Water Rights and Adjudications
Since 1974, HRA has been providing historical expertise in complex water rights litigation and adjudications. Our research helps attorneys, tribes, and federal agencies support or challenge claimed priority dates.
Our historians conduct research in federal and state archives, state engineer offices, government documents, special collections, and private manuscript collections. From these records, we prepare comprehensive, well-documented reports to explain the history of land and water use in a given watershed in order to help determine the legitimacy of water rights claims.
Our services include:
- Investigation of water rights filings
- Detailed histories of irrigation and reclamation projects
- Research concerning federally reserved water rights
- Assistance with discovery and records management
- Preparation of exhibits for trial, including in electronic format
- Expert witness testimony

Featured Members
Featured Projects
Arizona v. California (Fort Yuma Indian Reservation Water Rights)
Working with the U.S. Department of Justice on behalf of the Quechan Indian Tribe, HRA historians researched and prepared a report analyzing the history of land ownership and water use on the Fort Yuma Indian Reservation in California from the 1880s to the 1950s.
Little Colorado River Basin Adjudication, Arizona
HRA historians have worked with the Navajo Nation for nearly three decades on various aspects of the Nation’s water rights claims in the Little Colorado River (LCR) Basin in Arizona.
Snake River Basin Adjudication
For the U.S. Department of Justice and the Bureau of Reclamation (BOR), HRA conducted research and prepared reports for a number of specific water rights cases in the Snake River Basin Adjudication.
Litigation Support
Contaminated Sites
HRA helps clients identify companies, government agencies, and other entities that may be responsible for the cleanup of Superfund and other contaminated sites.
Expert Witness Services
HRA historians have served as expert witnesses in litigation, as well as providing research and writing support for outside experts.