WMOD00295

• Title: Guidelines for Cloud Seeding to Augment Precipitation
• Date: 1/1/1995
• Weather Modification - Doc Type: Report

ASPECTS OF PRECIPITATION ENHANCEMENT

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fall, realism was enhanced by considering timing of rainfall, new prices
corresponding to increased yields, associated changes in the cost of pro-
duction and marketing, changes in regional output and personal income,
changes in optimal planting patterns, and proper separation of precipita-
tion effects from those of temperature and technology. The economic
analyses were complicated by the natural va.riability of rainfall (as is the
evaluation of changes in rainfall due to seeding). Despite this, potential
increased direct benefits were estimated to substantially exceed costs,
even with assumptions of price decreases and minimum responses in
yield. For example, an additional 10% in ~;rowing season rainfall was
estimated to increase net farm and range revenues by as much as $43
million (1973 dollars) in Montana (Stroup 1973).
More recently, the economic effects of added growing season rainfall
on High Plains agriculture were examined at the North Dakota Agricul-
tural Experiment Station (Schaffner et al. 1983). This study addressed the
effects within four farming areas spread across the state by creating a
representative farm in each area. It is based on known effects of changes
in natural rainfall on crops. Five objectives were specified:

. Measure dollar values of direct benefits to farmers and ranchers of
added growing season rainfall
. Determine enterprise adjustments needed on the farm and ranch to
respond most profitably to increased rainfall
. Measure the total added direct benefits to the four farming areas and
the state
. Examine the broader enterprise shifts within farming areas due to
added growing season rainfall
. Measure the total impact of added growing season rainfall on the
economy of the state

Depending on the farming area, added rainfalls of 2 em for June-July
and 3 em for June-August were used to determine crop, livestock, and
economic responses. The rain increases would be realized over many
consecutive growing seasons. The added quantities represent much
larger percentage changes for the western than the eastern parts of the
state because the west is normally much drier. Linear programming
models were applied to select the most profitable farm enterprise plans
with normal and added rainfall. Changes expected in yield from 15
different crops and forages and in livestock numbers were estimated.
Five-year average prices for crop and livestock products in each farming
area were used in the economic analysis. An input/ output model based
on actual expenditure of North Dakota businesses was used to account
for spending and respending to estimate responses of other sectors of the
economy (e.g., finance, wholesale and agricultural processing, construc-
tion, retail, real estate, services, households, government).
In 1977-1981 average dollars, the assumed increases in rainfall pro-
duced increases in direct returns over variable costs to agriculture for the