by Sam Dolinar
Starting in 1978 after heavy winter rains obliterated all crossings of the wash between JPL's East Gate Bridge and Devil's Gate Dam, the race course for the Arroyo Seco Freako Microthon was lengthened to 4.2 miles. This course started and finished in Upper Oak Grove (now Hahamongna) Park and crossed the wash twice at Devil's Gate Dam. Once across Devil's Gate Dam, runners continued on the east side of the wash as far north as the foot of the East Gate Bridge before looping back by a different route to cross the dam a second time and return to the start/finish. This route was discontinued after the 1982 race because the Flint Canyon Bridge just west of Devil's Gate Dam was condemned in the early 1980s and later razed.
Here's the map describing the Arroyo Seco Freako Microthon 4.2-mile course used from 1978 through 1982.