FLAGSTAFF, Ariz.— Responding to opposition from the Navajo Nation, the Federal Energy Regulatory Commission on Thursday denied a preliminary permit application for the Big Canyon pumped storage project on the Little Colorado River near Grand Canyon National Park.

The project proposed to pump groundwater to fill reservoirs below and above the rim of the Little Colorado River gorge. It threatened to dewater Blue Springs, which provides baseflows for the river and sustains the largest remaining source population of humpback chub. These fish are protected as threatened under the Endangered Species Act.

“This disastrous project could have devastated the Little Colorado River and pushed the world’s last large source population of humpback chub toward extinction,” said Taylor McKinnon, Southwest director at the Center for Biological Diversity. “It’s good news for these embattled fish that federal officials heeded the Navajo Nation’s staunch opposition and rejected this project.”

The Phoenix-based firm pushing the Big Canyon project had also proposed two other pumped storage projects in the same area, the Little Colorado River and Salt Trail Canyon projects. Both would have dammed the Little Colorado River, also jeopardizing humpback chub, but have since been scrapped.

This week’s denial of the Big Canyon project is the result of a policy change announced in February to require Tribal support of projects on Tribal lands.

The Navajo Nation, Hopi Tribe, Hualapai Tribe and other Tribes opposed the Big Canyon project and the two other Little Colorado River pumped storage proposals.