A top official from the Southern Nevada Water Authority is calling on states that rely on the Colorado River to resolve their differences before a growing dispute derails decades of cooperation on the river.

The Upper Basin states of Colorado, New Mexico, Utah and Wyoming have accused one of Arizona’s largest purveyors of manipulating the river system to maximize the amount of water Lake Powell releases downstream to Lake Mead.

But officials from the Central Arizona Water Conservation District insist they are operating within the rules of the river as they deliver water through their Central Arizona Project canals to Phoenix, Tucson and farms in between.

“I think there’s been some mincing of words,” said Colby Pellegrino, Colorado River programs manager for the Southern Nevada Water Authority. “People have to sit down and talk these things through. We achieve certainty through collaboration.”

At the moment, that collaborative spirit is in jeopardy.