The collection consists of correspondence, reports, subject files, news clippings, maps, and other papers, pertaining to: groundwater; surface water supply; water rights; litigation involving Miller & Lux and others; irrigation works; water costs; and, irrigation districts in the San Joaquin Valley, particularly San Joaquin River Water Storage District, Madera Irrigation District,and Madera Canal & Irrigation Company.

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 consists of reports, legal opinions, and comments concerning the Central Valley Project, water districts and reclamation districts, and water rights on the San Joaquin River and elsewhere in California.

The collection consists of the United States Bureau of Reclamation contracts with California water districts, irrigation districts, wildlife refuges, and municipalities.