WSP11482

• File Number: 8143.600.30A
• Description: John Martin Reservoir - Other Studies
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1950
• Title: Administration of Caddoa Reservoir - 1950 -- Part 3 of 4
• Water Supply Pro - Doc Type: Report/Study

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-no C~inderlider
State Engineer

-2-

!'lay 28. 1943

the contrary, are based on the proposition that ~nile the downstream sen-
ior claims may prevent diversions by upstream juniors up to the point or
until the downstream senior ri Chts a!"B se.ti sfi ed.. the~,r may not GO beY011d
that limit. In other words. Mlen the upstream junior is passin6 suffi-
oient v'ater to satisfy trle dovmstream senior claims, then the upstream
junior may properly divert from the additional supply.

lie thin!:: hr. Knapp will agree. upon further consi deration of tile
matter, that the hmi ting cho.rge, ignoring return flows, cannot exceed
413 cfs. o.t Las Animo.s, or 495 cfs. at La Junta, less the amounts of
water contributed by the Purgatoire River, and further diminished by the
mo.in river strea.m flows at Las Animas or at La Junta. And we believe
that he will abree with you upon some value to be assigned to the net
gains due to return flows. 1n other words, that at las Animas something
less than 413 cfs. is required to satisfy tho.t amount of senior prior-
i ties at Lamar. and at La Junta sonething less t.han 495 cfs. will satisfy .
that aJnormt of priori ties dovpstrea..'"il. In our calcula.tio!ls we hB.~ u_s.!3d~.-
_ what l"1'e believe to be l.1inimwn avera.ge values. - i. e.. about 62 cfs. -'Le: ~~
Junta to Lamar. and e.bout 30 cfs. Las Animas to Lamar. L'1 j"our ad;:linis-
trati va prac"t;ice.. e:::::perience has demonstrated tnA.t wi t'h about 50 efs.
passing La Junto., the Las 4'1ime.s ditches may divert about 83 cf5.. and
with the river drained by the Las Animas ditches and the Purgatoire dry.
the Keesee and Lamar ditches nevertheless receive. about 30 cfs.

Under larger streB.'" floVl !l..'1d diversion conditions. the net effect
of return flows will be ;reater than above assu~~d. particularly durine
periods when the Ft. Lyon is naki~6 larGer dive~si~s. Gross accretions
La J;nta to lamar ll-rera:;ed 102 cfs. during 1908-1938. whi ch inchldes the
effects of tributary inflows ether ~her. the Pur;atoire river ccntribu-
tions, as well as canal regulation wastes !l...jd-,retu~-flows. During ~inter
mont:-ts.. when -tri but~y cont!"i buti ons are sma.ll or absent, the net :-ains
La. Junta -to I.e.:nar ve~e equi"'1alent to 89 cf's. of cC1Ytin'J.c\.\s flow. D-u.ring
the drouth. or tile !e~s 1931-1938, these net winter gains declL'1ed to
an avera~e of but 41 cfs. With the greaver rai~fall. stream flov~ and
diversions of 1941-1942. and the increased veter table le~ls nov, exist-
in~. it is probable that at least 62 cfs., if not more, may be counted
on for this 1943 season.

As indicated by Table 2. the charges agains" Colorado !l..'1d credits
to Kansas during I-jay 1-12, 1943 totalled 5..829 ,A..F. The previous figure
of 6,849 A.F. has since been revised, and still further re~~sion may be
needed when the automatic oharts become available for ano.l vsis. The fi'-,lre
of 5,829 A.F. based on the La Junta record differs from the fi~lre of ~
6.L~52 A.. F. ce.:.c'J.lated from the Las J...'1.iraas record~ ?!"incipally by reason
of the fact the.t the flow of 622 cfs. at La Junta on nay 12, had not as
yet reached Las Ani~as.