AGUACYCLE
Policy

The Colorado River's Oldest Water Rights Belong to Tribes

Native nations hold some of the most senior — and largest — claims on the river. After a century on the sidelines, they're shaping its future.

By AGUACYCLE News Room

When the Colorado River was divided up a century ago, tribal nations were largely left out — even though many hold water rights that, under the Winters doctrine, are senior to almost all others.

Quantifying long-ignored rights

A wave of negotiated settlements is now quantifying those rights and funding infrastructure to deliver water to reservations, many of which still lack reliable running water. Because the rights are senior and large, they reshape allocations in an already over-subscribed basin.

Tribes are now central players in the post-2026 negotiations over the river's future.