WSPC04625

• File Number: 8281.300
• Description: Colorado River Basin-Colorado River Studies and Investigations-Consumptive Uses and Losses Reports
• State: CO
• Water Division: 5
• Date: 6/1/1988
• Title: Blaney Criddle Estimates-Stream Lines-Volume1-No2-Lawngrass Consumptive Use
• Water Supply Pro - Doc Type: Report/Study

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'-""NRASS CDS.1'PT lVE LeE

Over tt"e past fE'Oool year-5 it has becone increasingly irnoor-tant to be able to calculate
the potential ccn~tive use of bluegrass wheon developing plans tor auqlfE'ntaticn. In
1983 a Qro..Jp 01 Color-ado w.ater "E"SO..J~e CO'1sul tants ttE't to discuss th? k.. values that
sl"o..Jld be c01sioe>r-E'd ~ using tt-e s:s Blaney Criddle fonTula. Tt"le values finally
selected were based upcn a pape>r by Borrelli, J., et al.. "Blaney-Criddle Coefficients
for'" I,.E>stern Tud Grasses," JCl.Jrnal of Ir,.-igatitrl & Drainage, ~I December 1981. with
minor revisicns recCJ'tfT1e.'!"lded by tl"e late R.a)l'TT'O'1d +-t::l;an of Wreeler & Assc:c. TI"'ese values
ha-...e been used to date primarily in tl'-E> Frcnt Range ar-e.a; r-o...eve,.... recently tl'"1er"e have
been several plans for augtrel'1taticn subni tted to Water Co...irt which requir-E calculating thE"
c:O"'SUtnptive use of bluegrass at high?r altitudes. Th? influence of elevatiCJ""l cn
CO'"Isurnptive use has been recognized for- years. Dc:JorE'rlbos and Pruitt (1977) in referring
to tt-e Blaney Cl"'itjdle metl"o::l stated tt"lat. "it st-o..Jld be used with skl!'pt.ic::isrn at high
altitudes due to the fairly 10,.., rrean daily temperatures (cold nights) E"Ven tt-o..Jgh daytirre
radiatien levels are high." Cuenca. et al. (1981) presented data st'"'ooling tt-e Blaney
Criddle rrett"od under-predicts crop ....ater use for- high altitude arid climates. This is due
to t~ fact that tl'-e Blaney Criddle rretl"'Cxj PVE'f'\ly looEighs day and night temperatures in
CO'T'p.Jting an ave-rage temperature. A Daper Presented by Poch:lp. Lo. Borrelli. J. and
9..ml'l,a.." R., "Elevatien A Bias Error in SCS Blaney Criddle ET Estimates," 1984
Tra..,sactiens of tt-e ASt€., PO. 125-128, uSE"d data collected en alfalfa and bluegrass
tht-o..&grcut tl'-e Weoster"T1 states to determine an elevaticn acUust.rrent fo.:;- the>~B.~~_.Cr;:_!c;?dle
!orlTlJla.., Tre stuoy indicated tiS!l...cor-resyc;n factor of' -.:._
lCXX) feel over base elevaticn 29 'be '1
~, . JPrC.~feet SttS\i ' se ~ INa en or.~ ~. ~..,';.,,~ ,__~. Lrte'
-..t1~~r:!~t-t...y.niO~l"1:iJ~~or:"b""10eg~as~~h?" study.-indicated- that-an eteva J.cn
\recticn..-tactor ,""Of 2 'percent for"eacH lCXO' feet over base elevatiO"' of 4129 feet st'o.Jld
l..oto" used for tl'-e ITO"'lths Aoril thro.Jgh O::tober and 2.8 percent per 1000 feet over the base
elevaticn for tt-e 5l...m'ner ITCI""lthS (June thro...agh A.Jgust) st-o.Jld be used for al fal fa. This
adJustsrEnt wi 11 resul t in an increase in the ET estimate 10r elE"\l'aticns greater than the
base elevatiO'1. The paper presented the follo,..,ing cal ibrated kc values for croo gro,..,th of
bluegrass and al1al fa which ITUst be used when using tt"e elevaticn correctiO"l factors
referred .above:

Apdl
"'"'v
June
July
.:t..Jgust
September
O::tober
The> caper a I so
eQuaticns to be

Bluegrass Alfal1a
o.rn 0.92
1.00 1.03
1.10 1.16
1.06 1.11
0.98 1.01
0.97 0.92
0.89 0.86
p:-ovioed revised tem=erature c:oef1iciE'!"lts for
used when u~~ng EngliSh units are as follOwS:
Bluegrass: k~ = O.oo328T + 0.65011
Alfalfa: k~ = 0.014lT - 0.0757
T is in oegrees Fahren~it

bluegrass a""ld alfalfa.

Tre

The Division 01 wat~r Resources comoa~ the results obtained using the original kc
values recO'1"fTenOed Oy the consul tal'"\t gro.JO with tr-e valuE"S Obtained using tt-e Poct'oO
rnetr-cd and 1=und tr-.ao:. esser'ltially t.r-e sarre ans,......er is o~tained for a" elevatiO"l eauivalent.
(..v,ver. I-o..ever, o...R 1Q...1..,d sig:'1ificant differences in results at elevatiO"ls at least
. _..:IJ feet diHe>rer\t than at Denver. Fer this reascn. D.oA is no,.., usi'!Q _the~top_mettcd'-
~alculating ..c:cnsumptive use at---e1~at..i~'which an:!'--atiea-st-IOcx:>~~gre:r-or-
l~f~-..roe;.;~':~-"~ _