GEOG Lab X Exercises 39, 41
The following questions (1, 3, 4) are based on Map T-3, the "Deer Peak, Montana" quadrangle, and Figure 39-3, a stereogram of the same area showing the drainage basin of Eds Creek. 1. The unimproved dirt road (the double-gray and white line) along "Ed's Ridge" roughly follows which natural feature associated with the Eds Creek drainage basin?
1. Drainage divide
The following questions (1-3) are based on Map T-6, the "Johnson City, Tennessee-Virginia-Kentucky-North Carolina" topographic map. This map shows a portion of the Appalachian Mountains at the Tennessee, Kentucky, and Virginia border. 1. a) Describe the general topography of the region between Clinch Mountain and Powell Mountain. b) What kind of stream drainage pattern has developed here? c) How has the road system been influenced by the topography?
1. a) The region is uneven, with ridges, and traversed by various eroded parallel valleys. b) Trellis c) Roads do influence the topography here. Roads follow the trellis pattern, and influence the structure of networks and transportation projects.
2. a) Describe the general topography in the region north of Poor Valley Ridge. b) What kind of stream drainage pattern has developed here? c) How has the road system been influenced by the topography?
2. a) It is uneven and has many hills and little evidence of structure. b) Dendritic c) Roads do influence the topography here. Roads generally follow the dendritic pattern.
3. a) How many first-order streams are shown? b) How many second-order streams are shown?
3. a) 14 b) 5
3. a) The Powell River has a meandering pattern. Is it flowing across a flat floodplain? b) How do you know?
3. a) No b) The river meanders around the hills.
The following questions are based on Map T-2, the "Umnak, Alaska" topographic map. 4. What kind of drainage pattern has developed around the outside of the Okmok Caldera? 5. What kind of drainage pattern has developed inside the Okmok Caldera?
4. Radial 5. Centripetal
How is the valley floor of Eds Creek different from the valley floors of the first-order streams?
Eds Creek has a slightly wider valley floor, while the first-order streams are in steeper and sharper V-shaped valleys.
What generally happens to the gradients of streams as the stream order increases?
The gradient decreases
Describe the general width and shape (cross-section) of the valley floors of first-order streams in the Eds Creek drainage basin.
They are steep, v-shaped, and narrow valley floors.
4. Using Map T-3, determine the gradients of the two first-order streams labeled "a" and "b" on the map above, the second-order stream labeled "c", as well as Eds Creek after it has become a third-order stream. Complete the table. a) Stream: a Order: 1st Elevation drop (feet): ? Length (miles): ? Gradient (feet/mile): ?
a) Elevation drop (feet): 680, 700 or 720 Length (miles): 0.4 Gradient (feet/mile): 1700, 1750 or 1800 (depending on elevation drop)
Using the data from the table in exercise 39 part II question #5, compute the following: a) Average gradient of all first-order streams b) Average gradient of all second-order streams
a) ~1463 ft/mi b) ~717 ft/mi
b) Stream: b Order: 1st Elevation drop (feet): ? Length (miles): ? Gradient (feet/mile): ?
b) Elevation drop (feet): 700, 720 or 740 Length (miles): 0.5 Gradient (feet/mile): 1400, 1440 or 1480 (depending on elevation drop)
c) Stream: c Order: 2nd Elevation drop (feet): ? Length (miles): ? Gradient (feet/mile): ?
c) Elevation drop (feet): 600, 620 or 640 Length (miles): 1.0 or 1.1 Gradient (feet/mile): 545 or 640 (depending on elevation drop)
d) Stream: Eds Creek Order: 3rd Elevation drop (feet): ? Length (miles): ? Gradient (feet/mile): ?
d) Elevation drop (feet): 640, 660 or 680 Length (miles): 2.2 Gradient (feet/mile): 291, 300 or 309 (depending on elevation drop)
