Regarding the Terrero spring (I can’t “comment” from here):
According to [a local], a fire once occurred in an upstream side canyon (trib to the Mora), and it colored the water. The Mora is maybe 1/2-mile upstream on the east side of the Pecos. The spring is on the west side.
So, the source water appears to be the main stem within 1/2 mile upstream of the spring.
(Call it a fortuitous tracer study.)
[Note: the Mora here is a trib to the Pecos, not the Mora on the east side of the Sangres that is a trib to the Canadian]
[Another local] took that culvert photo. I think it was north of SF.
The Red Dot Trail runs below White Rock. Down there, I saw a plumed serpent petroglyph near remnant irrigation ditches (lots of springs). (The “Aztec” Triple Alliance apparently arose only in 1300s.)