This Palmdale Ditch thing just intrigues Mom Green. It has been around for over 100 years, is still in use and it seems very few people even know it exists. We have encountered it while geocaching and even retrieved coordinates from it. It runs from Littlerock Reservoir to Lake Palmdale. Our cache Desert Colors (GCR5EA) is near a place where it crosses under the Aqueduct. It even runs near some of the Barrel Springs Trail caches.
Around this spot you can see two tunnels: where it comes out of the hill from the south and where it crosses under the service road.
The cache contains swag mostly for kids and kids at heart.
Good luck and happy caching.