WMOD00394

• Contract/Permit #: 14-06-D-6467
• Project Name: Weather Modification Pilot Project
• Title: Weather Modification - A Pilot Project - San Juan Mountains, Colorado River Basin - Final Report
• Date: 2/1/1974
• Weather Modification - Doc Type: Report

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FIG U RES

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Distribution of non-seeded precipitation at HAO as a
function of 500 mb temperature compared to a theoretical
distribution computed using the mean diffusional model.
Precipitation data are from Climax I sample (251)
and values are a running mean over a three-degree
temperature interval ..... ....... 5

Comparison of seeded area (target) streamflow with
control area streamflow for non-seeded (historical
and randomly selected) and seeded years . . . . . 12

Seeded to non-seeded ratios of total precipitation
change, precipitation duration change, and precipita-
tion intensity change as a function of 700 mb equivalent
potential temperature. Plotted values are computed
using a running mean over a 5K temperature interval.
Precipitation data was measured at the High Altitude
Qhservatory during experimental days of the total Climax
f' sample (623 days). ...... . . . . . . . 13

Seeded to non-seeded ratios of total precipitation
change, precipitation duration change, and precipita-
tion intensity change as a function of 700-mb
equivalent potential temperature. Plotted values are
computed using a running mean over a 5K temperature
interval. Precipitation data were measured at Wolf
Creek West . . . . . . . . . . 15

Seeded to non-seeded ratios of total precipitation
change, precipitation duration change, and precipita-
tion intensity change as a function of 700 mb equivalent
potential temperature. Plotted values are computed
using a running mean over a 5K temperature interval.
Precipitation dat.a were measured at Wolf Creek Summit. 16

Map of Upper Colorado River Drainage Basin

23

Map of San Juan Sub-Basin. . . .

24

Map of Upper Colorado Sub-Basin.

25

Typical probability of more than minor flood damage
for tributary streams to the San Juan during snow melt. 32

Time (years or events) required with different 500 mb
temperature design criteria to detect changes in
precipitation comparable to those found during the
Climax randomized experiments. This is the time
interval to provide a 50 percent chance of obtaining
significance at the 5 percent level with a one-sided
test. It assumes that (1) the weather modification
potential in the San Juan is the same as at Climax,
(2) the frequency of storms in any given year in the
San Juan area is the same as the average frequency
during the 1964-1970, and (3) 1/2 of all seedable
events are actually seeded . . . . . . . . . . . .

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