Water Rights & 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


Theodore Roosevelt Dam on the Salt River in Arizona. Our work in water rights litigation and adjudication often involves researching the history of large-scale federal irrigation and flood control projects.

Featured Projects

Fort Yuma

Fort Yuma Construction of the Laguna Dam at the edge of the Fort Yuma Indian Reservation in California. HRA’s research on Indian land ownership and water use as played a critical role in water rights litigation. As part of the Arizona v. California Supreme Court case...

Gila River Adjudication

Gila River Adjudication Construction of Sacaton Dam on the Gila River Indian Reservation in Arizona. HRA provided research and expert witness testimony for the adjudication of water rights on the Gila River. As part of the General Streamwide Adjudication of the Gila...

Snake River Basin Adjudication

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. HRA historians researched records in...

Featured Team Members

Litigation Support

Expert Witness Services

HRA historians have served as expert witnesses in litigation, as well as providing research and writing support for outside experts.

Native American Issues

HRA historians offer extensive expertise in Native American history and legal issues, ranging from treaty rights to jurisdictional matters.

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.