WSP06903

• File Number: 8549.600
• Description: Wagon Wheel Gap Reservoir
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 12/1/1941
• Title: Rio Grande Water Conservancy District and Wagon Wheel Gap Reservoir
• Water Supply Pro - Doc Type: Publication

.f!:)
Ii'
0J
<.:)
(--)
p

with hydraulics cooperated in compiling- the
report.
The United States Corps of Army Engi-
neers undci' Act of Congress made a sepa-
rate investigation.
The engineers of COlOrado, New 11cxieo
and Texas all checked the infol'lnatiol1 gath-
ered. No othCl' irrigation project has been
so cOlnplctcly and fully studif'd from an Cll-
g.inet~l'ing standpoint.

I

Water Supply

>

On account of these same inl l'l'national
and intel'stat<~ differences, l'cconls of I'llnoff
and \\'atcr production affecting this arca
co\'er fi long-cl' period and arc morp cornplete
than in any other irrigated basin.
The first water gaging station evel' in-
stalled in the United States was located b.y
the Geological Survey at 8mbuda, New
M(~xico at a point helow Uw last diversion
in Colorado and above tlw fit'st divcI'sion in
New Mexico, to dctcrmilW t1H' amount of
water produced in Colorado and has been
continuously maintained since that time.
Additional gaging stations were soon aftcI'
located at Del Nortc, at Lobatos at the Colo-
rado State Line, at Buc1{man the lowel' end
of the Espanola Vall!')', and at Courchesne
neal' EI Pa~w,
The records from these gaging stations
have been rclig-iouHly presel'ved and no other
basin in the United States has more com-
plet.e watel' runoff I'econls 01' rccords for a
longer period,
F'I'om tlH'se records covel'ing a period of
seventy years 01' more, as assembled by The
H,io Gl'an(h~ .Joint 1 nvcstigation under the
auspices of The Natural Resources Board,
it appeal's tha.t with the ,'cgulation provided
by the Pl'oposed works, a diversion of ()70,OOO
acre feet may be safely made ('aeh and
ev('I'Y YNU', 122,000 acre fed more than the
largest average amount (,V(,I' diverted in any
ten year period <1928 to 1938) in the past;
131,000 acre feet rnOl'e than was divL','ted dUI'-
ing the 15 yeal' period (1925 to 1H40), and
252,000 acre feet more than the average di-
version of the last fift).' years,
While slight shortages might occur in in-
tervals 01' 30 to 40 years even these would be
very much reduced and the slIppl:yi \vill
compare with any other sueh project in the
Western 8tat('s,
If, incident to proper regulat ion, a lesser
amount of watel' be consumed hy the hold-
ers of present rights, 01' if return wat.PI'
should increase incident to a unifol'm appli-
cation each year, the amount of 11('\.V water
available would be theI'cby ineJ'eased, It is
entirely n~asonable to suppose this may oc-
cur, but all comput.ations have been made
on the basis that futlll'(~ uses of }J1'(;sent
rights will continlle in the same way in t.o
tile game extent as in the pasl,
The 670,000 acre feet available is an aV(~l'-
age am.Ollnt, Less than this amount would
undoubtedly IH~ used in years of plentiful
rainfall, possibly more than t.hat amount in

;

partieularly dry years, An average of 670,000
acre feet can be produced by the proposed
l'egulat(}l'y works and will provide an ade-
quate dependable supply fo1' all lands now
under irrigation from the Ilio Grande,

This supply is now available under the
Compact, but in anlOunts varying frOlll
274,000 acre feet in IH40 to 1,300,000 in some
of the wet years,
In its present unregulated state, serious
water shortages OCCUI' in dry years and a
lu)'ge portion of the amount available in wet
Yt~ars is unusable and is lost.
If the Wagon Wheel Gap Dam had been
in operation during the period 1890 to 1938,
670,000 feet eQuid have been used each year
and still an average spill of 72,000 acre feet
per year from the reservoir would have oc-
curred and during the period 1907 to 1930 an
average spill of 180,000 acre feet would have
accrued.
\Vit.h the CabalIo Dam below the JiJlephant
Eutt.e and the EI Vado Reservoir On the
Chama, the Rio G}'ande Valley in New Mex-
ico and Tcxa~, above Fort QUitman, Texas,
now has over 3,000,000 acre feet of effective
stonlge space, sel'ving less than one half
the nunlbcr of acres now under irrigation in
the San Luis Vailey alone, while that portion
of the Rio Grande Valley located in Colo-
I'ado, now has not to exceed 80,000 acre feet
of effective storage including- the Fanncn;
Union, Santa Maria and Continetal Reser-
voil's.

The Compact

The Compact guarantees Colorado in the
future use of present water rights; removes
all }'estrictions on future reservoir construc-
tion, but pl'ovides for certain scheduled de-
livet'ies on a sliding scale, based on the flow
at t.he index gaging station at Del Norte.
The natul'al return flow will supply suffic-
i(~nt water to provide for these deliveries in
t.he gI'eat majority of years. In occasional
yeal's however, such as 1940, unless wet to
dry st.orage is provided, deficiencies will
occur.
In 1940 a debit to New Mexico and Texas
of 1wtween 9,000 and 10,000 acre feet develop-
ed on the Rio Grande and a like amount on
the Canejos, but so far in 1941 this debit has
heen wiped out and a very considerable
credit to Colorado has already accumu-
lated, which is being daily augmented by
about '1,000 acre feet of water passing down
the l'ivcr which is unusable without. wet to
dl'Y storage,
The future use and enjoyment of present:
rights are assured undcl' the Compact. But
the use of surpluses availablc under the
Compact can only be obtained by provision
for an adequate arnount of wct to dry stor-
age space, \vhich will not only mal{e those
sllrpluses now lost as unusable water, avail-
able hut this additional water will permit
each \vate!" user to regulate his present
rights in such a manncr as to make them
lOO'jI effective.

7-