| Arches National Park | |
|---|---|
IUCN category II (national park)
| |
Delicate Arch with background of La Sal Mountains
| |
 
Location in the United States
| |
| Location | Grand County, Utah, United States |
| Nearest city | Moab, Utah |
| Coordinates | 38.68333°N 109.56667°WCoordinates: 38.68333°N 109.56667°W |
| Area | 76,679 acres (119.811 sq mi; 31,031 ha; 310.31 km2) |
| Established | April 12, 1929, as a national monument |
| Visitors | 1,663,557 (in 2018) |
| Governing body | National Park Service |
| Website | Official website |
Arches National Park is a national park in eastern Utah, United States. The park is adjacent to the Colorado River, 4 miles (6 km) north of Moab, Utah. More than 2,000 natural sandstone arches are located in the park, including the well-known Delicate Arch, as well as a variety of unique geological resources and formations. The park contains the highest density of natural arches in the world.
The park consists of 76,679 acres (119.811 sq mi; 31,031 ha; 310.31 km2) of high desert located on the Colorado Plateau. The highest elevation in the park is 5,653 feet (1,723 m) at Elephant Butte, and the lowest elevation is 4,085 feet (1,245 m) at the visitor center. The park receives an average of less than 10 inches (250 mm) of rain annually.
Administered by the National Park Service, the area was originally named a national monument on April 12, 1929, and was redesignated as a national park on November 12, 1971.[6] The park received more than 1.6 million visitors in 2018.
Geology
Map of Arches National Park
The national park lies above an underground evaporite layer or salt bed, which is the main cause of the formation of the arches, spires, balanced rocks, sandstone fins, and eroded monoliths in the area. This salt bed is thousands of feet thick in places, and was deposited in the Paradox Basin of the Colorado Plateau
some 300 million years ago (Mya) when a sea flowed into the region and
eventually evaporated. Over millions of years, the salt bed was covered
with debris eroded from the Uncompahgre Uplift to the northeast. During the Early Jurassic (about 210 Mya), desert conditions prevailed in the region and the vast Navajo Sandstone was deposited. An additional sequence of stream-laid and windblown sediments, the Entrada Sandstone
(about 140 Mya), was deposited on top of the Navajo. Over 5,000 feet
(1,500 m) of younger sediments were deposited and have been mostly
eroded away. Remnants of the cover exist in the area including exposures
of the Cretaceous Mancos Shale. The arches of the area are developed mostly within the Entrada formation.
The weight of this cover caused the salt bed below it to liquefy and thrust up layers of rock into salt domes. The evaporites of the area formed more unusual "salt anticlines" or linear regions of uplift. Faulting
occurred and whole sections of rock subsided into the areas between the
domes. In some places, they turned almost on edge. The result of one
such 2,500-foot (760 m) displacement, the Moab Fault, is seen from the visitor center.
As this subsurface movement of salt shaped the landscape, erosion
removed the younger rock layers from the surface. Except for isolated
remnants, the major formations visible in the park today are the
salmon-colored Entrada Sandstone, in which most of the arches form, and
the buff-colored Navajo Sandstone. These are visible in layer-cake
fashion throughout most of the park. Over time, water seeped into the
surface cracks, joints, and folds of these layers. Ice formed in the
fissures, expanding and putting pressure on surrounding rock, breaking
off bits and pieces. Winds later cleaned out the loose particles. A
series of free-standing fins remained. Wind and water attacked these
fins until, in some, the cementing material gave way and chunks of rock
tumbled out. Many damaged fins collapsed. Others, with the right degree
of hardness and balance, survived despite their missing sections. These
became the famous arches.
Although the park's terrain may appear rugged and durable, it is
extremely fragile. More than 1 million visitors each year threaten the
fragile high-desert ecosystem. The problem lies within the soil's crust, which is composed of cyanobacteria,
algae, fungi, and lichens that grow in the dusty parts of the park.
Factors that make Arches National Park sensitive to visitor damage
include being a semiarid region, the scarce, unpredictable rainfall,
lack of deep freezing, and lack of plant litter, which results in soils
that have both a low resistance to, and slow recovery from,
compressional forces such as foot traffic. Methods of indicating effects
on the soil are cytophobic soil crust index, measuring of water
infiltration, and t-tests that are used to compare the values from the
undisturbed and disturbed areas.
Climate
According to the Köppen climate classification system, Arches Visitor Center has a cold semi-arid climate (BSk).
| Climate data for Arches National Park Headquarters (1981–2015 normals) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average high °F (°C) | 44 (7) |
52 (11) |
64 (18) |
71 (22) |
82 (28) |
93 (34) |
100 (38) |
97 (36) |
88 (31) |
74 (23) |
56 (13) |
45 (7) |
71.4 (21.9) |
| Average low °F (°C) | 22 (−6) |
28 (−2) |
35 (2) |
42 (6) |
51 (11) |
60 (16) |
67 (19) |
66 (19) |
55 (13) |
42 (6) |
30 (−1) |
23 (−5) |
44.8 (7.1) |
| Average precipitation inches (mm) | 0.58 (15) |
0.50 (13) |
0.78 (20) |
0.74 (19) |
0.68 (17) |
0.44 (11) |
0.83 (21) |
0.96 (24) |
0.84 (21) |
1.24 (31) |
0.60 (15) |
0.55 (14) |
8.74 (221) |
| Average snowfall inches (cm) | 1.9 (4.8) |
.9 (2.3) |
.7 (1.8) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
.6 (1.5) |
2.5 (6.4) |
6.6 (16.8) |
| Average precipitation days (≥ 0.01 in) | 4.0 | 4.4 | 6.1 | 5.3 | 4.6 | 3.1 | 5.2 | 6.6 | 5.2 | 5.5 | 4.5 | 3.9 | 58.4 |
| Average snowy days (≥ 0.1 in) | 1.3 | .8 | .4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | .4 | 1.4 | 4.3 |
History
Humans have occupied the region since the last ice age 10,000 years ago. Fremont people and ancestral Puebloans lived in the area until about 700 years ago. Spanish missionaries encountered Ute and Paiute
tribes in the area when they first came through in 1775, but the first
European-Americans to attempt settlement in the area were the Mormon
Elk Mountain Mission in 1855, who soon abandoned the area. Ranchers,
farmers, and prospectors later settled Moab in the neighboring Riverine
Valley in the 1880s. Word of the beauty of the surrounding rock formations spread beyond the settlement as a possible tourist destination.
The Arches area was first brought to the attention of the
National Park Service by Frank A. Wadleigh, passenger traffic manager of
the Denver and Rio Grande Western Railroad.
Wadleigh, accompanied by railroad photographer George L. Beam, visited
the area in September 1923 at the invitation of Alexander Ringhoffer, a Hungarian-born prospector
living in Salt Valley. Ringhoffer had written to the railroad in an
effort to interest them in the tourist potential of a scenic area he had
discovered the previous year with his two sons and a son-in-law, which
he called the Devils Garden (known today as the Klondike Bluffs).
Wadleigh was impressed by what Ringhoffer showed him, and suggested to
Park Service director Stephen T. Mather that the area be made a national
monument.
The following year, additional support for the monument idea came from Laurence Gould, a University of Michigan graduate student (and future polar explorer) studying the geology of the nearby La Sal Mountains, who was shown the scenic area by local physician Dr. J. W. "Doc" Williams.
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A succession of government investigators examined the area, in part
due to confusion as to the precise location. In the process, the name
Devils Garden was transposed to an area on the opposite side of Salt
Valley that includes Landscape Arch,
the longest arch in the park. Ringhoffer's original discovery was
omitted, while another area nearby, known locally as the Windows, was
included. Designation of the area as a national monument was supported
by the Park Service from 1926, but was resisted by President Calvin Coolidge's Interior Secretary, Hubert Work. Finally, in April 1929, shortly after his inauguration, President Herbert Hoover
signed a presidential proclamation creating Arches National Monument,
consisting of two comparatively small, disconnected sections. The
purpose of the reservation under the 1906 Antiquities Act
was to protect the arches, spires, balanced rocks, and other sandstone
formations for their scientific and educational value. The name Arches
was suggested by Frank Pinkely, superintendent of the Park Service's
southwestern national monuments, following a visit to the Windows
section in 1925.
In late 1938, President Franklin D. Roosevelt
signed a proclamation that enlarged Arches to protect additional scenic
features and permit development of facilities to promote tourism. A
small adjustment was made by President Dwight Eisenhower in 1960 to accommodate a new road alignment.
In early 1969, just before leaving office, President Lyndon B. Johnson signed a proclamation substantially enlarging Arches. Two years later, President Richard Nixon signed legislation enacted by Congress, which significantly reduced the total area enclosed, but changed its status to a national park.
Recreational activities
Exit rappel on the popular Elephant Butte
Climbing Balanced Rock
or any named or unnamed arch in Arches National Park with an opening
larger than 3 ft (0.9 m) is banned by park regulations. Climbing on
other features in the park is allowed, but regulated; in addition, slacklining and BASE jumping are banned parkwide.
Climbing on named arches within the park had long been banned by park regulations, but following Dean Potter's successful free climb on Delicate Arch in May 2006, the wording of the regulations was deemed unenforceable by the park attorney. In response, the park revised its regulations later that month,
eventually imposing the current ban on arch climbing in 2014.
Approved recreational activities include auto touring, hiking, bicycling, camping at the Devils Garden campground, backpacking, canyoneering, and rock climbing, with permits required for the last three activities. Guided commercial tours and ranger programs are also available.
Astronomy is also popular in the park due to its dark skies, despite the increasing light pollution from towns such as Moab.
Publicity
Arches quarter
Delicate Arch is the subject of the third 2014 quarter of the U.S. Mint's America the Beautiful Quarters
program commemorating national parks and historic sites. The Arches
quarter had the highest production of the five 2014 national park
quarters, with more than 465 million minted.
American writer Edward Abbey was a park ranger at Arches National Monument in 1956 and 1957, where he kept journals that became his book Desert Solitaire. The success of Abbey's book, as well as interest in adventure travel, has drawn many hikers, mountain bikers, and off-pavement
driving enthusiasts to the area. Permitted activities within the park
include camping, hiking along designated trails, backpacking,
canyoneering, rock climbing, bicycling, and driving along existing
roads, both paved and unpaved. The Hayduke Trail, an 812-mile (1,307 km) backpacking route named after one of Edward Abbey's characters, begins in the park.
Plants and animals
An abundance of wildlife occurs in Arches. The list includes: spadefoot toad, antelope squirrel, scrub jay, peregrine falcon, many kinds of sparrows, red fox, desert bighorn sheep, kangaroo rat, mule deer, cougar, midget faded rattlesnake, yucca moth, western rattlesnake, and the collared lizard.
Plants also dominate the landscape in the park. The list of plants includes: prickly pear cactus, Indian ricegrass, bunch grasses, cheatgrass, lichen, moss, liverworts, Utah juniper, Mormon tea, blackbrush, cliffrose, four-winged saltbrush, pinyon pine, evening primrose, sand verbena, yucca, and sacred datura.
Biological soil crust consisting of cyanobacteria, lichen, mosses, green algae, and microfungi
is found throughout southeastern Utah. The fibrous growths help keep
soil particles together, creating a layer that is more resistant to
erosion. The living soil layer readily absorbs and stores water,
allowing more complex forms of plant life to grow in places with low
precipitation levels.
Features
Balanced Rock
- Balanced Rock – a large balancing rock, the size of three school buses
- Courthouse Towers – a collection of tall stone columns
- Dark Angel – a free-standing 150-foot-tall (46 m) sandstone pillar at the end of the Devils Garden Trail
- Delicate Arch – a lone-standing arch which has become a symbol of Utah and the most recognized arch in the park
- Devils Garden – many arches and columns scattered along a ridge
- Double Arch – two arches that share a common end
- Fiery Furnace – an area of maze-like narrow passages and tall rock columns (see biblical reference, Book of Daniel, chapter 3)
- Landscape Arch – a very thin and long arch in the Devils Garden with a span of 290 feet (88 m) (the longest arch in the park)
- Petrified Dunes – petrified remnants of sand dunes blown from the ancient lakes that covered the area
- Wall Arch – located along the popular Devils Garden Trail; collapsed sometime on August 4/5, 2008
