Hail, Barges, and Bears—oh my! Along the shoreline of Emerald Bay in Lake Tahoe, a team of seven USC scientific divers working in collaboration with UC Davis, Cal Parks, and SCHNURS set up camp and prepared to conduct a dive of a lifetime. Over the coldest week of the season, this team of current students and alumni embraced high-altitude diving and created photogrammetric models of important material culture that reveals Lake Tahoe’s long history.
The research dive trip spanned five days along Emerald Bay to capture underwater photos of two huge wooden barges (one even spanning 165 feet in length) that would allow team members to create a 3D model of these sunken hulks. The team split into pairs and buddied up to complete this task. According to diver Fiona Hewitt, “Our goal was to create photogrammetry models. To ensure ample overlapping coverage among photos, we employed several techniques, including the “Christmas tree” method—swimming around the perimeter of the barges–and we also “mowed the lawn” by photographing in long lines across the structure. The team was able to accumulate a large quantity of photographic data and to produce a high-resolution 3D model. This model allows cultural resource managers to determine how quickly the underwater structures are deteriorating and whether heightened public access is having an impact.
The public became more aware of these submerged barges and other boats when Cal Parks inaugurated its first-ever underwater California Maritime Heritage Trail. Scientific diver and recent USC alumna Laura Findlay says, “We hope to use these models now and in the future when we return to create new ones. We can compare the two and see how much the environment and public attention is affecting these ships.”
Most of the image capture work was focused on the huge barges this time, but the scientific dive team also was able to document and explore smaller shipwrecks which also lie at the bottom of Emerald Bay, each telling a tale of Lake Tahoe’s popularity as a vacation, fishing, and adventure landscape. Additionally, the team hopes to increase understanding of the historical and environmental context.
The trip was an unqualified success, especially because the divers were willing to deal with wintry conditions. At night, the temperature dove to freezing and, during the day, it hailed. The divers’ resilience was tested. Diver and USC alumna, Anna Sun, stated “There was one dive we couldn’t complete because a thunderstorm appeared, and this is not a safe time to be diving.” “The weather fluctuations kept us on our toes. We stayed in a campsite with no showers and lived in tents. It was challenging, but I love that stuff,” Findlay said. Many members of the team commented that it felt warmer underwater than outside in the elements!
Most of the dive team was able to earn an NAUI Altitude Diving credential while in Lake Tahoe, where they dove at roughly 6500 feet above sea level, which is where most USC divers are accustomed to diving. According to Environmental Sciences student and Scientific Diver, Tati Velicier, “I’ve only ever dove in a marine ecosystem before, never in a lake, so it was my first time in freshwater and at altitude. The altitude diving training was a perfect way to ensure that I had the needed skills to allow me to safely adapt to diving so high in the mountains.” For many, At almost 6,500 feet, the physics of diving changes slightly, and most of us hadn’t experienced this kind of dive before so we were guided through the learning curve. We had to carefully plan for the conditions of diving at altitude in order to support our success and safety”, explained Findlay.
The dive team quickly adapted to the new elevation and acquired new skills that allowed them to SCUBA dive at altitude. The divers were thankful for the opportunity to learn these new skills because “you’re conducting science above a fragile historical structure which we don’t want to touch at all, because it could ruin it for all time. It’s historic and protected so that people in the future can enjoy it and learn from it, too. It was important for us to carefully control our position in the water, maintaining a good distance above the barges and kicking slowly and consistently. Also, we had to watch how we moved our fins so that we didn’t stir up any sediment that would wreck the visibility and make it hard to create good clear photos for the 3D models. There’s a lot to think about when you are hovering slowly above a protected cultural resource, keeping your buddy in sight, and the camera trained on the structure,” Velicier shared.
When not diving, the team downloaded photos, made meals in camp, and even enjoyed s’mores and singing around the evening fire. One day, we caught a glimpse of the bear that we’d heard was a regular resident in those parts. “We had just gotten back from the dive when I heard someone yell. It turned out there was a bear visiting the UC Davis camp! When you’re camping, you’re supposed to have everything that smells locked away in a bear box, to avoid attracting bears. That bear was on the other side of the campsite from our tents, luckily, but we named the bear Paul and took selfies with it in the background to remember the moment. He was big, even from far away,” Findlay explained.
This trip proved to be an expedition of a lifetime, fueled by the camaraderie of its participants and the sense of shared mission with the other teams who also were doing environmental surveys and preparation for diving in Antarctica, where it really is cold! “The scientific diving community is fairly small; there’s not as many of us as there are recreational divers. Our roughing it out together made me feel a strong sense of camaraderie. I hope to dive with these people again, ” Sun said. Hewitt recalled, “Actually, it felt a bit like a reunion. I reconnected with some of the divers who had helped teach my AAUS course through the summer Discovery Diving Program at Wrigley Marine Science Center.
“Also, I got to catch up with fellow archaeology majors and Catalina Maymester alumni, Laura (Findlay) and Anna (Sun), whom I hadn’t seen in nearly a year. It was wonderful to get to know the other science divers, Adham, Tati, and Victoria. You get to know people when there are few distractions at a remote campsite. We had lots of time when we weren’t diving because, to avoid “the bends” at altitude, we only dove two times per day, ” Hewitt explained.
For many, diving in Tahoe happened because the stars aligned, allowing them to make space in their schedule for this research trip to the California Maritime Heritage Trail. “I originally learned free diving during a course I took with Lynn Dodd on Catalina, and then she encouraged me to consider scientific diving. So I took a class at USC in the Spring term and became a Scientific Diver. This allowed me to get involved in a project like this and I hope to dive on other archaeology research projects around the world. Initially, I was afraid of the ocean, but soon diving became something I was really interested in,” Sun confessed. Velicer recommended, “Don’t be afraid to get into diving, it doesn’t matter who you are or where you come from. Try it if you think it looks cool because it is cool, and that’s what I did, and it has turned out great!”
For more information on diving courses offered at USC, check out the USC Dornsife Spring term course ENST 298: Introduction to Scientific Diving in the course catalog. Also, keep your eyes open for the publication of the study of these underwater structures and our 3D models! By comparing the changes in the models through time, we are able to investigate the impacts on California’s cultural resources.