BOARD01744

• Board Meeting Date: 4/18/1958
• Description: Minutes and Resolution
• Board Meetings - Doc Type: Meeting

\:136

Under ultimate conditions of development, return flow
from Colorado River uses will pass out of the Lower Basin
into Mexico. Although it is true that such water under the
Mexican Water Treaty will be utilized to fulfill a part of
the United States' obligation to deliver water to Mexico,
nevertheless the reason for the return flow is not the pro-
vision of the Treaty. The reason is that return flow is a
natural phenomenom incident to irrigation and that a certain
amount must be passed out of the Lower Basin to maintain the
salt balance. For example the Bureau of Reclamation estimates
that of the 1,100,000 acre-feet of water ,which is proposed to
be diverted from Colorado River to Central Arizona, 300,000
acre-feet must be passed out of the basin as return flow to
forestall further deterioration of some of the Central Valley
lands of Arizona by salt accumulations. This water will go to
Mexico, and would go to Mexico and be available for her use in
spite of the Mexican Water Treaty. In my opinion the return
flow passing out of the Lower Basin is no different from the
return flow which may pass out of Upper Colorado River Basin
States to states located outside of the basin.

I

I am not competent to comment on the incidental fish and
wild life and recreation benefits claimed for the Narrows
Reservoir. I have little knowledge of such matters.

It is my conclusion that there is no great urgency for a
reservoir such as the Narrows. As a matter of fact, the pro-
vision of such a reservoir might be somewhat premature. The
best use that can be made of South Platte River water, includ-
ing a part of Colorado-Big Thompson water, will be by an intell-
igent coordinated use of surface and ground water and a Dart of
the capacity of the ground-water reservoir. The ground water in
the South Platte river basin is far from being overdeveloped.
If a development were encouraged which would utilize a substan-
tial increment of the underground storage capacity below the
flood plai~, the basin development would become more nearly
stabilized and some "new" water would be made available for use
in the basin. The lowering of the ground water would salvage
some water which now is nonbeneficially used by evapotranspira-
tion in the flood plain. The increment of underground storage
would carry water over from flush periods to lean periods and
would provide some ,capacity for storing a portion of the South
Platte flood flows which now in part are evaporated and trans-
pired on the flood plain, and in part pass out of the state
unused. There are a number of ramifications surrounding such I
a plan which will not be discussed here. However, the plan is
so logical that with encouragement and proper control it is
inevitable that it will materialize. After stability has been
attained under such a plan, then the need for surface storage
can better be appraised. ,