New state figures show Napa County lost 998 acres of farmland between 2012 and 2014, an area roughly equivalent to the size of Skyline Wilderness Park.
The California Department of Conservation released the data this month. The agency has tracked farmland gains and losses throughout the state since 1984.
Whether the report sounds any alarm bells for a county devoted to agricultural protection is a question mark. Some of the farmland gave way to homes and development, some to Napa River habitat.
“I think concern is always warranted,” county Planning, Building and Environmental Services Director David Morrison said. “It keeps you alert and on your toes.”
But some counties see thousands of acres being converted, Morrison said. Napa County’s historic land-use policies continue to prove successful, he said.
Napa County had 255,177 acres of farmland in 2012 and 254,179 acres in 2014, the state reported. That accounts for the 998-acre loss, a drop of less than four-tenths of one percent.
To put things in perspective, the county has 75,192 acres classified by the state as “important” farmland and 178,987 as grazing land. Almost all of the 998-acre loss came from the “important” category.
The report depicts a complicated and fluid agricultural situation, with some farmland going out of production and some coming into production. The urban land category added 521 acres for a total of 24,055 acres and the “other lands” category added 479 acres for a total of 204,275 acres.
“Other lands” includes low-density, rural-residential development, vacant areas, mining areas and non-agricultural vegetation.
A state Department of Conservation report mentioned no single, big new subdivision as the reason for the county’s farmland loss. Rather, the redesignations from agricultural land to other categories came in dribs and drabs.
The state looked at large rural homes with vineyards near cities and decided they belonged to the urban category. St. Helena Montessori saw new construction, for example. The state decided Trinchero Family Estates in St. Helena had enough structures to qualify as urban.
“Standards for conversion of farmland are pretty tight,” Morrison said. “In the state’s view, if you have a 10-acre parcel and you have five buildings, the entire parcel is urban.”
The state report listed 121 instances of changing irrigated farmland to the category of “other lands.” Some involved farmland becoming large estates, others involved farmland now being mapped as riparian habitat along streams and the Napa River.
Urban land acreage grew in part because cities developed properties within their borders that the state hadn’t previously categorized as urban. One example is the 12-acre Century Theater development that debuted along Imola Avenue in Napa in November 2012. Another is the building of solar arrays and athletic fields on 18 acres at American Canyon High School.
The state Department of Conservation also listed 14 acres with a water treatment plant and ponds on the southwest shore of rural Lake Hennessey reservoir as now being urban.
Napa County saw rare instances of urban land being switched to farmland, a total of 187 acres. This included 33 acres of new vines at the Chardonnay Golf Club and 18 acres at the Eagle Vines Vineyards & Golf Club.
Changes from urban to farmland also came about simply because the state had more detailed digital imagery to see urban boundaries.
The Department of Conservation also provides a longer-term view of county land use changes. From 1984 through 2014, the county lost 6,918 acres of farmland, an average of 231 acres annually. It gained 6,605 acres of urban land or 10 square miles, an area about twice the size of American Canyon.