A few weeks ago, we answered a reader’s questions about the mound of dirt at Airport Boulevard and Highway 101 north of Santa Rosa. That prompted another reader to ask about the pile of dirt at Highway 12 and Farmers Lane. What’s it for?

Caltrans spokesman Bob Haus says the dirt, which came from the widening of 101 between Santa Rosa and Windsor, was being saved to be used on the Wilfred Avenue overpass project in Rohnert Park. But he said engineers decided to use dirt from a source closer to the Wilfred project. Now, the 12/Farmers Lane dirt is destined to be used in the remake of the Airport Boulevard interchange, such as building up embankments. That $45.8 million project is scheduled for construction in spring 2012 with completion about two years later. So the 12/Farmers Lane dirt is sticking around for a while.