BOARD01272

• Board Meeting Date: 7/23/2002
• Description: WSP Section - Colorado River Basin Issues - Update on Navajo- Gallup Project in New Mexico
• Board Meetings - Doc Type: Memo

,

Agenda Item 15
July 23-24, 2002 Board Meeting .
Page 2 ofl0 '

around a New Mexico only project that would deplete 26,000 AF\YR of which only 13,000 e
AF\YR would be exported from the Upper Colorado River Basin (12,000 AF\YR to the Little
Colorado and 1,000 AF\YR to the Rio Grande).

Pursuant to the Upper Colorado River Compllct, the water apportioned to the Upper Basin
States is allocated as follows:

Arizona
Colorado
New Mexico
Utah
Wyoming

50,000 AF\annum
51.75%
11.25%
23.00%
14.00%

7.5MAF
50,000
3,855,375
838,125
1,713,500
1,043,000

6.0MAF
50,000
3,079,125
669,375
1,368,500
833,000

Reclamation's current hydrologic determination of water available to the Upper Basin is only 6.0
MAF, significantly less than the 7.5 MAF apportioned under the Colorado River Compact.
Colorado does not accept this determination, but has acquiesced to its use for water resource
planning and certain administrative purposes. Both New Mexico and Arizona have contractually
obligated all the water apportioned to them under the current hydrologic determination. New
Mexico's consumptive use of Colorado River water at build-out, including the Navajo-Gallup
Project, was initially estimated to be approximately 695,000 AF.

New Mexico has just completed a detailed review of their consumptive use values and
now believes that Navajo-Gallup can be completed within their compact apportionment under A
the current hydrologic determination of 6.0 MAF. New Mexico estimates current consumptive ·
uses are approximately 508,000 AF\YR and that includes its share of Colorado River Storage
Project (CRSP) reservoir evaporation. We have reviewed the revised numbers and believe
they may understate New Mexico's future uses: because they assume 5% of the irrigated
acreage will be fallow in any given year (Section 7 consultations with the U.S. Fish & Wildlife
Service use the full irrigated acreage by contrast). Furthermore, New Mexico has a long-
standing history of utilizing the original Blaney~Criddle method for computing consumptive
use. These results tend to be approximately 5% less than the values obtained by the Modified
Blaney-Criddle method utilized in the rest ofthe 1)pper Basin.

Arizona's consumptive use of Colorado River water at build-out is estimated to be in excess
of 50,000 AF. Arizona's current consumptive uses a~e approximately 46,000 AFWR. Thus, Arizona
and possibly New Mexico may need to rely on unu~ed Upper Basin apportionment in Colorado and
Wyoming for contracting purposes, or have a contr~ct with another instate water user to cover any
shortages. Such a contract could take the form of a "Depletion Limit Guarantee" under which the
Navajo Nation would agree to operate its projects (Navajo-Gallup, Navajo Indian Irrigation Project,
Hogback-Cuedi and Fruitland) collectively in a manner that would not cause New Mexico to exceed
its apportionment under the current hydrologic determination. Alternatively, we could consider any
uses in the Lower Basin be accounted for as Lower Basin uses regardless of the source (Discussed
and not acceptable to Lower Basin interests).

Discussion

e

This memorandum provides updated information on the policy questions posed by the
Navajo-Gallup Project that were outlined in our July 13, September 14, November 7, 2001 and