FLOOD02713

• Designation Number: 56
• County: Routt
• Community: Steamboat Springs
• Stream Name: Yampa River and Tributaries
• Basin: Yampa/White
• Title: Flood Hazard Information - Yampa River and Tributaries, Steamboat Springs, Colorado
• Date: 2/1/1976
• Designation Date: 3/1/1976
• Floodplain - Doc Type: Floodplain Report/Masterplan

locations On the White River Plat,'au andth~
Park Range. This produced a 40-hou,.storm
with a 3.35 inch rainfall o\.er the Yampa
RiverdrainageaLo\'eAgnteCreekanda4.13
inch llserage rainfall on the Park RanRe.
l.u'\s rate" for the oasin weree~timateddue
to lack ofreprodllcible rainfioods in the area.
Swdy of runoff in theGrand:Mesaareadur.
ing the 1970 Four Corners storm indicated
high (grealer than 1.5 inches) initial losses. A
study 01 strMmfiows and backup precipita-
tion data in the U.S. Forest Service publi~B-
tion entitled "Annual Streamflow Summaries
Irom Four Subalpine Watersheds In

Colorado.. (which include, West Walton
Xorth Fish. and Soda Creeks) indicates th~t
about z.o inches of rain must fall in the
August to October period for appreciable
runoff to OCCur. l.os8 rates adopted for the
100- and 500.year general rainfloods were
1.60 inehrs initial loss and 0.15 inch per hour
constant loss on the '{ampa River. and 2,00
inches initial loss ILnd 0.1l> constant loss on
the tributary creeks. A lower ioitiallosswas
used for the river basin because the density of
vegctation is less th:1n in the basins of the
tributary creeks, The .resulting flows are
shown in Table 3.

TABLE 3

PEMFLOWS
100_AND 500_ YEAR FLOODS

Peak Flow
,',
Stream locatlon 100-year 500-year
Flood' Ftood'
YampaRiver Gaging Station (At Steamboat 8,000 20,000
Sprin!(>l)
Soda Creek Corporate Limit 1.300 2.900
ButcherknifeCr.,.'k Corporate Limit :I2() 1,300
SpringCrcck Corporate Limit 650 2,400
Fish Creek GagiogStation (Upper Station 1.800 4,600
near Steamboat Springs}
Walton Creek Gaging Station (:\ear Steamboat 2.700 5,COO
Springs)
Burgess Creek Near Storm Meadows Drive 360 10400

'F....m'na\\'m.I'.u~mon"dby,.ia
']-'Nm""ne,alra;nfo,tooYamp. Rivcr, r,om oIouJbu"t"",m, fo,' h. ',ibc"',y orc,"",

As previously stated, there are little
definitivcdatalLvailableondoudburstevents
in the Steamboat Springs area. The June
1921 fl<>Od may havt' been the result of a
cloudburst that a\lgmf'ntpil lIhnorm.a1
snowmelt runoff. Contributing rainfall
totlllled 2.57 i",-,he&, but the peri<Xl 01 ~ime in

whieh the rain fell is not definitely known, A
newspaper aceount indicated that it might
have been 1Z-20 hours. However. 2.0~ inches
of rain in 3 hOllrs and 3.Z4 inehos 01 rain i" 24
houn; ha\'r hppn re,ordro elswhprf' in the
reglOn,

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TABLE 4
oaSTRUCTIVEIIRIOGrSANOCUlVEIlTS'
Ele..llon'
I Unde,- 100_y..r 500-ye"
IdcnllllenllM lo.otlon' Slr.omWd d.oro.",,' Roodwoy' Flood f<ooo
YAMPARIVER
I S'oekDri\'O IS9.27 68,,6 lif,73 OOSO AA.'; ~f"'2
13th.'\".",\ 189.73 6&78 lil;~;1 6';9~ ~, 6699
F""lbrirl~. 1!M1.0& ';"~~ ""iS7 r",,,, 61)~8 61Q2
5thS",o: 190.31 6S9~ "'W ~71O 610~ 6108
D.&R.G,II',RR 190,70.... 610.1 6715 5118 &714 6717
D.&R.G.II' " In.zg- 67:16 6151 "" 0747 675..1
T>....II.",Hoad 192..~9 tn. 6751 "" 6749 615~

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Cloudbur,;l$torm criteria were deHlopt'd
from "Probable Maximum Thunderstorm
Pr..cipitation E~timates for Southwest
States," AUl(u'llDi2. A 40 ~rcentvalueol
the probabie maximum precipitation p<>int
rainfaH lor St<'amboat Springs. plotted at
ILbout the 500-rl'nr fre-qupneyon as-hour
rainfall (requcneyeuryC for Craig. Colorado
(the near~st r<'Corded), was seleeterl as a stan-
dlLrd project cloudburst storm. Loss ratcs

OBSTRUCTIONS
Natural obstructioos to floodflow include
trees. brush, and other vegetation growing
along stream" During- floods,vegetation im-
pedes f100dflo\\" nnd results io backwater con-
ditionsand increased fl<>Odheights. Brush or
tr<!<!s washed out during floods and carried
down"tream could coliect on bridge1; or plug
,ulverl~, thus creating a damming elfeetand
overbank flow. As floodflow increase.,
mnsscs of debr;" ean destroy a briilge or
cause watl'r le\'els to rise higher and more
rapidly than normnl. thus eroding and

adoptfd were identi,al to lh<>Of u,edfor
general rainfall. The re,;lIltin~ floodflow5 are
aiM shown in Table 3.
InformationOl\ jU. and 50.,'ear Iklod cveots
wa~ also developed in conjunction with the
hydrologic studies madc fur this report.
These are basiclLlIy snowmelt floods and. with
theexceptionofshowin~ thcirwatersorflLce
profiles on Plates 2.24. are not co,'ered in the
report.

damaging abutments. approache~. and the
overlying roadbed.
In generul. obstructions restrict f1oodflows
and maycauseoverbanknows.unpr~ilictable
areas of flooding, possible damage to or
destruction of bridges and other stream
crossings. and inereased velocity of flow im.
mediately downstream. Most of the stream
crossings in the study area (in Steamboat
Springs)areobstrlldivetofloodflows.l'erti-
nent data On these structurcs are shown in
Tabie 4. The effed of obstructions may be
seen on Plates 2-24.

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'Ili,t,"o< from m.mh of "".m to "'idpoint or ,~r"et",.. (Yam!" Ri,'.r in m;lo:; Md o,~or ,t,.."" ,n [""',)
'Al"".I',p.n,

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