WMOD00528

• Title: The Feasibility of Enhancing Streamflow in the Silver Iodide in the Sevier River Basin of Utah bt Seeding Winter Mountain Clouds
• Date: 12/1/1991
• Weather Modification - Doc Type: Report

Table 3.1. . STORM total SLW flux and preclpnatlon for three winters. . Continued

Storm Fraction of storm Total precip. Adjusted SLW
Storm begin date duration (hr) with flux obs. (mm) mass (Mg. per
(percent) m of ridgeline)
1987
Feb. 3 ~4.0 0 4.1
Feb. 10 -9-.5 0 1.3
Feb, 11 22.0 30 4.8 135.8 -
Feb. 13 20.0 78 13.7 212:.7
Feb. 15 22.0 100 4.6 6i.8
Feb. 18 -5.7 0 0.0
Feb. 23 61.0 69 13.5 33:.7
Mar. 7 12.0 88 0.0 31.5
Mar. 8 19.0 61 5.3 53.2-'
Mar. 13 4.5 100 3.1 124.4 ~
Mar. 14 -22.3.. 54 .La- -1i..2...
TOTALS 212.0 58.3 57Ei.3
1989
Feb. 2 48.0 100 29.5 409.6-
Feb. 8 104.0 60 8,9 216.8
Feb. 18 50.0 62 18.8 42.4
Mar. 1 48.0 86 59.4 367.6--
Mar. 5 J2.a.. 95 -2...5... --11A.
TOTALS 322.0 119.1 1047.8
. 1 acre-ft of water is 1233.5 Mg (1233.5 K1 06 gram).

Table 3.1 shows that stonn total amounts of SL W flux vary widely from none to about 400 Mg per meter
of ridgeline. It is seen that two or three stonns produced 3/4 or more of the total SL W flux each field
season. Nearly half of the early 1985 SLW flux passed over the barrier during a single 31-hour stonn
event while over 75 percent of the field season flux was due to only 2 of the 14 episodes willi SLW data.
One stonn produced 37 percent of the 1987 total flux and three of the eight sampled stonns accounted
for 82 percent of the field season's flux. During 1989 a single stonn produced 39 percent of !he total flux
and the second largest provided another 35 percent for. a combined total of 74 percent. The cumulative
distribution of SLW flux for the 1985, 1987 and 1989 field seasons is presented by Huggins (1990b)
which shows that during each project, half the total flux occurred in less than 15 percent of the
observational periods. Further, over 90 percent of the flux occurred in just 38 to 47 percent of the
observational time during the three seasons.

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