I was exploring the Arroyo, and could see that this secluded spot deserved a cache. GZ is near where runoff from Johnston Lake (well...more of a pond really) meets up with the main channel of the Arroyo Seco. To the North, bridle/hiking trails continue along both sides of the Arroyo. To the East is the trailhead, a large map of the trails in the area, and a drinking fountain. Your olfactory sense will perhaps have detected the Arroyo Seco Stables to the South. Further South, you'll find South Pasadena's Arroyo Park and LA's San Pascual Park.
The cache is a reimagined vitamin bottle. BYOP. Please initial the log, no stickers or John Hancocks...or spoilers. Note the method of concealment, and please put the cache back carefully, as you found it. GZ is off the main bridle/hiking trail, so relax, explore, stroll around.