Despite a $715,000 program to curtail erosion, the Bureau of Land Management has conceded that seepage is continuing along the cliffs containing the 3.5 million-year-old Hagerman fossil beds.
But BLM area manager Gary Carson said it will just take time for the program to work.Above the cliffs is the 26,000-acre Bell Rapids irrigated farming tract. The farmers draw water from the Snake River and pump it up to their farmland where it is distributed by canals.
Soils in the fossil beds area are unstable, and when they become saturated with water, they can slough off, as the BLM believes happened 15 months ago when a landslide destroyed some of the beds.
Last year BLM spent $572,000 and Bell Rapids Mutual Irrigation Co. picked up the $143,000 balance to line dirt irrigation canals with concrete to prevent seepage. The canal company participated even though it disagreed that seepage from the ditches was responsible for the slide.
The government said it was aware of water saturating the cliffs on both sides of the Hagerman horse quarry point, Carson said, with a number of rich green patches several hundred feet wide stretching across the cliffs.
That saturation indicated the new canal lining was not stopping the seepage, maintained Burt Holmes, chairman of the Hagerman Fossil National Monument Council that is seeking federal protection for the site.
But studies show that a man-made aquifer has built up in the cliffs, created over the past 18 years by water from the canals and continued irrigation, Carson said.
"Just because you line the canals, doesn't mean there will be an immediate result," he said.
The fossil beds offer one of the best preserved late Pliocene fossil sites in the world, including specimens of the Hagerman horse. They contain some 310 fossil sites covering 6 square miles to a depth of 500 feet. The beds document a 200,000 to 500,000 year period.