WSP03923

• File Number: 8210.137
• Description: Colorado River Basin-Colorado River Basin Organizations/Entities-Colorado River Forecast Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1984
• Author: NOAA
• Title: Water Supply Outlook for Colorado
• Water Supply Pro - Doc Type: Report/Study

as of April 1.

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WATER SUPPLY OUTLOOK FOR

COLORADO RIVER above CISCO, UTAH: The water supply outlook for the Colorado
Basin remains above normal with high runoff anticipated in the lower Gunnison
Basin as well as the reach from Glenwood Springs down to Lake Powell on the
Colorado River mainstem. Streamflow forecasts increased slightly (less than
10 percent) and range from 135% in the upper watersheds to 183% on the lower
Gunnison River.

The potential for some spring snowmelt flooding remains high particularly for
drainages in the Gunnision basin and Plateau Creek, east of Grand Junction.
The character of the weather during the next two months will determine the
extent of the flood problems. Interests along stream channels with high flow
volumes should take the necessary precautions and be prepared in the event of
adverse snowmelt conditions. Wet soils and the onset of the spring snowmelt
could caUse some rock and mud slides on steep slopes susceptible to failures
and local interests should be alerted.

March precipitation varied significantly throughout the basin. Amounts ranged
from less than 90% in the extreme headwaters near Lake Granby and the upper
Gunnison to nearly 200% at eight locations throughout the basin. The highest
reported amount was at Ouray, Colorado, 4.91 inches, 260%,

Seasonal precipitation, October tl~u March, is the highest over the Roaring
Fork drainage, Grand Mesa, and southern portions of the Guru1ison drainage where
amounts are 150 to 180%. Much of the rest of the basin is 135 to 150% of average.

April 1 snow surveys indicated that most basin snowpacks increased near normal
during March. However, the surveys did reveal that 21 snow course measurements
established new records (some dating back to 1938) for April 1 generally in the
Gunnison and Colorado River watersheds. Some basin averages include: Upper
Colorado - 141%; Roaring Fork - 139%; Dolores - 135%; and Gunnison - 137%.

Runoff during March remained above normal with the flow at Cisco, Utah of
305,000 acre-feet, 145% of normal. Since October 1 the flow at Cisco, Utah
has been 1.73 million acre-feet, 146% of 20-year (1961-1980) average and the
highest on record dating back to 1923.

End-of-month storage in the four major reservoirs above Cisco, Utah (Granby,
Dillon, Green Mountain and Blue Mesa) is 905,000 acre-feet, 109% of average,
53% of capacity and 100,000 acre-feet lower than last month as well as last
year at this time. Storage in Lake Powell is 21.1 million acre-feet, 84% of
capacity and 1.5 million acre-feet lower than last year at this time. The
April-July inflow forecast to Lake Powell is 11.5 million acre-feet, 154% of
the 20-year (1961-1980) average.

NOAA - NATIONAL WEATHER SERVICE
Colorado Basin River Forecast Center, Salt Lake City, Utar.
Gerald Williams, Hydrologist-in-Charge