California's lingering drought is putting pressure on city officials to be better water stewards as they maintain Balboa Park's lush landscaping. The park's historic buildings may be part of the answer.
Casa de Balboa sits in the heart of San Diego's premier park. The building is surrounded by lush vegetation, but the plants that grace the grounds of this civic centerpiece are thirsty. With water scarce and expensive, park officials are looking for options.
One of them may be on top of the Casa de Balboa building, where we find Friends of Balboa Park volunteer Jim Hughes. He said this building could be a significant source of new water.
"Between this building and the adjacent building, we may be able to capture 90,000 gallons of water per month, averaged over the year," Hughes said.
The mostly flat roof has a wall around the top. Water would build up here if it couldn't find a way to get off the roof, so architects installed drains. When it rains, water rushes to the low spots, pours into the drains and flows to the city's sewage system.
"We're trying to capture the water runoff," Hughes said. "That's both rainwater, dew water and mechanical condensate water. We're trying to capture that water. And instead of it going down a city drain pipe into the wastewater system, we want to use it for irrigation in a nearby garden area."
But when the San Diego region's average annual rainfall is around 10 inches, and it is even lower in the midst of a prolonged drought, relying on the weather isn't a practical water solution.
That's why Hughes said they are also taking advantage of another source of water on the roofs, the air conditioning units. Keeping the buildings cool in the summer creates a lot of condensation and that moisture is already being captured.
"They come out and they flow down here. They collect. The water runs down by gravity and will eventually end up in the condensation drain line. And this is water that's going right into the city sewer system," Hughes said.
Crews will install new pipes that divert the runoff and funnel it to a holding tank, he said. That tank will be built on the side of the Casa de Balboa building.
Once the system is in place, the captured water will feed the landscaping in a pocket garden that's right next door.
The project is a small part of a complete water infrastructure survey of the park being done by San Diego State University students.
"As we start looking into the future, we're going to have to start to identify areas for water conservation and efficiency strategies. And we have to manage the park in an increasingly sustainable way," said Matt Rahn, an SDSU environmental services professor.
The students hope to eventually quantify just how much water is consumed in the park. and the hope is that the information will open the door to more water-saving projects.
"We have aging infrastructure and increased demand on water resources throughout Southern California and indeed throughout the western United States," Rahn said. "And so this is an opportunity for the city and Balboa Park to serve as a model for the rest of our community on how to manage its water infrastructure."
This project is limited to one small corner of the park, and it is largely benefiting the Zorro Garden. But the San Diego Women's Foundation is hoping the project can extend its reach to spread the water wise message. The organization approved a $40,000 donation because the project includes a public information display at the Reuben H. Fleet Science Center.
"Because it's Balboa Park and our centennial, there will be a lot of people coming through the park this year," Marjorie O'Malley said. "And it will be terrific to have them see that we do care and are looking at different ways to conserve water."
Friends of the Park officials said if this demonstration project works, they'll look to expand the effort. The idea is to capture and use water that would otherwise be flushed away.
