WSP02560

• File Number: 8143.600.30.A
• Description: Caddoa Reservoir Studies
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 3/1/1946
• Author: ARCA
• Title: Discussion of Kansas - Caddoa Reservoir Studies
• Water Supply Pro - Doc Type: Report/Study

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1rrigation pool is filled with sediment, or is unavailable for purposes of
streamflow regulation and vrater conserve.tion, the regi".C1en of the river at ond
below Caddoa may be expected to resemble the conditions which IT evailed be-
fore Caddoa Reservoir came into operation. Perhaps one difference will exist,
that the flood pool may continue to control major floods by reducing their
crestflows to rates specified by the War Department or fixed by conveyance
oapacity of the river channel downstream.

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21. For the above mentioned renson, and because estimations and calcu-
lations of so-called "neVi" or "surplus" waters are dependent thereon, Colo-
rado sugGests that the attention of this Commission be directed to determina-
tions of the water supplies of the interstate stream heretofore diverted and
used in each State under pre-Caddoa conditions, and to plans for the operation
of the irrigation pool in Caddoa Reservoir and for the administration of
rights in the Arkansas River affeoted by such operations before previous in-
vestigations are e"tended, or further investigations or studies are undertaken,
to estimate or caloulate the amounts of "new" or "surplus" water to become
available for additional diversion and inoreased use in the two States, by
reason of operations of Caddo a Reservoir.

22. The oonstruction of Caddoa Project in Colorado has created problems,
by its locatio1, - which divides the appropriators along the Arkansas River
into two groups, one above, represented by ditches in Water Districts 14 and
17, and the other below, involving ditohes in Water District 67; and by its
operations, which affect the relative rights of the two groups and of individ-
ual appropriators in Water District 67, and the system of administering de-
oreed rights 'and distributing vrater, long-established in Colorado, under its
dootrine of appropriation and rule of priority. Any plan of operation assum-
ed or adopted should recognize that.

(a) When Caddoa Reservoir is empty, or unavailable, and diversions
from the Arkansas River are being 'II"ade from so-called "natural flows," the
long-established system of administration and distribution Vlill pre~il in
Colorado the same as if the Caddoa project had not been constructed; and at
such times the water supplies of the Arkansas River will be apportioned as be-
tween District 67 and other districts upstream, and as between the ditches of
District 67, in aocordance with their relative decreed priorities and needs
thereunderl

(b) When waters are impounded or stored in Caddoa Reservoir, and
are thus available for release, the decreed rights of ditches in District 67
are deemed to be temporarily satisfied, and at such times the appropriators
in District 67 may not call upon junior appropriators upstream for another
or second supply of waterj

(0) In the above mentioned way a portion of Colorado's share of
any water made available for additional diversion and increased use by reason
of Caddoa Reservoir will be diverted and used in Water Districts upstream
from Caddoa, principally in Water Districts 14 and 171

(d) When releases of water from Caddoa Reservoir are made for