Water rights deal may save Idaho fossil beds

HAGERMAN, Idaho – For decades, paleontologists have watched the richest deposit of fossils from the prehistoric period known as the Pliocene Epoch crushed to dust by frequent landslides crashing off the face of 600-foot-high bluffs along Idaho’s Snake River.

The Hagerman Fossil Beds National Monument – site of the discovery of 43 species, including eight found nowhere else – has become so unstable due to landslides that more than 10 percent of the site, some 4,400 acres, is permanently closed.

But recently, scientists have begun to believe the buried treasures of ancient eons won’t continually be lost in a pile of rubble.

For the past two summers, huge electric pumps that normally suck thousands of gallons of water from the adjacent Snake River and pump it to the top of the bluffs onto a plateau of farm fields have been silent. One of the fields is planted with dryland grain crops, but the rest lie fallow. The irrigation district that ran the pumps sold its water rights to the state for $24 million in 2005 as part of the settlement of one of the largest water rights claims in the West.

That agreement, known as the Snake River Basin Adjudication, was signed into law by President Bush in December 2004. It provides for the state, federal government and Nez Perce Indian tribe to exchange land and money in return for the tribe’s relinquishment of claims to nearly all the water in the Snake River basin.

The deal was never intended to help preserve a prehistoric trove of equine, mastodon, saber-toothed cat, fish, snake and waterfowl fossils. But by ending irrigation at the Bell Rapids project on the Bruneau Plateau above the fossil beds, monument officials believe the rate of landslides will decline significantly.

“If you would have asked me a few years ago if I could wave a magic wand and change anything to protect fossils here long-term, I would have said, ‘Quit pumping the water,” ” said Neil King, superintendent of the monument.

Greg Brown, president of Bell Rapids Irrigation Co., said farmers never agreed with monument studies that concluded their crop sprinkling was triggering the landslides.

“We did our own studies and it showed just the opposite,” said Brown, who sold all his cropland on the plateau after the water rights settlement and no longer farms. “To say we were the cause just doesn’t hold up.”

There have been 10 major landslides in the monument since 1979. A 1987 slide from the bluffs destroyed a $1 million irrigation pumping plant along the river. The 1993 Bliss landslide completely blocked off the Snake River, temporarily forming a lake. Today, along the edge of the plateau overlooking the river, giant cracks appear in the earth.

And when the face gives way, the fossilized record buried in the bluffs is lost.

“We have 600 feet of stratigraphy here that represents about one million years in time and each layer is like a page in a book,” said Gensler. “When all those fossils come down, even if you’re lucky enough to find them intact, they’ve lost all their provenance; we don’t know exactly what page they came off of, whether it was the beginning or the end of the book.”