Highway 1 Red-legged Frog Pond

Pacifica, CA

Caltrans
Fall 2000

Designed by District 4, this endangered species habitat was constructed in preparation of roadwork along Highway 1.  Red legged frogs will be relocated from a farm pond in the path of road construction to this temporary habitat, to be returned once the work is complete.

Hanford ARC implemented the design, which included installation of a concrete diversion structure, grading of a swale and pond, and erosion control.  Caltrans completed the planting following earthwork.

A perimeter barrier of keyed, overlapping plywood and t-posts was constructed around the graded area. This barrier served to prevent species from entering during construction, and to contain introduced frogs following construction.  The pond configuration included a low bench at the perimeter and an outlet swale controlling the water surface elevation.  Hanford ARC also placed a pre-cast concrete stop-log diversion structure that will allow controlled flow into the pond.  During this installation, a gravity stream diversion functioned to bypass the perennial flow in the source channel.