WSP01635

• File Number: 8200.400
• Description: Colorado River Basin - Briefing Documents-History-Correspondence
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1961
• Author: CSU Civil Engineerin
• Title: Analysis of Precipitation Data in the Upper Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

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D. DATES WITlllN THE WATER YEAR FOR AC-
QUIRING VARIOUS AMOUNTS OF PRECIPITATION

1. Dates of Acquiring 5 inches of Precipitation
During a Water Year

Figure to shows the mean number of days ,dler
the 1 at of October required to accumulate 5 inches
of precipitation. The number in parentheses in-
dicates the per cent of total years of record in
which 5 inches or more precipitation was received
during the water year. Only for the stations Grand
Junction. Delta, Duchesne, Escalante, and
Montrose were there any years in which less than
5 inches of precipitation was received.

2. Dates of Acquiring 10 inches of Precipitation
During a Water Year

The mean date, standard deviation in days.
and coefficient of variation of acquiring 10 inches
of precipitation during a water year are shown in
Figure 11. High-level stations such as Silverton
and Telluride received more than 10 inches of
precipitation for each water year for the period of
record, while stations such as Grand Junction,
Delta, and Montrose received 10 inches during the
water year less than 50 per cent of the time.

11

3. Dates of Acquiring 15 inches of Precipitation
During a Water Year

Only the high-altitude stations in Colorado
and the stations in Wyoming received more than
15 inches of precipitation during the water year
more than 50 per cent of the time. Low-altitude
stations such as Grand Junction, Delta, and
Montrose never received more than 15 inches of
precipitation during the period of record. (Fig~
ure 12).
4. Dates of Acquiring 20 inches of Precipitation
During a Water Year

Most of the stations in the Upper Colorado
River Basin did not receive 20 inches of pre-
cipitation at least half the time. Only Silver ton .
Telluride, and Bedford, Crested Butte and Steam-
boat Springs received more than 20 inches of
precipitation half the time. (Figure 13).

5. Dates of Acquiring 25 inches of Precipitation
During a Water Year

Figure 14 shows that the occurrence of 25
inches of annual precipitation is very rare through-
out the Upper Colorado River Basin.