This collection consists chiefly of reports, handwritten notes and typewritten correspondence written and gathered by John S. Longwell. Although a few papers are from his early work (1910-1920) with the U. S. Reclamation Service, the main body deals with projects he became involved with as a consulting engineer, from his retirement in 1950 as General Manager and Chief Engineer at the East Bay Municipal Utility District, until his death early in 1960.