WMOD00312 ‎(2)‎

• Title: Cloud Seeding Feasibility for the Shasta-Trinity Watershed
• Date: 12/1/1993
• Weather Modification - Doc Type: Report

CONTENTS - Continued

Page

6. Estimated benefit-cost ratio of cloud seeding .................................... 57
6.1 Estimated runoff augmentation ..................................... 57
6.2 Estimated value' of additional water ................................. 58
6.3 Estimated program costs .......................................... 58
6.3.1 Management staff ......................................... 58
6.3.2 Environmental compliance and monitoring ...................... 59
6.3.3 Equipment purchases ...................................... 59
6.3.4 Seeding contract .......................................... 59
6.3.5 Physical observations program ............................... 59
6.3.6 Program cost estimate ...................................... 59
6.4 . Estimated range of benefit-cost ratios ................................ 59

7. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 60

TABLES

Table

4.1 Daily precipitation stations analyzed ...................................... 18
4.2 Hourly precipitation stations available ..................................... 26
4.3 Icing events recorded at Shasta Bally Peak with precipitation observed at Clear Creek . 41
4.4 Estimated hours and seeding increases for Trinity above Lewiston ................ 43
4.5 Estimated hours and seeding increases above Shasta Dam excluding the Pit River .... 45
6.1 Estimated program costs ......................................... 60

FIGURES

Figure Page

2.1 Activity curve of various seeding agents vs. temperature as available in the
published literature ................................................... 3
3.1 Top: American River Basin with SCPP instrument locations noted. Bottom: elevation
transect over the American River Basin ............... .'. . . . . . . . . . . . . . . . . . .. 5
3.2 Cumulative distribution of integrated SLW as measured by a vertically pointing
microwave radiometer at various field site locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3 Icing occurrence as a function of temperature for three mountaintop locations along

the Sierra Nevada ...............;...................................... 8

3.4 Icing hours as a percent of precipitation hours for a mountaintop site in the
Feather River Basin (Red Hill) ............................................ 8
3.5 Simulated seedline widths at times noted on each line, assuming a 1 m s-1

dispersion rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12
3.6 SCPP 1986-87 AgI ground generator network ................................ 14
3.7 Output from numerical targeting model (GUIDE) showing seeding plumes superimposed
over the target area for December 5, 1986, 1200 G.m.t . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1 Shasta-Trinity area map and locations of data collection points used in the analyses. .. 19
4.2 Average annual precipitation (in.) above Claire Engle (Trinity) Reservoir. . . . . . . . . . . . 20
4.3 Average water year precipitation (in.) using daily precipitation records at

Pit #5 Reservoir ...................................................... 22

4.4 Same as figure 4.3 but showing number of days with precipitation above amounts shown

on bottom of figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.5 Same as figure 4.3 but for Shasta Dam ..................................... 23

VI

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