Make your own D-net. The net is named for the "D" shape of its frame. It
is used to collect stream insects from the bottom of a stream. You can
make one at home (but make sure an adult is around to help!).
Materials you will need
x 14" piece of screen •
42" x 2" piece of canvas or heavy cloth
Thread and needle •
Wire coat hanger •
Drill with 1/8" and 1/4" bits
Wooden broom handle
Building a D-net
1. Fold the screen in half (21" x 14") and cut screen (as shown).
2. Sew the two pieces of screen together along the cut edge.
3. Fold the canvas in half along the open edge of the net.
4. Untwist the wire hanger and cut off the top (as shown).
5. Bend the smaller cut piece into a U-shape.
6. Drill a 1/4" hole in the flat end of the broom stick.
7. Drill two shallow 1/8" holes on the sides of the broomstick, positioned
so you can fit U-shaped wire over the flat end and into the holes.
8. Slip large wire into the folded canvas slot of the net and twist the
9. Cut the twisted wire to no longer than 2" in length and insert into
hole at flat end of the broomstick.
10. Secure the net to the pole using the U-shaped wire and duct tape (as
Volunteer Water Quality Monitoring
Non-profit Stream Monitoring
County Stream Monitoring Groups
Maryland DNR's Teaching Environmental Awareness in Maryland (TEAM) program
offers students a two-part stream investigation in a local freshwater
stream of their choice. At this streamside setting, trained volunteers
guide them as they learn about water quality, stream habitats and the
community of organisms that inhabit the stream. Using the information they
collect, the students will then formulate conclusions about the health of
the stream they have investigated. If you are interested in becoming a
TEAM volunteer and helping educate Marylanders about our natural
resources, visit our website at
www.dnr.maryland.gov/education/teamdnr and fill out an application.
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.
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
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
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
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
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.
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
or contact Matthew Chasse at 410-260-8828, or
our website for more information at
is an Education Specialist for DNR's Conservation Education Division, the TEAM
Program Coordinator, and serves on the Education Matrix Team.