FLOOD02643

• County: Denver
• Community: Northeastern Colorado
• Stream Name: South Platte and Tributaries
• Basin: South Platte
• Title: Post Flood Report South Platte Floods of May-June 1973
• Date: 7/1/1974
• Prepared For: State of Colorado
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Flood Documentation Report

Table 17 presents average monthly rlil,eases from Alcova Reservoir
for January through October 1973.

Table n
ALCOVA DAM
AVERAGE MONTHLY HELl,ASE3 - 1973
(c.f.s" )

Jan - 927
Feb - 918
Mar - 880
Apr - 1,015
May - 3,615

Jun - 6,523
;Jul ... 4,195
Aug ... 2 ~641
8ep .. 1, 509
Oct.. 1,353

c. Diurnal effe!~ts. The Alcove. to Glenda runoff come!,
primaruy :from the right-bank drainage areas. ~'he drainage
areas consist of many' small, short tr'ibutaries draining directly
into the North Platte River. These streams originate in the
lIDunta:l.ns of the Laramie Range in thE' Medicine Bow National
Forest. Snowmelt runoff :from these streams is greatly influenced
by temperature variations. Daytime "arming and nighttime cooling
result in peaks and sags occurring ,approximately 12 hours apart
at the mouth of each stream. The d,aJ.ly pealt discharge occurs at
about 4:00 a.m. and the minimum dis,~harge at about 4:00 p.m" In
addition to these daily fluctuations,. there is an overall cycle
resulting from extended warming and cooling trends. The effectn
of these trends are reflected in the in.flow to Glendo Reservoir
between 2 and 3 days later.

d. Glendo Dam Q,ischarges. The discharges :from Glendo Dam
were Virtually zero between 27 Septelllber 1972 and 5 March 1973.
Glendo Dam releases averaged 660 cubic feet per second for the
remainder of March. The average discha.rge in April was 1,7139
cubic feet per second. Glendo Dam discharges were averaging
about 2,800 cubic feet per second in la.-te April; the release
rate was sharply reduced to 300 cubic: feet per second on 30 Apr:U.
Releases were slowly increased in the foD,O'Idng days to 1,700
cubic feet per second, then reduced ags,in to neaT zero on 10 ~lay.
Both of these flow reductions were m!Lde because of large inflcrwn
downstream, principally from the Lar!Lmi.,e River. At the same
time, a large flood lias moving dO'lm the South Platte River. ~'he
Glendo Dam reduction in discharge a.l'ao provided relief to Lake:
McConaughy, where efforts were bei.ng made to hold down flows s,t
the junction of the North Platte arid South Platte Rivera. As
the Glendo Reservoir was rising ra,pi,Uy, releases were again
started on 13 May and were progressively increased in the

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