Rancho Mission Viejo, located in Orange County, is the largest new community in California, and wildfire resilience is a central component of its site layout, building design, and marketing strategy. A long-standing project to convert 25 percent of a 23,000-acre, privately owned ranch, Rancho Mission Viejo (the Ranch) implemented many wildfire resilience tactics before they became state and county requirements. The remaining 75 percent of the site is protected as a habitat preserve, known as the Reserve at Rancho Mission Viejo.
When complete, the Ranch will be home to about 35,000 residents. About 10,000 residents live in 4,000 homes on the site as of July 2020, and the site is approved for 14,000 homes and 5 million square feet of retail and commercial office space.
“Rancho Mission Viejo is at the far urban edge of unincorporated Orange County, adjacent to the city of San Juan Capistrano. There have been wildfires in and around the Ranch. Consideration of wildfires has been part of every major land use decision we’ve made since we started considering developing the property,” says Jay Bullock, vice president of planning and entitlement for Rancho Mission Viejo.
WILDFIRE RESILIENCE SOLUTIONS
Data-informed planning drives the wildfire resilience strategy at Rancho Mission Viejo, which includes a fire master plan, conservation of open space, building guidelines, and strict landscaping and defensible space protocols. The development team began with a fire behavior modeling study, using the Behave software system, to assess risk throughout the entire ranch.
“Consideration of wildfires has been a part of every major land use decision we’ve made since we started considering developing the property.” – Jay Bullock, Vice President of Planning and Entitlement, Rancho Mission Viejo
The results of the study inform the Ranch Plan Fire Protection Program, which was created in 2007 in partnership with the Orange County Fire Authority and the California Department of Forestry and Fire Protection (CALFIRE) as the county’s first pilot test of community wildfire protection plans. The protection program includes requirements for noncombustible construction materials and standards for automatic fire sprinklers everywhere in the community—not just in the riskiest areas.
In addition, “our site density works in the direction of safety,” says Bullock. Residential areas range in density, yet are clustered in neighborhoods. Each neighborhood is surrounded by a 110-foot-wide fuel modification zone (a mix of no vegetation, fire-resistant vegetation, and irrigated vegetation), which is extended to 170 feet near higher-risk areas. Certain plant species (such as pines, eucalyptus, and palms or anything with peeling bark) are prohibited. The typical site plan calls for five- to 10-foot residential backyards of mostly nonvegetated hardscape.
The additional construction cost of making each Rancho Mission Viejo home wildfire resilient was initially between $4,000 and $10,000 when compared with the typical construction cost of a similar, but less wildfire resilient, home.
However, “as wildfire resilient construction techniques and materials become the new normal, the additional cost per home may be down to $1,000 or $2,000—far below the costs builders were facing when the state first introduced these requirements. It’s the cost of doing business in the wildland-urban interface,” says Bullock.
Much of the Ranch is in the wildland-urban interface because of its adjacency to the Reserve at Rancho Mission Viejo, a large habitat preserve that will ultimately grow to encompass nearly 21,000 acres of Rancho Mission Viejo land.
“The Ranch doesn’t feel like anywhere else in Orange County,” says Bullock. “Ranch residents love the access to open space and the beautiful backcountry views of the Reserve, but with this comes the expectation of homebuyers that wildfire has been considered.”