Geography
The Preserve has a desert climate with hot, dry summers and moderate winters. Rainfall is scarce, with an average annual total of 8 inches. Snow melt from the from the San Bernardino Mountains flows underground until it emerges from the mountains northwest of Morongo Valley and flows intermittantly on the surface of the creek bed. The water percolates quickly into the sandy soils as it crosses the Morongo Basin, but as the water enters Big Morongo Canyon it encounters finely pulverized rock called fault gorge along the earthquake fault. This layer of ground rock is impermeable to water, and acts like a dam, bringing water to the surface in a series of perenial springs, whose waters disappear into the sandy layers further downstream. Within the Preserve occur some of the oldest rocks in the state of California, dated at almost two billion years. They consist of former (metamorphic) granitic rocks that have been altered by heat and pressure to form gneisses and shists.
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SIZE & LOCATION
HISTORY
GEOGRAPHY
PLANTS
WILDLIFE
