The collection consists of project files, reprints of articles, technical reports, student term papers and projects, correspondence, photographs, maps, drawings, etc., compiled by J. W. Johnson during his career as a professional consulting engineer and professor of hydraulic engineering. Includes material relating to wave studies, littoral drift, sedimentation, flow of water, hydroelectric plants, harbors, breakwaters, jetties and other hydraulic structures, navigation channels, and shoreline stabilization in California, South America, Australia, and elsewhere. Of particular significance are studies of the mouth of the Russian River, Bolinas Lagoon, the Hawaii tsunami of April 1, 1946, the San Francisco ocean outfall at Ocean Beach, the Santa Ynez River Bridge, and coastal projects in the United States.

The collection also includes Johnson's research files and notes compiled for his two major "hobbies:" the history of hydraulic engineering in California and pioneer photographer Carleton E. Watkins. These files include extensive correspondence, copy prints of photographs, research notes, articles, newspaper clippings, etc.