High-altitude Archaeolgy - August 2017

February 16 2017

Our August 2017 expedition plans to conduct an expanded archaeological survey, including a series of dives at extreme elevation, to investigate, map, and document pre-Incan/Incan ruins and artifacts in and around Laguna Sibinacocha located at 16,000 ft in the Peruvian Andes. Our expedition will utilize an OpenROV remotely operated vehicle (ROV) to document ruins and artifacts that we have already discovered in the lake, and to investigate and document new underwater sites, including those too deep for diving at such extreme altitudes. The ROV will also help target new dive sites, conserving the limited diving gas we’ll have at this remote location. An unmanned aerial vehicle (UAV) will be used to facilitate pedestrian surveys and to map the terrestrial findings and the surrounding landscape features.

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February 16 2017

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Name: Preston Sowell
E-Mail: sibinacocha@gmail.com
Account ID: 69101699


Preparation Stage

One of the targets for exploration on our next expedition is a large spring formed by a sinkhole that is located about 600ft/200m above the lake (at 16,600ft/5092m) and at a potentially important location. It's about 30ft/10m deep and such locations were (and are) often considered sacred sites in the Andean cultures. Often called "ojos" or 'eyes', they sometimes received offerings, which were thrown into them. In the photo you see below, the nearly 20,000ft (6100m) mountain of Jatunriti can be seen in the background. The water that flows from its rapidly-receding glacier feeds the lake and, eventually, the Amazon river itself.


Since our limited diving gas is precious up there, and our dive gear has to move around on horses, the ROV will be critical for this site. We'll be able to explore the spring to determine if anything might be down there and therefore, if we should even attempt to dive at the site. Diving at these altitudes is serious business.

One concern I have are the aquatic plants growing around the edges and walls of the spring. Does anyone have experience with operating an OpenROV around aquatic vegetation? How much of a concern is prop-fouling? If the the propellers do foul, are they easily cleared without damaging the motors?

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Great post! Prop-fouling is definitely something to be on the watch for. Before each dive make sure to check to make sure the props are secure on the motor shafts (would hate to have you lose a prop there). If you start getting some uneven thrust when moving around then it would probably be good to check the motors. I think your best bet will be to do a trial dive for 5-10 minutes and then pull the ROV out and see if there is going to be any issues. To clear the motors you can unscrew the prop from the motor and then clear debris and then screw the prop back on (just make sure to tighten it all the way).

Thanks for the advice Brian. I'll do some testing in local ponds to try and test those limits and make sure that we have a 'pre-flight' checklist that is fulfilled before we drop our precious ROV into the water!

Well, it looks like our ROV learning curve has become considerably less steep. I toured the St. Vrain Valley Schools Innovation Center here in Colorado this week and I am incredibly impressed with what these kids are doing! I plan to recruit the team for our project.


Working with a team from the Denver Zoo, they actually built an OpenROV for scientists studying the Lake Titicaca Water Frog (Telmatobius culeus) in Bolivia. Some of the team members have Spanish language skills so they are communicating directly with the Bolivian scientists. They're also designing their own ROV for a specific need that the city has.

One team is also working on a remote-controlled water craft to collect bathymetry data for Colorado reservoirs to help with water management. We still need good bathymetry for our lake...

Another team is focused on adding instrumentation to an unmanned aerial vehicle (UAV) for the University Corporation for Atmospheric Research (UCAR).

Once we get our new ROV, I'm hoping lean on their experience and to work with this group to help us outfit it for our needs and to do some testing.

Thanks for Axel, Craig and the team for inviting me!

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Hi Preston,


We're glad you were able to come and we're glad to be able to assist you with your project!

-Aidan Sesnic and the rest of the Aquatic Robotics Team

Thanks Aidan! I'm looking forward to your team's help when the new ROV comes.

Although protecting Peru’s cultural heritage is the primary objective of the archaeological research, by documenting the cultural features in the watershed, our hope is to protect the incredible ecosystem that exists there, along with the mature climate and ecological research projects that have been ongoing since 2000. Nearly the entire Vilcanota range has been proposed as a conservation area due to its biological diversity and the fact that it is the most important reservoir of fresh water in southern Peru. Our team with the Sibinacocha Watershed Project is working with a local conservation group called the Association for the Conservation and Study of Andean Mountains – Amazonia (ACEMAA) to promote these conservation efforts.


Surrounded by 6,000m/20,000ft high glaciated peaks and lying entirely above 16,000 ft, the Sibinacocha watershed is an extreme environment by any standard, yet it contains stunning natural beauty and a remarkable array of wildlife. Herds of vicuña and taruka deer (a Vulnerable species) roam the local mountains, studies have documented 54 species of birds in the area — many at their world record altitudes — and the highest frog populations in the world live on a pass above the lake. Puma and Pampas cats (a Near-Threatened species) stalk the local hills, and the Endangered, Andean mountain cat, one of the world’s most rare and elusive felines, has recently been documented there. Surprisingly, a species of Liolaemus lizard even lives these altitudes. In fact, as climate change and rapid deglaciation occurs, the watershed serves as a “living laboratory” for multidisciplinary research investigations on climate change and alpine ecology. Still, previous studies have only scratched the surface and there is so much more to discover.

This vast, deep lake is full of life, yet it has never received a biological survey. Introduced trout are growing to enormous size feeding on the lake’s native fauna, which have evolved without the presence of such a predator.

Additional urgency to protect the watershed was added in 2006 when environmental scientist Preston Sowell glimpsed what was a different and larger species of the aquatic frog genus, Telmatobius. This frog is potentially a new species, unique to Sibinacocha and unknown to science; however, it also looked remarkably similar to the Critically Endangered, Lake Titicaca Water Frog (Telmatobius Culeus), which was famously documented in the depths of Titicaca by Jacques Cousteau when he took a submersible into the lake in 1973. With the ROV we also plan to search for our frog at depths that the divers can’t safely reach.

Whether it is indeed a new species or part of an introduced population of the Titicaca frog (they are smuggled throughout the region), scientific documentation of the amphibian would be important. With this in mind, Sowell searched for years to find the frog again. Using a different approach in 2011, he donned a wetsuit, mask, and snorkel, and entered the icy waters of Sibinacocha to look in deeper areas. Although he didn’t locate the frog, what Sowell found instead was astonishing. Far from shore, rock structures and other artifacts lay well below the surface.

Sowell’s discovery provides the extraordinary opportunity to document, study, and preserve a previously unknown, and significant pre-Hispanic cultural site, and in doing so, to hopefully provide the vehicle for protecting one of the world’s natural treasures.

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Here's an example of what we can create using UAV-generated orthophotos. This is a digital elevation model (DEM) of one of the archaeological sites that we've already found. It was done by our UAV wizard, Larkin Carey of Falkor Aerials using a DJI Phantom and DroneDeploy's software. We're hoping to produce DEM's for every one of the structures we find so that our archaeological team can more easily study them when we're out of the field. This tool also saves valuable time when we are working in such a large area and at elevations that make it difficult to cover ground quickly. Larkin reports that the altitude does make flying a bit more difficult and it really chews through batteries!


Also included is a still image from the same scene for comparison.

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Interesting. Are you using photogrammetry for the 3D models?

That's correct David. We program a flight path to collect sufficient photos (including enough oblique photos) so that an accurate 3D model can be generated using photogrammetry. The DEMs can then be collected from the same dataset. I'm finding that details jump out in the DEMs that are not as obvious in the still images or 3D models (and visa versa). If I can edit the post, I'll include a still image for comparison. Now, I'm looking into applying a similar technique underwater using an ROV, which I understand is a bit trickier.

Expedition Background

Lying at 5000m/16,000ft in the Cordillera Vilcanota range of southern Peru, Laguna Sibinacocha is the largest (2.4 x 18km/1.5x11mi) high-alpine lake in South America. In 2011, expedition leader Preston Sowell discovered submerged ruins in the lake and the finding corroborates local legends that tell of structures submerged there. A dam was constructed at the lake’s outlet in 1992, but the ruins are located below the maximum depth that the dam raised the water level, indicating that the ruin site’s immersion occurred in an earlier time period. Regional paleoclimate studies indicate that prolonged dry periods have caused significant fluctuations in regional lake levels. Notably, one of these droughts occurred between A.D. 1160 and 1500, which is when the structures were likely built on the lake’s historical shoreline.


The highland people viewed mountain lakes as sacred features in the landscape and ceremonial sites were often placed in proximity to significant lakes. It is also intriguing to note that archeologists consider the highland region around Sibinacocha to be a “blank spot on the map” relative to Andean archaeology.

In 2015 and 2016, Sowell mounted two National Geographic-funded archaeological expeditions to the site with a team of Peruvian archaeologists. Those expeditions revealed that one of the submerged structures is a 100m/300ft long structure depicting a snake and made entirely of golden-colored stone, which indicates sacred architecture. Zigzag lines representing a serpent appear repetitively in the region between A.D. 900 and 1532. What appear to be intact offering pots were also discovered on the surrounding lake bed. Ceramic experts in Peru dated one of the pots to the Late Intermediate Period (A.D. 1000-1470), which correlates to the dry period from A.D. 1160-1500.

On the 2016 expedition we discovered a complex of five to six structures in the area. Our archaeologists believe that the complex is the most significant find made at Sibinacocha to date. Ceramic fragments have been collected from the various sites that date from the Middle Horizon (A.D. 100-1000), Inca (A.D. 1470-1532), Colonial (A.D. 1532-1791), and contemporaneous periods. We’ve also collected numerous lithics, including arrowheads from the Archaic period (>1500 B.C.). The relatively high artifact densities were surprising for such a high and remote site, and the archaeological findings, coupled with an evaluation of sacred landscape features, indicate that Sibinacocha likely held ceremonial significance to pre-Hispanic populations.

As with the high altitude mountaintop, Incan, ceremonial sites, the submerged site presents an extraordinary opportunity to study a sacred, pre-Incan/Incan structure with its offerings intact and as they were originally placed. The discovery of such a site is a novel find, even in Peru. Unfortunately, the lake's rapidly dropping water level and its exceptionally clear waters are making the structures and artifacts more visible and more accessible from shore, which could facilitate looting.

In fact, the lake's entire watershed is currently under threat. As trekkers move through the area with increasing frequency (overflow from popular, nearby treks such as the Inca Trail), the historical structures and artifacts around the lakeshore remain unprotected. A mining concession has been granted on the pass above the north end of the lake, near its primarily water source. Prospecting is already being conducted and miners are frequenting the area. Laboratory analysis of the ore identifies high gold content, which means that the mining is likely to intensify. Alarmingly, the ore was also high in sulfur-bearing minerals (pyrite), which cause an irreversible reaction that creates acid rock drainage when exposed to air and water. This could irreversibly and catastrophically affect the cultural material and the riverine and lake ecology for many years to come.

EXPEDITION OBJECTIVES: The significance of the submerged structures and surrounding offerings lies in their extraordinary state of preservation and lack of physical disturbance. Rapidly changing environmental conditions in the Sibinacocha watershed, coupled with new anthropogenic threats, mean that the site is becoming vulnerable to damage and looting. Therefore, the goal of our 2017 expedition is to conduct a rapid survey of the area to define the extent, function(s), characteristics, construction material, and the amount and types of cultural material in order to facilitate a plan for site stabilization, protection, excavation, and the recovery of cultural material.

Due to the cold water, altitude, and remote location (limited scuba tanks can be carried in on horses), our team will use an OpenROV remotely operated vehicle (ROV) to document ruins and artifacts that we have already discovered in the lake, and to investigate and document new underwater sites, including those too deep for diving at such extreme altitudes. The ROV will also help target and prioritize new dive sites, maximizing the limited diving gas and underwater time that we’ll have at this remote location.

We will utilize a differential global positioning system (GPS) coupled with an unmanned aerial vehicle (UAV) copter with a high definition (HD) camera to capture drone-generated orthophotos, which will allow us to rapidly survey the cultural sites and their surrounding landscape features. This will allow us to generate maps and a 3D model of each location, which will help us better understand if/how the sites may be related to each other and to significant local and regional landscape features (i.e., their integration into the landscape). Under recent Peruvian law, landscapes designated as “Cultural Landscapes” (those modified and utilized for important cultural purposes), are afforded protection. Additionally, cosmological alignments were important to pre-Hispanic, Andean cultures and the 3D model will allow us to evaluate potential cosmological alignments between the structures and landscape features. We have already recognized important alignments at several of the sites.

Following the expedition, we will produce a written report for submittal to the Peruvian Ministry of Culture (MOC) to promote official cultural site recognition and associated protections.

This project is being conducted in conjunction with the Peruvian Center for Maritime and Underwater Archaeology/El Centro Peruano de Arqueología Marítima y Subacuática (CPAMS) and our expedition will mobilize in August 2017.

For more about the ecological and climate research being conducted in the area, please check out our non-profit's website: www.sibinacocha.org.

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Hello all! I'd love to hear your thoughts on creating 3D model using OpenROV products.

This is such a fascinating expedition. I'm really excited to learn more!

Thank you @margretsinsky! We have a lot to do and a ton to learn!