WSP13019 ‎(2)‎

• File Number: 8040.800
• Description: Colorado Water Resources
• State: CO
• Basin: Statewide
• Date: 7/1/1999
• Author: Division of Water Resources
• Title: Colorado Water Supply Conditions Update Reports
• Water Supply Pro - Doc Type: Data

RIO GRANDE BASIN

Basinwide Conditions Assessment
The SWSI value of 2.5 indicates that for July the
basin water supplies were above normal. Flow at the gaging
station Rio Grande near Del Norte was 2,397 cfs, as
compared to the long-term average of 1,408 cfs. The
Conejos River near Mogote had a mean flow of 535 cfs
(113% of normal). Storage in Platoro, Rio Grande, and
Santa Maria reservoirs totaled 133% of normal as of the end
of July.
Precipitation in Alamosa was 0.31 inches, 0.88
inches below normal. Alamosa temperatures ranged from
410 to 910, with an average of 64.70,0.210 below normal.
Frequent rain storms in the higher elevations
increased stream flow throughout the basin. Soil moisture
conditions are very good. Fortunately, this basin did not
receive the type of rainfall events that produced mudslides in
other areas of the state. The only significant flooding
occurred on Saguache Creek on July 25 when US-285 was
closed to travel for several hours.

Outlook
Stream flow throughout the upper Rio Grande Basin
will be above normal for the next several weeks.

Administrative/Manaaement Concerns
The extended runoff and unexpected rainfall have
increased the measured volume at the index gaging stations
beyond the forecasted levels. The burden of passing water to
the state line to meet Rio Grande Compact delivery
requirements dramatically increases as basin inflow rises.
The delivery target for the Conejos and its tributaries has
remained fairly steady for the summer. However, unusually
high streamflow in the Rio Grande drainage the last two
months has forced administrators to increase the amount of
native flow that is passed by Colorado diversions to New
Mexico.

Public Use Impacts
Untimely rainfall has already been a great hindrance
to the harvest of grain and grass crops in the San Luis
Valley. Moderate to severe economic losses are expected.
Late blight, the same fungus that led to the great potato
famine in Ireland, has once again been spotted in the valley.
This potentially devastating killer made its first appearance
in this region last year. It was successfully defended against
in 1998 by application of a large amount of chemicals at a
great cost to farmers.
Water users and recreators should expect above-
average stream flows and reservoir levels through the end of
the summer.

Aug-99

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