by Matthew Chasse

It's a known fact kids are drawn to streams and waterways. Some visit them to fish, hike, canoe and kayak or just enjoy nature; others want to learn more about them and how people affect their overall health. Streams offer students a unique outdoor field experience and a window to understanding their local environment and the Chesapeake Bay.

Why Streams?
Maryland's 8,800 miles of streams form the life support system for the Chesapeake Bay watershed by providing important habitats for many aquatic and terrestrial organisms. Each stream plays a vital role in linking the Chesapeake Bay to its surrounding watershed.

Many kids think of a stream in terms of the trout they caught while fishing or the crayfish they found while exploring its banks. These are some of the more visible examples but they are only a fraction of the diversity contained within Maryland's streams. Upon closer examination you can find fish, amphibians and insects that are invisible to the casual observer. More important, many of these organisms are biological indicators of stream health, especially the insects or macroinvertebrates.

An Outdoor Classroom Realized
Each year thousands of students experience Maryland's streams through programs offered by the Department of Natural Resources (DNR) outdoor education centers, and summer camps. However, students, parents or teachers can organize their own stream investigations. Using a stream as an outdoor classroom offers kids an incomparable hands-on learning experience that leads them to a greater understanding and appreciation of their natural environment.

Getting to Know Macroinvertebrates
Prior to going out and doing an actual field investigation, students should learn how to identify some of the basic types of stream insects and stream habitats they might encounter, either through classroom exercises or home study. Stream insects are one of the most important indicators of the long-term health of a stream. Many are long-lived and spend most of their lives within the stream. Some, like stoneflies, are highly sensitive to pollution while others such as blackfly larvae are very tolerant. During a field investigation, many of these insects may be seen; however without some initial preparation, students will not have the proper knowledge and skills to conduct a meaningful investigation of a stream.

In the Field
After completing the classroom or home study of stream insects and their habitats, it's time to consider a field investigation. The best time to conduct one is typically in spring or late fall when weather conditions are most favorable for being outside. First and foremost, the stream must be accessible to the students. Those on the school grounds are ideal but streams on other public lands are also an option.

Prior to going out to the stream, students will also need to have some sampling equipment. A net, preferably a D-net, is used to sample for macroinvertebrates. However you can also just use your hands and look under rocks to get a sample. It's also helpful to have a bucket to put your sample in, a magnifier, tweezers and a tray with a white background. The white background provides good contrast for seeing the darker macroinvertebrates.

Once at the stream, look for riffles or woody debris to sample. A stream riffle is a shallow area where rocks break up the flow of water. This area is highly enriched in oxygen and has lots of small spaces for macroinvertebrates to hide in. Woody debris found in the water -- leaves, sticks and tree roots -- is another important habitat as these materials provide an important food source for stream insects.

In addition to looking at the macroinvertebrate community within the stream, you may also decide to sample for dissolved oxygen levels, pH, depth, water flow and turbidity. All provide important information on the physical and biological conditions of the stream. You should end the investigation by making some basic conclusions about the health of the stream.

By using streams as outdoor classrooms, students are making an important and meaningful connection to the Chesapeake Bay watershed; they learn monitoring techniques and problem- solving skills that will benefit them for a lifetime.

Expanding Our Investigation
Maryland DNR currently offers opportunities for middle school students to conduct a stream investigation. Those interested in learning more about DNR's student streams investigations should visit www.dnr.maryland.gov/education/teamdnr or contact Matthew Chasse at 410-260-8828, or mchasse@dnr.state.md.us

Check out our website for more information at www.dnr.maryland.gov/education/teamdnr

Matthew Chasse
is an Education Specialist for DNR's Conservation Education Division, the TEAM Program Coordinator, and serves on the Education Matrix Team.