Rio Grande - Rio Grande Reservoir Multi-Use Enlargement_Application Addendum

• Basin Roundtable: Rio Grande
• Applicant: San Luis Valley Irrigation District
• Description: Rio Grande Reservoir Multi-Use Enlargement and Rehabilitation Preliminary Design
• Account Source: Statewide
• Board Meeting Date: 3/13/2007
• Contract/PO #: 150402
• WSRA - Doc Type: Grant Application

~ .1 ((I

DRAFT

HELTON & WILLIAMSEN, P.C.
CONSULTING ENGINEERS IN WATER RESOURCES
384 INVERNESS PARKWAYt SUITE 144
ENGLEWOOD, COLORADO 80112-5822
PHONE [phone]
FAX [phone]

October l' 6', 2003

Mr. Travis Smitht Superintendent
San Luis Valley I rrigation District
P.O. Box 637
Center, Colorado 81125

Subject: Water Available to a Potential Rio Grande Reservoir Enlargement

Dear Travis:

This report presents the results of our investigation of the water that would be available
for storage and regulatio~ in an enlargement of Rio Grande Reservoir. We understand that the
San Luis Valley Irrigation Dj~trict needs the results of this analysis for its consideration of the
feas i b i I ity of 5 U ch an en la rg em e nt. S pecifi cally IOU r i nvestig ati 0 n cove red (1) wate r th at wo u I d be
available for storage in the potential reservoir enlargement under the Rio Grande Compact and
the terms and conditions imposed on post-compact water rights in the "Tres Rios" decree, (2)
water that could be regulated in the reservoir enlargement for compact purposes, and (3) water
that could be regulated under the direct flow storage rights held by the Districtt Rio Grande
Canal Water Users Association, and Commonwealth Irrigation COlnpany. As explained later, we
used water years 1946-2002 for analysis because of the availability of data for the historical
reselVoir contents. Our general reasoning in this investigation was that water would be available
for the reservoir enlargement <;>nly when the existing reservoir filled historically or would have
filled under the current approach to administration for compliance with the Rio Grande Compact.

In addition to the results of our calculations, this report presents some background on
Rio Grande Reservoir, the Rio Grande Compact and the administration thereunder, and the
Tres Rios decree which was entered in Case No. 91 CW29.

RIO GRANDE RESERVOIR BACKGROUND

Rio Grande Reservoir is owned and operated by the San Luis Valley Irrigation District. It
is located on the mainstem of the Rio Grande in Hinsdale CountYl approximately 20 miles
southwest of Creede as shown in Figure 1. It is situated at an elevation of 9,449 feet and