Over the Easter holiday I had the chance to visit Grand Falls about 35 miles NE of Flagstaff, AZ on the Navajo Reservation. It's more commonly known by photographers as Chocolate Falls because of the color of the very muddy water flow. It's really worth a visit, however the flow only occurs during the spring melt and sometimes during a summer monsoon (which I wouldn't recommend). At present its flowing nicely as you can see in the attached HDR images taken with a Nikon D800, 24-70mm f/2.8 lens and a 3 stop GND filter.
I had only recently become aware of this place despite having lived in northern Arizona for nearly four years. In the past week I asked several life long residents of Arizona if they knew of this place and the vast majority had never heard of it before despite their considerable travels. Even though its not well known, you will likely encounter a fair number of visitors (many with tripods) on any given day when the spring melt is in progress. The Thursday evening I was there there were about a half dozen others still present just before sunset.
It's about an 8.5 hour drive from San Diego. Look for it on maps about 30 miles north east of Flagstaff. Once arriving in Flagstaff via I40, locate well marked Leupp Rd and proceed to Indian Route 70. Continue on Route 70 for about 9 miles and look for a dirt road on your left with a sign for Grand Falls Church. Proceed about 6 miles on this dirt road. There will be a dirt road/trail on your left a few hundred yards before the main dirt road ends at the Little Colorado River. The turn onto this last section is extra rough. A high clearance vehicle recommended especially in this section. If necessary walk quarter mile to the falls. There are picnic kiosks and plenty of places to park at the falls.