|
<br />100,000
<br />
<br />A,
<br />
<br />...-....
<br />
<br />10,000
<br />
<br />.... '"
<br />
<br />
<br />....
<br />
<br />EXPLANATION
<br />
<br />100
<br />
<br />UJ
<br />::J
<br />-'
<br />;g:
<br />z
<br />-<:
<br />Q
<br />~
<br />
<br />PRE-DAM
<br />(May 8, 1921-March 12, 1963)
<br />
<br />POST-DAM
<br />(March 14, 1963-September 30, 2000)
<br />
<br />1,000
<br />
<br />o
<br />z
<br />o
<br />o
<br />UJ
<br />rn
<br />a:
<br />UJ
<br />0-
<br />tu
<br />UJ
<br />LL
<br />o
<br />in
<br />::J
<br />o
<br />;;;::
<br />
<br />
<br />10
<br />
<br />o 10 20 30 40 50 60 70 80 90 100
<br />
<br />ui
<br />~ 100,000
<br />-<:
<br />:r:
<br />o
<br />rn
<br />Q
<br />;;;::
<br />~ 10,000
<br />
<br />~
<br />
<br />B.
<br />
<br />~
<br />
<br />EXPLANATION
<br />
<br />--. ----
<br />
<br />-.............
<br />
<br />'-,
<br />
<br />19208
<br />(May 8, 1921-December 31, 1930)
<br />
<br />19308
<br />(January 1, 1931-December31, 1940)
<br />
<br />19408
<br />(January 1, 1941-December31, 1950)
<br />- - - - 19S0s-early 19608
<br />(January 1, 1951-March 12, 1963)
<br />
<br />POST-DAM
<br />(March 14, 1963-September 30, 2000)
<br />
<br />100
<br />
<br />"..
<br />~.,
<br />.... "'-'"
<br />....,..... \
<br />.....~:....
<br />...~..::.,..... \
<br />
<br />.... ~.::--.. \
<br />L.U -~.., ",
<br />3 ............~
<br />-<:> ..... '.~
<br />,'':
<br />Z ~,
<br />-<: '
<br />Q ~
<br />UJ
<br />:;;
<br />
<br />'-
<br />
<br />>-
<br />-'
<br />;;:
<br />o
<br />
<br />
<br />"---
<br />
<br />-'--..
<br />
<br />'1,000
<br />
<br />10
<br />o 10 20 30 40 50 60 70 8Q 90 100
<br />P~RCENTAGE OF TIME EQUALED OR EXCEEDED
<br />
<br />Figure 25, Exccedance curves of the daily range in the discharge of 1118 Colorado River at Lees Ferry: (AI For the pre- and po:;t-dam periods,
<br />1/3) For the four pre'dam decades and the entire post.dam period,
<br />
<br />Operation of Glen Canyon Dam has evolved over
<br />the four decades since elosure of the dam on March] 3,
<br />1963 (fig, 2JA). From March 1963 through the latter part
<br />of 1964, releases from Glen Canyon Dam were kept low
<br />(with discharges kept close to 1,000 ft3/s for most of this
<br />period) to increase the storage of water in Lake Powell
<br />reservoir q~kly, Then, tram April through June 1965, a
<br />;'!, j4<, ~ .
<br />. . .
<br />
<br />series of artificial floods was released from the dam, with
<br />six of these floods having peak discharges greater than
<br />50,000 n3/s, Between these flood peaks, discharges were
<br />reduced to as little as lO,OOO 1l3/s, These 1965 floods were
<br />designed to raise the elevation of Lake Mead reservoir and
<br />to scour the reach immediately below Glen Canyon Dam
<br />in order to increase the efficiency of the power plant at the
<br />
<br />46 Computation and Analysis of the Instantaneous~Discharge Record fOf the Colorado River at lees Ferry. Arizona-May 8, 1921, through September 30, 2000
<br />
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