Domenigoni Valley Reservoir

by Dee S. Grover

Lithosphere (April 1996); Fallbrook Gem and Mineral Society, Inc.; Fallbrook, CA

In 1993, the Metropolitan Water District started work on a reservoir which, when completed, will be southern California's largest and will hold 800,000 acre-feet of water to supply the needs of 13 million people. Work had barely begun when some interesting and very important fossils were uncovered. They included ground sloths, huge mastodons, camels, lions, and many other varieties of animals. The fossils were discovered at depths between four and sixty feet, and date from the Pleistocene epoch, which began about two million years ago and ended about 10,000 years ago.

The area, the Domenigoni Valley near Hemet, is one of the richest fossil sites discovered in the coastal area of the country. Only the La Brea tar pits are richer. On a scale of ten, the La Brea tar pits rate a ten and the Domenigoni Valley rates a nine. The fossils of tree-eating animals discovered there indicate there was a multi-channel stream that flowed through this heavily forested area.

Kathlene Springer, who holds a Masters degree in geology, is supervising the collection and protection of the fossils retrieved from the construction sites. Early in the planning stages, she disagreed with the engineers of the project about the presence of fossils. Her knowledge of the local rock formations led her to believe that fossils occurred within the construction sites. Her suppositions were accurate, except there were thousands more fossils than she had surmised.

Springer has supervised the exploration of over 400 locations, and has retrieved bones of eight-foot-tall camels and six-foot-tall ground sloths, as well as small animals such as rabbits, turtles, and kangaroo rats. The animals lived between 10,000 and 120,000 years ago -- at the end of the last ice age. The same types of animals were found in the La Brea tar pits. The most notable were the bones of a 5-ton, 10-foot-high mastodon and a lion at least one-third larger than the lions of today.

Archaeologists have also been at work in the valley and have uncovered a wealth of information about native American inhabitants. Evidence shows that people lived in the area for more than 7,000 years.

Current plans call for native American artifacts to be housed at a permanent location near the new reservoir. At present, the fossils are stored and displayed at the San Bernardino County Museum. Another small display of fossils and artifacts is in a new building at the east end of the valley.

Copyright © 1996 by Fallbrook Gem and Mineral Society, Inc.

The preceding article was originally published in the April 1996 issue of Lithosphere, the official bulletin of the Fallbrook [California] Gem and Mineral Society, Inc; Richard Busch (Editor).

Permission to reproduce and distribute this material, in whole or in part, for non-commercial purposes, is hereby granted provided the sense or meaning of the material is not changed and the author's notice of copyright is retained.

Last updated: 18 September 2002