The Canyon Transformed

June 24, 2014

By Charles Koenig and Steve Black

It has been four days since Eagle Nest Canyon went on a historic flood, perhaps unrivaled since 1954.  We were fortunate that it hit on a Friday morning, peaked mid-day, stalled out in the afternoon as water backed up from the flooding Rio Grande, and then most of it drained out of the canyon overnight.  We were able to get back to work the next morning  (Saturday) in Eagle Cave.  We knew we would have to take the high trail into the canyon, but we weren’t really prepared for what we encountered when we looked over the edge for the first time.

Massive gravel dunes now cover the floor of the canyon.

Massive gravel dunes now cover the floor of the canyon.

The canyon bottom has been completely transformed.  There are massive gravel bars and dunes extending downstream from Eagle Cave, and they have covered the previous floor of the canyon with several meters of gravel.  The old water pump the Skiles family installed in the bottom of the canyon in the 1950s is either covered up by gravel or washed down into the Rio Grande.

Bottom of Eagle Nest Canyon after a small flood in May 2014 (left) versus June 20th (right). Several hundred tons of gravel and other debris was washed down and deposited in the canyon bottom just below Eagle Cave.

Bottom of Eagle Nest Canyon after a small flood in May 2014 (left) versus how it appeared on June 20th (right). Several hundred tons of gravel and other debris was washed down and deposited in the canyon bottom just below Eagle Cave.

Before the flood the lower canyon bottom had many trees including willow, salt cedar, cottonwood, mesquite, hackberry, and walnut, but the flood was so strong that most were ripped out, snapped in half or flattened by the flood waters.  We expect to see even fewer trees upstream from Eagle Cave once we have time to venture forth and boulder hop up the canyon.

The flood waters were so strong that even the large cottonwoods that once stood tall in the bottom of the canyon were bent over and snapped

The June 20th flood waters were so strong that even the large cottonwoods that once stood tall in the bottom of the canyon were bent over and snapped

The two sites that are most affected are Skiles and Kelley — the sites are fine, but getting to them and hauling dirt, or rather mud upslope to backfill our excavation units is … challenging.  For most of the season we were able to drive very close to the sites and take a short hike up the canyon wall to the rockshelters.  Now, the flood has left behind a massive gravel flat with braided streams below the sites.

SkilesKelley_Pre-Post

Kelley Cave and Skiles Shelter during the small flood in May 2014 (left), and the same shelters after the flood.

Fortunately, some of the denizens of Eagle Nest enjoy the mud.  When a small crew made their way to Kelley Cave Saturday afternoon, they followed in the footsteps of wild hogs that seem to enjoy the mud, contrary to the humans who slogged after them through the sticky slick mud.

Wild hogs seemed to enjoy the new mud that was on the trail into Skiles and Kelley.

Wild hogs seemed to enjoy the new mud that was on the trail into Skiles and Kelley.

After we collected ourselves from surveying the canyon and adjusting to the new landscape, we were able to work all day Saturday and put in a full day yesterday; however, this morning Mother Nature once again had plans for Eagle Nest …

View looking upstream to Eagle Cave just as the flood waters begin to flow across the gravel-dune field in the canyon bottom.

View looking upstream to Eagle Cave just as the surging flood waters begin to flow across the gravel-dune field in the canyon bottom.

We arrived at the canyon this morning after waiting out a thunderstorm that began just after dawn and passed just north of the canyon (Jack Skiles reported only just over 1/3″ of rain in his gauge above Eagle Cave).  When we drove over the highway bridge on our way to the canyon we saw water was running over the pour-off, so we knew another flood was headed our way.  Sure enough, not 20 minutes later we watched the water come rushing down the canyon once again, its thin leading edge advancing rapidly and swelling quickly.  From our canyon edge perch we watched with fascination as the flood torrent breached sand-gravel banks 15-20 feet high or went around them, carving new channels that crisscrossed the canyon floor and competed to see which would capture the main flow.

 

6-24 Flood: Mouth of ENC

The small flood from today winds its way through the bent over trees and gravel dunes from the massive flood 4 days ago.

The canyon ran until 1 pm, and sitting in Eagle Cave mid-morning the roaring water was loud enough that we had trouble hearing the person running the Total Data Station only a few meters away.  Today’s flood paled by comparison to Friday’s (perhaps 1/20th the volume or even less), but the water encountered virgin unconsolidated territory — the gravel bars. Over the course of the day a new channel cut through the gravel “dunes” and the floor of the canyon was once again transformed, albeit less dramatically than four days hence.

We are hopeful that our colleague the archaeo-sensing wizard Mark Willis will be able to come back out re-fly the canyon soon with his UAV to document how the canyon has changed since the flood.  It is rare to be able to watch an arid landscape dramatically change before your eyes, and Eagle Nest has done that twice in four days! Even though our best-laid plans were disrupted, we felt privileged to bear witness to flash floods massive and dinky.

 

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The Canyon Runs Deep

June 20, 2014

“Scattered thunderstorms” was the forecast for today.  We had shrugged and fully expected to see little if any rain as usual in Langtry, Texas.  Landowner Jack Skiles visited our digs yesterday and asked, “Have you considered moving any of the heavy stuff [equipment] out of the canyon while the road is open, they say it might rain?”   We nodded and went back to work busily trying to finish our excavations and get our final SfM photo documentation completed to make ready for the geoarchaeological sampling that was to happen today and tomorrow.   Jack had just got the road serviceable again last week — it had been washed out last month after a 1.5″ rain — but sunny windy weather had dried it out quickly.   “Scattered thunderstorms,”  no problem.

The rain began around 4 am at the Skiles’ house overlooking Eagle Nest Canyon, and in less than eight hours 11.6″ of rain fell.  The Canyon ran deep as the following sequence of photographs attest.

9 am, view up Canyon toward Eagle Cave.

9 am, view up Canyon toward Eagle Cave.

9am, Steve Black looks across to Kelley Cave and Skiles Shelter and ponders Plan B.

9am, Steve Black looks across to Kelley Cave and Skiles Shelter and ponders Plan B.

10am, view up Canyon, Eagle Cave on the left.

10am, view up Canyon, Eagle Cave on the left.

10am, Wilmuth and Jack Skiles with Eagle Cave in the background.

10am, Wilmuth and Jack Skiles with Eagle Cave in the background.

10 am, view upstream from above Eagle Cave

10 am, view upstream from above Eagle Cave

10 am, lower Canyon with Kelley Cave on the left. The Eagle Nest Canyon flow is so strong that it is pushing water up the Rio Grande (to the right in background).

10 am, lower Canyon with Kelley Cave on the left. The Eagle Nest Canyon flow is so strong that it is pushing water up the Rio Grande (to the right in background).

ENC Pour-Off 11:30 am. Around this time is when the flood peaked.

ENC Pour-Off 11:30 am. Around this time is when the flood peaked.

Eagle Nest Canyon Flooding in 2010 (left) versus 2014 (right). This flood was not the first massive flood event ASWT has experienced at Eagle Nest. In 2010, after receiving 12" of rain over a 4 day period, the canyon went on what we thought was a massive flood (photo on left). Little did we know that by 11:30 am the flow of water over the pour-off into Eagle Nest Canyon would dwarf anything we had ever seen.

Eagle Nest Canyon Flooding in 2010 (left) versus 2014 (right).
This flood was not the first massive flood event ASWT has experienced at Eagle Nest. In 2010, after receiving 12″ of rain over a 4 day period, the canyon went on what we thought was a massive flood (photo on left). Little did we know that by 11:30 am the flow of water over the pour-off into Eagle Nest Canyon would dwarf anything we had ever seen.

Noon, view downstream from Eagle Cave

Noon, view downstream from Eagle Cave

Noon, Kelley Cave and Skiles Shelter with the Rio Grande in the background.

Noon, Kelley Cave and Skiles Shelter with the Rio Grande in the background.

Noon, view down Canyon, Eagle Cave on right with watefalls.

Noon, view down Canyon, Eagle Cave on right with waterfalls.

Noon, view upstream from above Eagle Cave.

Noon, view upstream from above Eagle Cave.

 

By 12:30 the flooding had started to subside. The water level did not get up into the shelter, but the lower couple dozen feet of our trail was washed away down to bedrock.

By 12:30 the flooding had started to subside. The water level did not get up into the shelter, but the lower couple dozen feet of our trail was washed away down to bedrock.

12:15 pm, mouth of the Canyon, Skiles Shelter on the left.

12:15 pm, mouth of the Canyon, Skiles Shelter on the left.

Noon, Kelley Cave and Skiles Shelter with the Rio Grande in the background.

12:30 pm, Kelley Cave and Skiles Shelter with the Rio Grande in the background.

2:30 pm, view of the mouth of the Canyon. Most of the flow is now coming back into the Canyon from the Rio Grande.

2:30 pm, view of the mouth of the Canyon. The flow is now starting to flow back into the Canyon from the Rio Grande.

6 pm, mouth of the Canyon. The water is slack and backed up from the Rio Grande.

6 pm, mouth of the Canyon. The water is slack and backed up from the Rio Grande.

6 pm, view upstream to Eagle Cave.

6 pm, view upstream to Eagle Cave.

 

Tomorrow we will venture into Eagle Cave using the upper “Goat Trail” and continue working with Charles Frederick and Ken Lawrence while they do geoarchaeological sampling of the deposits in Eagle.  This flood event has reminded us of the power of water in the desert, and how all of the sites within Eagle Nest have been (and are being) impacted by flooding.

Cord-Wrapped Fiber Bundle: A Most Curious Artifact Comes to Light

By Kevin Hanselka

Cord-wrapped bundle as initially exposed.

Cord-wrapped bundle as initially exposed.

As discussed in the blog post of March 3, 2014, Leslie Bush and I recently joined Phil Dering as members of the Ancient Southwest Texas Project archaeobotany team. Our role is to study the massive amounts of well-preserved plant remains that are expected to be found in Eagle Cave, Kelley Cave, and Skiles Shelter.  And we have not been disappointed! While excavations and the analyses are ongoing, the bulk matrix samples we have looked at so far are overflowing with fascinating perishable materials reflecting the prehistoric inhabitants’ use of local plants for artifacts, fiber, and food.

In early May I returned to Eagle Nest Canyon to assist in the excavation of a remarkable plant processing feature in Kelley Cave.  When first encountered by Dan Rodriguez and Steve Black last summer, Feature 4 appeared to consist of a thick fiber layer capped by a uniform and seemingly purposeful layer of alluvial mud about 3-5 cm thick.  They hypothesized the mud layer was a prepared surface, presumably created by dumping basket loads of fine Rio Grande alluvium like that found in a flood deposit in adjacent Skiles Shelter.  However, sediment size analysis and comparison led geoarchaeologist Charles Frederick to favor an alternative idea: that the layer is a naturally deposited thin mud drape from the same impressive  flood that left an alluvial layer over one meter thick in the back of Skiles Shelter.  This fits with the fact that Kelley is some 5 meters higher in elevation than Skiles.  A tentative assessment of new radiocarbon dates from both sites suggests this extraordinarily massive flood may have occurred around AD 1350.

Kevin Hanselka pointing to cord-wrapped bundle when initially exposed.

Kevin Hanselka pointing to cord-wrapped bundle when initially exposed.

 

My interest in Feature 4 is in its layers of plant matter and the information they may contain about the cultural use of plant resources in the shelter. In other words, as Brooke Bonorden so eloquently stated in the March 3rd blog post, I want to assess these deposits for “… well-preserved evidence of full behavioral chains from plant collecting to baking to food consumption to fiber production to weaving and plaiting to finished object to final discard.” Most of the plant remains from Feature 4 probably represent the accumulation of waste products of food prepared in nearby earth ovens.  Mainly  trimmed-off outer leaf bases from baked agave lechuguilla stems or “hearts,” but also discarded agave quids (masticated inner leaf bases)  and other plant remains such as wild onion skins.   The food remains, however, may also be intermingled with manufacturing waste produced as leaves were stripped into fiber for weaving mats or baskets or for twisted twine.

Kevin using dental pick to gingerly free the artifact from the mud and fiber in which it was embedded.

Kevin using dental pick to gingerly free the artifact from the mud and fiber in which it was embedded.

Steve and Dan’s working hypothesis is that the Kelley Shelter occupants cooked plant foods such as lechuguilla, sotol, prickly pear, and wild onion in earth ovens near the mouth of the shelter, and then discarded the waste vegetal debris in dense layers, like that in the upper Feature 4.  A desirable side effect of this patterned behavior would be that plant layers would help suppress dust, making the shelter a more comfortable place to live and work.  We have been kicking around these ideas for several months and Steve had promised he would wait until I came back in early May to further explore Feature 4.

Hanselka takes photos of his handy work.

Hanselka takes photos of his handy work.

And so it was that Steve, fellow visiting archaeologist Drew Sitters, and I began to excavate a 50-x-100 cm unit placed just downslope (west) of the previously exposed mud-capped fiber layer in hopes of encountering buried cooking facilities just inside the shelter drip line.

After removing the disturbed surface layer and remnants of the mud drape/surface and exposing the underlying fiber layer (along with some scattered small burned rocks), we paused to thoroughly document the exposed layer using Structure from Motion (SfM) photogrammetry, as described by Charles Koenig in the January 23rd blog entry. While Steve and Drew took the photos, I busied myself with closely examining the floor of the shelter for interesting perishable artifacts. From my previous experiences in similar sites in Mexico and New Mexico, I know that tiny textile fragments, cordage, and unusual plant parts are often found just lying about the surface in dry rockshelters.

Again, I was not disappointed. In the middle of the previously exposed area of Feature 4 I noticed a small loop of tightly-wound fiber cordage protruding from the dust. Based on the coarseness of the strands, I tentatively interpreted it to be made from twisted lechuguilla leaf fibers. Carefully blowing and brushing away the surrounding dust revealed that the cord was exposed in a drying crack of the mud surface and that in seemed to be encircling a fibrous mass of what appeared to be lechuguilla leaves, and was tied in a simple knot on top. However, the exact nature of the artifact was unclear because it was embedded in the hardened mud drape atop the thick upper fiber layer of Feature 4.

As I later learned, Dan had spotted the same embedded cord last summer when the mud surface was first exposed.  He had left in place to be looked at more closely as the feature was more thoroughly documented. In the intervening months the mud cracks had widened such that I could see the cord was wrapping something.  Given that Dan and Steve had thoroughly documented the upper part of the feature exposure using SfM, Steve authorized me to expose the object in order to thoroughly document it before removal. Although most of Feature 4 will be left unexcavated and carefully protected for the future, Steve decided the collection of the specimen was justified.  Such perishable artifacts are extremely rare in the archaeological record except under the best preservation conditions, and because it will be vulnerable to future destruction by foot traffic in the shelter.  While human visitors can be encouraged to avoid sensitive areas of the site, feral hogs are known to frequent the shelter and wallow out sizable depressions where they sleep.

Cord-wrapped bundle as initially exposed.

Cord-wrapped bundle as initially exposed.

As all experienced archaeologists know, a time-honored rule in fieldwork is that the most interesting finds will most often occur in the last hours of your last day in the field. As it happened, I discovered the artifact about an hour before the end of the work day on a Saturday, and the crew takes Sunday off. What is more, I was scheduled to return home to Austin the next morning, so literally the find was made in the final minutes of my planned field visit before I had to leave Eagle Nest Canyon.  Rather than trying to stay late with the entire crew waiting around for me to finish exposing and removing the artifact (knowing that it would take some time), Steve and I elected to call it a day and return refreshed and alone the first thing the next morning.

Exposing and removing the artifact was a delicate and tedious process, and ultimately took several hours. Although it is well-preserved, the fibrous mass and cordage are very fragile, and they were firmly embedded in the mud drape.  In fact, the cord-wrapped bundle’s mud encasement is probably what protected and preserved it so well in the first place.  I worked to remove it hunched close to the ground, using a dental pick and tweezers (and occasionally the pliers on my multi-tool!) to carefully break up the hardened mud and separate it from the cordage, fibers, and thin fragments of prickly pear leaf epidermis (the “skin”) encircling the bundle. I constantly alternated between picking and tweezing and carefully brushing/blowing away the resulting debris.  Meanwhile Steve photographed the action, took notes, and lined a plastic container with paper towels in which we would cradle the artifact once it was freed.

Kevin lifts bundle out from where it has rested for 650 years.

Kevin lifts bundle out from where it has rested for 650 years.

The revealed artifact proved to be a short “bundle” of fibrous leaf material and a desiccated prickly pear pad bound with a short length of fiber cordage that had been tied into a simple knot on one side. Overall, it was less than 20 cm long and was found to be on top of two additional fragmentary prickly pear pads within the dense vegetal layer in Feature 4. The item must have been sitting on top of the fiber layer when the massive flood event deposited the sheet of mud that then hardened around it, encasing it and preserving it for us to find centuries later (although this is only our preliminary interpretation). Steve took several rounds of SfM photographs as the artifact was exposed and cut free.  The artifact was finally removed by severing the extraneous fibers and leaf fragments that clung to it and fused it to the vegetal layer below. We gingerly lifted it out and carefully put it in the box.

Cord-wrapped bundle awaits further investigation.

Cord-wrapped bundle awaits further investigation.

Back in the ASWT field lab on the Shumla Campus the cord-wrapped bundle awaits thorough documentation and cautious exploration. Next month the archaeobotany team hopes to more thoroughly clean the bundle and examine it in Phil Dering’s laboratory. We will have to strike a delicate balance between exposing it further for identification and interpretation and keeping it intact and preserving it for future study. As the analysis progresses, we will more fully assess what it is and what purpose it served, but for now, I simply classify it as a “bundle of fibrous leaf material, bound by knotted fiber cordage.”

Perishable items such as this more than likely comprised the vast majority of the material culture of the indigenous hunter-gatherer populations who called the Lower Pecos Canyonlands home.  But most perishable artifacts are simply no longer observable in the archaeological record in most settings.  They aren’t preserved in open campsites and, sadly, over the past 80 years most of the rockshelters of the region have been dug into by artifact collectors. The mere fact that this simple artifact has survived the centuries to be discovered and studied is testimony to the spectacular preservation conditions in the Eagle Nest Canyon shelters, and the rare window they provide into the daily lives of the ancient inhabitants of the Lower Pecos Canyonlands.  Once again we must tip our hats to the Skiles family for their stewardship of the canyon.

[Postscript by Steve Black:  We have enjoyed showing the curious cord-wrapped bundle nested in its box to our volunteer and visiting archaeologists.  Several have put forth interesting ideas.  Steve Davis pointed to the fact that the leaf sections protruding from one end of the bundle are charred, and suggested the object might be some sort of torch.  Carolyn Boyd reminded me in many ethnographic accounts from Mexico and the Southwest bundled plant materials were burned to create smoke during rituals. Elton Prewitt pronounced that the prickly pear skin visible within the bundle is part of a prickly pear pouch containing quids and leaf bases. Amy Reid made the excellent suggestion that we get the artifact x-ray CT scanned before dissection. All these ideas are being pondered and I expect the bundle has more than one secret yet to be revealed.

Feature 4 is proving to be much more substantial and complex than Dan and I had realized.  The 2014 Expedition crew is continuing to excavate several small excavation units through what we now think is a large earth oven facility that was used many times.  The upper fiber layer, cord-wrapped bundle, and the mud cap/drape are merely the last episodes of a much longer story.  I suspect the multiple lines of evidence we are developing on Feature 4 will be studied and written about for years to come.]