Results from a Winter Cloud Seeding Feasibility Study Conducted for the Lopez Lake and Salinas Reservoir Drainage Basins in Southern San Luis Obispo County, California


  • Don Griffith North American Weather Consultants


winter cloud seeding, cloud seeding feasibility studies, weather modification operations



The San Luis Obispo County Flood Control and Water Conservation District (District) to conduct a feasibility/design study for a winter cloud seeding program to target the Lopez Lake and Salinas Reservoir (LLSR) drainage basins located in southern San Luis Obispo County, California contracted north American Weather Consultants (NAWC) in 2016.  Recommendations from the American Society of Civil Engineers (ASCE 2016) publication entitled “Guidelines for Cloud Seeding to Augment Precipitation” were followed in determining that the proposed project was both technically and economically feasible. NAWC reviewed available information, compiled and analyzed data, and then developed a proposed program design.  Regression relationships were established between November through April precipitation and annual runoff into the two target reservoirs.  Estimated increases in precipitation of 9% or 17%, from an analysis of the long-term effects of an operational cloud seeding program conducted by the Santa Barbara County Water Agency in an adjacent drainage were inserted into the regression equations to estimate average increases in inflow to the two target drainages.  The District provided NAWC with estimates of the value of this augmented runoff. The costs of conducting a seasonal cloud seeding program were estimated.  These steps provided data that could be used to estimate benefit to cost ratios.  NAWC concluded that the proposed program was both technically and economically feasible based upon ASCE 2016 criteria.

Author Biography

Don Griffith, North American Weather Consultants

President North American Weather Consultants Sandy, UT






Technical Notes and Correspondence