GOUGED HILLSIDE REPLANTED\Native trees, flowers to share building site.

Byline: Michael Coit Daily News Staff Writer

Three years after carving a barren swath across a hillside to build a new treatment plant, the Calleguas Municipal Water District has planted the slope with native trees, flowers, shrubs and other brush.

Now if only they would take root.

Don Kendall, the Calleguas Municipal Water District general manager, said the district planted grass, shrubs and trees late last year to soften the plant's boxy, stark appearance - a source of complaints from a nearby Sunset Hills neighborhood. To spur growth, the district has been watering the landscaping three days a week during a 90-day maintenance period that ends in March.

"That stuff just doesn't grow, and we've been getting a lot of complaints about it," Kendall said.

Neighboring homeowners who look down on the 17-acre site have kept close watch since bulldozers first cut into the hillside along Olsen Road.

The homeowners have never been pleased with the plant's design, but they welcome the agency's landscaping efforts.

"It's taken awhile, but they've responded in good faith," said Brenda Megerle, an East Hill Homeowners Association board member who has worked with Calleguas officials. "I know, from seeing what neighboring homeowners go through, that it will be difficult to grow."

Ventura County planning guidelines required Calleguas to plant vegetation that requires little water for growth. The shrubs include California sage and toyon and the trees include Australian willow, crape myrtle and valley oak. The open spaces have been filled in with a mixture of native grasses, such as oat grass, and wildflowers, such as lupine and the California poppy.

Kendall said the planting effort also keeps with the district's expanded water conservation effort. The district has helped develop reclaimed water systems in Agoura Hills, Oak Park and the North Ranch area of Thousand Oaks. The district also has administered a rebate program to encourage homeowners, schools and businesses to convert to low-flow toilets.

The landscape architect for the treatment plant project said the prominence of the site on Olsen Road could serve as a model for what homeowners and businesses can do in their yards.

"Calleguas has to kind of set the standard," said Mike Gilbert, with Jordan/Gilbert landscape architects. "People will change their opinion a few years down the road."

The native vegetation is intended to appear natural and blend with surrounding hills when mature. The grasses, wildflowers and shrubs will be able to thrive without irrigation in about five years.

"Most of the California native plant material has a tendency to have a slower growth rate compared to some typical ornamentals that you might see in the average home," Gilbert said.

The treatment plant replaced the original chlorination plant used to treat water pumped from Bard Reservoir, behind the Calleguas office on Olsen Road.

Calleguas takes water from the reservoir in summer months when peak demand exceeds supplies available from the State Water Project.

Calleguas built the new plant to meet federal water-quality standards for water stored in open reservoirs.

With the new process, drinking water is treated with ozone gas, blended with chemicals that bind to bacteria, and then pumped through charcoal filters.