Page 89 - 2002 DT 12 issues_Neat

Wha t’ s Insi d e !
Featured Articles
The Great Lakes of the Great Basin...........1
Boot Tracks.................................................5
Special
Quiz............................................................7

Departments
December 2002 News & Notes............................................2
Programs & Hikes........................................4
Desk Schedule............................................6
Bulletin Board.............................................8

The Great Lakes extend throughout the Pahrump Valley ○ stops dead . . . because those mountains
○
and to the bottom of the Las Vegas Val- ○ sit on a block of volcanic rock and clay
Of The Great Basin ley. ○ ○ that dams the water and effectively ends
The Spring Mountains go up almost ○ the aquifer network. After each storm,
○
by Jack Ryan
12,000 feet and, in elevations above ○ fresh water enters the aquifers and the ad-
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ny Las Vegan with more than ○ 5,000 feet, receive between 12 and 16 ○ ditions build pressure on the existing
○ ○
two years residency knows he ○ inches of rain or snow in average years. ○ supply. It must escape. It can’t go back-
○
○
A or she lives in the Mojave ○ Much of the rain or snow-melt quickly ○ ward; the downslope is blocked. Upward
○
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Desert, the driest of the four deserts in ○ drains off the rocky surfaces and runs ○ is the only release from pressure. So the
North America. And regardless of resi- ○ ○ through ravines and canyons, much as it ○ ○ water seeks cracks or fissures in the earth
dency tenure, they know that the Mojave ○ does in drain pipes on the roof of your ○ above and bursts out in the form of big
○ ○
is experiencing its driest period in ○ house. Sometime it drains so heavily and springs. “Big Springs” . . . one of the early
recorded history. ○ ○ appellations of
So don’t try to tell them that they also ○ ○ Las Vegas.
live in the Great Lakes of the Great Basin. ○ ○ And Las Ve-
It’ll get you, at best, a mocking guffaw. ○ gas had big
○
But it’s true. The Great Basin encom- ○ springs. They
○ spewed out an
passes almost all Nevada, and the Great ○
○ estimated 4,000
Lakes are all around us. No, they aren’t ○
gallons of water
○
mirages. They’re very real and under ○
our feet. ○ a minute. Local
museums have
○
The “Great Lakes of the Great Ba- ○
sin” is a fanciful description of one of ○ ○ swiftly it creates dangerous flash floods ○ early 20th Century photos of the unfet-
○ tered springs gushing like open fire
○
○
the greatest aquifer systems in the West. ○ in its dash to the Colorado River or
○ hydrants.
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Huge honeycombed caves of limestone, ○ through the washes of the Pahrump Val- ○ When the Spanish merchants first
some 70 feet to 700 feet beneath the ○ ley (see Desert Trumpet, July, 2001). ○
○
○ ○ discovered our valley in 1830, they came
Mojave’s arid surface, are packed with ○ But that’s the surface water. Sub-sur-
○ ○ from the Colorado River and climbed
hundreds of thousands of tons of water— ○ face water seeps into the porous ○
○ along a ridge expecting to see another
○
or, we should say were packed with water. ○ limestone and percolates into aquifers ○ ○ barren valley like others they had
○
But more on that later. ○ stretching like fingers to the east and west ○ traversed. Instead, they were stunned.
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The Las Vegas Valley’s pinch-a- ○ of the range. On the Pahrump side, it ○ Below them was an emerald green oasis
○
penny 4.5 inches of rainfall per average feeds irrigation for thriving agricultural ○ ○ 6 miles long and 3 miles wide with waist-
year didn’t provide all that water. It came businesses all through the valley. On the ○ high grasses fed by creeks 5 feet deep.
○
○
largely from the blue-gray mountains that ○ Las Vegas side, it’s a different story. Towering cottonwoods draped over
○ ○
provide a breathtaking stage-drop for Red ○ On the eastern slope, the subterranean ○ lagoons almost a city block in diameter.
○
Rock Canyon. The Spring Mountains, ○ water follows the downward course of ○ They named the garden “Las Vegas”: the
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and the Sheep Mountains to the east ○ surface water rushing to the Colorado— ○ meadows.
○
○
which also contribute to the aquifer sup- ○ but only to a point. When it hits French- ○ ○
○
ply, feed a network of reservoirs which ○ man Mountain and Sunrise Mountain, it ○ Great Lakes, continued on page 6