Santa Ana Watershed Weather Modification Project

2 Documents in Project


SCH Number
Lead Agency
Santa Ana Watershed Project Authority (SAWPA)
Document Title
Santa Ana Watershed Weather Modification Project
Document Type
MND - Mitigated Negative Declaration
Document Description
The Project is a four-year pilot project that would include the installation and operation of 15 ground-based weather modification units throughout the Santa Ana River watershed to increase precipitation in the region. The Project would be operated for four years. Two types of ground-based cloud seeding methods would be used: North American Weather Consultants (NAWC) proprietary automated high output ground seeding (AHOGS) systems and ground-based cloud nuclei generators (CNGs). AHOGS are triggered by the Project meteorologist operating remotely; once triggered the units burn flares that rapidly release a concentrated amount of silver iodide (NAWC 2020). These generators are used for seeding convective bands with high concentrations of supercooled liquid water and strong vertical updrafts. CNGs are manually-operated systems that burn a solution of silver iodide and acetone to create a constant cloud of seeding material that provides broad coverage over mountainous terrain with strong orographic effects.

Contact Information

Mark Norton
Agency Name
Santa Ana Watershed Project Authority
Job Title
Water Resources and Planning Manager
Contact Types
Lead/Public Agency


Orange, Riverside, San Bernardino
Countywide, Southern California
Other Location Info
The project involves installation of 15 weather modification units in the Santa Ana River Watershed. These proposed locations have been chosen based on their upwind proximity to high precipitation target areas as follows: • Northwest: The northwest target area bordering Los Angeles and San Bernardino Counties encompasses a portion of the Central Transverse Ranges, to the west of the Interstate (I)-15 freeway. Estimated average seasonal runoff: 25,000 acre-feet (AF). Four sites are proposed in this area, two sit just south of the Transverse Ranges on the Angeles National Forest just north of the 210 freeway, and two are located south of the 210 freeway. • Northeast: The northeast target area target area in San Bernardino County encompasses the area of the Central Transverse Ranges east of I-15, extending down to I-10 north of Palm Springs. Estimated average seasonal runoff: 65,000 AF. Six sites are proposed within or just south of the Central Transverse Ranges on the San Bernardino National Forest. • Southeast: The southeast target area includes the mountains in Riverside County centered just to the west and southwest of Palm Springs. Estimated average seasonal runoff: 10,000 AF. Three sites are located at the base of the San Jacinto Mountains. • Southwest: The southwest target area includes the mountain range that lies on the border of Orange and Riverside counties. Estimated average seasonal runoff: 5,000 AF. Two sites are near the base of the Santa Ana Mountains.
Other Information
List of Sites and Coordinates is below Waterwise - CBWCD 34.078103, -117.704509 Upland - CBWCD 34.101183, -117.695932 SAWC-1 34.137955, -117.639953 SAWC-2 34.156470, -117.671847 EVWD 34.136848, -117.188404 Thousand Pines Christian Camp 34.249539, -117.278552 Sycamore Water Plant 34.186745, -117.309273 SBVWCD-1 34.070031, -117.114747 SBVWCD-2 34.107975, -117.099455 San Gorgonio Pass Water Agency 33.975799, -116.981613 EMWD - N 33.780236, -117.072465 EMWD - S 33.668970, -116.970352 Mary Lea Gardiner 33.536251, -116.805057 Irvine Ranch Water District 33.776528, -117.754128 El Toro Reservoir 33.6234824, -117.6697852

Notice of Completion

State Review Period Start
State Review Period End
State Reviewing Agencies
California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Habitat Conservation Planning (CDFW), California Department of Fish and Wildlife, Inland Deserts Region 6 (CDFW), California Department of Fish and Wildlife, South Coast Region 5 (CDFW), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Transportation, District 12 (DOT), California Department of Transportation, District 8 (DOT), California Department of Water Resources (DWR), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, Santa Ana Region 8 (RWQCB), California State Lands Commission (SLC), Department of Toxic Substances Control, Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality
Development Types
Other (Weather Modification Project)
Local Actions
weather modification pilot project
Project Issues
Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Mineral Resources, Noise, Population/Housing, Public Services, Recreation, Schools/Universities, Solid Waste, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire
Local Review Period Start
Local Review Period End


Draft Environmental Document [Draft IS, NOI_NOA_Public notices, OPR Summary Form, Appx,]
Notice of Completion [NOC] Transmittal form

Disclaimer: The Governor’s Office of Planning and Research (OPR) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at or via phone at (916) 445-0613. For more information, please visit OPR’s Accessibility Site.

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