Adam Spencer, The Triplicate

The primary reason that the Smith River has such remarkably clear water is the geologic character that forms the basin. Serpentine soils are abundant in the Smith River watershed even though that type of geology is rare elsewhere.

A free field trip introducing the geology and formation of the Smith River will be offered all day Saturday, Oct. 12. Limited space is available and guests must RSVP with trip organizer Connor Caldwell (831-428-2754 or

The field trip will be lead by Dylan Caldwell, who holds a master's degree in geology from Humboldt State University and completed a master's thesis focused on the Smith River and the physical development of the basin.

"What's present in the Smith River is different from the rocks or the type of river you typically see anywhere else," said Dylan Caldwell. "It's the perfect setting to look at a unique phenomenon."

The field trip will not be solely focused on the rocks of the basin, Caldwell said, but it will focus on the "larger picture of the whole physical environment."

There are three main factors that influence geomorphology: rock type, tectonics and the climate.

"We have unique versions of all three of those factors, which produces a one-of-a-kind watershed," Caldwell said.

High annual rainfall and close proximity to subduction zones is common in the Pacific Northwest, but the serpentine soils are the kicker that sets the Smith apart.

The field trip will start Saturday morning in the lower Smith River estuary, progressing upriver with stops along the way, eventually exploring large-scale landslides near Big Flat on South Fork Smith River. Lunch and dinner will be had at Rock Creek Ranch on South Fork Road and camping at the ranch is optional.

The field trip, "Geology of the Smith River: How to Interpret the Watershed's Physical Environment," is presented by the Smith River Alliance and the Del Norte Resource Advisory Committee.

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