Waypoints

 

Eaton Canyon is not just a beautiful hiking location and natural area in the San Gabriel Mountains. It serves multiple purposes to the communities of Pasadena, Altadena, and the county of Los Angeles. There are several pieces of infrastructure that are located within the canyon; high voltage wires, city storm drains and weather stations.

 

High Voltage Towers (orange pins)

 

Visitors to the canyon often note the set of large high-voltage lines towering over the park. These power lines help deliver electricity to our homes. They are owned and operated by Southern California Edison, however the company does not own the land underneath. There are three sets of power lines that traverse Eaton Canyon, two of which carry 220,000 volts each, and another that used to carry 66,000 volts. The smaller line carrying 66,000 volts must be out of operation as the wires abruptly end at the set of towers next to Coyote Canyon. These high tension lines follow the cemented-in Eaton Wash north through the San Gabriel Valley in Temple City and Pasadena before reaching Eaton Canyon. The wires enter the foothills on the east side of the wash before crossing Eaton Creek near the mouth of Eaton Canyon. From here, the high tension wires head west towards La Canada Flintridge.

If you happen to be in Eaton Canyon during a down-sloping Santa Ana windstorm, you may be able to hear these high tension wires roaring overhead, especially near the Mount Wilson Toll Bridge. These high tension wires are designed to withstand winds in excess of 100 MPH given their mountainous location. However, they must be regularly inspected by SoCal Edison to ensure their stability. https://cecgis-caenergy.opendata.arcgis.com/apps/ad8323410d9b47c1b1a9f751d62fe495/explore

 

Storm Drains (blue pins)

 

In addition to housing high voltage lines, Eaton Canyon is also a useful location for storm drains. Eaton Canyon is technically a ravine in the south face of the San Gabriel Mountains and can therefore serve as a good location to shed flood waters. Following the humongous 1938 and 1943 Southern California floods, the Army Corp of Engineers set out to rebuild Los Angeles in a manner that allowed it to shed excessive rain quickly and efficiently. Many of these projects were conducted in Altadena and Pasadena, and Eaton Canyon’s elevation changes were taken advantage of. Today, eight storm drains of various sizes dump into Eaton Canyon’s wash, all of which are below the Mount Wilson Toll Bridge.

 

Eaton Canyon’s storm drain waters begin all the way at the top of Las Flores Canyon in Altadena. Here, the steep slopes of the San Gabriels produce the rarely-flowing Las Flores Creek which runs beside Cobb Estate, a historical mansion owned by Charles Cobb that was torn down in 1959. The water collects in the Las Flores Debris Basin where it begins to flow southeast in a concreted-in channel named the “Rubio Diversion.” On its way to the Rubio Canyon Debris Basin, runoff from the nearby Rubio Vista neighborhood joins this flow. Water from the more frequently flowing Rubio Creek then joins the Rubio Diversion flow in that canyon’s debris catch basin. The water then flows south through the dense urban forest of Altadena towards Holliston Avenue. If there is an extreme amount of water within this channel, a secondary channel will take some of the excess water away and further south into Altadena. However, that doesn’t happen often and even exceptionally high rain totals may not be enough for this secondary channel to be utilized.

 

The flow then continues its journey southeast where water from Gooseberry Creek joins the Rubio Diversion flow. Gooseberry Canyon is a small, little-known canyon located between Rubio Canyon and Eaton Canyon. During this time, most of the water coming in from these channels is from city street runoff. From here, the Rubio Diversion flows directly underneath Altadena Drive beginning at Porter Avenue. Every city block north of Altadena Drive and between Porter Avenue and Crescent Drive drains into the Rubio Diversion Channel. From here, the channel turns northeast and dumps into Eaton Canyon between the Midwick and Pinecrest trailheads. This particular storm drain is the largest drain in the canyon and is responsible for copious amounts of trash within the creekbed. Cleanup crews frequently find Styrofoam, plastics, packaging, and clothing. Anybody who litters trash on any of these city blocks may inadvertently be littering trash in Eaton Canyon should that litter get stuck in storm drains. Typically storms in November and December produce the most amount of trash, as items had been building up all summer with no water to carry them away.

  

Other storm drains are either much smaller or do not enter the park until after the wash passes the Nature Center. All of them, however, are known to produce trash. Each one must be inspected for litter after heavy rainfall. If the litter is not cleaned up, it eventually arrives in the Eaton Canyon’s Debris Basin located south of New York Drive.

  

 Weather Stations (green pins)

The area in and around Eaton Canyon houses 11 official weather stations managed by either the National Weather Service (NWS) or Southern California Edison (SCE). These weather stations include 4 that measure precipitation, 9 that measure temperature, and 9 that measure wind gusts. These stations are well spread out throughout the canyon, including 4 at the base of the mountains, 3 on elevated ridgelines half way up the canyon, and 4 at or near the top of Eaton Canyon. However, there are no weather station within upper Eaton Canyon, only on the surrounding ridges.

These weather stations help meteorologists and climatologists better understand the atmospheric tendencies and conditions of the canyon. Such weather stations have revealed that the windiest part of Eaton Canyon is the Henninger Helipad, while the rainiest location is Camp Hi-Hill just behind Mount Wilson. The hottest temperatures are typically as the base of the canyon in the wash, while the coolest location is at the high elevations of Mount Disappointment and San Gabriel Peak. At night, however, the Pinecrest Gate remains the warmest location.

  

Storm Drain

Weather Station

High Voltage Tower