EXERCISE 10.3: Why Some Streams Meander But Others Are Straight In this exercise, you will use the maps in Figures 10.4, 10.5, and 10.6 on pp. 240-242 of your lab manual.

Part c.5. What is the valley width/channel width ratio of the Genesee River and those of Streams A-B and C-D in the Casino Lakes area? (Don't forget to convert the valley and channel widths to the same units.)

Genessee River: 2/1 ft Streams A-B: 3/1 ft Streams C-D: 1/1 ft

Part a.5. What are the lowest elevations of the Bighorn River and its unnamed tributary? (Scan the entire stream looking for and estimating the lowest point on each stream. Give your answers in feet.)

Lowest elevation for the Bighorn: 3879 feet Lowest elevation for the unnamed tributary: 3880 feet

Part a.2. What are the straight-line lengths of the Bighorn River and its unnamed tributary? (Give your measurements to the nearest 1/10 of a mile.)

The straight length is 3.7 miles The straight line length of the unnamed tributary is 2.2

Test this hypothesis on the Genesee River of New York (Fig. 10.5 on p. 241) and the Casino Lakes area of Idaho (Fig. 10.6 on p. 242). Part c.1. What are the valley shapes of the Genesee River and Streams A-B and C-D in the Casino Lakes area?

V-shaped: Streams A-B and C-D; Broad with flat bottom: Genessee River

Part a.6. What is the vertical drop of the Bighorn River and that of its unnamed tributary? (Vertical drop equals the highest elevation minus lowest elevation. Give your answers in feet.)

Vertical drop of the Bighorn: 41 feet Vertical drop of the unnamed tributary: 240 feet

Part c.2. What are the gradients of the Genesee River and Streams A-B and C-D in the Casino Lakes area? (Give your answers in ft/mile.)

Genessee River gradient : 8.83 ft Streams A-B : 9.04 ft Streams C-D: 8.48 ft

Part c.3. What are the valley widths of the Genesee River and Streams A-B and C-D in the Casino Lakes area? (Give your measurements to the nearest 1/10 of a mile.)

Genessee River: .2 miles Streams A-B: .1 mi Streams C-D: .1mi

Part c.4. What are the channel widths of the Genesee River and Streams A-B and C-D in the Casino Lakes area? (Give your answers in feet.)

Genessee River: 1056 ft Streams A-B: 528 ft Streams C-D: 528 ft

Part c.6. What is the sinuosity of the Genesee River and those of Streams A-B and C-D in the Casino Lakes area? (Sinuosity equals the length of stream channel divided by straight-line distance between the same points.)

Genessee River: 2.9818181 Streams A-B: 1.08333 Streams C-D: 1.19047

Part a.4. What are the highest elevations of the Bighorn River and its unnamed tributary? (Streams aren't considerate; they don't begin and end on contour lines. Scan the entire stream looking for and estimating the highest point on each stream. Give your answers in feet.)

Highest elevation for the Bighorn: 3920 feet Highest elevation for the unnamed tributary: 4120 feet

Compare the course of the Bighorn River between points A and B with that of its tributary between points C and D (Fig. 10.4 on p. 240). Part a.1. What are the channel lengths of the Bighorn River and its unnamed tributary? (Give your measurements to the nearest 1/10 of a mile.)

The channel length of Bighorn is 7 miles The channel length of the unnamed tributary is 2.3

Part a.3. What is the sinuosity of the Bighorn River and that of its unnamed tributary? Sinuosity equals channel length divided by straight-line length and has no units.

The sinuosity of the Bighorn River is high. The sinuosity of the unnamed tributary is low.