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Tumamoc Hill, the Desert Laboratory, and Tumamoc Resilience Garden

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Tumamoc Hill, or Cemamagi Du’ag (O’odham), “Horned Lizard Mountain” is a 700’ high hill of volcanic rock with prominent cultural and sacred significance, along with pre-historic, historic, and contemporary water-harvesting systems.

Tumamoc Hill is also an 860-acre ecological/research reserve just west of downtown Tucson.

Tumamoc Hill in background, Tumamoc Resilience Garden water-harvesting basins under development in foreground. Basins will be planted with native food-bearing trees and understory plants.
Scroll down to see a video of how well all these basins worked when they captured all the runoff from a water pipe that broke upstream, and where in the next big rain event runoff from the Hill will flow.
Photo: Brad Lancaster 4-2022

The horned lizard, after which the Tumamoc Hill was named, has evolved to harvest rainwater off its back, from which water runs down gutters between the lizard’s scales to its mouth.

Horned lizard on Tumamoc Hill.
Photo: Brad Lancaster

Ancient people harvested runoff water on the hill’s slopes with stone trincheras/terraces that grew agave and other food crops. In the early 1900s when the Desert Laboratoy’s main building was built, roof runoff started to be harvested from the roof within a mortared stone cistern.

And the Tumamoc Resilience Garden being developed at the base of the Hill today has a foundation of passive water-harvesting earthworks that plants the rain and stormwater runoff.

Video of Tumamoc Resilience Garden water-harvesting earthworks (yet to be planted)

Tumamoc Hill historical timeline

You can walk up the hill (1.5 mile to the top) for a good workout and beautiful views via its paved road (not open to cars or bicycles), as about a thousand people a day do.

All the way up the hill is a rich diversity of food- and medicinal-bearing native plants that can inspire/inform your home and neighborhood plantings. (In the Sonoran Desert there are over 400 native food-bearing plants).

Historic active rainwater harvesting system

Midway up the hill is the main Desert Laboratory building complex began in 1905. There, on the south side of the largest and U-shaped building, is an historic active rainwater harvesting system that has recently been renovated for use today.

Note that water is gravity-fed to the tank from the building’s roof gutter via wet system plumbing painted green.

The above-ground 4-foot tall, 12-foot diameter stone and concrete cistern has about a 2,500-gallon capacity. Photo was taken December 2016 pre-renovation. Harvested water is currently used for irrigation of courtyard plantings.
Photo: Brad Lancaster
Water was gravity-fed to the tank from the building’s roof via this green-piped wet system plumbing. Wet system plumbing always has some water in the pipe, since the pipe goes down from the roof gutter to the ground then back up to the inlet into the rainwater tank. (The water inlet into the wet system pipe at roof gutter is higher than the pipe outlet into the tank, so gravity distribution of the water works). You can see the original faded-green cast-iron plumbing still in place, but on the site today, the old pipe is now disconnected from roof gutter and cistern; and new plumbing is now connected to gutter and cistern.

Note the organ-pipe cactus to the left. Tumamoc Hill has a banana-belt microclimate in that it is warmer than the surrounding Tucson Basin, so less cold-tolerant plants such as the organ-pipe cactus can grow there without frost/freezing damage/death.
Photo: Brad Lancaster, 12-2016 pre-renovation.

The faucet at the base of the wet-system plumbing could drain the system as needed, and provide water for plantings below.
Photo: Brad Lancaster 12-15-2016

All plantings below the cistern can be passively irrigated with a gravity-fed irrigation system. Much cheaper and simpler than a pumped system (the cistern’s pump box is currently a pack rat midden).

All the way up the hill is a rich diversity of food- and medicinal-bearing native plants that can inspire your home and neighborhood plantings. (In the Sonoran Desert there are over 400 native food-bearing plants).

Where:

Intersection of Tumamoc Hill Road and West Anklam Road, Tucson, Arizona 85745
32.226020645481455, -111.00099083540287

Hours: 4am – 10pm

Cost: Free

No pets allowed

Related sites
For another historical rainwater cistern/tank site see the Historic Rainwater-Harvesting Systems at the Shrine of Santa Rita in Vail, Arizona

active water harvesting in tankshistoric water management and infrastructurepassive water harvesting in soil and vegetationrainwater harvestingstormwater harvesting

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