Snell & Wilmer Expands Nationally Recognized Water Law Practice with Karlene Martorana and Rhett Larson

PHOENIX – Snell & Wilmer is pleased to announce that Partner Karlene E. Martorana and Counsel Rhett B. Larson have joined the firm’s Environmental and Natural Resources Practice Group in Phoenix, Arizona. Their arrival marks a strategic expansion of the firm’s water law capabilities as businesses and governments confront evolving water challenges, including the long-term management of the Colorado River and increasing demands on limited water resources.

Martorana rejoins Snell & Wilmer following nearly a decade in-house with global mining companies, bringing a business-minded perspective on how resource companies weigh legal risk, permitting, and water supply. Larson, a leading authority on water law and policy, is the Richard Morrison Professor of Water Law at Arizona State University’s Sandra Day O’Connor College of Law, and a Senior Research Fellow at the Kyl Center for Water Policy. 

“Water is the defining resource issue in the West, and the challenges on the Colorado River continue to grow in both complexity and consequence,” said Bill Staudenmaier, an environmental partner in the firm’s Phoenix office. “Karlene’s understanding of water and mining issues facing resource companies, combined with Rhett’s nationally recognized water law experience, will strengthen the counsel we provide for clients across our entire footprint.”

“The firm’s involvement in water law issues spans back to the days of our founders, when Mark Wilmer won a key case before the US Supreme Court defining water rights in the West,” added Firm Chair Barbara Dawson. “We are so pleased to grow our strong team with these exceptional water lawyers at this critical time.”

Martorana most recently served as Senior Legal Counsel at Rio Tinto where she helped the Resolution Copper project break free from regulatory and litigation gridlock. At Rio Tinto, she partnered with Resolution’s senior leadership to align business goals with legal and regulatory frameworks, while managing litigation, employment, environmental, land use, safety, and compliance matters.  Prior to Rio Tinto, she was in-house counsel at CMOC International (China Molybdenum Co. Ltd.) an international mining company. She currently serves as Vice President of the American Exploration & Mining Association (AEMA) and will assume the role of President in 2027.

“I’m excited to return to Snell & Wilmer and rejoin one of the premier water law teams in the country,” said Martorana. “Having navigated water and permitting challenges from inside global mining companies, I’ve seen firsthand how these issues shape business decisions and long-term strategy.”

Larson focuses on dispute resolution and water rights adjudications in Arizona and the Colorado River Basin. He serves as chief legal counsel to the Arizona Municipal Water Users Association, which represents 10 of Arizona’s largest cities, and previously practiced in Phoenix on matters involving water rights, water quality, water utility transactions, energy, mining, and Native American law. He is also the author of Just Add Water: Solving the World’s Problems Using its Most Precious Resource (Oxford University Press, 2020). Larson serves on the Board of Directors of the Arizona Mexico Commission and has extensive experience on cross-border water issues between the United States and Mexico, as well as water policies in Mexico. He serves as a commissioner on the Arizona Navigable Streams Adjudication Commission and as a member of the Water Conservation Grant Committee of Arizona’s Water Infrastructure Finance Authority. He founded the Holistic Water Solutions Initiative, which provides improved water supplies to refugees and host communities in Lebanon and Jordan. Larson has extensive experience in international water law and policy, having worked on water projects in the Middle East, Australia, Europe, South Africa, India, and Latin America.

“Snell & Wilmer stands apart for its depth of experience advising on the full spectrum of water law issues facing business and communities across the West,” said Larson. “With the long-term future of the Colorado River still taking shape, clients need counsel who can connect policy, litigation, and transactional considerations.”

Snell & Wilmer’s leadership in water law dates to co-founder Mark Wilmer’s role as Arizona’s lead counsel in Arizona v. California, the landmark U.S. Supreme Court case that produced the 1964 decree dividing the lower Colorado River among Arizona, California, and Nevada.

Today, Martorana and Larson join a deep bench of water law lawyers that include Bill Staudenmaier, John Burnside, Sarah Ajeti, John Habib, Jason Brinkley, and Mary Katherine Andrews. The team works seamlessly with attorneys across the firm’s litigation, commercial transactions, real estate, mining, and broader environmental and natural resources groups to advise businesses and government agencies on compliance, regulatory and legislative advocacy, litigation, and transactions throughout the western United States.

Martorana earned her J.D. from the University of Maryland’s Francis King Carey School of Law and her B.S. from the University of Arizona. Larson earned his J.D. from the University of Chicago Law School, his M.Sc. in Water Science, Policy and Management from the University of Oxford, where he was a Weidenfeld Scholar, and his B.A. from Bringham Young University.