[caption id="attachment_12528" align="alignleft" width="216"] Airport Business Center north of Santa Rosa plans to modify landscaping around its monument signs, such as this one at the corner of Airport and Skylane boulevards, to comply with a call from Windsor for 50 percent reduction in irrigation.[/caption]

Landscapers and commercial property owners are making tough choices on how to maintain curb appeal while complying with new local rules for cutting irrigation by up to half this summer to avoid a state ban next year on watering.

Developers of Airport Business Center, a 469-acre business park near Sonoma County Airport, are rallying their property owners and tenants to cut back collective irrigation usage to 50 percent of 2004 levels, so turf will have to go brown to save water for trees and revenue-generating operations.

The Windsor Town Council, whose water serves the business parks, on July 1 approved the reduction as part of a goal to cut total town usage by 25 percent.

"The goal is to move to serious water conservation in business parks," said Carolyn Wasem, whose family is one of the owners of Airport Business Center.

For RNM Properties, which has been developing hundreds of thousands of square feet of commercial space in south Petaluma, the choice was turf or trees. The Petaluma City Council on July 1 called for a 15 percent voluntary water reduction.

"We can let our frontage non-usable turf go dark, but then we have to worry about the trees," said Jamie Milliner, director of project management. "We'd have to modify irrigation all over the place to save the trees."

Another major challenge with cutting off water to turf is that surrounding trees will require more water than they normally would for a given species, even if mature, according to Dave Penry, co-owner of Pacific Landscape.

The cost of modifying the sod and the irrigation at a time when about a third of Petaluma office space is available for lease is challenging, he said. RNM isn't planning to tug out its turf.

"Nobody wants to spend money, especially now in this business climate," he said.

Fortunately, RNM in the past few years installed high-tech irrigation controllers from Petaluma-based HydroPoint that continuously receive local climate data from satellites to calibrate watering. Mr. Milliner is hoping that calibration will help.

Some help with the landscaping changes is available. The Sonoma County Energy Independence program offers financing for water-conservation retrofits through property-tax payments. And some jurisdictions, such as Windsor and Santa Rosa, offer rebates for turf removal.

The State Water Resources Control Board in April decided Windsor and other cities that buy Russian River water from Sonoma County Water Agency must submit proof that they are meeting an overall 25 percent reduction in irrigation use between June 15 and Oct. 2. This reduction is based on the amount of water plants use in various weather conditions, a measure called evapotranspiration, or ET.

Trouble is, ET measurements based on old weather stations can be a week or more out of date, which for the cool-hot summer weather cycles of the North Coast can lead to inaccurate irrigation, according to Mr. Penry.

In April, the water agency called on the water board to limit the amount of water released from Lake Mendocino into the Russian River as the lake level dropped rapidly after a relatively dry winter. That reservoir and Lake Pillsbury are major sources for water agency pumps in the Russian River because of limitations on how much water can be released from Lake Sonoma as protected fish migrate up Dry Creek and its tributaries.

The challenge with implementing the irrigation cutbacks is that local governments involved largely haven't had control or enforcement measures in place to the degree needed. Windsor's utilities records go back to only October 2004, so Airport Business Center has called on landscapers that serve the park to use water meter readings to create and follow irrigation budgets.

About one-third of the business park is involved in the conservation effort so far. For the 80 tenants managed by Airport Business Center, water consumption was 47,000 gallons for one month this year, compared with 247,000 gallons for the same users in the same month of 2004, according to Sheree Meehan, senior property manager.

Santa Rosa started requiring water budgets with its 1992 Water Efficient Landscape Policy, which was recently updated, and North Marin Water District, also mandates such budgeting. Rohnert Park just implemented a 25 percent reduction based on an ET-based budget for a given site, and Cotati is working on such budgeting.

At a presentation for airport-area landscapers, tenants and owners in mid-July, several tenants said they don't use Windsor water because they have irrigation wells.

However, use of garden and municipal wells could be in jeopardy long-term, as state water regulators increasingly study certain groundwater as river "underflow" and thus connected to the Russian River watershed, according to Mr. Penry of Pacific Landscape. He represented the California Commercial Landscape Association at the state water board hearing in April.

And reining in commercial property irrigation isn't just a Sonoma-Marin matter. Owners of property in southern Napa Valley have been wrestling with water restrictions looming with another regulation-based artificial drought, reductions in water supplied from the Bay-Delta system. American Canyon obtains some of that water, yet Napa Sanitation District does supply treated wastewater to the Napa County Airport-area business parks.

A planned recycled water geothermal and irrigation pipeline would get to Sonoma County Airport properties in 2011 at the earliest.