The collection consists of correspondence, reports, documents, and memoranda, relating to California's Central Valley Project, Lake Tahoe, East Bay Municipal Utility District, Pacific Gas and Electric Company, and public water and power supply system for other California municipalities.

This collection is composed primarily of research files compiled for Hansen's study of federal-state relations in the Central Valley, which resulted in his dissertation, The Central Valley Project: Federal or State?(also published by the California State Assembly Interim Committee on Conservation, Planning and Public Works as Volume 13, no. 6, of the Committee's reports). Includes extensive interview notes, correspondence, reports, and detailed annotations of sources consulted.

The collection includes correspondence, reports, drafts, notes, legal documents, maps, diagrams, and photographs relating to geologic investigation done for the Pacific Gas and Electric Company and other firms and agencies. The more important projects include Bodega Bay Atomic Park, Diablo Canyon Nuclear Power Plant, and Union Valley Dam. Also includes material on water disputes in Southern California.