The Warner Springs route: Temecula to Ranchita

The green line on the project map, traced through Temecula, along Temecula Creek past Vail Lake and Aguanga, then down the Highway 79 corridor through Oak Grove and Warner Springs, and on past Lake Henshaw and Ranchita. Green dots mark illustrative tower positions about 1,600 ft apart. The Ranchita stretch is shown as a wider, approximate band.

Why this matters

Fire country, end to end

Power lines can start wildfires. Cal Fire found that SDG&E power lines started the 2007 Witch, Guejito and Rice fires in North County. This route would run towers up to about 200 feet tall through the chaparral and grassland of the Temecula Creek and Warner valleys, beside the one highway many residents would use to evacuate.

Walk the dots

Dot – of –

Base map

Place names and minor roads on the aerial

Layers

Highway 79 and roads off itBold yellow for 79, white for the roads that join it, gray for other main roads Orange haze: the line’s magnetic fieldDims the base map so the field stands out Green dots– tower positions about 1,600 ft apart, numbered west to east Line through the dots Position ringsGround each dot could really be on Parcel lines and APNsLive county data for San Diego and Riverside counties; loads when zoomed in

Ranchita stretch (approximate)The route from Lake Henshaw east past Ranchita, traced from SDG&E’s overview map; accurate to about half a mile South Mountain alternative (blue)The other route on the project map, for comparison Project map, rectifiedFade it over the base map to check the fit

60%

What the orange haze shows

Under the line
~87 mG100 ft
~13200 ft
~3350 ft
~1

Typical published magnetic-field levels for a 500 kV line at average load, in milligauss (mG). A typical home reads about 1 mG. The solid orange edge, about 195 ft out, is where the field falls to 3.5 mG. That's the middle of the 3–4 mG range where some studies found childhood leukemia about twice as common.

Parcels near the line

Key

Illustrative tower position on the traced line, about 1,600 ft from the next Position ring: 660 ft radius (1,000 ft west of Vail Lake) Highway 79 Named road that joins Highway 79 Ranchita stretch: approximate corridor, within about half a mile South Mountain alternative, for comparison Assessor parcel boundary Parcel on the “near the line” list

The science, in detail

The World Health Organization's cancer agency (IARC) classifies power-frequency magnetic fields as possibly carcinogenic to humans (Group 2B). That rests on pooled studies finding childhood leukemia about twice as common where children's average exposure is above 3–4 mG. Along a 500 kV line, that level reaches roughly 200 ft from the centerline.

A cause-and-effect link has not been established, and the international exposure guideline for the public is 2,000 mG. The haze uses typical published values for 500 kV lines (87 mG under the line, 29 at 50 ft, 12.6 at 100 ft, 3.2 at 200 ft, 1.4 at 300 ft); real values depend on the tower design and how much power the line carries.

How accurate this is

Parcel lines are exact; the line is not. The green line is traced from a photo of the project's corridor-level map. No engineered alignment or tower sites have been published. The dots are spaced evenly at about 1,600 ft, the middle of the 1,400 to 1,800 ft span range reported for this project; real spans vary with terrain.

The photo was placed on the map by fitting the blue South Mountain line it shows to that line's known position (RMS fit about 140 ft), and its Riverside–San Diego county line to the Census boundary (within about 60 m). From Vail Lake east, positions should be good to roughly 600 ft. West of Vail Lake, in Temecula, the photo is farther from those reference lines, so allow up to about 1,000 ft.

Turn on the project map layer and fade it to judge the fit yourself. Its roads and county line should sit on the real ones. The line continues west out of frame past Temecula. At its east end it meets the South Mountain alignment near Lake Henshaw.

Sources: project corridor map (photo); U.S. Census Bureau TIGER county boundaries; SANDAG/SanGIS and County of Riverside parcels and address points; road lines © OpenStreetMap contributors; Esri and USGS base maps; magnetic-field values from published typical 500 kV profiles; IARC Monograph 80 and WHO Fact Sheet 322.

How close is my property to the line?

San Diego or Riverside County. Or tap anywhere on the map.

move the pointer over the map