OK, I've been trying to dig up more info on that pipeline. Here's what I'm finding out.
The start of the pipeline is indeed at "Mountain Spring" on Tom's Thumb trail at trail marker TT13. It's interrupted (opened) at the oasis where the running water crosses the trail, as johnlp points out. It picks up again across the trail, on the north side of the oasis then flows down eventually to near that big house at 33.670994N 111.838012W. There used to be a tank where one of those homes is now. And just up the hill from those homes, there was a prospect. The tank was a watering hole used when driving cattle south from Brown's ranch toward the railyards in Phoenix. Up until just about 15 yrs ago, that area was still widely used by ranchers to free range their cattle. There is still a rancher just north of the new Tom's Thumb trailhead who allows his cattle and horses to free range through the preserve and through McDowell Mtn Park to the east.
But back to the pipeline...
Some info I found on the interwebs:
"The spring used to supply water to Brown's Ranch. A concrete water trough, with what looks like "EO Brown, 7-14-1923" carved into it, can still be seen near the spring. On the way up, you'll see the rusted remains of the metal pipes that brought water down from the mountain to thirsty cattle and people. You'll also see newer, plastic pipes that carry the water down now. I'm not sure where that water is going, or who is using it- the golf course, perhaps? There is even a spigot where you can turn the water on and off- just watch out for the bees that are attracted to the water that drips into a puddle under the spigot."
and
"On the way up, you'll pass the remains of some kind of rock shelter. It will be on the right side of the trail. Take a breather and look at the names and dates carved into the rocks there."
and
"The petroglyphs can be found alongside the trail, below the spring. I actually walked right past them on the way up. There are small, orange flags marking the petroglyphs all over the rock outcropping. Be careful not to step on them, or touch them, or disturb them in any way.
Across the gully, high on a steep hillside, are what I consider to be the best petroglyphs I've seen in the area. There are a number of representations of what appear to be antelopes, or ibexes, or some similar mammal. You'll have to climb and scramble up the steep hillside to see these petroglyphs, so be careful and use some common sense."
I have never seen the concrete trough, plastic pipes, remains of a stone shelter, orange flags or petroglyphs. But you can bet the next time I go up there, I will certainly look more intently for those remnants of man made-ness. Not sure how I feel about orange flags. I think if those are present, they're asking for trouble.
There is still a seperate pipe that I can't account for at 33.670116N 111.835287W. That pipe runs from somewhere south of the houses, downhill, northward toward the houses (the former tank). There's a bit of a game trail leading both directions parallel to that pipe. But I don't like to go off trail and tramp around in the more undisturbed areas (and it's illegal). So I won't be able to investigate that one much further.
Pipeline CROSSING the Desert Park to Tom's Thumb cutoff. Looking generally EAST, toward Tom's Thumb -
Same pipeline looking NORTH toward the luxury home, former tank -
Same pipeline looking SOUTH toward the MSP, toward Horseshoe Mtn.
Sgt Lumpy - n0eq
