|
<br />-19-
<br />
<br />comparative purposes. The spring snowmelt phenomena produces the peak
<br />streamflow discharges for the main stem Gore Creek. The values derived
<br />
<br />from the fourteen log-Normal snowmelt discharge probability analysis
<br />
<br />were utilized in developing the Snowmelt Discharge curves, as pre~
<br />
<br />sented on Figures 111-7 to 1II-12. The curve fitting process included
<br />
<br />a least squares computation for the best fit or mean discharge curve
<br />
<br />and fitting an upper envelope curve based upon a 1,5 standard deviation.
<br />The upper envelope'curve provides a confidence level of 93+% that
<br />resultant peak discharges will fall below the curve. Due to the relative
<br />
<br />shortness of many of the streamflow records. the upper envelope curve
<br />
<br />was utilized in defining peak discharges for the floodplain compu-
<br />tations in this study.
<br />The 500 year snowmelt discharge curves were established by
<br />
<br />extrapolating the curves for other recurrence intervals based upon a
<br />
<br />criteria defined by the Colorado Water Conservation Board and in
<br />accordancewithF.I.A.practices. Amore detailed discussion of the
<br />procedures and the data are contained in the technical addendum to
<br />this report.
<br />Effects of Development on Discharges
<br />Increased imperviousness within the Gore Creek Valley is not
<br />expected to increase snowmelt flooding, This is because snow in the
<br />lower valley will be melted early in the thaw before the creek is
<br />near flood stage. Consequently. any additional runoff caused by
<br />development in the valley will have already been discharged days
<br />
<br />before the peak. Increasedimperviousnesswil1,however, increase
<br />discharges within the very small basins where the development occurs.
<br />
<br />-
<br />
<br />"
<br />""
<br />ww
<br />""
<br />~<"
<br />.'0
<br />. w
<br />~
<br />o
<br /><
<br />
<br />
<br />. . W
<br /> "
<br /> <
<br /> 0
<br /> "
<br /> < "
<br /> " "z
<br /> ~ ww
<br /> ""
<br /> ~ ~<z
<br /> ~ .'0
<br /> < . w
<br /> . ~
<br /> - 0
<br /> w <
<br /> zw_ "
<br /> __~:;c.....
<br /> ~ 0:0: 00..
<br /> 0 U zw
<br /> " ~< ~o
<br /> 0
<br /> w
<br /> w
<br /> " w
<br /> "
<br /> " g
<br /> w
<br /> "
<br /> .
<br /> ,
<br /> 0
<br /> z
<br /> ~
<br /> ,
<br /> ~
<br /> w
<br /> ~
<br /> -
<br /> ,
<br /> -
<br /> -
<br /> -
<br /> w
<br /> W
<br /> m
<br /> <
<br /> "
<br /> W
<br /> "
<br /> <
<br /> 0
<br /> 0
<br /> -
<br /> " "
<br /> ~ "z
<br /> Ww
<br /> ~ ""
<br /> ~<z
<br /> ~ .'0
<br /> ~ . u
<br /> < ~
<br />'j ._0
<br />. <
<br />. --' --,.~ "
<br /> --~;:.:.....
<br />! <:Co: 0"-
<br /> >"- ...,'"
<br />, < ~o
<br />:i
<br />, w
<br />",;; "
<br /> <
<br />, 0
<br />, "
<br />-?f ~
<br /> >
<br />:!
<br />'_f
<br />'k
<br />
<br />
<br />~~';1~~~':
<br />"""<D..,.~<'.IM""'<D
<br />_......-l'~NN-
<br />
<br /><D""0~""'''''''''<7'
<br />"'..,. ",,,,"" ",,,,...
<br />I
<br /><'.I""........""""""......
<br />ONOJjNNNN
<br />,",',' ,
<br />"'..,.'" ..,...,......,.
<br />
<br />""0<0<01""""..,.",
<br />"cN....:--1"cc::i;;"":
<br />.....N.....;::J..............
<br />
<br />"'_.........1..,.<0...0
<br />"'''''''''''''''''<0'''
<br />I
<br />
<br />NO"~O:O""'''''''''
<br />O""'N NONN
<br />""", ,
<br />...,...,,...,,,...,..,.M,...,
<br />
<br />",oa-...J""""_,,,
<br />"';N;;O-;N""':"':""':
<br />NN..........~NNNN
<br />I
<br />
<br />~--:~~';I~o::~"': .....
<br />"""'............~I""<t:>""...........CM"""'C
<br />.....N......_" ............. NN.....NN
<br />
<br />
<br />
<br />""",""'N..,.I..,.o:o",,<o
<br />","''''M 1<0"'''' '"
<br />...... ""'0 oJ",..,. ""0
<br />NN""~~<'.INN'"
<br />""""" ,
<br />..,...,......,. ..,...,...,...,.
<br />
<br />"'N "'''' "'10 <0""'"
<br />",<OM"''''..,...,.'''..,.
<br />
<br />"''''...........''''
<br />"'''''''<0'''
<br />
<br />1
<br />....."'''''0]''''......''''''''
<br />NNNM NN<"-IN
<br />"""" ,
<br />..,...,...,...,...,...,......,...,.
<br />I
<br />
<br />""......"''''''''
<br />NNNNN
<br />,," ,
<br />..,...,...,...,...,.
<br />
<br />..,......."'J"'......N<O
<br />N"':;;"":MN"":O"":
<br />NN..........'1<'.1NN...
<br />
<br />M"""'...<'.IM.....O:O......
<br />M;;,.;",..,.io.....:.o..o
<br />..................N"I....................
<br />
<br /><0<0""""'''''
<br />..., .
<br />M ""... cO
<br />N..........NN
<br />
<br />"'''''.... 0..,.1..,. "''''M
<br />"'.........."'Ci1I<o"''''<o
<br />
<br />......"'........,...,1"''''''''<0
<br />...<o...",r:::.jM"''''''''
<br />
<br />......OMM""
<br />",,,,"''''<0
<br />
<br />""""'......~O......"'...
<br />NNOO MNNM
<br />"""" ,
<br />MM.....,. MMMM
<br />
<br />1
<br />o""'''''o~_o''''<O
<br />MNNM OMNN
<br />"""" ,
<br />MMMM "'MMM
<br />I
<br />
<br />0""""<0<0
<br />MNNN""
<br />",' ,
<br />MMMMM
<br />
<br />I
<br />............""~....."''''...... ~~--:--:~~~';~..,.~~~';';
<br />,.;N"~~";"';N"'; M"''''''''''~''''''''''''O """,<ON'"
<br />N_ INNN- __ .....N ................ _..._<'.1.....
<br />1 I
<br />..,.O..,.............,.NM """'''''OJON''''<O
<br />""'~N1.........."'~N~~N~lN,..,...N
<br />""'NC~"'..,.""OO:O......"'''''o]''''......''''<o "'......"'....""
<br />NOMNNNNMNNNNM NNNN NNNNN
<br />.""""""""""" ,
<br />..,.......,.1..,..,...,............,...,...,.1..,.........,...,...,......,...,...,
<br />
<br />
<br />M""..........'"
<br />"'M"'''''''
<br />
<br />O"'OjMN<O.....N<O"'_N......~....""ON ~~~~~
<br />.o"";""':"';I..n,.;oo 'OMN~"''''':''':'''':..n N........,."""'"
<br />N......4NNNN..........N..._N ........_NN_...........
<br />1
<br />
<br />"""''''~..,.<X>''''O......''''..,......''''_I''''<ONO:OMN''''......''''...
<br />.........~~<O"'''''''...M'''M...<ON~'''..,.''''''.....,.''''''
<br /><o"".....~o............_......o<X><ooJ....o<o"'......o""~~~
<br />NNMNMNNMNMNNMMloMNNNMN "
<br />"""""""""'" ,
<br />MMM~MMMMMMMMMM"'MMMMMMMMM
<br />
<br />NM""~"'''''''<O'''' ....NM..,."''''......''''''''O...NM...''''''......<o''''O.....''''M..,.....
<br />....,...,.........,......."'''''''''''''....''''''''''''''''''''''''''''''1''''''<0'''....................................
<br />""""""""I""""""""""""""""""""I""""""""""""""""""""""""""""""""~~~~
<br />--......-...................................................................................-...................................
<br />
|