Other than rain and fog drip, Alcatraz has no fresh water.

And yet, walk through the gardens at any time of the year, especially in spring and summer, and you’ll see beautiful flowers in bloom. How do we do it?

Alcatraz gets its freshwater in two ways: shipped in from the city, and collected from the rain. The city water is shipped in on a daily basis and is used to supply the entire island: the water you drink, the water you use to wash your hands, the water we clean with, all shipped in. This can be a problem for the gardens as the humans get priority. If the water is running low, our irrigation systems will be shut off.

The tanks on the West Side Lawn. Photo by Tyrha Delger

So, we needed to come up with a way to get water without competing with thirsty guests. This is where the rainwater comes in. The first garden to test out a rainwater catchment system was the West Side Gardens. The large tanks at the back of the lawn collect rainwater from the cellhouse and stores it to be used throughout the summer, and fall. With a maze of hoses, we’re able to connect this system to the entire West Side and water it for most of the dry season. This allows us to be more environmentally friendly with our gardening practices, and also saves the park money.

The solar panels and pump behind the greenhouse. This system allows us to access the 70,000 gallon cistern on the island. Photo by Tyrha Delger

This catchment system was a success, which meant it was time to turn to other gardens. There is a cistern behind the water tower that was thought to provide fresh water to the laundry building during the Federal Penitentiary. Upon removing the covering, we discovered there was over 70,000 gallons of water still in the cistern, enough to water all of the gardens for 10 years! Now there was the question of how to use it, and how to refill it. With a specially designed water pump from WaterSprout, we use a solar panel behind the greenhouse in the Rose Terrace to pump water from the cistern and to the Rose Terrace. From there, the hose is attached to our irrigation system and waters the Rose Terrace. To refill the cistern, we are testing out a method in which we take water from the roof of the Laundry Building and pump it to the cistern. This is still in a trial and error phase, but hopefully we can get it down to an art during the rainy season.

The next development for our water catchment system is to refill the rainwater tanks behind the upper restroom. Currently we have 3000 gallons of water being collected. This supply runs out by early summer and then we revert back to using water barged in from the city. We aim to refill these tanks with the cistern water and keep off imported city water year-round. There may be no natural freshwater on Alcatraz, but with patience and ingenuity, we can make our gardens beautiful with the rain water freely given.