|
<br />54
<br />
<br />24.000
<br />
<br />"
<br />~ 20,000
<br /><.>
<br />w
<br />'"
<br />'"
<br />w
<br />..
<br />I-
<br />w
<br />~ 16,000
<br /><.>
<br />iii
<br />::>
<br /><.>
<br />~
<br />~ 12,000
<br />'"
<br /><
<br />:J:
<br /><.>
<br />'"
<br />o
<br />"
<br />~ 8000
<br />..
<br />
<br />
<br />LAWN LAKE DAM AND CASCADE LAKE DAM FAILURES, COLORADO
<br />
<br />50,000
<br />
<br />
<br />NOTE: Results are for actual
<br />breach dImensions
<br />
<br />\
<br />\
<br />\
<br />\\
<br />'\
<br />>[.
<br />,,,-
<br />\~
<br />"-
<br />"
<br />"
<br />"-
<br />ltacade lake Dam ,
<br />
<br />.......
<br />...............
<br />
<br />
<br />4000'
<br />o 30 60 90 120
<br />TIME TO FULL BREACH DEVELOPMENT, IN MINUTES
<br />
<br />FIGURE 47.-0utflow discharge for various times of breach
<br />development for Lawn Lake dam and Cascade Lake dam.
<br />
<br />
<br />"
<br />z
<br />8 40,000
<br />w
<br />'"
<br />'"
<br />w
<br />..
<br />I-
<br />W
<br />~ 30,000
<br />u
<br />iii
<br />::>
<br /><.>
<br />~
<br />S 20,000
<br />'"
<br /><
<br />:J:
<br />U
<br />"'
<br />o
<br />~ 10,000
<br />w
<br />..
<br />
<br />NOTE: Results are for a time of
<br />failure of 10 minutes
<br />
<br />o
<br />o
<br />
<br />
<br />50
<br />
<br />100 150 200
<br />BREACH WIDTH, IN FEET
<br />
<br />FIGURE 48.-0utflow discharge for hypothetical breach width for
<br />Lawn Lake dam, assuming l()'minute time of failure.
<br />
<br />250
<br />
<br />TABLE lO.-Comparison of model results of a hypothetical breach width of 25 feet to the actual
<br />breach width of 55 feet
<br />
<br /> Difference in peBk
<br />Distance dowtl- dlscluorgefrom
<br />stream from Lawn Peak discharge, in model with failure,
<br />Lake dam. in cubic feet per in cubic feet per
<br />miles "'""" "'"""
<br />0.0 Il,OOO .7,000
<br />.55 10,000 -6,600
<br />1.50 9,400 -5,800
<br />3,83 8,500 -4,100
<br />b 4.73 8,400 -3,400
<br />5.36 7,500 .3,400
<br />5.78 5,800 -1,900
<br />c 6.50 5,200 -1,500
<br />d 6.67 15,500 .500
<br />· 7.68 9,500 ,400
<br />
<br />Flood elevation, in Maximum Rood
<br />feet depth, in feet
<br />
<br />Difference from.
<br />.maxUnum flood
<br />depth of 55-foot
<br />width, in feet
<br />
<br />(al lal
<br />lal lal
<br />(a) (a)
<br />(a) (a)
<br />8,514.7 9,8
<br />8,510.3 9.3
<br />8,492.3 9,7
<br />8,054.8 9.8
<br />
<br />(a)
<br />(a)
<br />(aj
<br />(a)
<br />
<br />..9
<br />'.9
<br />-,9
<br />
<br />'.1
<br />
<br />7,74 9,300 .400 8,042.8 10.8 -.2
<br />8,78 6,700 0 7,862.7 10.7 -.1
<br />110.28 6,200 -1,400 7,697.9 8.9 '.7
<br />gII.45 4,800 -1,300 7,579.8 6.8 ',5
<br />hI2.50 4,800 -1,300 7,502.3 9,8 ,1.3
<br />Average difference from maximum flood deptb 01 55,Ioot width, in leet=-.6
<br />
<br />"severe clwmel erosion; eompu~tions and compariSODs are not applicable.
<br />bSynthetic cross section based on croee section at river mile 5.36.
<br />cSite 1.
<br />dCascade Lake dam and Site 2.
<br />eSite3.
<br />fSite4.
<br />'siteS.
<br />hsite6.
<br />
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