Geology Reference
In-Depth Information
16. Using the information in Question 15, what is the expected
18. At other sites along the river, significant changes (erosion
discharge for the 100-year flood? (Hint: The ratio shown is:
and deposition) also occurred on the floodplain and on allu-
discharge for 1976 storm/discharge for 100-year flood.)
vial and debris fans. Large accumulations of boulders and
debris occurred on some of the fans; other fans underwent
erosion. Study Figure 10.13. Would it have been safer to
reside during the 1976 storm on the inside or outside of a
meander? Explain.
17. Study Figure 10.12 showing the Waltonia area before and
after the flood. Describe the changes in buildings, roads,
vegetation, and stream bed.
FIGURE 10.12
Aerial photos of Waltonia, 1.5 miles southwest of Site 12 before (A) and after (B) the flood. Approximate scale:
1 in. = 200 ft. Most of the community is on a debris fan. Highway 34 and two large motels are shown in the floodplain in A. Big
Thompson River is immediately behind (north of) the motels (Shroba et al., 1979).
