Cascades to Coast GK12 Curriculum

Using Aquatic Macroinvertebrate Bioassement to Evaluate Stream

Quality in the Cascades and Willamette Valley Ecoregions.

Fellow: Kit Rouhe (Environmental Science)

Teacher: Laurie McDowell (Lent Middle School)

Advisor: Dr. John Rueter (Environmental Science)

Learning goals:

• Upon completion of this curriculum, students should become familiar with stream

Aquatic Macroinvertebrate Bioassessment as a method for evaluating stream

quality using the stream. The students should also know how to use one type of

bioassessment metric (percent EPT of stream macroinvertebrates) to compare

stream quality between two streams.

• Understand the ecological impact of human activities and land development in the

on the quality of streams in the Cascades to Coast Ecoregion.

Objectives:

• Be able to identify stream macroinvertebrates to the order level

• Learn how to collect samples of live macroinvertebrates from a stream

• Learn how to calculate percent EPT for stream samples

• Be able to determine the quality of a stream using percent EPT

• Be able to compare streams with tow different land use intensities using percent

EPT

Target Grade: Sixth

State Standards:

State Standards (Oregon State Board of Education) Addressed in this Curriculum

6.2L.2 Explain how individual organisms and populations in an ecosystem interact and

how changes in populations are related to resources

6.2E.1 Explain the water cycle and the relationship to landforms and weather

6.3S.1 Based on observations and science principles, propose questions and hypotheses

that can be examined through scientific investigation. Design and conduct an

investigation that uses appropriate tools and techniques to collect relevant data.

6.3S.2 Organize and display relevant data, construct an evidence-based explanation of

the results of an investigation, and communicate the conclusions.

Background

This curriculum was developed to show 6th

grade students, with no prior training

or knowledge of bioassessment, how to use aquatic macroinvertebrates to determine the

quality of a stream. This four day, inquiry-based curriculum was introduced to the

students during a unit on Salmon, the water cycle, and water quality. The main goal of

this curriculum was to allow the students to compare two streams and determine which

one had the highest quality. The two-stream comparison was also a part the general

theme of our water unit: “From the Cascades to the Coast, what’s in the water?” Our

school is located in Portland, Oregon. Portland is in the Willamette Valley, which lies

between the Cascades and Coast Range mountains. The theme was chosen to provide a

context for studying water quality in the Cascades and Willamette Valley ecoregions. The

goal of this unit is to compare the similarities and differences of streams in all three areas

(Cascade Mountains, Willamette Valley, and Coast Range mountains), but the goal of the

four-day curriculum presented here is to compare just two of the three areas. For each

activity in this four day curriculum a general question was asked by the instructor (see

activity plan), written down by the students, and used to form the basis for the activity.

Student learning was assessed through his/her answer to the inquiry question for each

activity.

Site description

The two streams chosen for the comparison activity presented in this curriculum

are from two very different ecoregions of Oregon. Sixes Creek (Cascades ecoregion) is a

small stream that flows into the Wilson River. The Wilson River and Sixes Creek both

contain runoff and snowmelt from the slopes of Mount Hood and the surrounding

foothills of Mount Hood in the Northwest Oregon Cascades. This area is dominated by

fir, pine, and cedar forest with very little human influence from residences or industry.

The Willamette Valley stream, Johnson Creek, flows from the foothills of the Cascades

in northwest Oregon and empties into the Willamette River just south of downtown

Portland, Oregon. The headwaters are dominated by fir, pine and cedar forest but the

river mainly runs through the Willamette Valley. A large portion of the river runs

through agriculture land and the lower reach, just before it enters the Willamette River, is

highly urbanized and is directly influenced by human residences and industry. It is in the

lower, urbanized reach, just before it enters the Willamette River, that the samples for

this project were collected.

Bioassessment

In order to compare two streams, there are many ways to measure water quality

and pollution levels including chemical analysis of pollutants, water chemistry. The

chemical analysis of nutrients, oxygen, and oxygen demand of the water are a great ways

of determining stream water quality at the time of collection. However, stream chemicals

can fluctuate from day-to-day and season-to-season, so chemical analysis for pollution

influences is only useful if measured many times throughout a season. If it is only

possible to visit a stream a few times per year (once or twice each season), determining

pollution of the stream using chemical analysis is not very accurate because of the high

variability associated with chemical measurements. Stream condition may be more

accurately determined by examining the organisms living in the stream. This type of

analysis is called bioassessment. Bioassessment has several advantages over traditional

chemical measurements because the organisms live in the streams year round and

therefore reflect long-term stream conditions. In essence, Bioassessment presents a broad

scale view of stream habitat and water quality with the convenience of infrequent

sampling. For this activity we chose to use stream macroinvertebrate communities to

bioasses two streams with different land use pressures. We used a method of analysis

that compares the percentage of pollution tolerant to pollution intolerant

macroinvertebrates.

Description of stream EPT and Percent EPT metrics

There are many different bioassessment collection and analysis methods that can

be used to measure stream pollution. The curriculum presented here is based on

assessing water quality using a bioassessment method called percent EPT. EPT stands

for Ephemeroptera, Plecoptera, Tricoptera. These are the order names for the insects

known as mayflies (E), Stoneflies (P), and Caddisflies (T). For these three orders of

insects, and for many others, the first developmental stages of the life cycle are aquatic.

These larval stages can last from months to years, but all the stages survive in streams by

living in on the stream bottom or by floating and swimming in the water. To calculate

percent EPT, one first collects all the sediment macroinvertebrates from a small area of a

stream using a specialized net. Second, a total count is made of all the

macroinvertebrates found in the sample. Next, organize the macroinvertebrates in to

groups based upon orders. Lastly, calculate a percent of organisms in each order based

on the total and add the three percents for E, P, and T together. If those percents total

greater than 50%, the stream is considered not polluted. If EPT percent falls below 50%,

then the stream is considered polluted. The farther above 50%, the less polluted the

stream. The farther below 50%, the more polluted the stream.

This assessment in this activity is based on the assumption that for most streams,

if there are more mayfly, stonefly, and caddisfly larva living in the stream sediment than

all the other macroinvertebrates collected from a stream bed, then the stream is

considered of high water quality. It is important to note here that this is based on the

general assumption that species from these orders do not tolerate polluted waters.

However, this is not always the case. Some species from these orders can tolerate

polluted waters, but as a general assumption EPT percent works well for most streams,

particularly in regions outside of the Pacific Northwest. . While there are polluted

streams that have an EPT above 50 percent, most streams fit the general assumption and

so EPT percent works well as a practical tool for assessing stream quality. The reason

this is important for this activity is that it is not designed for students to identify each

species of mayfly, stonefly, or caddisfly. Without knowing the exact species, it is difficult

or impossible to determine if each organism found was pollution tolerant or pollution

intolerant. To account for this possible error, this activity was designed to compare the

EPT percent of two streams and then make a conclusion about which stream was less

polluted base on EPT percent.

A major advantage of using EPT percent for water quality assessment is that

students can easily and quickly identify mayflies, stoneflies, and caddisflies with just a

little training. There are many more aquatic macroinvertebrates that are found on the

stream bed besides EPT species. Aquatic macroinvertebrates include the three orders of

EPT insects, other orders of insects, crustaceans, arachnids, worms, mollusks, and

cnidarians are just of few of the major orders, phylums, and classes. Learning to identify

all of the major groups, the species in those groups, and the pollution tolerance of each

species would take a lot of class and field time. Just learning the three EPT orders

allows the students to gain an adequate level of knowledge in order to quickly determine

the water quality of the stream.

Curriculum overview

The four day curriculum explained here involves first learning the general

characteristics of the EPT orders, followed by practice with identification in the

classroom of macroinvertebrates collected from one of the comparison streams, a field

trip to collect and identify aquatic macroinvertebrates at the second comparison stream,

and finally a day in the classroom to analyze the data and create a poster of the results.

Links to field guides for pictures and characteristic can be found in the resources section

of this curriculum plan. Also in the resource section are some links to protocols for

collecting stream macroinvertebrates. If you have not sampled for stream

macroinvertebrates before, it is not difficult to learn. However, you need a specialized

net and some other tools that you may have to order or borrow a head of time.

Activity Summary:

This curriculum describes a Four-day activity. Day one: identify similarities and

difference between drawings of mayflies, caddisflies, and stoneflies, and learn how to

identify each of them. Day two: instructor brings macroinvertebrates collected from a

local stream into the classroom and the students tally number of EPT organisms, total

macroinvertebrates, and then calculate percent EPT. Day three: visit second stream site.

Students collect macroinvertebrates from the stream sediment. Students tally number of

EPT organisms, total macroinvertebrates, and then calculate percent EPT (if field trip is

not an option, instructor can bring the samples from the second site into the classroom as

in day 2). Day four: create a bar chart of total percent mayflies, percent caddisflies, and

percent stoneflies. Answer assessment question each day (see appendix).

Activity Plan:

Day 1 – Introduction to stream macroinvertebrate identification

Question: What is similar and different about Mayflies, Caddisflies, and Stoneflies

1. Students work in pairs

2. Students are given a handout with 3 pictures/drawings (one caddisfly, one mayfly,

and one Stonefly).

3. On the handout, each student pair makes a list of things that are similar and things

that are different about each drawing (students are not given any names or

background information about drawings). 5 minutes

4. On the bottom section of the handout, students write down characteristics of each

of the macro groups (led by instructor)

5. Visual quiz – 10 photographs of mayflies, stoneflies, and caddisflies. They write

answers in their lab books by simply writing mayfly, stonefly, or caddisfly for

each photograph. (quiz to be graded at the beginning of the next lesson)

6. Visual quiz answers: (1) mayfly, (2) stonefly, (3) mayfly, (4) caddisfly, (5)

stonefly, (6) mayfly, (7) stonefly, (8) caddisfly, (9) stonefly, (10) caddisfly

Day 2 – Willamette Valley stream analysis

The day before “Day 2” of the in class activity

The day before you are going to do this activity, the instructor goes to one of the

stream sites and collects macroinvertebrates from the stream sediment. Place

macroinvertebrates in a plastic container with a lid (one for each classroom group).

Put containers on ice to keep them at stream temperature until you take them to the

classroom. Keep the lid cracked overnight to allow oxygen into the container. Keep

container outside so that the invertebrates are exposed to natural light and dark cycles.

Question: Is Johnson Creek a polluted or pristine stream?

Hypothesis: If Johnson Creek has more mayflies, stoneflies, and caddisflies than other

macroinvertebrates, then Johnson Creek is a pristine stream.

In the classroom on the day of the activity:

1. Grade visual quiz from last lesson and recap characteristics of Mayflies (E),

Stoneflies (P), and Caddisflies (T).

2. Students work in groups (3 or 4)

3. Students write question and hypothesis into lab book.

4. Water sample of macroinvertebrates collected from Johnson Creek in a container

given to each group.

5. Group dumps sample into a plastic bin.

6. Use forceps and plastic pipettes to remove macroinvertebrates from the plastic bin

and place them in the sections of an ice cube tray. Place similar looking bugs into

the same section of the ice cube tray.

7. Count total number of macroinvertebrates found in the water sample.

8. Use ID skills learned from intro activity (Day 1) and a provided Freshwater

Macroinvertebrate ID guide to aid in identification of mayflies, caddisflies, and

stoneflies.

9. Count up total number of Mayflies (E), Stoneflies (P), and caddisflies (T) and

write those numbers on the Macroinvertebrate Calculation Johnson Creek Creek

handout.

10. Write down total of all other (non EPT) macroinvertebrates on the calculation

sheet under other.

11. Write down the fraction of total mayflies (E), stoneflies (P), and caddisflies (T) to

total number of macroinvertebrates found in the sample. This is the EPT fraction.

12. Calculate percent from EPT fraction. This is percent EPT.

13. Complete bar chart on Macroinvertebrate Calculation Sheet Johnson Creek

14. Students paste/tape calculation sheet into lab book.

15. Answer question for Day 2 based on Macroinvertebrate Calculation Sheet

Johnson Creek – Write questions and answer into lab book.

Day 3- Cascade Mountain Stream analysis

*If you’re unable to take the class on a field trip, complete day 3 just as day 2 (instructor

collect samples and bring them to the classroom). If you are able to schedule a field trip,

complete the activity as follows:

Question: Is Sixes Creek a polluted or pristine stream?

Hypothesis: If Sixes Creek has more mayflies, stoneflies, and caddisflies than other

macroinvertebrates, then Sixes Creek is a pristine stream.

1. Students work in groups (3 or 4)

2. Students write question and hypothesis into lab book.

3. Groups collect macroinvertebrates from the stream using nets and then dump

macroinvertebrates into a plastic bin for counting.

4. Use forceps and plastic pipettes to remove macroinvertebrates from the plastic bin

and place them in the sections of an ice cube tray. Place similar looking bugs into

the same section of the ice cube tray.

5. Count total number of macroinvertebrates found in the water sample.

6. Use ID skills learned from intro activity (Day 1) and a provided Freshwater

Macroinvertebrate ID guide to aid in identification of mayflies, caddisflies, and

stoneflies.

7. Count up total number of mayflies (E), stoneflies (P), and caddisflies (T) and

write those numbers on the Macroinvertebrate Calculation Sheet Sixes Creek

handout.

8. Write down total of all other (non EPT) macroinvertebrates on the calculation

sheet under other.

9. Write down the fraction of total mayflies (E), stoneflies (P), and caddisflies (T) to

total number of macroinvertebrates found in the sample. This is the EPT fraction.

10. Calculate percent from EPT fraction. This is percent EPT.

11. Complete bar chart on Macroinvertebrate Calculation Sheet Sixes Creek

12. Students paste/tape calculation sheet into lab book.

13. Answer question for Day 3 based on Macroinvertebrate Calculation Sheet Sixes

Creek – Write questions and answer into lab book.

Day 4 – Data analysis

Question: Which stream is more polluted: Johnson Creek or Sixes Creek?

Hypothesis: If Johnson Creek has a higher percent of EPT than Sixes Creek, it is a less

polluted stream.

1. Groups of 3 or 4

2. Use Macroinvertebrate Calculation Sheet from Sixes Creek and Johnson Creek.

3. Create a poster that includes a title, the question to be answered (ie which stream

is more polluted), the hypothesis, a short description of the methods used to

collect and count macroinvertebrates, a bar chart of data (example below), and a

paragraph that answers the question and explains why the hypothesis is correct or

incorrect.

4. Present group findings by hanging the posters on the classroom wall.

5. Have students write question, hypothesis into lab book.

6. Have students draw bar chart from their group in their lab book.

7. Answer Day 4 question in lab book.

0

5

10

15

20

25

30

35

E P T

Macroinvertebrate Group

Johnson Creek

Eagle Creek

Figure 1: Comparison of percent mayflies (E), stoneflies (P), and caddisflies (T)

between Johnson Creek located in the Willamette valley and Eagle creek located in the

Cascade mountains.

Related Concepts: Testing a hypothesis, Classifying macroinvertebrates to order level,

Bio assessment, Fractions, Percents, Bar Charts.

Materials: Macroinvertebrate ID key, Lab Book, bins for water sample collection, ice

cube trays and forceps for isolating macroinvertebrates, magnifying glasses for

macroinvertebrate ID, poster paper for creating a large bar chart of EPT percent.

Handouts and worksheets: Comparison pictures for Day 1, Day 1 Visual Quiz pictures,

Macroinvertebrate Calculation Sheet Johnson Creek, and Macroinvertebrate Calculation

Sheet Sixes Creek. All handouts are included below.

Resources:

Macroinvertebrate ID guides and keys can be found for different regions using a simple

internet search for “Stream macroinvertebrate identification guides” The ones used for

this curriculum are created by NW nature and can be ordered and view at:

www.nwnature.net. There is also an online guide at this site. The EPA also has online

guides at: www.epa.gov/bioiweb1/html/benthosclean.html

Stream sampling tools and protocols will be crucial for collecting macroinvertebrates in

a local stream. You will need what is called a “D” shaped net and the other items listed

under materials. A You tube search for “Stream Macroinvertebrate sampling protocol”

will bring up some helpful videos and the following links are good too:

http://www.cbr.washington.edu/salmonweb/oregon/Macro.html

http://tinyurl.com/WatershedHealth

http://www.ecy.wa.gov/programs/eap/stsmf/index.html

Assessment Questions:

Day 1: For the Day One quiz: Is each picture a mayfly, caddisfly, or Stonefly

Day 2: What is the fraction and percent of EPT in the activity water sample?

Day 3: What is the fraction and percent of EPT collected from the stream?

Day 4: Which stream is more polluted? Use the data from this activity to explain

your answer.

Introduction to macroinvertebrates in streams

1 2 3

Write down all the things you find similar and different about this group of pictures Question: What is different about Mayflies, Stoneflies, and Caddisflies?

Stoneflies Mayflies Caddisflies

Macroinvertebrate visual quiz

Answer Stonefly, Caddisfly, or Mayfly for each picture.

1. 2.

3. 4.

5. 6.

7. 8.

9. 10.

Names: Date:

Macroinvertebrate Calculation Sheet

Johnson Creek

1. Macro Totals Macroinvertebrate Number

Mayflies (E)

Stoneflies (P)

Caddisflies (T)

Other

2. Macro Calculations Most Common: Least Common: Total EPT ________ Total Macro’s ________ Fraction EPT ________

Percent EPT ________

3. Macro charts

Mayflies Stoneflies Caddisflies Other

Names: Date:

Macroinvertebrate Calculation Sheet

Sixes Creek

1. Macro Totals Macroinvertebrate Number

Mayflies (E)

Stoneflies (P)

Caddisflies (T)

Other

2. Macro Calculations Most Common: Least Common: Total EPT ________ Total Macro’s ________ Fraction EPT ________

Percent EPT ________

3. Macro charts

Mayflies Stoneflies Caddisflies Other