WSP09717

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1969
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 4 - January 1969
• Water Supply Pro - Doc Type: Report/Study

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HISToRY OF DEN ll.OfMENr

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~ 2. Mexican Treal~

The treaty with Mexico~ Gigncd in 1944, provide~ basically for a
guaranteed annual delivery by thp. United States to Mexico of 1,500,000
acre_ i'eet of Colorado River water.

3. Upper Colorado River BaGin Compact

With the water allocut(~ to the Upper &~sin by the COlorado River
Compact and with the M0Xicnn Treaty signed, thp Upper Basin States began
negotiations l,{hich reSulted 1n the :;lr:ning of the Upper Colorado River
Ba::;10 Compact in 191J8. Under the term~ at' the compact, Arizonu b per-
mitted to USe 50,000 acre-feet of ....ater UIlnually frOm the upper Colorado
River system, and the remaining ....ater is apportioned to the other Upper
Basin StateD in the l'ollo....ine percentages.

State or Colorado 51. 75 perCent
State of New Mexico 11. 25 percent
State of Utah , 23.00 percent
State or Wyoming 14.00 percent

Concresr; had prc.'viously been unwilling to approV(O" projects without
assurance that a ....ater supply 'Would be available) ::;0 t.hi:i division of'
water aIOClng the States permitted development in the Upper Basin to pro-
ceed and resulted primrlly in the nuthorj 7.ation of most of the Federal
projects above Lee Ferry that ure mentioned in lhi~ T"-'!-Ort.

Neither 01' tht' compacts :;peeifieally mention ....ater quality.. but it
"as been recognized as a fador to b,. eoncidered i<. d.,velopine projects,
and W"ater quality studi(~s have b('cn requir0d by r..~eent leGislation au-
t.horizing the construction of projects in the Upper Basin.

1j. Ari<::ona v. CalU'ornic. Sui t in tht':' :";upremc' C~u.r'-

The Staten of the' 1.o;.'<:>r Baeln hay, 1';':">'er U{';reul to a 20:;;r..uct for the
division of USE 0::' the waters of' th", 1.0''''('r r:oloI'~~tlo Riv~r !3a~,in. The
State of Arizonu filed suit in the 2.upreme Court of ti-J, United States in
OctOber 1952 against the State of Cal; fornla anu oUwn; fur t.he' determi_
nation of the right" to u"e the ~aLers or tto,,' lOwer 'olorado River sys-
tem. The f-hprer.Je- r;Ourt gave 1t.s dec i ::;ion on June .. 1%.), and issued a
deeree on }.hrCh 9) 1964 J providing for the apportior...n'~nt or the USe of
the waters of the omi" streo.m of the COlorado Rive,' below Lee Ferry among
the States of Arizona, CalHom'", anJ !leved., The .'tates of Arizona and
I/e" Mexico were granted the uelusive u'o of Lhe waters Of the Gila River
system in :.he United St~te!". The deeree did not affect the rights or
priorities to the Use Of ~ater in any of th~ other Lower Basin tributar_
ies of the Colontdo River.

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