Video
Business in Great Waters A Review and Assessment of Marine Archeological Remote Sensing Techniques and Technology 2
Transcript
Karen: Hello, and welcome to the NPS Archeology Program speaker series for Fall 2013 and Winter 201. My name is Karen Mudar and I'm an archeologist in the Washington office. This is the last lecture in a series devoted to geophysical technologies and archeological site locations. If you missed any of the previous webinars, you will be happy to know that you can access them through the archeology Program at the URL on your computer screen, that was formerly there. Dave, or Jim, you have to switch back to my introduction.
Jim: I didn't do anything.
Karen: There we go.
Dave: That was me. Sorry.
Karen: That's all right. Let's see if I can do this. Can everybody see the URL? There's the URL, at the bottom of the screen. We plan to hold another ad hoc seminar series in May and host talks by the Cotter Award winners. If you want to nominate a person or a project for the Cotter Award, instructions were sent in a special edition of the Archeology E-gram, or you can contact the award committee chair, Kari Kreshak. Her name is K-R-E-S-H-A-K.
Along with the Cotter Award winners, we're also happy to host talks that were given at professional meetings such as regional meetings, the Society for Historical Archeology, the Society for American Archeology, or other venues. If you've recently prepared a professional talk about NPS archeology, you would be doing your colleagues who couldn't be present a favor by giving it in the Archeology Program webinar series. Let me know if you want to give a webinar in May.
We also plan to launch another webinar series next fall, and the theme is yet to be determined. If you would like to see webinars devoted to a particular topic, send us your suggestions and we'll consider them. Two weeks ago, NPS archeologists Anne Vawser and Amanda Davies presented a talk about GIS entitled “Advancing Archeology In The Midwest Region Through GIS: Information Management, Modeling, And Analysis.” Their presentation discussed the Midwest Center's approach to data management and current projects, including the creation of standardized digital archeological base maps for each park unit in the region, recent modeling and analysis projects, and future plans to offer web GIS and mapping services. This was a very useful webinar, especially when coupled with the presentation given by Drew Labounty on GIS-based research conducted at Voyagers National Park, that was given in December. I want to give a big shout-out to Drew, Anne, and Amanda for pulling those presentations together for us.
Today we will hear a talk entitled “Business In Great Waters: A Review And Assessment Of Marine Archeological Remote Sensing Techniques And Technologies.” I want to read the summary to you, the abstract to you, exactly as it was sent to me:
“A talk not just for nerds, but also for any archeologist, manager, solicitor, or resource professional who may come into contact with marine remote sensing technologies and techniques. Hosted by the very charming and talented duo of NOAA's James P. Delgado, and NPS' Dave L. Conlin, and underwater team that should be compared to Click and Clack, the Tappet Brothers. This talk will take a global excursion on marine remote sensing to look at how underwater sites are located, interpreted, and documented utilizing remote sensing technology. Case studies, including deep water work on the wreck of the RMF Titanic, will be used extensively.
Two weeks ago I characterized myself as the Terry Gross of cultural resources in the park service, and I was challenged, in a good sort of way, for a more appropriate comparison. I think that my role is probably more like Jad Abumrad and Robert Krulwich at Radiolab, especially if there were two of me, or maybe Ira Glass from This American Life, although perhaps not so witty. Hosting these webinars has certainly given me an appreciation for people who speak to a radio audience week after week.
Jim: I personally was holding out for Paula Poundstone, but she dodged that one.
Karen: Before I introduce today's speakers, I want to remind people that the presentation is recorded, so set your phone to mute. Also, if you're having difficulty viewing the images, you might check your computer's operating system.
This is a good example of why we want to set our phones to mute. Thank you. Windows 7 and Internet Explorer appear to give the best results if you're having trouble with the viewing. There we go. One of our speakers today, as we've heard, is Dave Conlin, Chief of the NPS Submerged Resources Center. After undergraduate work at Reed College, Dave received a master's degree from Oxford University in Aegean and underwater archeology, and then followed this with a second master's degree and a Ph.D. in anthropology and archeology from Brown University. Following years of diving and research on the shipwrecks of the Aegean, Dave took a job as an underwater archeologist for the navy. While with the navy he helped plan and execute the recovery of the world's first successful combat submarine, the Confederate submersible H.L. Hunley, lost off Charleston, South Carolina, in 1864. Then he joined the Submerged Resources Center. Recent projects while he's been a park service employee include the search for John Paul Jones' ship, the Bonhomme Richard, diving on the wreck of a B-29 Superfortress that crashed into Lake Mead, diving on the wreck of the USS Arizona, working to document and preserve portions of the historic ferry, the Ellis Island, assisting the government of Mozambique in the creation of national parks to preserve historic shipwrecks and sensitive ecological areas off the African coast, and assisting with the study and documentation of the Titanic.
Our other speaker today is James Delgado, Director of Maritime Heritage in the office of National Marine Sanctuaries for NOAA, where he oversees heritage programs and active research in the nation's waters, as well as outreach and education on America's underwater and marine heritage. Among his duties is administering NOAA's oversight of the Titanic. Previously he served a four-year term as president and CEO of the Institute of Nautical Archeology, which is the world's leading scientific and educational organization, that is dedicated to the understanding of humanity's seafaring history through the excavation and scientific study of shipwrecks. Prior to that, he was the executive director of the Vancouver Maritime Museum in British Columbia, Canada for 15 years. Before that, he was the maritime historian for the park service, so he's one of us. He's the author of more than 30 books, the most recent being Misadventures of A Civil War Submarine: Iron, Guns, And Pearls, a book about the remains of the first successful deep diving submersible, built in 1864, that was recently discovered off the coast of Panama.
Thanks very much, Jim and Dave, for being with us today.
Jim: It's a pleasure and an honor.
Karen: Okay, you're on.
Dave: Thanks for organizing the seminar. I won't speak for my esteemed colleague Jim, but I will say that, for myself, my lectures are kind of like my cooking: Sometimes it's really good and sometimes it's absolutely horrible. Sometimes I think I'm talking about something and making sense, but often times I am not. If it's all right with you, Jim, let's just open this up. If people have questions, please don't wait until the end of the talk; butt right in and ask your question and we'll answer it as best we can at the time, because I think a lot of this is going to deal with visual information and examples, and I think it's always easier for people to ask questions while they are looking at what it is they have a question about.
Jim: Absolutely.
Dave: Just on another note I need to ... Full disclosure here, last time I did one of these things I ended up in the hospital for two and a half days, so I'm actually wearing hockey pads and a helmet as I'm talking here. Karen assures me that this will not happen again. If I'm mumbling a little bit, that's just my voice coming through the facemask.
Jim: You just lost somebody with that.
Karen: I wish I could assure you that's going to be true, but you never know.
Dave: Jim, why don't you talk a little bit about the program here, your program, and then I'll talk about what we use for the park service.
Jim: By all means, let's go to that slide. NOAA's Maritime Heritage Program has not been around as long as the park service Submerged Cultural Resources Center, but I will say that the two work hand in glove. Not only because we all hang out in the same night clubs, ride in the same limousines, or drink the same scotch, but because like-minded agencies with similar missions, oftentimes overlapping and connecting through parks and sanctuaries, but also through an understanding that there's a limited number of us out there who actively get the opportunity to work with this material on behalf of the people. An awful lot of what we do is absolutely cooperative, including being on each other's products, and a big shout-out to Dave and the Submerged Resources Center for all of the work they've done helping our teams out in the Atlantic along with BOEM, who funded the projects of the Battle of the Atlantic.
We're headquartered in Silver Springs just outside of DC, and we work in the 14 different units of the national marine sanctuary system. We also work outside, in the country, and internationally. In that vein, we've done projects where we've assessed sites that have recently been discovered by our colleagues in the Coast Survey, we've worked cooperatively with BOEM, for example, on new discoveries, as well as trying to characterize resources. We'll talk a little bit about one of those projects, actually two of those projects, a little later on.
An awful lot of what we do is not only initial survey location and characterization, but taking it a step further for management. Dave?
Dave: We're very, very similar to the Maritime Heritage Program at NOAA. For those of you who I haven't met, I hope to meet you at some point in time. We are park service, we are through and through, and our mission is to support our parks and to provide direct services to you guys as resource managers throughout the entire National Park Service system. We're always available. Pick up the phone if you have a question, if there's something that you need. Please give us a call, and we're happy to help out any way we can. We are a national program, but we're located in a region which provides an opportunity for us to get out into the field quite a bit, and we can show up at your park with the tools that we will all need to get jobs done if you have a particular resource need.
Of the 403 units of the National Park Service, approximately 200 of them have submerged lands, and on those submerged lands are thousands and thousands of archeological sites, ranging from shipwrecks to aircraft to submerged ranch houses to prehistoric sites, and everything in between. Our job is to assist our parks in the location, documentation, and interpretation of those resources. In that, marine remote sensing integrated into GIS is one of the primary ways that we conduct our research, organize our research, and understand what it is that we're doing.
Just really quickly, by the end of the webinar you'll be able to understand the most common types of marine remote sensing instruments, understand the strengths and weaknesses of each of the different kinds of instruments, understand the role of survey design in the collection and interpretation of marine remote sensing data. Again, I won't speak for my colleague, Jim, but I would say that the fourth thing, which is most important, is to wow your fellow archeologists a cocktail parties with your arcane knowledge of marine remote sensing techniques.
This is my brother, cutting pizza for the family. I'm just kidding. I put this slide in here because marine remote sensing equipment is a diverse array of tools, and really the point here of this webinar is to give you guys some familiarity with the range of tools out there so that you can collect the right tool for the job. Do you need, for example, the office special tool, or do you need the one-size-fits-all tool to address your resource and marine remote sensing needs here? Actually we've got a couple of these, we'll give them out as a prize at the end of the webinar for the best question that's asked over the course of the talk.
Jim: Actually, isn't this the tool that we use for budgeting?
Dave: Yeah, actually you can't see it, but it says FBMS on the back of it. Starting at the top of the hit parade, we'll talk a little bit about marine magnetometers. A marine magnetometer is very, very similar to a terrestrial magnetometer, except obviously it's towed behind a boat. You tow it behind a boat so it's clear of any sort of electromagnetic interference from engines or other things. It detects variations in Earth's ambient magnetic field caused by ferrous material. The earth has an ambient magnetic field, and then the presence of iron distorts that field positively or negatively, and offers an indication of what might be there. Typically it's towed in the towfish behind the boats, in a survey grid just like a terrestrial archeological field survey, and it's one of the most common marine remote sensing instruments used for marine archeology.
This is the principle of operation here. You can see these lines here. These are the survey track lines. This right here is the object itself. As you tow the magnetometer through the magnetic field, what happens is that you're going along, everything's fine, everything's fine, and then you get a slight dip, and then you get a negative and positive, or a positive and a negative. This sort of heartbeat curve is very characteristic for a magnetometer anomaly.
I'll say this now and I'll say this again: you cannot tell, and do not let anyone convince you otherwise, from looking at the magnetic anomaly, what that thing is. We have found a television set at Dry Tortugas National Park out in the middle of the Gulf of Mexico that threw off a huge magnetic anomaly, and we were sure it was a shipwreck, and it was not. We've found milk crates, we've found car axles, we've found all sorts of things. You cannot tell, just by looking at something like this, what the object actually is.
Up here you can see this is how we in the park service, and also our colleagues at NOAA, this is typically how they interpret their magnetometer data, as contour lines of isogammas around the different objects. This is typically provided to our resource managers as a GIS layer in a GIS.
Here is an example of actual in-field data. This line right here is the boundary between Biscayne National Park up here, and Florida Keys National Marine Sanctuary down here. Jim, we found some pipe and a rope in the sanctuary for you. You're welcome.
Jim: Thank you.
Dave: You can see here, this piece right here, this piece is a huge magnetic anomaly. What that actually is, is it's a relic channel marker for the in-shore channel there, the intercoastal waterway. If you look over here you can see these marks, and what these are, these are magnetic anomalies that the team has actually gone out and had a look at because, as I said, you can't tell just by looking at the anomaly what it is, so you actually have to put eyes on it. We've got a lobster trap, another lobster trap, and then a buried lobster trap. There's lots and lots of lobster traps down at Biscayne National Park.
Every once in a while we come up on something pretty spectacular. This is an anchor from HMS Fowey, a British warship that sank at Biscayne National Park, and this is one of our archeologists, Jessica Keller, doing a in-field documentation of the anchor itself. While I said that you cannot tell by looking at the magnetic anomaly what the object is, you can tell sort of by looking at the data, how big the ferrous material actually is. Over here, this is a table of historic anchor weights, discussing various sizes of anchor for various sizes of ships. This anchor is the appropriate size for a ketch anchor, for HMS Fowey, and its proximity to the wreck site gives us some confidence that that's actually a related artifact.
The strengths of a marine magnetometer are that it can detect materials buried under the sea floor, it is capable of finding very, very small objects, sometimes less than a kilogram, under ideal circumstances, and you can move very quickly towing a magnetometer behind a boat. You don't have to go slowly, you so you can survey a very large area in a small amount of time. That's about a square mile a day, depending on conditions and also on survey design, so how closely your lane spacing is, so how close together consecutive tows of the towfish are going to be over your survey area.
Some of the weaknesses of the marine magnetometer are that the magnetometer data is often ambiguous, and it requires experience to interpret. It's not immediately obvious looking at stuff, necessarily, that one thing is a magnetic anomaly or not, and if it's noise that was produced by the instrument, or produced as a result of the post processing of the data. Then - this is really a big issue, it has to do with physics, and that is that because magnetic intensity decreases as a cube function of distance - the instrument effectiveness drops off dramatically the further you get from an object. We were helping our colleagues at BOEM do a little bit of post-project analysis on some data that they got from a contractor, and we looked at their lane spacing. They had 200-meter lane spacing, I think, and then we did some theoretical calculations and it turned out that if a small trawler had sunk in between their two survey lanes, there's no way that the instrument would have picked it up. I think they were a little disappointed when we told them that they didn't have the coverage that they thought they had. And again, you cannot tell, simply by looking at magnetometer data, what's been located by the instrument.
Jim, anything to add?
Jim: No, that's great.
Dave: The two instruments you're really going to see a lot of in underwater archeology for remote sensing are a magnetometer and then a side scan sonar. This is a Klein 5000. The park service, we have one of them, we're trying to get another one for our parks. The way that the side scan sonar works is, it emits a sound pulse from these ... There's one of these emitters on either side, and it sends a sound pulse out sideways and then catches the return, and it uses that to kind of paint an acoustic picture of the bottom. What it does is, it translates the two-way sound travel time into distance, and then the strength of the signal return into brightness of an image. Again, it's one of the most common remote sensing instruments used in marine archeological surveys.
This is an example of a side scan sonar image. This is the wreck of the Dixie Arrow, which was a American tanker torpedoed by German U-boats off the coast of North Carolina in the opening days of World War II. Incidentally, a huge shout-out to NOAA for a great show on National Geographic Chanel last night, by the way.
Jim: Thank you, Joe Hoyt will be is signing autographs later.
Dave: You look good, Joe, I have to say you added an appropriate amount of gravitas to an otherwise fairly young crew. It was a great show.
Joe: That's entirely why I dyed my hair white and grew the beard.
Dave: You can see here, these are three boilers for the wreck. After the war the wreck was dynamited and leveled to reduce it as a hazard to navigation, but you can see right here, the ship was torpedoed and actually broke in half before it hit the bottom. This sort of data doesn't take a lot of imagination to interpret. This is another wreck in Flower Garden Bank ... No, I'm sorry, it's in Stellwagen Bank, in Massachusetts, which is a national marine sanctuary. I don't know much about that particular site.
The strengths of side scan sonar are that it can provide images that result in the positive identification of a target. Contrary to a magnetometer, where the data's always ambiguous, a side scan sonar can sometimes offer up a clear picture of something, and you can determine sometimes from the data that it is or is not the site that you're looking for. It collects data in a much wider swath than a magnetometer, so 100 to 300 meters per side. Each one of the sides of the sonar emits a sound pulse up to 100 or 300 meters, and depending on the frequency. So, as the frequency gets lower, the ability for the sound pulse to travel through water increases, but you lose resolution, so you don't get as clear of a picture, but the sound pulse goes further. You can survey a very large area in a small amount of time, about two square miles per day, depending on conditions and survey design.
Some of the weaknesses of side scan sonar are that you have to tow pretty slowly to ensure good image quality. If you move too quickly the image gets really streaky and you lose data resolution. Obviously it can only shine a sound pulse onto something that's sticking up off the bottom, so it can't detect material buried in the bottom. Sea conditions have to be pretty good. If you're bouncing around and the boat is heaving and yawing, it'll jerk the fish around and then you'll get uneven data quality.
Multibeam sonar, and I think that this is something that Jim has a little bit more experience with than I do, so Jim, you want to ... ?
Jim: Multibeam – thanks, Dave - multibeam sonar, is sonar, just like side scan, but instead of beams broadcasting out the sides, this thing broadcasts forward. It's got a multitude of beams, and what it's giving you is a much more 3D picture, if you will. We love these things, and they're a part of the regular suite of tools that NOAA has in its Office of Coast Survey. We've got a number of boats around the country that do this. One of the nice things about being part of NOAA for us at Maritime Heritage is that they're out there surveying waters, we oftentimes will get this data, and if it happens to be a cultural target we're able to use that, not always in one of our areas, but sometimes they're out there. Like the slide says, by looking down it gives you, really, a contoured 3D image. Why don't we show them one, Dave.
Dave: Okay.
Jim: Yeah, they do cost. Here, you've got a standard boat out there deploying its multibeam system, and as you can see at the bottom you can see, the characterization of the bottom there, how this thing works in lanes and paints it, is exactly what you see. Next one, Dave.
This is a target actually, just outside of Golden Gate National Recreation Area at the entrance to the Golden Gate in San Francisco. I'm going to point out a couple things. While this is a pretty crisp multibeam image, it's way up high. The wreck's in 240 feet of water, it's largely covered in mud, but what you're looking at here is the 1888 shipwreck of the coastal steamer City of Chester, which was rammed and sunk with the loss of 13 lives by an incoming ocean liner, the Oceanic, with in inbound cargo of immigrants.
Here you can see, this isn't a completely processed image, I sent Dave one of the ones that still had to be smoothed out. All those little peaks and spikes you see there are actual anomalies that, in post-processing would get cleaned out. What you can see on the bed right here at the base of this slope is the wreck of City of Chester. Unlike a magnetometer, you can make some conclusions. Coming out of it, you can see that there appears to be structure amidships, more towards the back end. That can either be exposed machinery or superstructure, we just don't know, it's not crisp enough, because the instrument that took this was up on the surface, and it had to go through 240 feet of water. Then forward, you see the buried hull.
When you get closer, multibeam gets much tighter. This is a recent project that we did with our colleagues with BOEM, BSEE, Maryland Center for Ocean And The Environment, the Ocean Exploration Trust, the Maryland Historical Society, the Texas Historical Commission, NOAA's Office of Ocean Exploration and Research and NOAA's Office of National Marine Sanctuaries. This is a shipwreck which was found in 4,300 feet of water off of Galveston in the Gulf of Mexico. It is a wooden-hulled vessel, copper sheathed, with a variety of artifacts inside.
This multibeam sonar on an ROV, which ran lanes, stitched back together by the digitalization lab of Dr. Chris Roman at the University of Rhode Island, shows you a contoured view that is, in the original program, maneuverable 3D. What you can see is the sharp outline of the hull, you can see sediment which has built up on the starboard side of the hull. You can also see up forward, you can see the anchor. You can also move farther out, there's a pile of artifacts which includes a long gun, a series of buried guns underneath it which don't really jump out, a long reinforcing bar or a pivot for what was a center mounted pivoting gun. The more reddish-looking box is the ship's stove. Then farther aft there's a couple of greenish anomalies, and those are small carronades or guns which were found lying in that area. If you look carefully in this as well, you can see striations in the mud which are not found artifacts, but which do represent the floors or the frames of the vessel. This is about the best and the tightest that we'll get with a multibeam.
Karen: How deep is the water?
Jim: 4,300 feet.
Karen: Oh my goodness!
Jim: Here's the bow of that shipwreck, known as the Monterey Bay Wreck. This is one that, working with Jack Irion and Chris Horell , Amy Borgens , Frank Cantelas, a number of us, we went out and looked at these wrecks past summer. As you can see, it's a copper sheathed sharp hull, probably early 19th century, maybe late 18th, a very unique and interesting site. All of this work was done with ROVs, and in this case the ROV mounted the sonar head.
Dave, I actually don't have the ability to drive the slides, so ...
Dave: If you move your mouse down to the lower left hand corner you can click on the arrow at 2458.
Jim: Oh my God!
Dave: Yeah, go ahead and [crosstalk 00:34:12]
Jim: You're showing what a Luddite I am, dude. Awesome.
Karen: Sorry, that should've been part of my pre-training.
Jim: Okay. As you see here, these can really give you crisp images that can really help to [say] ... “Yes, it is a shipwreck.” In some cases they can be sharp enough where you can actually say, "Yeah, it really matches the characteristics." In the Battle of the Atlantic survey, some of the multibeams are crisp enough that you can actually make out diagnostic hull features. Where exactly is that arrow?
Dave: It's right down there. See?
Jim: Sorry, not showing up on my screen. Like I said, they're on the hull, click, and they can go faster. We cover a lot of ground as NOAA did KOKOA survey with these.
Moving on, these 3D point clouds really give us solid bathic data, which is what they're designed to do, and we can use that data for a variety of reasons, or means. Go ahead. How is it weak? It is costly. Very costly.
Dave: That's why NOAA has them and park service doesn't.
Jim: That's because we've got a coast survey, and we've got to keep those nation's waterways open after storms. It can't find stuff that's buried, and we really have to have good conditions, absolutely good conditions, for it to work. If it's really rough or bouncy it ain't going to happen, and deep water, shallow water, both give us problems. Again, go back to City of Chester image. It would've been sharper, like the other one, had we been able to get the head down there. And it's difficult to process at times. It takes specific software and it's tough to interpret.
Dave: All right Jim, you've done the most recent work with sector scanning sonar too, do you want to-
Jim: Okay. Sector scanning sonar is one of the latest toys, so a couple of systems that are out there on the market. One that I've used more often than not is BlueView, which is the commercial name of one of these. It basically works by deploying, either on an ROV or a sub or a set platform. You can take a tripod down and put it on the bottom, gives a sound pulse, and then looks at everything around it. It translates that two-way sound into distance, and the brighter the image, that is the sharper it is, the more metal, sometimes it'll give you a stronger return. It is stationary, and you actually put it in place, and it rotates and then you move on. It's a great documentation tool, but you don't use it for surveys.
This is the BlueView system on the back of the Flower Garden Banks National Marine Sanctuary vessel, Manta. You can see the actual head itself, different sizes and different configurations. These things are rated for depth, they've been working now to get these down to Titanic-type depths. They're not very expensive, a Titanic-type of sonar head capable of withstanding that pressure's well over a quarter of a million dollars.
This is the BlueView scan that we just did with our colleagues from BOEM and BSEE and Texas Historical Commission, of the exposing remains of the USS Hatteras, a Civil War ironclad gunboat which was sunk in combat with the Confederate raider CSS Alabama off the coast of Galveston on January 11th, 1863. What you have coming out of the sediment here, here, is a bit of structural machinery. You've got the paddle wheel shaft with part of the engine mechanism amidships. You've got the hubs of the paddle wheels, and then you actually have, particularly if you look toward the bottom of the image, some of the paddle wheels themselves. Then if you move further back you can see the outline of the frames of the stern of the vessel. Everything else you're seeing there is the bottom contour. The little circles are artifacts from the sound processing. That's where that head was placed.
In the case of this project, and there's the Alabama being sunk by the Hatteras, visibility is pretty bad. We had divers that were deployed off Manta using comms, they would go down, they’d position that head as best they could, they'd have to crouch down, that thing would rotate, get the readings, it's cabled back up to the surface, and with that, with the technician saying, "Okay, good," then these guys would have to swim and move it. This was a very labor-intensive project, a lot of diver time and, thank goodness, we were only in 60 feet of water, but as you can see, it gave us a really good detailed sense. That data is 3D. You can even animate this, and in some cases we've done fly-throughs that we've put on BlueView. Also it allows us, above and beyond flick presentation, it gives us a chance to 3D-document these things. In the case of the Hatteras paddle wheel shaft, all the dents and distortions were clearly delineated.
This is another project using BlueView, and in this case this was the first time we used it on a shipwreck. This is the H.A. Goddard, a prefabricated iron hulled vessel built within San Francisco, Portland and Seattle, disassembled and shipped to Alaska, it was hauled in pieces over the passes, and then reassembled on the shores of Lake Labarge, and in 1897, 98, 99, and 100, was an active participant in the Klondike gold rush. It sank in a winter storm in October, October 27th 1901, on Lake Labarge, and was rediscovered by a project team from Yukon and the Institute of Nautical Archeology.
In using this, and again you see the circles that show you where the BlueView unit was situated, this is a vessel in 45 feet of cold water in a wilderness area. It has survived with remarkably good preservation. What you can see there is not only the hull itself, but the white structure you see is actually two and a half inch diameter galvanized steel pipe which formed the framework on which canvas was stowed. If you move aft you can see, in lighter green, the paddle wheels themselves. Off to one side there's a green thicker object that's just up at the edge of the scanned seabed; that's the detached steam whistle and blowoff valve for the steam engine. You can also see that the hull has a bulwark, or a stanchion, right up ahead of ...
Dave: No sign of Sam McGee anywhere?
Jim: Nope. No, but indeed this is the lake where on the marsh of Lake Labarge they cremated Sam McGee, in a vessel not unlike this. Here a closeup view of what they were able to do, again you can see the white ghosting, which has been dialed back. The resolution is very, very sharp. This is a resolution that's been done for simple presentation. The final detailed BlueView on this is so sharp that it's a massive multimegabyte-sized TIFF. In this case, what you can see are the outlines of the boiler in white, the pipework, and you can see a bit of the stanchions at the bulwarks at the bow. They lowered the instrument into the bow, just stuck the head in quickly and did a quick rotation in the bow compartment, and so what you see there is the actual interior and the shape of the bow with its compartments delineated. Pretty cool.
This stuff works great. It gives a superb 3D, even in zero vis, it gives us better detail than even a multibeam can, and it gets you everything possible, if you can move that head around and capture enough data. Again, like with multibeam, you get these point clouds that can be used for all sorts of stuff, including the size of a hull, that you can determine the tonnage of a ship, even if you BlueViewed a barrel, you could determine what its capacity was.
But it's short, you have to get it pretty close to the site, you have to keep it stationary, you can't move it or jostle it, you've got to make sure it makes its rotations, you've got to really move it and haul it all over, which means that if there's any kind of current, any kind of sea running, it gets to be dicey. The first open water ocean test of it was the Hatteras, and it showed us that we needed to take a lot more time. For example, we weren't able to BlueView the entire Hatteras wreck. Over time, the more data you get, it can be tough to sort of meld it all together, but we're hoping to go back to Hatteras later this year and re-BlueView it, and see if we can merge the two together and determine change over time. Even with that, it's tough to process, it takes time, it takes specialized software, and it can be difficult to interpret.
Dave: Again, I hate to keep ceding the floor to ... I don't actually hate to keep ceding the floor to my colleague from NOAA, but a lot of these techniques and technologies have been used extensively by NOAA, so again, Jim, do you want to just talk about your LiDar project?
Jim: I will, but I'm going to give a shout-out to the park service because LiDar has been used by the Historic American Engineering Record to document sites for quite a while, and now, increasingly, in marine operations. This is light radar. We use it out there. We don't use this stuff underwater, but not every maritime archeological site is underwater. Some of them are out there on land, on beaches, they're exposed. Shipwreck remains, there's a number of those out at Cape Hatteras National Seashore, Cape Cod has them, Golden Gate has them. You've also got stuff in wilderness environments, so you can use it.
Like the sound, it translates two-way travel into distance with the head, and it has incredible resolution, as you'll see. It's a pretty spiffy system. Again, you can mount these, you can put them on helicopters, you can put them on drones, you can also put them on a tripod. Some people have actually deployed them from aerial balloons.
To give you a sense of how great this stuff is, Hollywood is currently using LiDar. They'll do something like fly a chopper over an area, say downtown New York, LiDar map it, and then that point cloud system goes into software, and that's what Hollywood will use to then CGI a scene. For those of you who saw The Day After Tomorrow, with Dennis Quaid rescuing his son from a global freeze and the flooding of New York, they LiDar'd downtown, and then using the LiDar of downtown New York to the public library, then used that as their real data point, on which they then digitally flooded Manhattan.
Dave: I thought they just used the Midwest last week for that whole thing.
Jim: No, just Colorado and Kansas. Here you can see a LiDar system as it's mounted on an aircraft, and there you can see the actual head. We've used it in marine applications in a couple of cases. We used it in Panama as a test with a Civil War submarine that comes out of the water at low tide, but we also used it in the first big archeological documentation of a wreck. This is Evelyn, another Klondike gold rush vessel, that was abandoned in the early 1920s in the middle of an island in the middle of the Yukon. Nobody gets here unless they ... It's a wilderness camping situation. You have to get in, backpack in, get into a kayak or a canoe, and then go down the river, stop, get off, and then in the wilderness on this tiny island that had been a shipyard, in the middle of the forest, is the wreck of the Evelyn.
It is an incredible craft. All they did was take the engines out to use them in another vessel. The boilers remain in place and the hull is there. You can still see the stack, rigging, it is starting to fall apart in the elements, it's rickety. It's so rickety that it was feared that if the team went in and started really crawling all over it, trying to map it by hand, not only could they not do it in time, but the thing might collapse, so they LiDar'd the whole thing. This is one profile view of it. Here's the other.
What's spiffy about this is that it's more than just a photographic capture. This is 3D, it is incredibly measured data, and you can manipulate and use this is a variety of ways. You can rotate it, look at it. You can, by putting these things inside, what you do is, you literally create a fly-through that, at this resolution, sort of dialed down, is nothing like the almost ... Well it is practically photographic. Often times we don't show the fully processed LiDar because people don't believe it's just done with LiDar, they think it's a photograph.
With this you're able to actually measure the space in nails, or bolts, or rivets in a hull. You're able to determine the sag of a line. And because it's much like a full-on CTI scan, you can even slice it and dice it and begin to look at things. In this case, with the Evelyn, what you're seeing is superstructure, you're seeing the hull, you can see how the hull is starting to sag, you can see braces. Those things that are hanging down like stalactites in the lower hull, that's actually oakum, or caulking, between the deck planks, that's hanging and sagging down.
It's an amazing tool, to say the least, and has tremendous application in dealing with maritime sites, as well as buildings or any other archeological site. If we've got a wreck that's out there, in 3D, I'd much rather LiDar it if it's on a beach or sticking out of the water. What we're able to do now is, in a partnership with some of the LiDar guys and the BlueView guys, you can actually merge the two systems together. You get a loss of some resolution once you go beneath the water, but even so, it gives you a tremendous capture of a site. We get tremendous detail, and if you've got it, like I said, you can slice it, dice it, it is the Ginsu knife set of maritime documentation.
Dave: We're also working with our colleagues at Parks Canada. Parks Canada has an underwater archeology team very similar to NOAA's and to ours, and they are experimenting with in-water LiDar. They have to use a different color laser, a more powerful one too, but they're getting some results. Unfortunately it doesn't work in water yet, but it looks like it may be possible.
Jim: Absolutely, because that's the biggest weakness, though they've started to work on this with some algorithms. In cold or still water, say the Great Lakes, they think that if you can get it to within 10 meters, we should be able to get very high resolution. Dave, we might be trying one of those out at Thunder Bay this year, so if so, we'll invite you. Again, just in terms of weaknesses, you've got to carefully deploy it, and it's tough sometimes to stitch together, tough, to process and interpret, and it is not cheap. Dave, over to you.
Dave: I just kind of put this in here, sub-bottom profiler, because one of my pet peeves dealing with my archeological colleagues is, they say, "we're going to go out and we're going to look for a buried ship wreck and we're going to use a sub-bottom profiler." I just put that in there. We'll talk a little bit about it. I have a particular viewpoint about sub-bottom profilers which I'm going to share with you in just a second, but let's talk about how it works.
It uses one or more high-amplitude, low-frequency acoustic pulses to ... Pointing downwards, you can see here this is a towed array, but actually the emitter is this black thing on the bottom here. It's the sound frequency and the amplitude ... The strength of the sound frequency is designed to actually penetrate the bottom and to give you some information about what is below the bottom. Again, like BlueView, like sector scanning sonar, and like a side scan sonar, it translates two-way sound travel time into distance, but it is a low-resolution system. The high-resolution, like the sector scanning sonars, those high-frequency sounds have much better resolution, but they travel a shorter distance and they're incapable of penetrating sediment. What happens with the sub-bottom profiler is, they use a much lower frequency of sound that's able to penetrate, but the tradeoff there is, you just lose your ability to resolve things. Again, typically deployed as a towfish or mounted on the hull.
This is how it works. Here's a survey vessel with the sub-bottom profiler transducer, and this is actually what sub-bottom profile data looks like. You can see this is the sea floor, you can see a geological strata underneath there, and then this would be a geological feature that exists above or around the other strata.
Here is a sub-bottom profiler image of the sea floor off of Charleston, South Carolina prior to the H.L. Hunley Project, and I have a SRC T-shirt for the first person on the phone who can tell me where the Confederate submarine is located in this picture.
Jim: It's on the next slide.
Dave: Any takers out there? The truth of the matter is, it turned out it was right there. The only reason that we were able to know that it was right there, because right there, there was a buoy that went to the surface, and as we towed the sub-bottom profiler over it, the tech who was looking at the screen on the computer, and also looking over his shoulder as we towed past it, once he got to the point where he was pretty sure that the towfish was over the site, he looked at his data and said, "Oh yeah, it's right there, can't miss it."
Here is another ... This is a Henry VIII’s ship, Grace Dew, that was sunk off of England. What they did is, a team of geophysical researchers from Southampton got together and decided that they were going to document the shipwreck using a sub-bottom profiler. Again, if you know that the shipwreck is right there, which they did because actually the frame stuck up out of the bottom, you can tell that that's where the shipwreck is.
I just include that because every time my underwater archeological colleagues say, "We're going to go out, we're going to look for a shipwreck using the sub-bottom profiler," I want to scream. We've had a number of conversations about using a sub-bottom profiler to find paleoindian sites offshore; not going to work. Find other sites that are buried in lakes; not going to work.
The strengths of it, though, are that it penetrates the sea floor, and it compliments other remote sensing technologies. Its weaknesses are, it's low-frequency, lacks resolution capability, and it does not work to locate or to document shipwrecks.
What it does work well at, let me just back up here, is that it does tell you something about the geology of where a site is located, and what you can say based on that. These are layers ... This is the scour pocket caused by H.R. Hunley, but these geological layers are layers that have a different consistency than the other geology around it. What you can say is that, for Hunley and the Housatonic, which is the ship that Hunley sank in 1864, what we found is that both of these sites had scoured down to be pretty close to resting on this relatively impermeable layer. That has been my experience of the utility of sub-bottom profilers in underwater archeology.
Next we'll move back to the realm of really cool expensive toys. Jim, do you want to talk a little bit about AUVs?
Jim: AUVs are pretty cool. They are, basically, small submersibles that fly on their own, can carry all sorts of payloads. We've used them extensively, with increasing frequency now, to do surveys. You don't have to tow, you just launch them. Off they go, they can run for hours, come back up, and if you're not there to pick them up, they call you on your cellphone. They're cheaper, they're more common, this former defense technology is becoming much more achievable for budget, and actually over time I think they'll prove to be cheaper than going and sending a boat out to survey. But they're not cheap yet, they're still pretty costly.
Karen: Are they like the drones of the sea?
Jim: They are drones of the sea. This is the Remus 6000, this is the big boy. 6000 refers to its depth capacity in meters, and as you can see, has a whole range of sensors. This guy is capable of going on a 20-hour mission to those kinds of depths. It can run a tight survey grid collecting all of this information, it can avoid collisions with a forward collision-avoidance laser, and it packs a lot of data in. It's deployed off the stern of a ship in a launch such as you see here. This is the systems that we used out on Titanic in 2010, and this is how it's also recovered. This is multibeam survey data of Titanic, starting with, everything in color is NOAA bathymetry-gathered with multibeam, 2003, 2004.
The inset in this box is what we did with the AUVs on Titanic. Moving in, you see a broader survey box, and then as you get closer - this is the Titanic site, again - done entirely by stitching together the AUV data. The sonar, as you see here, really starts to define it brilliantly.
Dave: This is side scan sonar data. Jim, how deep is Titanic?
Jim: 12,436 feet.
Dave: The AUVs really address a fundamental flaw with a lot of marine remote sensing technology, especially when you're talking about trying to deploy instruments that deep. 12,000 feet deep, two and a half miles, what happens is that if you're trying to tow an instrument behind a ship that's that deep, your tow cable is going to be six miles long, and you're going to have to put thousands and thousands of pounds of weight onto it to get down. It's just very, very clumsy to run one survey lane, and then turn around when you've got six miles of cable behind you. The whole thing is very clumsy. AUVs have really filled an important niche, and have advanced possibilities for deep water marine remote sensing that we hadn't had beforehand. Sorry to interrupt.
Jim: No, that's great. What you can see is, there's different resolutions. We started with a bigger box, and then as we started encountering the full spread of the Titanic site, we got closer and tighter. As I've zoomed in with this, you can see that. Here you can see the bow of the Titanic, and what the side scan also shows, the dark area, is displaced bottom sediment from the impact. The stern of Titanic, there is an artifact field, which is defined in this area, and as we zoomed in we were able to get down to that in much closer detail. Here's the stern of Titanic, for example, just from the AUV site scan data.
Dave: I put this here to jog our memory, because I think one of the things that we'd really like to spend a little bit of time talking with you all about is survey design, and survey parameters. This is the original plan for the survey. These individual lines, those are the programmed survey tracks for the AUV. Then you can see they ran it both ways. Then over the smaller area that's higher resolution, you can see that the survey tracks are much, much tighter.
One of the other things that I want to talk a little bit about is these lines here that are really perfectly spaced. That is the pre-programmed, that's what we wanted the AUV to do, but if you could zoom in here and look at these things, you'll see that there's a little bit of variation here, because you never quite get what it is that you want.
Jim: One of the things we discovered with that, by the way, is that the collision avoidance lasers often times would detect artifacts, or a portion of hull structure on the bottom, and it would force the instrument to go off of its previously designed course. That created widows, gaps ... We had planned to do 100% survey coverage. We did a little better than that. We should've done 300% to account for all of those variations.
Dave: 300% survey coverage would mean, on a side scan sonar, that would mean each beam off the side would overlap three-fold. Each part of the sea floor would be imaged on three separate occasions. 100% coverage, when you guys are talking, people who are doing sonar work, if they say, "We're going to do 100% coverage," that's not good enough. Because a plan for 100% coverage never turns into 100% coverage, so we want more than that for our parks and for our sanctuaries. Jim?
Jim: The strengths, any kind of boat that's big enough can take them out there, launch, recover them. We had to have them in their own little trailer, so you're not exactly talking about your average Hatteras fishing boat to take it out there, but for very little cost in terms of a platform, sometimes you can get them out there. They work super, as you've seen, in deep water. With one instrument alone you can get a whole variety of data with sensors.
But you're absolutely right, it's scary, it costs a lot, and you can lose them. With the two systems we have, the AUVs you see there, codenamed Ginger and Maryanne by the Weight [?] Institute that owned them, one of them got lost because it flew too close to the bottom, got some mud in it, couldn't drop its drop weight, and hovered within 100 feet of the surface while the boat chased it until finally they lost it. With that went a few million bucks.
Dave: Yeah, scary in terms of how much intestinal fortitude do you have, who is going to be the person who's going to throw an instrument that costs $2 million off the back of a ship in the middle of the Atlantic, and then wait for a cellphone call? If you think sending your teenage daughter out on a Friday night is scary, wait until you launch one of these things in the middle of the ocean.
I think one of the things I'd like you all to take away from this is some appreciation of the various strengths and limitations of marine remote sensing instruments. I think that before you even get to that point, you have to know the kinds of questions that you're asking, and that falls into the realm of survey design. Survey design is, as I say here, as much of an art as it is a science. Because variables like lane spacing, instrument selection, sample rate, height over bottom, survey speed, all of those things, can radically affect what is located or not.
The bottom line is, you can go out, look very, very busy, spend a lot of time and money, and find absolutely nothing. You can go out and you can say you're doing your 106 compliance, you can either intentionally or unintentionally trick yourself and others into believing that you have fulfilled your obligations for compliance work, or that you have adequately searched an area and the reason you didn't find something is because it's not there, and you can be completely wrong.
The problem is that the standards for marine remote sensing are hard to find, but we've been working with our colleagues at BOEM and at NOAA to develop some commonsense standards that are grounded in operational reality. You'll be able to say to us, "We're looking for two 24-pound cannons," and we can say, "All right, we'll design a survey for you to make sure we have a 95% chance of finding them." If we don't find them where we're looking we can say that we didn't find them because they're not there, not because we didn't look well enough.
I would like to share with you all, this is some work that we did for our friends up at Saratoga National Historical Park. This is a section of the Hudson River pretty close to the park itself. For those of you who may know, General Electric, in the 50s, 60s, and 70s, spilled tons and tons of PCBs into the Hudson River. Now, huge sections of the upper Hudson River have been declared a Superfund site, and the contaminated sediments need to be dredged out of there and cleared away.
Our involvement came several years ago. The superintendent called me and said, "General Electric says they're going to come by and they're going to dredge all these sediments, and they say there's nothing there that is of cultural interest." I said, "Huh, that's kind of interesting, considering it has been a major highway for north-south communication for 14,000 years, and the reason that the park is there is because the waterway was a highway, and the two armies, the British army and the Continental army, fought over control of that highway. I'm quite skeptical that there isn't anything in the river itself."
If you look here on the left, this is the data that the contractors for General Electric provided to General Electric, and what they did is, they took variations in magnetic intensity and they assigned them a color value. I don't know exactly how it went. High-intensity was red and low-intensity was blue, so a negative was blue and a positive was red or something like that. What they did is, they took this magnetic intensity and they divided it into a color spectrum, and 4/5 of the color spectrum in the middle was green. Only the very top 1/5 split in two pieces, so 1/10 on either end, was red or was blue. What that meant was, when they looked at their data and presented their data, it looks like there's nothing there.
Well I got really irritated, and I went through and took the same data that they had provided to us, and analyzed it the way that the park service looks at magnetic data, and you can see there is stuff all over the place. None of it, or very little of it, shows up in any of the magnetic data that was presented as a justification for this dredging activity. It's just an object lesson that you can - I'm not going to say that there was an intention to mislead - but I will say that the presentation and the criteria of presentation has a huge impact on what it is that you're looking for and looking at.
That's just kind of a cautionary tale. These different tools and instruments, they have their own strengths and weaknesses, but also the number one strength or weakness is going to be how you, or how we, choose to deploy them and interpret the data that we generate. Jim, you want to take this one?
Jim: Exactly. The right tool for the right job. I think that we have evolved, both as a discipline and the technology has evolved. We're not quite there yet to the 22nd century and to the Star Trek type of marine surveying, but the leaps and bounds that we've seen just over the last few years, and that I think some of you are seeing, particularly those of you participating from BOEM, also from NOAA and in park service, clearly demonstrates that we're on the right track. As Dave's pointed out, it's only as good as the analysis you do, and the followup is going to be key as well, because with all of this, I still say that the good old mark-1 mod-1 human eyeball remains an absolutely great tool for assessing what you're looking at.
Increasingly, particularly with the higher-resolution multibeams, sector scanning sonars, and if we can get LiDar working down there, we can cost-effectively in time, quickly and with great accuracy and detail, document these resources. It has the ability not only to connect us as the resource managers to these in assessing and dealing with them, but I think ultimately it'll be a powerful tool for conveying the importance of these resources and connecting the public to them, and showing that in another way, not only what we do is relevant, but that it is something that we will share with the public.
Karen: Jim and Dave, thank you very much for that presentation. Do we have questions from our audience?
Brad: Yeah, I have a question. Hi, my name is ... I have a bad connection, sorry. This is Brad Barr. I was wondering, David, if you had any experience with using a gradiometer with the twin magnetometer setups, sort of thing?
Dave: Yeah, or multiple magnetometers. I personally have not had any experience with a gradiometer, but this data here is actually gradiometer data. It is amenable to processing and interpretation the way that we normally do it. What we have done, Brad, is we have kind of a virtual gradiometer, in the sense that we do gradient analysis between consecutive data points in a magnetic survey area. It's not quite the same as a real gradiometer, but it's kind of a virtual gradiometer.
Brad: Just curious, because you don't see a lot of gradiometer use.
Dave: Because they're really expensive, I think only NOAA can afford gradiometers.
Brad: It's just 2 megs, Dave. I just had another comment, and that was, one should be careful about low frequency sub-bottom profiles, and even now low-frequency multibeam systems, because once you get down past about 200 kilohertz, you run into issues having to do with conflicts with impacts on marine mammals. You didn't mention any of that, but that's becoming a much more difficult situation now. It's important to remember that there is a potential interaction with those animals, particularly when you're getting down into the single-number kilohertz systems.
Dave: Thank you.
Jim: Any other questions?
Bob: Yeah. Dave and Jim, Bob Shermer. Have you guys applied remote sensing payload to unmanned aircraft systems for remote regions, and do you see any future applications there?
Dave: Yeah, for beached shipwrecks, Bob, we're working with some colleagues in South Africa to put a aerial magnetometer on a drone and fly it over the surf zone in a couple of beaches just north of Cape Town, South Africa. The issue is, in that sort of environment where you're actually spanning water to a very dynamic environment onto dry land, creating a single survey block and covering that whole area where you might have a shipwreck is very, very difficult. Aerial magnetometry came up early on as a possibility, and now with the proliferation of drones, it's a potentially less expensive proposition. It's kind of in the experimental stages at this point.
Jim: Yeah, we're going to be trying to do that as well in California pretty soon Bob, and so stay tuned. We've had a couple of possibilities, and Dave we should talk offline about all of us trying that and ... NOAA has [inaudible 01:15:07] that we've been given to test out. There are a couple more out with Bob right now.
Dave: Cool.
Jim: Any other questions?
Alex: Hi, this is Alex from SEAC I had a question. If you were going to look for submerged prehistoric sites, which of these technologies would be the best strategy to do that?
Jim: I would tow Conlin behind the boat.
Dave: Or put Jim on the bow with a long stick and have him poke into the bottom. The very best model for this, for locating prehistoric sites, is a very, very solid terrestrial model, GIS model, of site location criteria, and then a paleolandscape reconstruction of a submerged landscape, and then a little measure of good luck. Dr. Michael Faught, who used to be at Florida State, had some success working on paleo sites on the Aucilla River off the west coast of Florida, and Dr. Amanda Evans, who was at University of Louisiana, actually located a submerged shell midden and did some test excavation and work on that. Everyone talks about the paleo potential, and so far it's been kind of hit or miss. What you could do is, you could use a sub-bottom profiler to define relic land forms that would have a higher probability of containing and preserving paleo sites, but ultimately you're going to have to go out and dig a hole and get lucky.
Male: Yes. They did try that application on the Arlington site on Santa Rosa Island with some success, but they ended up digging.
Jim: Yes, but you do ultimately have to dig, which is what Norm Easton had to do with his site up in British Columbia. Any other questions?
Karen: No other questions?
Dave: If you guys have other questions, if you're like me, usually what I do is I wake up in the middle of the night and go, "Wow, I really wish that I had asked that question." Karen, could you send out our email address to people? If they have questions, or if something comes up later, we'd be more than happy to discuss with them, or provide answers if we can after this little webinar.
Karen: Yes, I'd be happy to send your email address. You want me to send out whose, Dave's?
Jim: And mine. Jim.
Dave: And Jim's.
Karen: All right, thanks very much.
Stan: Dave and Jim, this is Stan Bond. In terms of LiDar, you see that at some point you may be able to have waterproof casing or something, where you'll be able to take LiDar across underwater sites?
Jim: Absolutely.
Dave: Yeah, the Parks Canada underwater archeology team already have a proof of concept system that they've been trying to use. You have to use a different frequency of light, and it's a much more powerful laser, but they've got some pretty promising initial results. Actually the picture that you can see on the screen, this is the Cement Barrel wreck, this is Dry Tortugas site 036 on South Waterhead Reef. We've been working with our colleagues at SEAC and with the cultural resources staff at Everglades to develop a project to go out and document the site. It's been impacted by heavier storm frequency and it seems to be kind of going away. What we're going to do, Parks Canada has agreed to loan us their underwater LiDar system, so the plan is to go out to this exact site and do some tests to see if we can't get the blue-green laser to work in what you can see is pretty clear Florida water. That's happening this summer.
Jim: Stan, we're hoping to use the commercial system as a test up in the Great Lakes, by actually going inside a couple of our more intact wrecks and trying to scan them in cold, clear, still water.
Stan: Great, thanks for your help.
Karen: Dave, I want to caution you, don't do any diving in the next couple of days.
Dave: Do you want me to call and check in in a couple of days and assure you that I'm okay?
Karen: Yes, please.
Stan: You'd better be okay for our meeting on Tuesday.
Jim: Exactly.
Jim: Just because you and I have to be the bulldogs with the lawyer.
Dave: I think actually we're going to have to ... I think Jim is going to be throwing an elbow to be first in line there as well.
Jim: I'm bringing my own bulldog as well, who I actually see is on this call.
Dave: Jim, you be careful too, and everyone have a great weekend. Like I say, if people have other questions, please give us a call. We are a national program and we're here to help out our parks and our superintendents. If there's anything we can do, let us know.
Jim: Likewise from NOAA's side indeed, and if there's anything we can do to continue working in parks, and helping you guys, count us in.
Karen: Thank you very much, both of you. This concludes the program series for Fall 2013 and Winter 2014. We'll see you back here in May, hopefully, to hear the Cotter Award winners. Thank you.
Jim: Thank you.
Dave: Thank you.
Stan: Thanks.
Description
Dave Conlin James Delgado, 2/6/2014, ArcheoThursday
Duration
1 hour, 21 minutes, 29 seconds
Credit
NPS
Date Created
02/06/2014
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