1. Effects of urbanization on stream health… and what we can do about it
-This interactive lecture constitutes the Explanation section of this unit and should come immediately after the Exploration activity and before the Elaboration activity.
-This interactive lecture requires approximately 90 minutes of class time.
-In addition to a computer with Microsoft PowerPoint and an LCD projector, you will need a way for your students to access information about the eight Creek Smart® practices. This can be via the Creek Smart® website ( or via paper copies of the Creek Smart® practices pdf document provided with this unit.
-Urban stream during rain event. Photo courtesy Emily Bernhardt.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

2. Why do urban streams tend to be less healthy than natural streams?
Turn to your neighbor and discuss your answers to this question.
Be ready to share your ideas with the class.
-After posing this to question to the class, do a think-pair-share activity. Then ask pairs of students to share their ideas with the class as a whole.
-Increased percentage of impervious surface
-Storm drains connect impervious surfaces directly to streams
-Extremely fast stormflow rates cause erosion
-This results in channel incision, increased turbidity, decreased habitat complexity, death of riparian vegetation, and ultimately increased temperature and light levels
-Photos courtesy Emily Bernhardt
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

3. Percentage of runoff
How does the amount of impervious surface affect streamflow?
Relationship between impervious cover and surface runoff. Impervious cover in a watershed results in increased surface runoff. As little as 10 percent impervious cover in a watershed can result in stream degradation. From Stream Corridor Restoration: Principles, Processes, and Practices. Federal Interagency Stream Restoration Working Group, 1998.
Humans affect stream ecosystems in a number of ways, both directly and indirectly. Streams in urban areas are exposed to particular types of human impacts that cause characteristic physical, chemical, and biological attributes. These attributes of urban streams are sometimes referred to as the “urban stream syndrome.”
Humans in towns and cities impact urban streams by creating large amounts of impervious surfaces. Impervious surfaces include roads, parking lots, rooftops, sidewalks, and driveways — constructed surfaces that prevent rainfall from penetrating the soil. Since a large portion of the rainfall in urban areas no longer penetrates into the ground, it is intentionally routed to storm drains and enters directly into urban streams as run off. (From Learn NC. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

4. Runoff is transported directly to streams through stormwater pipes
Rain water falls onto impervious surfaces and runs into stormwater drains which carry water through stormwater pipes directly into streams.
-Storm water flowing into storm drain. Photo by EPA. Public domain. Available at:
-Hydrologic short circuit. Image by Joanna Blaszczak. Used with permission. -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

5. Rate of water discharge
How does the rate of water flow affect the course (shape) of a stream?
How does the rate of water flow affect the kind and diversity of sediment found in a stream?
Stream flow after a storm surge, pre-development (natural stream) and post-development (urban stream). Available at:
Runoff entering urban streams can carry all kinds of chemicals and pollutants with it (e.g., motor oil, pet waste, lawn fertilizers, and even sewer leakage). Perhaps the biggest impact of runoff entering urban streams, though, is the increased rate of storm flow. When an urban (post-development) stream experiences a rain event, the flow rate is much higher than in a natural stream, and this high flow rate brings with it energy that can erode stream banks and push sediment into the water, increasing turbidity. Urban streams may also have lower base flow rates (rates of water flow in the absence of rain events) than natural streams. This means that organisms in urban streams must be able to cope with both fast flows just after storm events and slow flows between storm events. (From Learn NC. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

6. Shape of stream channel
How does the shape of a stream channel affect the turbidity of the water?
How does the shape of a stream channel affect riparian vegetation?
Changes in stream channel shape, floodplain, and water table after development. Available at:
Stream flow after a storm surge, pre-development (natural stream) and post-development (urban stream). Available at:
Over time, the faster storm flow rates and resulting erosion in urban streams can lead stream channels to become deeper and more incised. The water table then typically becomes lower because of the deeper, narrower streambed. The result is a “floodplain” that rarely floods, a riparian zone where tree roots cannot reach the water table, and riparian trees that die of drought stress. When riparian trees die, urban streams receive more direct sunlight and experience increased temperatures (and thus have lower saturated dissolved oxygen levels) and greater diurnal variation in temperature. (From Learn NC. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

7. Substrate and habitat diversity
Comparison of flow rates, substrate sizes, and habitat types provided by natural and urban streams. Available at:
The high energy storm flow in urban streams also affects the diversity of habitats present. The stream channel can become straighter and more spatially homogenous in terms of width, depth, flow rate and substrate type. Thus, urban streams tend to have decreased habitat diversity, which affects the type and diversity of organisms they can support. The diagram below shows a natural stream that meanders, varies spatially in flow rates, and has both riffle and pool habit. It shows an urban stream with a straight channel and uniformity of flow rates, substrate sizes, and habitat types. (From Learn NC. Available at:
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

8. The result? Increased % impervious surface leads to decreased richness of stream macroinvertebrate taxes
Graph from Moore & Palmer 2005 Ecol. App.
-Stream macroinvertebrates are invertebrates living a stream that are visible with the naked eye- primarily insect larva, mollusks, crustaceans, and worms.
-The number of macroinvertebrate taxonomic groups (taxa richness) and the number of taxomomic groups of mayflies, stoneflies, and caddisflies (EPT richness) are common measures of stream health.
-Because stream health can be defined as the ability of a stream to support life, measuring the number and types or organisms living a stream is a direct measure of stream health.
-Numerous studies (including the Moore & Palmer study whose results are shown in the graph above) have demonstrated that increased percentage of impervious surface is correlated with decreased numbers of taxomomic groups in streams. This has been observed for macroinvertebrates, fish, and other types of organisms.
"SteinfliegenLarve2" by böhringer friedrich - Own work. Licensed under CC BY-SA 2.5 via Commons -
"Caddisfly Larva" by MyForest - Own work. Licensed under CC BY-SA 3.0 via Commons - -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

9. What can we do to decrease the negative impacts of urbanization on stream health?
-After posing this to question to the class, do a think-pair-share activity. Then ask pairs of students to share their ideas with the class as a whole.
-Urban stream during rain event. Photo courtesy Emily Bernhardt.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

10. Decrease the % of impervious surface
What can we do to decrease the negative impacts of urbanization on stream health?
Decrease the % of impervious surface
But often this is not an option
How can we make impervious cover have less of an impact?
-Photo by Joseph Delesantro. Used with permission.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

11. Why do you see the same taxa richness for streams with very different % impervious surface?
In other words, what can explain the scatter in this graph?
Graph from Moore & Palmer 2005 Ecol. App.
-Notice that even though there is a general negative relationship between % impervious surface and taxa richness, there is also a great deal of variation in the data. The circled area shows how watersheds with a wide range of % impervious surface vary greatly in macroinvertebrate taxa richness (a measure of stream health).
"SteinfliegenLarve2" by böhringer friedrich - Own work. Licensed under CC BY-SA 2.5 via Commons -
"Caddisfly Larva" by MyForest - Own work. Licensed under CC BY-SA 3.0 via Commons - -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

12. How can we develop at 30% impervious surface and maintain high taxa richness?
Graph from Moore & Palmer 2005 Ecol. App.
-Notice that even though there is a general negative relationship between % impervious surface and taxa richness, there is also a great deal of variation in the data. The circled area shows a wide range of taxa richness for a given % impervious surface.
-What can explain the difference in stream health between streams with the same percentage of impervious surface? This questions is the focus of current ecological research by Dr. Emily Bernhardt and Dr. Dean Urban or Duke University.
-After posing this to question to the class, do a think-pair-share activity. Then ask pairs of students to share their ideas with the class as a whole.
"SteinfliegenLarve2" by böhringer friedrich - Own work. Licensed under CC BY-SA 2.5 via Commons -
"Caddisfly Larva" by MyForest - Own work. Licensed under CC BY-SA 3.0 via Commons - -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

13. What can explain the difference in stream health between streams with the same percentage of impervious surface?
Could be differences in Creek Smart® practices between the watersheds
Could be differences in land cover variables between the watersheds
-All land cover maps courtesy Emily Bernhardt and Dean Urban
-Remind students that they have already viewed land cover maps in the exploration activity for this unit when they compared two watersheds that differed in taxa richness and EPT richness but had the same percentage of impervious surface.
200 gallon cistern in backyard. Photo by Ellerbe Creek Watershed Associtation, Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

14. Creek Smart® Practices
Disconnect Your Roof from the Creek
Harvest Rainwater
Build a Rain Garden
Don't Fertilize the Creek
Protect Your Backyard Creek
Build a Wetland Garden
Build Healthy Soil
Add a Green Roof
-The Ellerbe Creek Watershed Association, a nonprofit conservation organization based in Durham, North Carolina, has developed the following Creek Smart® practices for residential areas. The practices are designed to disconnect urban areas from streams and decrease runoff into urban streams.
-At this point, break the class into 8 groups and ask each group to read about one of the Creek Smart® practices listed above. They can view the information online at or on the pdf files provided with this curriculum unit.
-After becoming “experts” on one Creek Smart Practice ®, each group should report back to the class on the problem and solution for their Creek Smart® practice.
-The slides that follow can act as visual aids as the students share what they have learned.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

15. 1. Disconnect your roof from the creek
-Problem: Many of our homes have gutters and downspouts that are piped directly to the driveway, sidewalk, or street, allowing the stormwater to run unmanaged to the stormwater pipes, which go directly to the creek. This contributes massive amounts of runoff to the creek. For example, if you have a 2,000 square-foot home, your roof sheds over 1,000 gallons of water during a one-inch rainfall! With so many people piping the runoff directly to the creek, it never gets the chance to recover.
-Solution: Most yards have some area downhill that can safely infiltrate that water. So, run the downspout to where they can benefit trees, plants, or grass in your yard without affecting structures on your property or your neighbor’s.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Downspout disconnection heading to the creek. Photo by Environmental Protection Agency. Public Domain. Available at:
Downspouts heading to the creek. Photo by Ellerbe Creek Watershed Association. Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

16. 2. Harvest rainwater
-Problem: A huge source of demand on our drinking water supply comes from yard and garden irrigation. There are several major problems with this. First, municipal drinking water is expensive and was treated for you to drink. Your tap water isn’t as good for your garden as rainwater, which has lots of nutrients. And during every one-inch rainfall, the average 2,000-square-foot roof can yield more than 1,000 gallons of rainwater. Unfortunately this rainfall is usually piped directly to the street, which damages the creek downstream because it enters the creek at a high volume and carries pollutants and trash.
-Solution: Collecting rainwater from your roof with a cistern can help protect the creek while at the same time providing valuable, healthy water for your yard and gardens. Rain water is naturally high in important plant nutrients like nitrogen, so the plants will like it much better than your treated tap water.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Rainwater flowing off roof. Photo by Flicrk user s58y. CC BY 2.0. Available at:
200 gallon cistern in backyard. Photo by Ellerbe Creek Watershed Associtation, Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

17. 3. Build a rain garden
-Problem: A huge source of demand on our drinking water supply comes from yard and garden irrigation. We spend good money watering plants and lawns with drinking water, while we treat rainwater as waste, sending it through gutters, downspouts, driveways, sidewalks, and pipes directly into the stormwater system. All of this rainwater is problematic for the creek downstream because it contributes to pollution and stream bank erosion, and the opportunity to capture and use the water in our yards is lost.
-Solution: A rain garden is a practical and beautiful solution for many yards. By capturing rain water in your yard and allowing it to infiltrate into the soil, you help protect the creek from pollution, reduce sedimentation and recharge groundwater sources. By planting the garden with native plants, you help attract native pollinators, increase biodiversity in the watershed, and create beautiful landscape features. There are specific guidelines to ensure that your rain garden’s site will properly capture rainwater while protecting structures on your property. 
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Downspout outlet at curb. Photo by Ellerbe Creek Watershed Associtation, Used with permission. Available at:
Rain garden. Photo by Ellerbe Creek Watershed Associtation, Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

18. 4. Don’t fertilize the creek
-Problem: Stormwater runoff collects everything in its path and carries it to the creek. Fertilizer runoff from yards and other landscaped areas is a major source of nitrogen and phosphorus pollution in our creek. Excessive nitrogen and phosphorus contribute to harmful, even toxic, algae growth in downstream water, which is dangerous to aquatic life and to us.
-Solution: Having some lawn can help manage stormwater by allowing some stormwater infiltration, especially if you combine this with a downspout disconnection. Keeping your grass to around three inches tall helps reduce water use and protects the soil. Often, unhealthy soil is the problem, so testing your soil and building ahealthier soil can help get your lawn off drugs. But, if you must to fertilize, keep the stream in mind and: use as little fertilizer as possible, don’t fertilize before a big rain, don’t get fertilizer on the street, sidewalk, or driveway because it will wash into the creek.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Applying liquid lawn fertilizer. Photo by David Reber. CC BY-SA 2.0. Available at:
Lawn Cared For Organically. Photo by Sarah McGowen. CC BY-NC-SA 2.0. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

19. 5. Protect your backyard creek
-Problem: Before the Ellerbe Creek watershed was developed in the 1800’s, there were 3 miles of small, headwater stream s for every one mile of larger streams. Lacking modern stream protections, the early developers often built houses too close to these streams. The stormwater management approach of the time was to get the water off of the property as quickly and efficiently as possible, the opposite of how a natural system functions. Unfortunately, this additional stormwater overwhelmed streams with runoff, causing massive stream erosion. As a result, Ellerbe Creek’s small tributary streams are often deeply eroded and lacking protective natural streamside buffers.
-Solution: To help protect the streams from further impact, build at least a 10-foot natural stream buffer, by planting native trees or shrubs, removing invasive plants and removing all the pipes leading to the creek. The buffers and natural infiltration allows stormwater to enter into the stream slowly, helping to protect the creek from damage and drought. 
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Stream erosion from storm water runoff. Photo by Flickr user Kid Cowboy. CC BY-SA 2.0. Available at:
Natural Stream Buffer. Photo by US Department of Agriculture. Public Domain. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

20. 6. Build a wetland garden
-Problem: In some yards, stormwater runoff can create an area of standing water that lasts for longer than three days. This perennial moisture is often caused by a heavy layer of clay soil and/or a high water table.
-Solution: Standing water can be a nuisance, but not necessarily. If the wet area is in a part of your yard that is away and downhill from your house or other structures, go with the flow! Use native wetland plants to filter pollutants from stormwater runoff. Native wetland plants can handle having their roots in standing water for long periods of time. The plant roots will also help to improve soil quality, and therefore infiltration, by helping to break through the heavy clay layer and adding organic matter to the soil which in turn encourages more soil organisms which help to build soil. Many wetland plants are very pretty, and will create a beautiful garden that will attract dragonflies and frogs.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Standing water in garden. Photo by Flicrk user circulating. CC BY-NC-SA 2.0. Available at:
Constructed wetland. Photo by Flickr user SuSanA Secretariat. CC BY 2.0. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

21. 7. Build Healthy Soil
-Problem: Many of our urban soils lost their natural layer of topsoil or were compacted during development. These unhealthy, compacted soils cannot maintain healthy plants or infiltrate large amounts of rainfall the way a native landscape would do. Since these soils cannot retain water and lack nutrients, homeowners end up using excessive water and fertilizer to grow plants and grass. The result is that unhealthy soils create lots of nutrient-laden runoff that goes directly to Ellerbe Creek, causing flooding and stream bank erosion.
-Solution: Consider converting at least 20% of your yard to a more natural landscape to help protect the creek. Start by building new topsoil that can support native plants or a beautiful garden for you to enjoy. A healthy forest soil has up to 50% air, so just 1,000 square feet (a 33x33 foot area) of a healthy, 6-inch deep soil can store over 1,500 gallons of water. Having a diversity of plants, specifically native plants and trees, helps build healthy soil and provides biodiversity for wildlife and pollinators. Using no or minimal fertilizer allows soil organisms to break down leaves and other organic matter, creating healthier soil which provides nutrients for plants and holds water naturally for dry times.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Compacted soil. Photo by Flickr user srv007. CC BY-NC 2.0. Available at:
Native garden with lawn. Photo by Ellerbe Creek Wataershed Association. Used with permission. Availalble at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

22. 8. Add a green roof
-Problem: Many roofs contribute massive amounts of stormwater runoff to the creek because the downspouts are sent directly to the street. In a 1- inch rainfall, a 3,000 square-foot roof can shed 1,800 gallons of stormwater. Across a city, thousands of rooftops create millions of gallons of stormwater runoff that fill the creeks in an unnatural and harmful way. This runoff also carries with it any pollutants from the roof itself, such as animal droppings or grit from roof shingles.
-Solution: Catch and treat the runoff where it falls by adding a green roof to your house or garage. Green roofs are the gold standard for urban stormwater management, consisting of a layer of vegetation and soil installed on top of an impermeable layer on an existing roof. In addition to reducing stormwater runoff and pollutants, green roofs may also: reduce roofing maintenance, improve energy efficiency, reduce the urban heat island effect, provide habitat for wildlife, and improve air quality. While green roofs have been used for centuries in Europe, modern versions are engineered to be used on existing rooftops. However, green roofs usually require professional engineering to ensure that the integrity of the roof is not compromised by the weight of the material and retained water.
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
Green Roof. Photo by EPA. Public domain. Available at:
Storm water flowing into storm drain. Photo by EPA. Public domain. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

23. Creek Smart® Practices
Disconnect Your Roof from the Creek
Harvest Rainwater
Build a Rain Garden
Don't Fertilize the Creek
Protect Your Backyard Creek
Build a Wetland Garden
Build Healthy Soil
Add a Green Roof
-From the Ellerbe Creek Watershed Association Creek Smart® webpage. Used with permission. Available at:
-All of these approaches can be implemented by an individual homeowner or at a larger scale by developers. -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

24. What can explain the difference in stream health between streams with the same percentage of impervious surface?
In other words, what can explain the scatter in this graph?
Graph from Moore & Palmer 2005 Ecol. App.
-Notice that even though there is a general negative relationship between % impervious surface and taxa richness, there is also a great deal of variation in the data. The circled area shows a wide range of taxa richness for a given % impervious surface.
-What can explain the difference in stream health between streams with the same percentage of impervious surface? This questions is the focus of current ecological research by Dr. Emily Bernhardt and Dr. Dean Urban or Duke University.
-After posing this to question to the class, do a think-pair-share activity. Then ask pairs of students to share their ideas with the class as a whole.
"SteinfliegenLarve2" by böhringer friedrich - Own work. Licensed under CC BY-SA 2.5 via Commons -
"Caddisfly Larva" by MyForest - Own work. Licensed under CC BY-SA 3.0 via Commons - -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship

25. What can explain the difference in stream health between streams with the same percentage of impervious surface?
Could be differences in Creek Smart® practices between the watersheds
Could be differences in land cover variables between the watersheds
-All land cover maps courtesy Emily Bernhardt and Dean Urban
-Remind students that they have already viewed land cover maps in the exploration activity for this unit when they compared two watersheds that differed in taxa richness and EPT richness but had the same percentage of impervious surface.
200 gallon cistern in backyard. Photo by Ellerbe Creek Watershed Associtation, Used with permission. Available at: -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

26. Geographic Information Systems (GIS) can be used to quantify differences in land cover variables from maps, satellite data, and field data.
Example of layers used in GIS work. This map is of an Athens County, Ohio property, and was made using ArcView GIS 3.3. Prepared by John Knouse. Creative Commons Attribution 3.0 Unported. Available at:
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

27. What land cover variables could we quantify to help us understand why these watersheds with the same percentage of impervious surface differ in taxa richness and EPT richness?
-After posing this to question to the class, do a think-pair-share activity. Then ask pairs of students to share their ideas with the class as a whole.
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

28. Land cover variables to investigate:
Percentage developed
Percentage forested
Road density
Pipe density
Size of largest developed patch
Size of largest forested patch
Number of forest patches
-All land cover maps courtesy Emily Bernhardt and Dean Urban
-Remind students that they have already viewed land cover maps in the exploration activity for this unit when they compared two watersheds that differed in taxa richness and EPT richness but had the same percentage of impervious surface.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

29. Land cover data: Based on satellite images
Available to the public from the National Land Cover Database (NLCD) of the US Geological Survey
Images are divided into pixels of 30 m x 30 m (900 m2)
Each pixel is classified into land cover categories like deciduous forest, cultivated crops, 20-49% impervious surface cover, etc.
- Landsat Data Continuity Mission. NASA. Public Domain. Available at:
- NLCD 2011 CONUS. US Geolgical Survey. Public Domain. Available at:
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

30. Percentage developed- Percentage of the watershed that is developed
Sum of all land area classified as % imperious surface (NLCD classes 22, 23, and 24)
divided by the total land area
of the watershed
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

31. Percentage of the watershed that is forested
Percentage forested-
Percentage of the watershed that is forested
Sum of all land area classified as forest (NLCD classes 41, 42, and 43) divided by the total land area of the watershed
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
-In addition to percentage forested, location of forest patches relative to the stream can play an important role in determining stream health.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

32. Road density-
Length of all roads in the watershed divided by total area of watershed (expressed in meters of road per km2 of land area)
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

33. Pipe density-
Length of all pipes in the watershed divided by total area of watershed (expressed in meters of pipe per km2 of land area)
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
-Pipes shown in gray and often overlap with roads (shown in black) in this watershed map
-Remind students that rainfall that lands on impervious surfaces typically runs off rapidly into storm water drains and flows through storm water pipes directly into streams.
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

34. Size of largest developed patch-
Size (in km2) of the largest developed patch in the watershed
-Images are divided into pixels of 30 m x 30 m (900 m2) Any ---Any pixels that are touching are considered part of the same patch.
-Includes all land area classified as % imperious surface (NLCD classes 22, 23, and 24)
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

35. Size of largest forested patch-
Size (in km2) of the largest forested patch in the watershed
-Images are divided into pixels of 30 m x 30 m (900 m2) Any ---Any pixels that are touching are considered part of the same patch.
-Includes all land area classified as forest (NLCD classes 41, 42, and 43)
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

36. Number of forest patches-
Total number of forest patches in the watershed
-Images are divided into pixels of 30 m x 30 m (900 m2) Any ---Any pixels that are touching are considered part of the same patch.
-Includes all land area classified as forest (NLCD classes 41, 42, and 43)
What do you predict about the relationship between this land cover variable and stream health?
-All land cover maps courtesy Emily Bernhardt and Dean Urban
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship -

37. Which land cover variables do you think are most important in explaining variation in stream health?
Percentage developed
Percentage forested
Road density
Pipe density
Size of largest developed patch
Size of largest forested patch
Number of forest patches
How could this understanding help us to design Creek Smart® neighborhoods?
-Invite students to share their ideas
-Remind students that they compared these two watersheds (22 and 148) in the Exploration activity of this unit. What differences do they think these two watersheds have in terms of the seven land cover variables that we will investigate?
-Inform the students that in the next section of this unit (Elaboration) they will have the opportunity to analyze land cover data and determine which of these land cover variables are most important in explaining variation in stream health.
-All land cover maps courtesy Emily Bernhardt and Dean Urban -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.

38. References
Bernhardt, E.S. and M.A. Palmer Restoring streams in an urbanizing world. Freshwater Biology 52:
Hauer, F.H. and G.A. Lamberti Methods in Stream Ecology, 2nd ed. Academic Press, New York.
Homer, C.H., Fry, J.A., and Barnes C.A., 2012, The National Land Cover Database, U.S. Geological Survey Fact Sheet , 4 p.
Mitchell, M.K. and W.B. Stapp Field manual for water quality monitoring: An environmental education program for schools. Thomson-Shore Printers, Dexter, Michigan.
Muth C., L. Brinson, and E.S. Bernhardt Inquiry-based exploration of human impacts on stream ecosystems: The Mud Creek case study. Learn NC publication. Available at:
Walsh, C.J., A.H. Roy, J.W. Feminella, P.D. Cottingham, P.M. Groffman, R.P. Morgan, II The urban stream syndrome: Current knowledge and the search for a cure. Journal of the North America Benthological Society 24(3): -
Created by Christine Muth (NC School of Science & Math) and Joanna Blaszczak and Emily Bernhardt (Duke University) as part of an NSF Funded Research Experience for Teachers Fellowship
The term Creek Smart® and information about the Creek Smart® practices is used with permission of the Ellerbe Creek Watershed Association.