WMOD00298 ‎(2)‎

• Project Name: Project Skywater
• Title: Project Skywater - Fiscal Year 1979 Report
• Prepared By: US Department of Interior Bureau of Reclaimation
• Date: 3/1/1981
• Weather Modification - Doc Type: Report

Contract Summaries

CONTRACTOR: Pacific Southwest Forest and Range Experiment Station, Forest
Service, U.S. Department of Agriculture, Berkeley,Cal ifornia
CONTRACT NO. 6-07-DR-2 010 (Interagency Agreement)
PRINCIPAL INVESTIGATOR: James L. Smith
CONTRACT PERIOD: July 1, 1975, to September 30, 1982
FY79 FUNDING: $55,341
PURPOSE: Study of the effect of winter precipitation augmentation on snowpack
and ecolog in the Sierra Nevada

The long-term goal of the Sierra Ecology Project is to project and assess the
possible effects of additional precipitation and melt water produc'ed as a
result of the SCPP on t e Sierra Nevada environment. Inferences about
possible effects based n historical snowpack and precipitation data will be
superimposed on climati and geologic patterns, soils, vegetation,: wildlife,
and natural and man-caused disturbances in the region. Recommendations for
additional research, fu ure environmental monitoring activities, and criteria
for evaluating SCPP res arch results are direct products of the Sierra
Ecology Project.

The effects of a possib e 5- to 7.5-percent increase in winter precipitation
on Sierra Nevada ecosys ems are believed to be undetectable under the usual
plot-type study. Becau e of this factor, teams of specialists con~ucted
state-of-the-art examin tions in 1978 of expected effects on: (1) forest
diseases and insects, ( ) vegetation, (3) deer herd migration and fawning,
(4) hydrologic processe , and (5) lake and stream biota. A report on the
first three workshops w s publ ished in fiscal year 1978. During fiscal year
1979, the Pacific South est Forest and Range Experiment Station supmitted
reports on the final tw workshops for publishing by Water and Power. These
reports comprise Volume II of the Sierra Ecology Project report series.

The report on Workshop V reviews the hydrology of the American River Basin,
including inputs of sed "ments and nutrients in the watershed. Workshop
participants proposed r search and monitoring recommendations and concluded
that precipitation incr ases expected as a result of the SCPP will not
significantly alter exi ting nutrient and particulate matter in th~ watershed.
Benefits may be realize at certain elevations because increased snow may
enhance the snowpack's ater-holding capacity.

Workshop V participants reported that lake and stream biota would rot undergo'
significant change as a result of SCPP cloud seeding. The group concluded
that streamflow tempera ures at high elevations in the study area might
remain lower during ext nded snowmelt due to increased precipitation. In
addition, exotic fish p pulations introduced to lakes in the regio~ may
increase at the expense of native trout species if weather modification
results in less year-to year stream and lake level fluctuations. However,
fluctuations due to ext nsive hydroelectric power generation may n~utralize
this effect. The scien ists also reviewed silver iodide monitorin$ techniques.

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