WSP05654

• File Number: 8541
• Description: San Luis Valley Project
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 1/1/1939
• Title: Period of Study
• Water Supply Pro - Doc Type: Report/Study

~

,
\

I
"
l.
>-.n
I.

APPENDlX E

::tnfloW" ,.. Wa!!on Wheel GaD to DElINorte

The inflOlf between Wagon Wheel Gap ani DEll Norte was obtai red by
subtracting the computed now at Wagon Wheel Gap from the recorded now at
Del Norte. This was done on a daily basis. Whee the inflow between Wagon
Wheel Gap am Del Narte was less than the irrigation requirement at DEll
Norte, it was considered to be divertible. ,

Non-dd.vertible in:flows 'I1ere the in:flows between Wagon Wheel Gap
an:l Del Nortethat exceeded the irrigation requirement at Del Narte. .

Return nows - Del Norte to ,~amosa

Mr. R. J. Tipton, Consulting Enginaer, Colorado Water
Conservation Board, determined in his 1939 report that usable return news
in this reach of river would average 50,000 acre-feet per year during years
of full irrigation water supply. This reduction in use of return flows
from the 66,100 acre-feet historic re-use, subsequently derived in Table
E-7, is caused by the change in water use am to regulation afforded by
Wagon Wheel Gap 2ieservoir. Historically, large diversions were made in
May, June am early July during noocLstages. Return flows from these
diversions reached the river for re-use by late July am early August. .
Un:ler the recomme1Xled plan, early season diversions td1l not be as large
as 'I1ere made historicallyo Therefore, by reason of the regulation of the
river, use of water will be more efficient and return news thereby
reduced. This average usable return now of 50,000 acre-feet per year
has been further substantiated by recent pt'oject studies am is used in
Study 12-R. During.years of shortage, the return nows are corrected to
refiect reduced diversions.

Diversion Reauirements

'.

!Ilanalyl!is of the average annual diversions from the Rio Grande
for lanis within the Rio Grame Division service area made in 1939 by
1IiIr. R. J. .Tipton, Consulting E~ineer, established tl~ ideal diversion
deman:l for approximately 300,000 acres, then bei~ irr:l.gated, to be about
670,000 acre-feet and the usable return flow that would re-e.nter the Rio
Grande between Pel Narte am Alamosa as the result of such diversions to
be about 50,000 acre-feet. On this basis, it was concluded that to fur-
nish a full surface. water supply for irrigation of 271.,000 acres within the
same area, as pt'oposed by the plan of develoIJIIBnt, would involve a diver-
si,on.req!lirement of. about 605,300 .acre-feet annu.ally ani. the usable .retl11'n
:. n?~,.t'estl;I:ting .');he~f.t'9m i1o.o1d.:~" a"0ut .50,n0?" Et\l~t~et.:' .. '.:

FlolV Divertibleunder Rio Grame Comooct

!II analysis was made to determine the average a!ll)Ual depletion
of the surfaCe water supply and the correspoming averageannuaJ. diver- .
sions which could be made by the P.io Grame Division service .area without
depleting the now or the Rio Grande below that permitted under the terms
of the Rio Grarrle Compact. The analysis was made for the reach of the
river betvreen Del Norte am Lobatos, excluding the Cone~os River flows far

E-30

".

r - ,." :'. ,.",
~) ... ..I.. \,.;-'.u