FLOOD00927

• Designation Number: 216
• County: Logan
• Community: Sterling
• Stream Name: Sand Creek and Pawnee Creek Overflow
• Title: Floodplain Information and Drainage Plan - Sand Creek and Pawnee Creek Overflow
• Date: 5/1/1983
• Designation Date: 7/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

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lIt. BASIN CHARACTERISTICS AND HYDROLOGY

Pawnee Creek
F1gure8 is amapwhichshows each watershed considered in this study.
Pawnee Creek drains an area of approximately 703 square miles upstream
from its confluence with the South Platte River about 5 miles southwest
ofSterl;ng. Although Pawnee Creek is located several miles southwest
from Sterling, U.S. Highway 6 and the Burlington/Union Pacific Railroad
tracks are major obstructions whiCh divert runoff fror.l the Palmee flood
p]ain into Sterling via the so-called "Pawnee Overflow" nearRiv erside
Cemetary. According to a recent analysis made by the U.S. Army Corps of
Engineers, the lOO-year flood at the Pawnee Overflow is approximately
5,000 cubic feet per second (U.S. Army. 1982). Ina recently published
flood plain information report. the U.S. Army (1978) estimated the 100-
year flood to be 41.000 c.f.s. for Pawnee Creek at U.S. Highway 6. This
COlOparesfavorablywith35.200c.f.s.measuredatthebridgeonColorJGO
Hi9hway 14 some 13 miles upstream and west of Sterling un June 15, 1965
(see Matthai. 1969). Finally, a review of the flood history indicated that
the South Platte River is generally at flood stage during major flood events
on Sand C~ek and Pawnee Creek. Accordingly design floods on Pawnee Creek
and Sand Creek were assumed to be coincident with 10-year flood flows in
the River.

Sand Creek WaterSheds
That portion of the Sand Creek drainage lying north of Highway 14 and
upstream from the Springdale and Sterling No.1 ditches was resol~ed into three
subwatcrsheds as follows:
Subwatershed OrainageAre.l(mi.2)
Sand Creek 29.58

S-l

1.13

5-'
5-3

3.80
0.70

These wat!!rsh!!ds are shown ilL Figur'e 8.
11

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