NORTHEAST GLENDALE — A row of four mature eucalyptus trees at Glorietta Park will be removed Monday after years of unsuccessful attempts to keep their roots from damaging the city’s second-largest underground concrete reservoir, city water officials said.
Roots from the trees — which line the east side of a softball field along Verdugo Avenue — have slithered into tiny openings in the reservoir’s wall-to-ceiling joint, expanding to create cracks that have compromised the assured quality of the water inside, said Pat Hayes, principal water engineer for Glendale Water & Power.
“Trees are very good about finding wherever there might be water sources, and they’re pretty invasive,” he said.
Engineers have tried to stop root intrusion with root-barrier materials several times over the past few years, but each time the roots have found the concrete structure, water services administrator Peter Kavounas said when presenting the plan to the Glendale Water & Power Commission last week.
Cracks in a reservoir mean irrigation and ground water can get into protected water supplies. Regular monitoring of the reservoir’s water has revealed “bacterialogical issues with it, but not to the point of affecting the usability of the water,” Hayes said.
While disinfection materials have historically been sufficient to take care of the issue, he said engineers are eager to reseal the reservoir and neutralize the likely source of the contamination.
“Our job is to make and keep these water structures as tight as possible,” he said.
Crews will spend Monday cutting down and removing the trees — which stand at least two stories tall — before taking two weeks to remove the 2 or 3 feet of topsoil above the concrete reservoir for repairs.
That large reservoir, with a capacity of 22.7 million gallons, is 25 feet deep and encompasses nearly the entire footprint of the park east of the concrete aqueduct, according to the utility.
Comparatively, the underground Chevy Chase Reservoir that is in the process of being uncovered for a $22-million replacement project had a capacity of 14.5-million gallons.
Water officials expect repairs to the concrete joint to cost substantially less and require fewer resources.
“It’s fairly trivial once you get to it,” Hayes said.
The city’s parks department will replace the trees with a “California-friendly” garden, which will feature native plants that require minimal or no irrigation.
Once the sloping garden has taken root and had time to mature, parks officials said it will be entirely self-sufficient and require no irrigation.
As Margerie Shia stopped for a break from jogging along the row of trees Friday, news of their removal was met with sadness from someone who has used the adjacent softball field in the past.
“That’s too bad because it’s like a wall of green right here,” she said.
“But I guess water’s more important than looks.”
City officials expect the project to take about two weeks.
JASON WELLS covers City Hall. He may be reached at (818) 637-3235 or by e-mail at email@example.com.