ES 555, Small-Format Aerial Photography with Dr. James Aber, Emporia State University Final Project, Summer, 2006

SUPAI, AZ

by Larry Kuss

INTRODUCTION

In northwestern Arizona, there is a magical place called Supai. Located about 17 miles south of the Colorado River, Supai is home to approximately 450 residents of the 600 member Havasupai Tribe, the "people of the blue-green water". It is believed they have occupied the region since the 1300s, although their ancestors undoubtably lived here for a much longer span of time. Their name comes from the magnificent turquoise colored streams and waterfalls resulting from the extreme alkalinity of the lime-rich water. The Havasupai reservation consists of about 300 square miles of canyon country, formed of the erosional forces of wind and water gradually wearing away layers of limestone, sandstone and shales that form the canyon walls. The purpose of this project is to explore how small-format aerial photography can be employed to examine features associated with various types of rock as well as to see some really cool photos of this beautiful location.

The Approach

Getting to Supai is not a simple task, adding to the mystique of the location. Driving along Interstate 40, one takes Route 66 either going west or east, for 30 or 55 miles respectively to the Route 18 turnoff on the north side of the road. Driving 60 miles north takes one to the "end of the road", a parking spot called Hualapai Hilltop on the edge of the Hualapai Canyon rim. Named for the tribal people living to the west of the canyon's edge, Hualapai means the "pine-tree people" for the vegetation found at the higher elevations. From here the choices include hiking the eight mile trail down into the canyon to the villlage of Supai, riding horses or mules or flying in a helicopter, reducing a trip of many hours down to a five minute flight. Since I generally arrive to this location for business equipped with a heavy toolbox and considering the unique opportunity to capture digital images for this project, we decided to take advantage of the "aerial option". Observe the helicoptor to the left, used to transport food and passengers as well as building supplies and farming equipment into the village. It served well as a powered, manned supporting platform for hand-held photography. The considerable costs and technical support required were supplied by the tribe, making this type of transport possible for us. The mail, however, is still carried in and out on the backs of mules. This is the only place in the United States where this still occurs, and mail sent out of the canyon bears the unique postal stamp seen below.

Canyon Wall Layers

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Layers of the Canyon Wall

In the high oblique image to the right taken from the helicoptor, one can see the various layers comprising this canyon. The whitish cliffs near the top consist of highly resistant upper Kaibab limestone. Below is the Toroweap Formation, followed by Coconino Sandstone, the much softer Hermit Shale, the Supai Group, the great Redwall Limestone, and finally the Tonto Group. More than 1000 feet thick, the Kaibab and Toroweep formations were both formed from warm, shallow seas. The Hermit Shale, more than 500 feet thick, consists of siltstones and mudstones. The differences in hardness of the various rock groups give the Grand Canyon its classic geological stepped profile often referred to as "cliff, slope, bench." The limestones and sandstones generally produce the great escarpments with drops of hundreds of feet, while the softer shales are responsible for the slopes. The white Coconino Sandstone, found just below the start of the trail and called the "White Cliff" by the locals, was created from the ancient crossbedding of layers deposited in a vast dune field. The broad bench of the inner canyon is referred to as "The Esplanade". This red sandstone marks the top layer of the Supai Group and was produced by the advance and retreat of four ancient seas, depositing shales, sandstones and limestones in a coastal environment including floodplains, deltas and streams. If the sun had been lower in the sky, increased shadowing would have simplified identification of the specific rock layers.

Below left is a low-oblique view with a depression angle of around 45 degrees showing the eroded sandstone of The Esplanade above the canyon floor. Diffficult to capture at this height, you may be able to see the mud cracks preserved in the deposits when arid conditions prevailed. The trail actually follows this narrow slot worn deep within this layer. Here it is clear that the flow of water down a steep elevation gradient has created many "shelves" as it encountered materials of differing resistances to weathering. The nine inches of average annual rainfall in this canyon falls mostly in August and September, creating torrents of fast moving water. The strongest winds are present in March, when horizontal weathering predominates.

Mesa Erosional Patterns

Unique Erosional Forms

Below is a horizontal high-oblique view of "The Sentinels", also called "Wigleeva", believed by the locals to be the guardian spirits who watch over the people of Supai. The shadow of the left formation on the rock wall formed from the late-morning sun gives depth to the composition.

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Water Chemistry

The 38 million gallons of water per day supplying the village is captured in a huge subterranean formation referred to as the "Havasupai Downwarp", a funnel-shaped collection of rock layers that direct all the rainfall and snowmelt over a 3,000 square mile area into an aquifer that is transected by the stream. After percolating through permeable limestones and sandstones, the water picks up calcium and magnesium carbonates, calcium sulfate and magnesium chloride. Not only does this combination give the water its magnificent color, but as it evaporates in the dry canyon air and gives up much of its carbon dioxide, travertine deposits are produced around the falls, brown from iron oxides. Below is a good example of the travertine deposits formed around Mooney Falls. Although not taken from the air, this vantage point high above the pool below the falls replicates the low-oblique perspective one might achieve from an airborn platform.

Relief Displacement

In the image above, an effect called "relief displacement" can be seen with reference to these cottonwood trees. This is where tall objects toward the edge of a photograph appear to lean away from the center of the image. The illusion is more pronounced as one looks more toward the edge of the frame, and allows for a side view of the objects closest to the edges. Shorter objects appear to lean toward the center. The effect is accentuated due to the recent snowfall. The effect results from the fact that a camera's view is taken from a single point in space, and all objects in the field of view are referenced to this perspective. Similar to paralax, relief displacement can be used to determine the height of objects in a photo with the help of simple trigonometric relationships.

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Shadows

With aerial photography, much information can be obtained by examining the shadows cast by the objects in the scene. In this view of a corner of the village captured just prior to landing, the shadows not only reveal the fact that the sun is almost directly overhead, but by using trigonometric relationships as mentioned with relief displacement they can also be used to calculate the height of the objects that produced them.

Snow Accents

An unexpected benefit of the snowstorm we experienced can be seen in the photo above. The snow made it easier for one to identify the individual layers in the stone formations, as this is sometimes difficult in a region where many structures are the same color and shadows are minimal due to the typical "toplighting" from a midday summer sun. The snow clings to the horizontal surfaces without significant adhesion to the vertical rock faces.

Reflections on Water

The two images above, although not taken from the helicopter, are good examples of "specular reflection" and "sun glitter". With specular reflection, as in the scene on the left, a smooth glass-like surface reflects light similar to what you might expect from a mirror. Notice the reflections of the sandstone formations in the distance and the trees along the left bank. Sun glitter refers to the effect of light bouncing off the wave crests of rippling water as is evident in the photo on the right, visible on the water's surface below the falls.

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CONCLUSION

Small-format aerial photography is a versatile technique for obtaining unique views of ground features. Land-based images are limited in their ability to reveal spatial relationships, but photography from above with the use of whatever means are available to place the camera high above the subject can afford quite spectacular and unusual perspectives.

REFERENCES

All Photos Taken by Larry Kuss Using a Nikon Coolpix 5700 5.0 Mega Pixel Digital Camera

The Havasupai, John F. Martin, 1990

Havasu, Grand Canyon Trail Guide, 1998

Arizona Traveler's Handbook, Bill Weir, 1992

The Sierra Club Guide to the Natural Areas of New Mexico, Arizona And Nevada, John and Jane Greverus Perry, 1986

Native Roads, Fran Kosik, 1996

Hiking the Southwest's Canyon Country, Sandra Hinchman, 1990

Hiking the Southwest's Geology, Four Corners region, Ralph Lee Hopkins, 2002

Supai and the Havasupai Reservation; http://www.kaibab.org/supai/gc_supai.htm

Supai/Havasu Canyon; http://www.http://gorp.away.com/gorp/resource/us_national_park/az/sup_grand.htm.htm

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