheet, copy and paste (download) the values they investigate.
• Save the original database and make a backup copy to discover the outliers. That way a good
computer protocol is performed. Backup data frequently.
• Sort all data
• Use MS Excel to find the minimum and maximum, median, 1st and 3rd quartiles.
• Create a box plot and find outliers.
• Identify and report the suspected outliers to the Project Watershed website.
Time Requirement
1-2 Periods or a full period in a block-scheduling format.
Instructional Strategies:
Cooperative learning groups
Individual learning
Direct instruction
Class presentations
Background
• This exercise involves the use of five-number Box plots to determine if there are numbers that
are far outside of the probable range of accuracy.
• The columns are highlighted and the function tabs can be used to select Median, Max, Min
and Q1 and Q3. These numbers will allow students to determine the Outliers.
• Find the Inter-Quartile Range or IQR
• The IQR = Q3-Q1.
• When you find the IQR, multiply your value by 1.5.
• After performing this step, take 1.5 *IQR and add it to Q3 and then subtract it from Q1.
• These values are then the upper and lower limits for outliers for this set of data.
• Any data point that is higher than Q3+ 1.5 *IQR or lower than Q1- 1.5 *IQR will now be
considered an outlier.
• Teach with the three samples from Butternut Creek as examples.
• Once students have mastered the process, move to the peer review exercise to study the entire
database for outliers.
Assessment
• Continual observation by the teacher provides immediate assessment.
• Cooperative groups will be responsible for presenting their findings to the class.
• Peer review of their work will be performed as a check on their evaluation at the time of their oral
presentation.
• Students will also be required to hand in a hard copy of their oral report for grading. (A rubric will
be provided to them)
• If outliers are discovered and the material is checked and confirmed by the other students (their
peers), a letter will prepared to inform the host of the website.
• Finally, the usual assessment on this knowledge will show up on tests and quizzes.
Rubric for Box Plots and Outliers:
100-point lab: analyze these sets of data (pH, temp, DO, BOD, phosphates, nitrates, chlorides,
turbidity, fecal coliform and total dissolved solids); make each analysis worth 10 points for each
correct box plot and outlier. Within each analysis expect the following:
A 3.5 in floppy disk will be submitted to hand in:
• a folder on the disk called Project Watershed in which all student documents will be
stored.
• a data analysis on each of 10 different variables of the given stream to determine the
outlier limits and identify the previously existing outliers.
2
Students will need to:
1.) Develop a spreadsheet of each variable containing FORMULAS for finding the 5 number
summary, the IQR, the 1.5*IQR and finally the outlier limits (upper and lower).
a)
5 # Summary
2pts
b)
IQR & 1.5*IQR 2pts
c)
Outlier limits
3pts
2.) Create a box-plot for each set of data on a piece of graph paper and denote all existing outliers and
outlier limits. Correct explanation of outlier limits is needed to receive full credit for that part of the
assignment.
d)
Box-plot and outliers
3pts
3) 10 points a piece and 10 variables to study allow credit to be given to each part and add up to a
total of 100 points.
Extensions/Options
In this investigation, we assumed that all outliers were the result of data collection and entry errors. Is
this a good or bad assumption? Justify your answer.
Key Terms
Outliers
Box Plots
Quality Assurance (QA)
Quality Control (QC)
Database
Parameters
Prerequisite Knowledge
•
Firm understanding in the measures of Central Tendency (Mean, Median, Mode)
•
Students must have an understanding of how to use any of the acceptable statistical tools, for
example calculators or computer programs
•
Basic knowledge of water quality parameters
Equipment Needed
A computer with Microsoft Excel
Mini Tab
TI-80 series calculator
Microsoft Excel
Mini Tab
TI-80 series calculator
Handouts
References For Teachers
Moore, David The Basic Practice of Statistics 2nd Edition 2000 W.H Freeman and Company
Websites:
www.projectwatershed.org
References For Students
McClave/Sincich Statistics 9th Edition 2003 Prentice Hall Inc
Handouts
3
Student Name ____________________________
Statistics
Date ______________
Chapter 2
Box-plots / Outlier Project
Directions Go to this site and copy all information stated below into an excel spreadsheet. Today
we will be studying the pH, dissolved oxygen and water temperature of Butternut
Creek. Copy them from http://watershed.syr.edu/chemdisplay.php .
Step 1: Use the formula options in excel to find the five number summary of each set of data.
Remember that the 5 number summaries consist of {Minimum, Quartile 1,
Median, Quartile 3, and Maximum}.
Step 2: Using the numbers from your 5 number summary of each variable, make a box-plot on a
separate piece of graph paper and completely label it and the axis. Excel cannot
make box plots, but software like mini-tab or a graphing calculator can. Use
whatever technology you have to complete this task.
Min Q1
Med Q3 Max
Step 3: Using your 5 number summaries, find the Inter-Quartile-Range. Recall that the I.Q.R. is
= (Q3 – Q1).
Step 4: Multiply the IQR by 1.5 and write down that number. You now need to add this number
to your Q3 and subtract this number from your Q1. This will give you the outlier
limits.
Q3 + 1.5*IQR = your upper outlier limit:
Q1 - 1.5*IQR = your lower outlier limit:
This means that given your set of data, any data point above the upper limit or any data point
below the lower limit is considered too far away from the median to be
considered a good observation. Usually any observation that falls outside these
two ranges would be disregarded when you study data.
Step 5: Find the upper and lower outlier limits and find any outliers that may exist in your given
data set.
Step 6: Give some reasons why you think we could get outliers in this study. When you look at
the sets of data, are there any numbers that don’t make sense at all? What should
we do with those?
Step 7: Class project and Peer review of the entire database. Break up into groups of three to five
students in each group. Select one or more of the nine physical or chemical tests
included in the Project Watershed database. Determine the box plots and find
any possible outliers in your portion of the database.
4
Step 8: At the same website each group will select the chemical or physical test they have
chosen to evaluate. Once the page has opened select every stream in the OneidaSeneca-Oswego rivers watershed and hit the submit button. Highlight all of the
data by using the Ctrl+A keys, then copy and paste it to your spreadsheet. Follow
the same directions to find the outliers.
Step 9: Once outliers are found, make a report to the class.
Step 10: Mail a report to the Host of the website.
Butternut Creek
pH
Dissolved O2
(mg/L)
Water
Temp (C)
4.67
5.89
5.98
6.02
6.03
6.15
6.25
6.25
6.35
6.39
6.44
6.5
6.54
6.59
6.7
6.77
6.79
6.84
7
7.02
7.24
7.31
7.36
7.38
7.56
7.58
7.59
7.61
7.65
7.74
7.77
7.77
7.89
8.09
8.1
8.11
8.12
8.18
8.2
7.9
12.5
8.5
11
8.4
8
9.7
9.7
5.7
8.1
14.7
11.9
9.2
6.7
8.9
7.9
7.1
13
5.8
11
9.3
14.1
6.2
7.8
7.9
9.2
10
9
9.8
8.7
10.3
10.9
9.9
9.3
9.5
10.3
8
23.1
13.9
3
11.5
6.8
20
2.3
14.2
24
15.7
7.2
16.5
11.2
9.2
0
19.7
17.2
4.4
19.8
23.7
8
6
21
10.9
19
0
5.1
4.3
17.5
15.7
17.6
9.1
20.3
8.2
17.6
23.6
4.5
17.2
5
Min
Quartile1
Median
Quartile3
Max
IQR
(Q3 - Q1)
8.19
8.24
8.26
8.3
8.3
8.35
8.37
8.55
8.67
8.67
8.69
8.81
8.95
9.01
12.6
8.2
10.3
10
9.8
10
10.9
11.3
11.8
11
13.4
14.4
9
9.7
14
22.5
4.3
16
4.67
6.58
7.58
8.20
9.01
5.7
8.20
9.7
10.90
14.7
0
7.20
14
17.60
24
Inter-Quartile Range
1.63
2.70
10.40
1.5*IQR
2.43
4.05
15.6
Lower Outlier
Limit
Upper Outlier Limit
4.14
10.64
4.15
14.95
-8.40
33.20
Denoted Outliers
None
None
None
6
Student’s Guide
Using a Statistical Procedure To Search A Database For
Out of the Ordinary Values (Outliers)
Introduction
This lesson will show you how to detect possible outliers out of ordinary values from a given
set of data. The method that we will use will introduce and utilize our knowledge of box-plots
and 5 number-summaries. The reason for doing this type of investigation is that outliers
severely affect the values for the average and standard deviations of sets of data.
This website is a summary of information accumulated by students, their teachers and
volunteers from our CNY region who have worked to produce a database that represents a
summary of water quality in streams. This database is the largest volunteer stream study
available in New York State that is publicly accessible through the Internet.
This is a dynamic database that has yearly input with monitoring by students in the area. Your
investigation is part of an ongoing process of quality assurance (QA) for this website. We
need to consistently identify outliers in order to get as close as possible to the real story the
data are supposed to tell us. By applying the statistical formula that locates values outside of
the probable range of the collective data, we can determine if the extremes of the ranges are
unrealistic.
The outliers may, however, be the product of some interesting event or phenomenon that is
worth investigating in another study. The ozone hole at the South Pole was so far outside of
the expected values that it was ignored for several years because it was thought to be an
outlier. For these reasons, all reported outliers will be investigated.
Learning Outcomes
Students will be able to:
• Access the www.projectwatershed.org site on the Internet.
• Open a spreadsheet, download the values
• Save the original database and make a backup copy. Backup data frequently.
• Sort all data
• Use MS Excel to find the minimum and maximum, median, 1st and 3rd quartiles.
• Create a box plot and find outliers.
• Identify and report the suspected outliers to the Project Watershed website.
Skills Required
• Use computer technology of choice to analyze a data set.
• Work cooperatively in groups.
• Make a short class presentation
• Write and send an informative letter
New Terms
• Quartile
• Parameter
• Quality Assurance (QA)
• Mean
7
•
•
•
•
•
•
•
Median
Mode
Box-plot
Outlier
Upper Limit
Lower Limit
5# Summary
Quest
Actually you are a cyberspace bounty hunter (a predator) in the habitat of the Project
Watershed website. Your prey are the outliers that are in the data on this website. Your
hunting techniques will be to use computer technology to stalk the prey. I would suggest a
manufacturers suggested retail price (MSRP) of $1000.00 Dead or Alive for a bounty on each
outlier you find. Of course, he MSRP will carry little weight with your teacher. You can
negotiate the final payment for each outlier.
Materials
• A computer with Microsoft Excel
• Mini Tab Calculator
• TI-80 series calculator
• Microsoft Excel
• Handouts
Procedure
1. Divide into groups of three to five students per group. The exercise will use Butternut
Creek: dissolved oxygen, temperature and pH.
2. Use some form of mathematical technology (ex. MS Excel) to find the 5-number
summaries. That summary consists of: minimum value, Q1, median, Q3, maximum
value.
3. Find what is called the Inter-Quartile Range or IQR. The IQR = Q3-Q1.
4. When you find the IQR, multiply your value by 1.5.
5. After you get this value, take 1.5 X IQR and add it to Q3, and then subtract it from
Q1.
6. These values are your upper and lower limits for outliers for this set of data.
7. Any data point that is higher than Q3 + 1.5 IQR or lower than Q1- 1.5 X IQR will
now be considered an outlier.
8. Access the www.projectwatershed.org site on the Internet.
9. Select a set of data from the website database.
10. Download the values into an open spreadsheet.
11. Save the original database and make a backup copy to discover the outliers. Follow
good computer protocol. Backup your data frequently.
12. Follow the directions using MS Excel (or other technology of choice) to find the
minimum and maximum, median, 1st and 3rd quartiles (the five numbers for the box
plot.)
13. Create a box plot and identify outliers.
14. Report the outliers to the host website so they can investigate.
15. Once you have set up the box plot for a set of data, it will be relatively easy to divide
the class into smaller groups and each group will be responsible for finding outliers
in one or more of the physical and chemical data sets.
• Water temperature
• Dissolved oxygen
• Turbidity
• Nitrates
• Phosphates
8
•
•
•
•
•
Biochemical Oxygen Demand,
pH
Chlorides
Total dissolved solids
Fecal Coliform
16. Report your information to the class for a class peer review of your 5 number
summaries. If you have found outliers and the class agrees with your results, submit
that information to the website host.
Extensions/Options
• In this investigation we assumed that all outliers were the result of data collection and
entry errors. Is this a good or bad assumption? Justify your answer.
Assessment
• Continual observation with Q and A by the teacher will provide initial assessment.
• Cooperative groups will be responsible for presenting their findings to the class.
• Students will be required to hand in a hard copy of their report for grading. (See rubric
below.)
• A separate letter should be prepared to notify Project Watershed that you have discovered
a possible outlier, and they can review the data to verify the results and investigate the
problem to see if it is valid.
• Finally, the usual assessment on this knowledge will show up on tests and quizzes.
Rubric
100 Point lab exercise will be broken down this way: Students will be analyzing these sets of
data (pH, temp, DO, BOD, phosphates, nitrates, chlorides, turbidity, fecal Coliform and total
dissolved solids). Each analysis is worth up to 10 points. Within each piece the following will
be expected:
1. A 3.5 in floppy disk to hand in.
2. A folder on the disk called Project Watershed and in this folder is where all
documents will be stored.
3. 10 different data analysis experiments on each variable of your given stream to
determine the outlier limits and remove any already existing outliers.
You will also need to:
4. Create a spreadsheet of each variable containing FORMULAS for finding the 5
number summary, the IQR, the 1.5*IQR and finally the outlier limits (upper and
lower).
a)
5 # Summary
2pts
b)
IQR & 1.5*IQR
2pts
c)
Outlier limits
3pts
5. Create a box-plot for each set of data on a piece of graph paper and there denote all
the existing outliers and outlier limits. Correct explanation of outlier limits is needed
to receive full credit for that part of the assignment.
d)
Box-plot and outliers 3pts
A total of 100 points will be divided into 10 points for each of the 10 variables. All groups
will be responsible for performing box plots and discovering outliers if they can be found.
Reports will be given and compared to other groups work.
Handouts
Box plots/Outlier project
9
Date
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Limestone Creek, Kirkville Rd. Bridge
Crossing
Dissolved
O2 (mg/L)
Water
Temp (C)
5/22/1995
2449860
4.7
18
10/23/1997
2450745
8
7.7
1/29/1998
2450843
12.5
4.2
5/20/1998
2450954
7.1
23.3
10/9/1998
2451096
8.6
14.4
6/8/1999
2451338
6.5
22.1
10/8/1999
2451460
4.7
11.2
2/24/2001
2451965
9.4
2
10/19/2001
2452202
9.7
12.3
4/5/2002
2452370
10.5
5.8
10/24/2002
2452572
10.2
8.8
10/17/2003
2452930
8.9
11.6
10/21/2004
2453300
9.6
10.8
Limestone Creek, Mill Run Park
6/5/1997
2450605
8.9
20.1
Limestone Creek, Mill Run Park
10/28/1998
2451115
9.5
12.4
Limestone Creek, Mill Run Park
5/3/1999
2451302
10.6
14.2
10/23/1997
2450745
10
7.3
7/9/2002
2452465
9.2
19
Limestone Creek, Minoa Shepps
Corners Rd--Smith's Market
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Pleasant Street
service road by former Manlius STP
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
Limestone Creek, Rte. 5 Bridge
Crossing, Fayetteville/Town Hall
8/20/2002
2452507
7.9
20.3
10/10/2002
2452558
10.4
14.2
6/7/2003
2452798
8
14
7/8/2003
2452829
7.8
21.5
6/15/1995
2449884
10
18
10/23/1997
2450745
9.6
7.7
1/29/1998
2450843
11
3.3
5/20/1998
2450954
8.8
21.7
5/29/1998
2450963
11
3.3
10/9/1998
2451096
9.5
14.1
6/8/1999
2451338
7.4
23.5
10/8/1999
2451460
10.5
9.5
10/23/2000
2451841
10.8
9.1
2/24/2001
2451965
13.2
1.7
10/19/2001
2452202
10.9
10.1
4/5/2002
2452370
12.5
3.9
10/24/2002
2452572
11.2
7.2
10/17/2003
2452930
10.5
9.5
10/21/2004
2453300
10.3
9.6
Teacher’s Guide
Comparison of Different Methods for Determining Stream Flow at a Stream Site
Lesson Description
Streams moving at a high speed can carry larger sizes of sediment and cause extreme erosion, while slow moving
streams deposit sediments that can cause excessive build up. Stream flow is an important factor in the stream
ecosystem and is responsible for many of the physical characteristics of a stream. Stream flow can also modify the
chemical and biological aspects of a stream. Aquatic plants and animals depend upon stream flow to bring vital
food and nutrients from upstream, or remove wastes downstream. For this reason, stream flow must be carefully
monitored at regular intervals. There are several ways to measure the stream flow, but which way is the best? In
this lesson, students will measure the stream flow using different methods and will determine the most accurate
method for determining discharge, the measure of stream flow.
Stream discharge has two variables: flow velocity and the volume of water in the stream. Both variables are
influenced by several environmental factors. The slope of the surrounding terrain, the depth of the stream, the
width of the stream, and the roughness of the substrate or stream bottom influence flow velocity. If the
surrounding terrain is steep, then rainwater and snowmelt will have less time to soak into the ground, and runoff
will be greater. In an area with level terrain such as farmland, the rainwater has plenty of time to soak into the
ground, and there is less runoff. The flow velocity will also vary as the width or depth of a stream changes. For
instance, if you squeeze a water hose with your hand, the flow velocity of the water increases. This is because you
have reduced the area that the water must flow through, while the volume of water passing through the hose
remains constant. The same thing happens in a stream when the stream channel changes in its width or depth. The
substrate of the stream bottom also affects the flow velocity since water moves faster over a smooth surface than a
rough surface. Flow velocity is greater when the stream bottom is comprised of sand and clay and lower when it is
cobble, rock, and boulders.
Calculating the discharge of a stream is a challenge due to the difficulty in assessing the fluid dynamics. The flow
will be fastest in the middle of the deepest part of the stream and at the middle of the stream depth. If you can
imagine the water flowing more slowly in contact with the streambed and shoreline while flowing faster at the
surface and flowing fastest at about the middle of the depth of the stream. A flat smooth bottom will promote flow
faster than a rocky bottom. An uneven rocky bottom creates turbulence slowing the stream flow.
The volume of water in a stream is affected by the climate of the region. Areas with more rain and snow will have
more water draining into surrounding streams and rivers. Seasonal changes affect stream volume as well. In the
summer there will be less water in a stream compared to the winter. The numbers of small tributaries that merge
into a stream or river contribute more water to the system, increasing the stream volume. Humans are also
responsible for altering the volume of water in streams. Water is removed for consumption, industry, and
irrigation. Roads and parking lots cover vast areas, preventing rainwater from soaking into the ground. Instead, the
water is forced to run off into streams and rivers increasing the rate and volume (discharge) of stream flow.
Science Concepts Introduced
• Scientific inquiry
• Reliability of data.
• Stream flow
• Discharge
Process Skills Emphasized
• Using scientific inquiry.
• Comparing stream flow data.
• Describing percent of error in three methods for determining stream flow.
Technology Used
• Flow meter (flow rate sensor)
MST Standards
• Standard 1 – key ideas 1 and 3.
• Standard 2 - key ideas 1.
• Standard 3 – key idea 5
• Standard 5 - key idea 2 and 3
• Standard 6 – key idea 2
• Standard 7 – key idea 1
Learning Outcomes
Students will be able to:
• Accurately construct a transect (cross sectional area) across a stream
• Measure the velocity of the stream flow using three different methods
• Calculate stream discharge for each of these methods
• Compare the three methods for measuring stream discharge
• Compute the % of error between each of the discharge measurement methods
Time Requirement
4 Class periods or 2 double periods (block)
o Data collection and analysis
o Methods comparisons and computation of error
Instructional Strategies
•
Communicating and learning through group work
•
Using scientific inquiry
•
Using basic math.
•
Calculating scientific error
Background
• Safety in the stream environment.
• Wearing appropriate water gear
• Knowledge and skill of how to operate the flow meter
Assessment
1. Each of the three groups will submit a written report comparing the three different methods for
determining stream discharge which includes:
• a comparative data table
• a graphic representation of the results
• an explanation of the comparative accuracy and reliability of each of the methods based on
percent of error computations and student observations
2. The data attained by the three groups will be quantified and compared as a class presentation
3. Teacher overview of each group's performance
A Suggested Rubric:
1. Develop a comparative data table and a graphic representation of the results using algebraic and
geometric representations. (40 points)
2. Demonstrate a reasonable skill using the Flow Rate Sensor system. (10 points)
3. Understand and explain the comparative accuracy and reliability of each of the methods based on
your percent of error computations and observations of the discharge methods. (30 points)
4. Quantify the data compiled by the three groups and present them to the class. (20 points)
Extensions/Options
• Determine how the varying stream flow affects the stream ecosystem, including: biological, chemical and
physical components.
• Compare pre and post precipitation discharge measurement analyses.
• Observe and compare discharge for fast and slow moving sites on the same stream.
• Describe the impact of stream flow variations on a stream ecosystem
• Suggest an alternative method to measure stream flow
Key Terms
Scientific inquiry, percent of error, stream discharge, stream flow, flow velocity, stream transect, stream run,
qualitative, quantitative.
Prerequisite Knowledge:
Basic mathematical competency
Experience with inquiry process
Flow meter operation
Equipment Needed
Waders, flow meter equipment (available to Project Watershed participants), 2 pieces of line the width of the
stream, 100 ft. tape measure, yardstick, stopwatch, floating object
References
Ely, Eleanor, Volunteer Monitor, Summer 2003, Measuring Stream Flow, How Much and How Fast,
Stream Flow Measurements from Vernier Company
Geology Labs Online: www.flash.calstatela.edu/VirtualRiver
See “Waterwatch Australia” for Background and alternatives http://www.waterwatch.org.au
Handouts For Students
Method 1: Estimation of Discharge
Method 2: Manual Measurement of Discharge
Method 3: Flow Meter Measurement of Discharge
Method 1: Estimation of Discharge
Name of Stream_________________________
Date____________________________
School or Group Name___________________________________________________________
Width in feet or meters at selected stream site. ____________________
Estimation of stream flow as high, normal, low or negligible at 5 designated points:
1 __________ 2 __________ 3 __________ 4 __________ 5 ___________
Estimate the stream flow rate in feet or meters per second.
1 __________ 2 __________ 3 __________ 4 __________ 5 ___________
Write an assessment of Method 1 for measuring the stream discharge in cubic feet or cubic meters/sec
Method 2: Manual Measurement of Discharge
Name of Stream_________________________
Date____________________________
School or Group Name___________________________________________________________
Discharge = Area X Velocity = Cubic Feet Per Second Or Cubic Meters Per Second.
Stream width __________________
Depths in feet or meters (hint: convert inches or centimeters into feet or meters.)
1 __________ 2 __________ 3 __________ 4 __________ 5 ___________
Average stream depth _______________________
Average Depth X Width = Area of Stream Transect = ___________________ square feet or square meters
Length of stream run ________________________
Float time trials 1 __________ 2 __________ 3 __________ 4 __________ 5 ___________ seconds
Average Velocity = __________________________ feet or meters per second
Discharge = Area X Average Velocity = ___________Cubic Feet Per Second Or Cubic Meters Per Second.
Multiply the discharge calculation by .9 for a SMOOTH bottom and by .8 for a ROCKY bottom for the
corrected measurement.
Corrected Discharge = ___________Cubic Feet Per Second Or Cubic Meters Per Second.
Write an assessment of Method 2 for measuring the stream discharge in cubic feet or cubic meters/sec
Method 3: Flow Meter Measurement of Discharge
Name of Stream_________________________
Date____________________________
School or Group Name___________________________________________________________
Discharge = Area X Velocity = Cubic Feet/Meters Per Second Or Cubic Meters Per Second.
Stream width __________________
Depths in feet or meters (hint: convert inches or centimeters into feet or meters.)
1 __________ 2 __________ 3 __________ 4 __________ 5 ___________
Average stream depth _______________________
Average Depth X Width = Area of Stream Transect = ________________________ square feet or square meters
Length of stream run ________________________
Velocity measurements with flow rate sensor 1 _________ 2 _________ 3 _________ 4 _________ 5 __________
Feet Per Second Or Meters Per Second
Average Velocity = __________________________ feet or meters per second.
Discharge = Area X Average Velocity = ___________Cubic Feet Per Second Or Cubic Meters Per Second.
Write an assessment of Method 3 for measuring the stream discharge in cubic feet or cubic meters/sec
Student’s Guide
Comparison of Different Methods for Determining Stream Flow at a Stream Site
Introduction
Streams moving at a high speed can carry larger sizes of sediment and cause extreme erosion, while slow moving
streams deposit sediments that can cause excessive build up. Stream flow is an important factor in the stream
ecosystem and is responsible for many of the physical characteristics of a stream. Stream flow can also modify the
chemical and biological aspects of a stream. Aquatic plants and animals depend upon stream flow to bring vital
food and nutrients from upstream, or remove wastes downstream. For this reason, stream flow must be continually
and carefully monitored on a regular basis.
Stream flow has two variables: flow velocity and the volume of water in the stream. Both variables are influenced
by several environmental factors. The slope of the surrounding terrain, the depth of the stream, the width of the
stream, and the roughness of the substrate or stream bottom influences flow velocity. If the surrounding terrain is
steep, then rainwater and snowmelt will have less time to soak into the ground, and runoff will be greater. In an
area with level terrain, such as farmland, the rainwater has plenty of time to soak into the ground and there is less
runoff. The flow velocity will also vary as the width or depth of a stream changes. For instance, if you squeeze a
water hose with your hand, the flow velocity of the water increases. This is because you have reduced the area that
the water must flow through, while the volume of water passing through the hose remained constant. The same
thing happens in a stream when the stream channel changes in its width or depth. The substrate of the stream
bottom also affects the flow velocity since water moves faster over a smooth surface than a rough surface. Flow
velocity is greater when the stream bottom is comprised of sand and clay and lower when it is cobble, rock, and
boulders.
The volume of water in the stream is affected by the climate of the region. Areas with more rain and snow will
have more water draining into surrounding streams and rivers. Seasonal changes affect stream volume as well. In
the summer there will be less water in the stream compared to the winter. The numbers of tributaries that merge
with a stream or river contribute more water to the system, increasing the stream volume. Humans are also
responsible for altering the volume of water in streams. Water is removed for consumption, industry, and
irrigation. Roads and parking lots cover vast areas, preventing rainwater from soaking into the ground. Instead, the
water is forced to run off into surrounding streams and rivers.
You have to realize that it is nearly impossible to measure the actual flow of a stream. Scholars and scientists such
as Einstein have thrown their hands in the air in the frustration of trying to calculate an accurate measurement of
stream flow. Einstein refused to continue with his work on fluid dynamics of rivers and streams and found the
theory of relativity a simpler topic to understand because it was easier to quantify. Please follow the directions in
this lesson as carefully as possible, and go with courage where Einstein feared to tread.
Learning Outcomes
Students will be able to:
• Accurately construct a transect (cross sectional area) across a stream
• Measure the velocity of the stream flow using three different methods
• Calculate stream discharge for each of these methods
• Compare the three methods for measuring stream discharge
• Compute the % of error between each of the discharge measurement methods
Skills required
Measuring, timing, observing, calculating, summarizing, comparing, communicating
New Terms
Scientific method, % error, stream discharge, stream flow, riffle, run, transect, velocity, impeller, riser rods
Quest
A heavy rain is causing a stream to rise and threaten the homes and businesses in your community. Since you are a
professional hydrologist, you are asked to periodically measure the stream flow to predict if and when the stream
overflows its banks and floods the area. What method would you use to accurately measure the ever-increasing
stream flow in cubic feet per second?
Materials
Waders, flow meter equipment (available to Project Watershed participants), 2 pieces of line the width of the
stream, 100 ft. tape measure, yardstick, stopwatch, floating object, clothespins.
Procedure
CAUTION: Always follow safety precautions when entering the stream. If the water is too deep or swift, select
another site. Never venture out into the stream alone without another person available to assist you in case of
emergency. When you are unable to see the bottom, wear a safety vest and attach a lifeline (safety rope) to the
volunteer. Use a staff to sound the surface in front of you and to maintain balance against the current trying to
sweep you downstream.
Background information
How To Select The Site At Or In The Stream
1. Select a site that is a representative part of the stream as a whole. Avoid sites with bends or breaks in the
stream caused by rocks or sandbars. Try to choose a site where some flow can be observed with a swift
movement similar to that found near a riffle.
2. At this site, you are going to take a cross section of the stream and measure its width and depth. Try to
select a cross section that is shallow enough to measure the depth with a yard or meter stick and is easy to
cross. Avoid sites where the stream depth is less than 10 cm (4 inches).
How To Measure And Mark The Five Points In The Stream
In each of the three methods, you will measure the width of the stream from shore to shore and stretch a line
across the stream and anchor it on each side. Divide that value by six (shore to shore measurement) to obtain
five points that will separate the stream into six equal parts. Mark these five points on the line with clothespins
or some other easily attachable device. Use these points to estimate/measure the stream velocity for each of the
three methods.
Since the performance of the three methods for measuring stream discharge requires 8 students, it is
suggested that 3 groups conduct this exercise.
Procedural Steps
Method 1: Estimation of Discharge
1. Using a tape measure, measure and record the width of the stream at a selected site.
2. Two students stretch a line (rope or string) across the measured width of the stream. Divide the
width into 6 equal segments. Mark the 5 points where the segments intersect with clothespins or
other material.
3. With waders on, walk into the stream, stand at each of the marked points on the line for 30
seconds. Can you feel how fast the water is flowing? Is it flowing at the same rate at each of the 5
points as you walk across the stream?
4. Estimate and record the stream flow at each of the 5 points as high, normal, low or negligible.
5. Estimate and record the stream flow at each of the 5 points in feet or meters per second.
6. How effective is Method 1 for measuring stream discharge? Write your assessment of Method
1.
Method 2: Manual Measurement of Discharge
1. Repeat steps 1 and 2 in Method 1 at the same selected stream site. Record the stream width.
2. At each of the 5 points marked on the line stretched across the stream at the selected site in
Method 1, measure the depth of the water at each point with a yardstick or meter stick. Record
each depth in feet or meters.
3. Calculate the average depth and multiply this number by the width of the stream. Record this
cross-sectional area or transect in square feet or square meters.
4. Two more students stretch another line across the stream 15 to 30 feet (5 to 10 meters)
downstream from the transect line. Record this distance as the run for the float trials.
5. The float trials are conducted as follows by four students who manage the trials - Starter, Float
Putter, Finish Line Timer and Catcher. The Starter and Float Putter will be positioned at the
transect line, and the Finish Line Timer and Catcher(s) will be located at the downstream line.
When the Finish Line Timer is ready, he/she yells to the Float Putter to throw the selected
float into the water. (Important: the float should be thrown upstream of the transect line to
allow enough distance and time for the float to surface and be observable to the Starter before
it approaches the transect line.)
Once the float passes the transect line, the Starter calls "Start!", and the Finish Line Timer
starts the timer. The finish Line timer stops the timer when the float crosses the downstream
line and records the time expended. The Catcher(s) retrieves the float.
Repeat step 5 five times, compute the average number of seconds for the float trials and
record the average.
Note: different types of floats may be used in this procedure and compared with regard to the
time taken from start to finish.
6. Compute the velocity of the float and stream flow. (Divide the run distance by the average time
for the float trials.) Record the velocity of the stream flow.
7. Calculate the discharge of the stream.
DISCHARGE = AREA X VELOCITY = CUBIC FEET PER SECOND OR CUBIC METERS
PER
SECOND
8. How effective is Method 2 for measuring stream discharge? Write your assessment of Method
2.
Method 3: Flow Meter Measurement of Discharge
1. Repeat steps 1, 2 and 3 in Method 2.
2. Connect the Flow Rate Sensor to the Lab Pro instrument.
Directions for operating Calculator/LabPro unit:
1. Press ON button;
2. Press APPS button;
3. Select DATAMATE program which then shows CH 1: Flow Rate (Feet/Second);
4. With impeller in position, select START to begin collecting stream flow data; view
velocity in feet/second on screen; press ENTER to collect data at the next impeller
position; to turn off unit, select QUIT and press 2ND and then ON.
3. Using the same 5 points on the transect line in Methods 1 and 2, place the Flow Rate Sensor at
point 1 near the stream bank. Submerge the impeller of the Flow Rate Sensor at about 40% of the
depth (as measured from the surface) at point 1. If point 1 is shallow enough, use the plastic risers
included with the Flow rate Sensor to support and protect the impeller on the stream bed. The
risers make it easier to keep the impeller in the same spot and oriented in the same direction.
4. Point the impeller of the Flow Rate Sensor upstream and directly into the flow. Turn on the
Lab Pro instrument’s counter and time the impeller’s rotation for 1 minute. After 1 minute, stop
the counter and proceed to point 2 on the transect line. (If using a velocity flow graph, compare
the number of revolutions per minute with the graph and calculate the flow rate.) Record the flow
rate (velocity) for each point on the transect line.
5. Calculate the average velocity for the stream in feet per second or meters per second.
6. Using the transect area previously determined and the average velocity, calculate the stream
discharge.
DISCHARGE = AREA X VELOCITY = CUBIC FEET PER SECOND OR CUBIC METERS
PER SECOND
7. How effective is Method 3 for measuring stream discharge? Write your assessment of Method
Calculation Of The Percent Of Error
There is no way to know the true (absolute) discharge value. After using each of these methods, we
believe that the use of the flow meter will produce the most accurate results. For that reason, the value
measured by the flow meter will be used as the accepted value in our formula for the percent error. All
calculations for percent error will use this procedure.
(Accepted Value) – (Measured Value) x 100 = % of Error
Accepted Value
Extension/Options
1. Determine the impact of stream flow variations on the stream ecosystem (physical, chemical and biological)
2. Compare the discharge at this site with another nearby site (within fifty meters).
3. Determine if there is any variation in the pre and post discharge of a large rain event.
4. Observe and compare discharge in fast and slow moving parts of the same stream.
5. Suggest an alternative method of measuring stream flow
Assessment
1. Each of the three groups will submit a written report comparing the three different methods for
determining stream discharge which includes:
•
•
•
a comparative data table
a graphic representation of the results
an explanation of the comparative accuracy and reliability of each of the methods based on
percent of error computations and student observations
2. The data attained by the three groups will be quantified and compared as a class presentation
3. Teacher overview of each group's performance
•
•
•
•
A Suggested Rubric:
Develop a comparative data table and a graphic representation of the results using algebraic and
geometric representations. (40 points)
Demonstrate a reasonable skill using the Flow Rate Sensor system. (10 points)
Understand and explain the comparative accuracy and reliability of each of the methods based on
your percent of error computations and observations of the discharge methods. (30 points)
Quantify the data compiled by the three groups and present them to the class. (20 points)
Handout;
Method 1: Estimation of Discharge
Method 2: Manual Measurement of Discharge
Method 3: Flow Meter Measurement of Discharge