LOCATION Tonner Canyon is the 5700 acre undeveloped canyon that
extends in a crescent shape from the 60 freeway on the north in Diamond Bar in
Los Angeles County to the 57 freeway on the south near Brea in Orange County. It
passes through Chino Hills in San Bernardino County. There are three parts of
Tonner Canyon: Upper Tonner (Tres Hermanos Ranch), Middle Tonner (the former
Firestone Scout Reservation and Lower Tonner (formerly owned by Brea Canon Oil).
JURISDICTION •
Upper Tonner Canyon lies within the jurisdiction of Chino Hills and
Diamond Bar.
• Middle Tonner Canyon is within the Sphere of Influence of the Cities of
Diamond Bar and Brea.
• Lower Tonner Canyon is within the Sphere of Influence of Brea.
The land is within the Sphere of Influence of the Cities of
Diamond Bar and Brea and is located at the juncture of the Counties of Los
Angeles, San Bernardino and Orange. The City of Industry has acquired land
outside its city limits and recently purchased the Lower Tonner Canyon.
Follow this link to see a Map of Industry's lands.
The City of Industry has proposed three massive dams in the hills upstream of
Brea. This dam requires numerous saddle dams to prevent flooding of
neighboring canyon homes and would lie along an active fault line. See the
map below for an aerial view of these plans.
STATUS OF UPPER TONNER CANYON (TRES HERMANOS) In the early 1980’s, the City of Industry bought Upper Tonner
Canyon. They bought it with redevelopment money even though it is neither in
their city nor in a redevelopment area. The land lies in both Los Angeles and
San Bernardino Counties and is not contiguous with the City of Industry. No one
contested the purchase.
Under the San Bernardino County Specific Plan in the early 1980's, Tres Hermanos
was zoned for thousands of houses. Industry’s land was later “down zoned” to 300
houses under the leadership of San Bernardino County Supervisor Larry Walker.
They then began talking about building a water reservoir. When the residents of
the City of Chino Hills passed Measure U in 1999, the zoning was frozen at the
300-unit level. Only a vote of the residents of Chino Hills will allow the
number of residential units to be increased.
STATUS OF middle TONNER CANYON (former firestone scout
reservation) In 2001, the City of Industry bought 2/3 of the Firestone Boy
Scout Reservation in Middle Tonner Canyon. Conservationists offered $1.5 million
more for the land. However, under the leadership of Majestic Realty VP John
Semcken who also served on the Board of the Los Angeles Council of Scouts,
Industry purchased the Reservation. Click the link to
Industry
property photos.
STATUS OF LOWER TONNER CANYON (FORMER BREA CAÑON
OIL) In 2004, the City of Industry purchased lower Tonner
Canyon from Tonner Canyon LLC (formerly Brea Cañon Oil).
Industry has spent $800,000 over several decades planning to build massive
dams in Tonner Canyon that will both store water and generate electricity.
To do so they will need to bulldoze the entire canyon including the former
Firestone Boy Scout Reservation. These series of dams require numerous
saddle dams to prevent flooding of neighboring canyon homes (in the
Country). The most southerly dam would lie along the active Whittier-Elsinore fault.
See the map below for an aerial view of these plans. If you click on the
map it will enlarge.
Industry and Diamond Bar want to build a highway on Tonner Ridge to funnel
Inland Empire traffic into Orange County. The road would sever the Puente
Chino Hills Wildlife Corridor.
