Ahart Preserve

Placer County, California

Foothill Associates designed and supervised construction of 1.26 acres of vernal pools on soils derived from the Mehrten Formation. This soil has an unusually thin soil over cemented volcanic mudflow. The thin soils and the presence of existing wetlands required special care in construction management. Five performance monitoring periods spanning ten years were required to comply with conditions of the Biological Opinion and Nationwide Permit. Wetlands met hydrology and vegetation performance standards.


Hardpan layer allows water to pool in the rainy season.


Vernal pool flowers as water recedes.