WSP11716

• File Number: 8507
• Description: Rio Grande Project
• State: CO
• Basin: Rio Grande
• Date: 7/1/1997
• Title: Water Management Study: Upper Rio Grande Basin part 1
• Water Supply Pro - Doc Type: Report/Study

Water Management Study: Upper Rio Grande Basin

New Mexico or from thunderstorms. Average annual precipitation exceeds
25 inches only at the highest elevations; for over two-thirds of the Basin,
precipitation is between 7 and 15 inches. Precipitation is highly variable.
Snowfall in the high mountains can be as little as 30 percent and as much as
75 percent of the Basin's total. On average, summer precipitation supplies
almost half of the Basin's annual moisture in brief, intense thunderstorms.
Mountain tops in the Basin reach 12,000 feet. Most of the human population
occurs at about 5,300 feet near Albuquerque and 3,800 feet near EI Paso.

The Colorado portion of the Basin produces about 975,000 acre-feet (at) of
water annually (Daves 1994).' Approximately 650,000 af of this total is
consumed by agricultural production in the San Luis Valley or "lost" to
seepage and evaporation. From the border, the river passes through a steep
canyon for about 100 miles, emerging near Santa Fe into a broad valley
known as the Middle Rio Grande. The Middle Rio Grande receives about
300,000 affrom Colorado, 400,000 affrom a major tributary, the Rio Chama,
and 250,000 affrom tributary streams in the mountains of northern New
Mexico. Since 1971, the Middle Rio Grande also receives about 100,000 af
imported into the Basin from the San Juan Basin (part of the Colorado
Basin) on the other side of the Continental Divide from the transfer of water
from Colorado's San-Juan Basin to the Rio Chama (Rio Grande Compact
Commission 1991).

I:'
,

Ii

Flows on the river receive the greatest attention at two locations. Flows at
the gauging station at Otowi Bridge, about 100 miles north of Albuquerque,
are used to determine deliveries of surface water to New Mexico from
Colorado and flows into Elephant Butte Reservoir, about 120 miles south of
Albuquerque, are used to determine deliveries from New Mexico to Texas.

\.';

~:~

;1
1-.:
,~':

Flows in the Rio Grande vary considerably, as shown in Figure 1.1. It shows
the annual flows at Otowi Bridge from 1950 through 1994 and does not
include water from the San Juan River. For the time period 1895(1993,
average flow at Otowi was 1,060,000 af, with a standard deviation of
525,000 af, indicating that 66 percent of the time the flows of the river varied

c~

!',

!:-~

~/",
\ ~~

2 An acre-foot of water is the amount of water that would cover one acre ofIand one foot
deep. It is equivalent to 326,000 gallons and 43,560 cubic feet of water.

~~
;~
fix

4

('('l88
! '.t.. 1

k~
r
~