The High Plains
Riparian Areas: Healthy or Unhealthy?
In this activity, students visit and make observations at a riparian area of a stream. Then, as a class, they think of projects that can make it a better home for wildlife, plants, and people.
Objectives: Students will be able to develop skills in observing and collecting data about the environment of a stream, apply this data in analyzing the health of the riparian areas along the stream, and consider actions they can take to improve the stream's condition.
Materials: You will need pencils, notebooks or clipboards for recording data, and a topographic map showing the location of the stream or river being studied.
Before and After. South Fork of the Crooked River in Oregon. Left, unhealthy riparian area in 1976. Right, healthy riparian area in 1986.
Photos: Wayne Elmore, BLM
Background: Riparian areas are the green, vegetated areas on each side of streams and rivers. They serve many important functions, including:
- purifying water by removing sediments and other contaminants;
- reducing the risk of flooding and associated damage;
- reducing stream channel and streambank erosion;
- increasing available water and stream flow duration by holding water in stream banks and aquifers;
- supporting a diversity of plant and wildlife species;
- maintaining a habitat for healthy fish populations;
- providing water, forage, and shade for wildlife and livestock;
- and creating opportunities for recreationists to fish, camp, picnic, and enjoy other activities.
Scientists who study these areas recognize that the well-being of riparian areas affects the well-being of entire communities. Many riparian areas, however, have become damaged by cattle and sheep, logging and mining activities, road building, poor agricultural practices, removal of woody vegetation, pavement in urban areas, industrial use of streams, and recreation activities such as hiking, camping, boating, or biking.
Both animals and people are drawn to the water, especially in arid regions of the West. These popular areas become quickly degraded when overused, resulting in erosion and water pollution. Communities must balance the uses of these fragile areas in order to protect them for future generations.
Procedure: Before taking your students to study a stream, discuss the following concepts:
Inventory: A listing of all the different kinds of plants and animals found in an area. The total number of organisms.
Riparian: On or near a stream or river. Plants in a riparian ecosystem need to have their roots in the water or moist ground for much of the year.
Flood Plain: An area near a stream or river that floods regularly. These areas hold floodwater, minimizing flood damage to other areas.
Watershed: The larger geographic area that drains into a given stream, river, or body of water.
|Before and After. Texas Creek, Colorado. Left, unhealthy riparian area in 1976. Right, healthy riparian area in 1985 after restoration. |
Photos: Wayne Elmore
Next, distribute copies of Figures 1 and 2 (below) and lead students in a discussion of the attributes of healthy and unhealthy riparian areas.
Healthy riparian areas are characterized by the following:
- banks are stable with no excessive erosion or sediment deposition;
- banks have heavy vegetation (could include trees) and overhang any running water; water is shaded;
- plants are vigorous; and
- channels are narrow and deep.
Attributes of unhealthy riparian areas include the following:
- poor vegetation growth or non-native, invasive plants are crowding out native species; and
- excessive bank erosion so that channels are too wide.
To the Field
Select a small stream, close to school if possible. Visit the site prior to setting up your field trip. Arrange for parents, teacher assistants, or volunteers to help supervise students. If you choose a site at a nature center or park, a resident naturalist (staff or volunteer) may be available to assist the students in identifying signs of animal life or identifying plants and other characteristics of the riparian area.
Prior to the trip, have students make data sheets for recording their observations. Headings should include "plants," "animals," "rocks," "soil," "water," and "other." Discuss with students that this exercise will help develop observation skills. Have students think about the connection between the selected stream and the larger geographic area-the watershed-and consider the source of the water flowing through the stream. Explain that a watershed is the land area that delivers runoff water and sediment to a major river and its tributaries. Using the topographic map, have students identify what watershed feeds the stream. Review the discussion questions below so students will know what to look for at the stream.
Figure 1 - Healthy Riparian Area
Figure 2 - Unhealthy Riparian Area
At the site, allow students time to make individual observations about the stream and its surroundings and record these observations on their data sheets. For example, under the heading "animals," students should record evidence that animals are living nearby and using the plants in the riparian community. Students should write down the names or descriptions of any animals they see within the study area. They should look for and record such things as footprints, scat (feces), holes in leaves or tree bark, cones that have the scales eaten, holes in acorns, webs, nests, and so on.
Back in the Classroom
Once you return to the classroom, you might ask the students the following questions for discussion:
- What did you notice about the stream environment?
- What types of plants increased in number as you approached the stream, and what plants decreased?
- What evidence of animals was present?
- What do the rocks in or near the stream tell you? (For example, exposed rocks with lighter and darker shades of coloration might indicate that the stream level is higher or lower at different times of the year.)
- What are the indicators that the riparian zone is healthy or unhealthy? (Stable or eroded banks, heavy or sparse vegetation, well-defined or poorly defined stream channels, diverse native plants or monocultures of invasive species.)
- What activities in the area might be threatening the health of the riparian area?
- What is the likely source of the water in the stream? What are some of the ways that water gets from a mountain top (melting snow) to the stream? Where does the water ultimately come from?
- How big is this watershed compared to other watersheds?
- How important is the stream in the environment?
- How important is the stream to the people who inhabit the area?
Forbs are not grass but are herbaceous plants. Their beautiful flowers attract wildlife.
Grasses in the High Plains have a specialized adaptation that allows the roots to store water. The roots of blue grama grass are extremely extensive, containing up to 90 percent of the plant's mass. The leaves extend only a few centimeters above the ground and the seed heads grow less than half a meter tall.
Note: If a field trip is not possible, an alternative activity could be conducted using photographs of various healthy and unhealthy riparian areas. Photograph nearby stream areas or contact a local office of the Bureau of Land Management or U.S. Forest Service to obtain photographs of riparian areas. These offices sometimes keep "before" and "after" photographs to document progress in restoring riparian areas. Have students assess the condition of the areas shown in the photographs using criteria listed above.
Finally, have students consider projects for improving the health of the stream and riparian areas they observed (for example, cleaning up trash and debris in and around riparian areas, planting vegetation along streams, stabilizing eroding streambanks). Consider the feasibility of implementing some of these measures, making sure to contact the proper land-managing authorities before initiating any projects, and consulting with experts on the benefits of the proposed measures.
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