Caltrans intends to plant more than 1 million square feet of freeway landscaping through Riverside that will be irrigated with overhead sprinklers, despite a drought-driven state crackdown on water use.

Agency plans show that the six-mile stretch of landscaping along the 91 freeway, between Adams Street and the 60 freeway, would use 155,620 gallons of potable water per day. The project would draw an additional 39,000 gallons a day in the first year while the plants are getting established.

Altogether, that’s more than a typical California family uses in a year, a fact that doesn’t sit well with some residents.

“All my neighbors are letting their lawns die. It’s awful to see. For the taxpayers to have to (pay to) water landscaping in the highway … while we must forgo watering our lawns is an abomination,” said Barbara Sieg of Grand Terrace, who recommended paving the space with stones or bricks.

A spokeswoman for the Inland Caltrans office, Tyeisha Prunty, said the agency is replacing plants that were torn out in 2012 at the start of a $232 million project to add carpool lanes.

“We’re not adding landscaping, we’re just replacing what was removed,” Prunty said. “It’s less (landscaping) because we are putting in a lot more hardscape. There will be retaining walls where there was greenery.”

Caltrans’ policy is to replace plants removed during construction, according to the department’s landscape inspection manual. Landscaping helps with aesthetics, safety, erosion control and glare reduction, the manual says.

Installation of the 91 freeway irrigation system and plants was planned for this summer, but has been postponed indefinitely because of the heat, Prunty said.

More than half the water used in California goes to irrigation, which has been the target of state efforts to cut consumption 25 percent by next February. Some water officials have warned residents that newly planted drought-tolerant landscaping won’t survive the summer with rationing.

BETTER ALTERNATIVE?

The 91 freeway plans call for hundreds of thousands of containers of freeway daisies, ice plant, bougainvillea and trees. None of them are California natives, which are climate appropriate and use the least amount of water.

They will be irrigated with sprinklers, an irrigation method largely discouraged in the state’s emergency drought regulations unless used with a “smart” irrigation controller that automatically adjusts watering based on weather conditions and soil moisture.

The project calls for smart controllers, Caltrans spokeswoman Vanessa Wiseman said.

Veteran drought-tolerant landscape architect Jean Marsh of Corona takes issue with the project’s irrigation method and plant list.

Sprinkler “water coming down out of the sky is good for plants because it mimics rainfall, but in terms of water conservation, it’s not the best way to go,” she said. “The thing I find very, very frustrating is, why are we planting jacaranda when we could be planting native oaks?”

A better alternative, Marsh said, would be drip irrigation, which can be up to 45 percent more efficient than overhead spray because it is not subject to wind and evaporation. She also recommended planting natives such as toyon, coyote bush, lemonade berry and Alpine Cleveland sage.

“There is such a complete disconnect in terms of folks understanding what was meant to grow here,” Marsh said.

The agency’s chief landscape architect defended the use of overhead irrigation, which he said can still conserve water when used on groundcovers such as ice plant. It also costs less than placing drip heads at each plant and is safer for maintenance staff because having fewer heads to fix means less exposure to traffic, Wiseman said.

CONSERVATION GOAL

Caltrans decreased water use 30 percent between 2013 and 2014, largely through the use of smart irrigation controllers, Wiseman said.

Director Malcolm Dougherty said the agency also has postponed landscaping projects, particularly in the Central Valley, and stopped watering grass with potable water. His goal for the department is 50 percent savings.

The 91 freeway landscape project is connected to 10 water meters through the city of Riverside and five more are to be installed, said Todd Jorgenson, interim assistant general manager. Jorgenson didn’t know how many of the meters were new, but said they were approved in 2011, before the drought was declared.

Recycled water can’t be used on the project because the city’s system doesn’t extend that far east, Jorgenson said.

As California plods into a fourth year of drought, Riverside has been ordered by the State Water Resources Control Board to trim water use by 28 percent. That equates to 20 million to 30 million gallons, Jorgenson said.

At a recently completed railroad undercrossing on Streeter Avenue, the city added 105,000 square feet of plants, some of them drought-tolerant, and all on drip irrigation, with bubblers around the trees, he said.

Postponing the 91 freeway landscaping could help the city reach its state-mandated conservation goal, Jorgenson said. “It certainly wouldn’t hurt.”

Contact the writer: jzimmerman@pe.com or 951-368-9586