WSP10149

• File Number: 8143.600.30A
• Description: John Martin Reservoir - Other Studies
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 3/1/1946
• Title: Discussion of Kansas --Caddoa Reservoir Studies-- by Arkansas River Commission of Colorado
• Water Supply Pro - Doc Type: Report/Study

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~and longer duration when the reservoir will be empty. This means that the
assumed greater relcases from, storage must be made during shorter periods of
time, and that any release in excess of essential irrigation requirements at
the ti:ne\ even though such excoss release be at divertible rates, may in fact
be wasted and lost through non-use. Elements of ti:ne as well as volume are
necessarily involved in such water supply and irrigation requirement consider-
at ions, and estimlltes of losses of vater should include totals from both river
and reservoir.

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18. As shoml by availa. ble streamflow records at the State line and Garden
City, relatively large volumes of divertible streamflows (and of so-called
"usable ~ater" as here calculated by Kansas)~ wasted and lost through non-
, use for the reason that, at the inter:dttent ti~es of their occurrence1their
volumes were in excess of essential irrigation requirements at the tue.
Plans for operating the irrigation pool in Caddoa Reservoir should not be based
on arbitrarily assumeq releases from storage, but should recognize, among
other things, that water supplies at and belOl7 Caddo a are related to each other,
are' parts of the ,,'aters of'the interstate stream, end are net unli:nited in
amount; and that reservoir operations, to regulate Caddo a flows heretofore
divertsd and used in Coloraeo and Kansas, and to CO!lserve Caddoa fl:l\vs hereto-
fore unused and wasted by Garden City, should contemplate releases from stor-
age to supplement the su:.::plies diverted from unregulated streamflows and re-
oeived from natural precipitation.

19. From river and reservoir operation studies previously ma.de by Colo-
rado it appears that "demands on the reservoir" assumed by K8l1Sas in Studies
3 and 4 were arbitrary and excessive, with the result that the caloulated
greater "lUIlOUZIt s of usable water ,'" and of so-called "new water" estimated
therefrom, are mislsading. The'reported results of Study 2, after correotion
for "Caddoa flows heretofore used in Kansas," indicate an average annual quan-
tity of so-called "new Y/llt3r" that appears to be consistent with the quantity
of so-called "surplus" calculated by Colorado for the same period used by Kan-
sas, whsn too two results are adjusted to the same' basis for the amounts of
water heretofore used in Water District 67 and in Kansas.

20. Both the "new water" and "surplus" quantities above mentioned were
calculated, and reported as averages, for a study period representing What may
be termed the first-half, of the useful Ufe of Caddoa Reservoir irrigation
pool, during which the effective lftorage capacity, progressively diminished
cy siltation, averaged about 300,000 acre feet. Similar studies covering the
second-half of the useful life of the irrigation pool, if made, would involve
an effect~'re storage capacity a',-eraging about 100,000 acre feet, or one-third
that assumed for the studies under discussion, and probably would disclose
correspondingly smaller quantities of "new" or "surplus" water. 'When the
irrigation pool is filled with sediment, or is unavailahle for purposes of
streamflow regulation and ~~ter conservation, the regimen of the river at and
below Caddoamn.y be expected to resemble the conditions which prevlliled befo:-e
Caddoa Reservoir Came into operation. Perhaps one difference will exist,
that the flood pool ~y continue to control major floods by reducing their
- -- crestflolvs to rates specified by the -War -Department or fixed -by conveyance --
capacity of the river channel dOl'fOstream.