Geology Reference
In-Depth Information
714
E
,
1
r
FIGURE 10.6
Frequency of floods above the 703-feet elevation on Licking River at Dillon Falls, Ohio.
3.
Using the data in Table 10.4 construct a graph of elevation
versus discharge (rating curve) in Figure 10.7.
backwater effects from the Muskingum River and channel
constrictions may affect the profile.
Using the 1959 flood profile (Figure 10.8) as a guide
and the 40-year flood elevation at the gaging station as given
in Table 10.4, determine the expected maximum stage of a
40-year flood at the floodmark elevation 2.9 miles upstream
from the river mouth (Figure 10.8). Assume a similar drop in
flood level (from the 1959 flood level) at the gaging station
and at this floodmark elevation.
4.
Discharge can be obtained for a flood of a given frequency
by using information on the flood frequency-elevation curve
(Figure 10.6) and the rating curve (Figure 10.7). What is the
expected discharge at Dillon, Ohio
a.
for a 30-year flood?
7. List several approaches that have been applied to reduce
losses from river floods. (Consult your notes, textbooks, or
references, if necessary.) Group the approaches as either con-
trol of the river and/or control of land use or human activity.
b.
for a 50-year flood?
5.
If you visit a flood area after the water recedes, what indi-
cations might there be on buildings, trees, and land surfaces
of the level of the flood maximum?
PART C. CENTENNIAL FLOOD ON BIG
THOMPSON RIVER, COLORADO
Flash floods and associated erosion, deposition, and
mass movement devastated parts of north-central
Colorado in the Front Range on the night of July
31-August 1, 1976. This event caused 139 deaths and
$35 million damage, mainly on the Big Thompson
6.
Figure 10.8 is a flood profile of the Licking River for the
1959 flood at Zanesville. Elevations are plotted against the
distance upstream from the mouth (in miles along the cen-
terline of the river). The maximum elevation of the 1959
flood at the gage given in the introduction. Profiles of higher
or lower floods can be plotted on this diagram, although
