DWR_4151812

• Title: MAY 1990 SWSI: COLORADO WATER SUPPLY CONDITIONS UPDATE, SURFACE WATER SUPPLY INDEX
• Year: 1990
• Document Type - Publications and Reports: SWSI Monthly Report

BASIN ASSESSMENTS cont.
Colorado
The basinwide runoff is forecast to be 75% of average ranging from 62%
for the lower Colorado River to 90% for the upper Colorado River. Flow for
the month of April at the key index station, Colorado River near the
Colorado-Utah stateline, averaged 2340 cfs as, compared to the normal flow of
5539 cfs. Soil moisture is classified as being fair at lower elevations.
Water shortages are expected to develop on the smaller tributaries in the
lower reaches of the basin and in the Grand Mesa drainage area. The runoff
has been delayed by cooler than normal temperatures. The Cameo "river call "
has already been put into effect this spring and is likely to be implemented
throughout most of the summer months. Granby Reservoir had 78,100 acre feet
in storage on May 1, 1990, as compared to 314,900 acre-feet in storage on
May 1, 1989.
Yampa/White
The SWSI value of -2.6 is the lowest in the state and classifies the
basin as being in a "moderate drought." The basinwide runoff is forecast to
be 62% of average ranging from 60% for the Little Snake River to 94% for the
Laramie River. Flow for the month of April at the key index station, White
River near Boise, averaged 390 cfs as compared to the normal flow of 769 cfs.
Soil moisture is classified as being moderately low. Low elevation runoff is
already complete. "River calls" are likely to be placed on the lower Yampa
River and the White River this summer. Stagecoach Reservoir currently has
25,000 acre-feet in storage out of a capacity of 31,000 acre-feet.
San Juan/Dolores
The SWSI value of -1.7 is a significant improvement from the April 1
value of -3.3. This upgraded the basinwide classification from "severe
drought" to "below normal" to "moderate drought." The basinwide runoff
forecast is 47% of average ranging from 22% for the Dolores River above McPhee
Reservoir to 53% for the Florida River above Lemon Reservoir. Flow for the
month of April at the key index station, La Plata River near Hesperus,
averaged 22 cfs as compared to the normal flow of 84 cfs. McPhee Reservoir
currently has 288,000 acre-feet in storage. Soil moisture is classified as
being fair at lower elevations. Water shortages are expected throughout the
basin with the exception of the mainstem of the San Juan River and Animas
River. Reservoir storage is expected to be severely depleted by late summer
if precipitation is below average during the summer months.
Forecasts provided by the Soil Conservation Service, Snow Survey Office
(Denver), U.S. Department of Agriculture