Hobbies And Interests
Identify Contour Lines
When reading a topographic map for the purpose of determining stream flow, the first activity requires identification of the contour lines. The lines appear as irregular circles or long lines that constantly change due to the fact that every point on a given line is the same elevation above sea level. The more the lines change on a map, the more the elevation of the area mapped changes, with the changes being the first step in the identification of stream flow.
Identify Streams
Once the contour lines have been identified, the next activity involves locating the streams, or if the study consists of one particular stream, that one stream. Water is blue on the topographic map while a stream's representation consists of a thin, blue line for a permanent stream, with broken lines for a stream that may only exist during part of the year. Follow the desired blue line on the map to observe its length and path from beginning to end in order to be ready for the next activity.
Interaction Between Lines and Stream
Determining stream flow involves studying and discerning the interaction between the previously identified contour lines and stream, which, according to the National Resources Conservation Services, shows that water flows downhill perpendicular to the lines. Focus on the points of intersection and the positions of the lines and stream at those intersections to determine stream flow. The direction of the flow of the stream depends on how the contour lines bend upon crossing a stream: the lines bend and point upstream.