NOAA Ship Fairweather: “We made it!”

by Ensign Hadley Owen, NOAA, Junior Officer, NOAA Ship Fairweather (S-220)

1200 hours, Saturday, August 18, 2012:  69°41.4’N  141°03.3’W, at anchor, 1.5 nautical miles west of Demarcation Point, on the United States/Canadian border

We made it!

Zacharias Demarcation Point
Photo by Caryn Zacharias, LT/NOAA

I must admit, I had my doubts a week ago. But we made it safely through relatively ice-free seas to the northern border between Alaska and Canada’s Yukon Territory.

We were able to collect multibeam echo sounder data along the entire route. The area continues to be relatively shallow (8 to 25 meters) and relatively flat (1 to 1.5 meters of relief). However, dramatic ice scours and scars on the seafloor are easily visible in the data collected.

This “pseudo-side-scan” image – which looks at only a preliminary selection of the initial acoustic data recorded – was obtained in real time.

Image by Chief Survey Tech Tami Beduhn, NOAA Ship Fairweather

We are now surveying from both the Fairweather and from one of her launches (during the day, at least). By using both platforms, we are able to obtain even more soundings on our return track to Barrow and send the launch into shallower, near-shore areas.

But this update cannot be complete, I feel, without a personal first. Thanks to the eagle eyes from the Bridge, we had the first of two polar bear sightings from the Fairweather – this one a mother and her two cubs.

A mother polar bear and her two cubs
Photo by Casey Marwine, ENS/NOAA

And now we are heading west.

NOAA Ship Fairweather crew takes in Arctic beauty as they collect hydro data off Alaska’s North Slope

by Ensign Hadley Owen, NOAA, Junior Officer, NOAA Ship Fairweather (S-220)

1200 hours, August 17, 2012: 70°13.7’N  144°49.6’W, approximately 250 nautical miles along the coast SSE of Barrow, AK

The water turned a silty gray-green early afternoon yesterday, Thursday, August 16. The Fairweather was transiting through areas with depths under our keel of between 8 and 20 meters – a somewhat caution-inducing sight for a vessel of our size. But the ice has opened up and we have made it east of Barrow. We are currently the furthest east along the North Slope of any NOAA or U.S. Coast and Geodetic Survey hydrographic ship, as previous surveys were last conducted by field parties with much smaller boats, in the 1950s and 1960s. As the crow flies, we are currently 90 miles or so west of the Canadian border and our turn-around point. However, we are of course not transiting in a straight line but in the zigzag/argyle pattern, so have a bit more sea floor to cover.

For a normal hydrographic survey, we use the Fairweather and her launches to drive over an area slowly and methodically with set parallel line spacing. With the multibeam echo-sounders, we are able to record data for a swath of between five and seven times the depth in which we are surveying. The survey lines are spaced to have a minimum of 25% overlap and thus comprehensive coverage of an area as well as moderate redundancy to ensure accuracy of the data collected.

As this Arctic trip is a “reconnaissance” survey, we are using the argyle pattern to cover as much area as possible while still ensuring quality of data via some overlap of tracklines. The image below provides a good visual. This pattern allows us to evaluate the data on the charts though varying depths. The blue lines represent one year (out and back) and the red the next year (out and back again). By crossing over previously surveyed lines – both within one season’s trip to the border and back, and potentially from one year to the next – we can both verify the data from the prior acquisition and help determine where there might be relatively rapid changes in the bottom characteristics (due to strong currents and a soft bottom, for instance).

argyle pattern of survey tracklines

Our current trackline has been modified yet again. Due to the ice, instead of surveying an area between 5 nautical miles (nm) and 60 nm out from shore, we have compressed our accordion to range between 1.5 nm and 30 nm out. From our observations, looking at aerial images of the sea ice, and listening in on radio traffic between the limited vessels transiting the area, it is looking promising that we will make it to Demarkation Point, on the Canadian border.

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We weren’t feeling so optimistic a week ago.

A combination of heavy fog and ice fields unexpectedly far south made data acquisition – bottom samples and CTD casts (measuring conductivity, temperature, and depth) – impossible at our scientists’ scheduled sample sites, and required deviation from the intended survey route. However, our plans on the Fairweather continued to adapt to the developing conditions, and not only were we able to satisfy our scientists research needs, but we also were able to experience some pretty cool Arctic phenomena. Oh, and squeeze in a little extra surveying just outside of the town of Barrow – in order to provide “ground truth” data to support a study on the feasibility of satellite-derived bathymetry to update nautical charts.

This past week, however, is best told in pictures taken this Arctic trip by NOAA Ship Fairweather crewmembers.

view from FA alidade
Our first sight of ice on the Fairweather, August 10, 2012 (71°14’N 160°56’W), through the eye of the ship’s alidade. Photo by Tim Smith, LT/NOAA
While waiting for the ice and fog to clear sufficiently for the Fairweather to continue its mission, the crew all took part in a “reconnaissance” by small boat along the ice edge. Photo by Grant Froelich, NOAA
Photo by Brian Glunz, NOAA
Photo by Scott Broo, ENS/NOAA
We all felt a little bad for the folks who had to wait until the end of the day to go explore the ice in the launch. Until they came back with pictures of walruses.
Photo by Tim Smith, LT/NOAA
A couple of days later, there was a hurried call on the radio from the bridge to survey, requesting that they pull in their MVP (moving vessel sound speed profiler) “fish” being towed behind the Fairweather – we were approaching a large field of ice and needed to be prepared to maneuver. However, the ice never got any closer. It turned out to be an example of Fata Morgana – an Arctic mirage, caused by the refraction of light rays due to the cold and dense polar air. Photo by Shauna Glasser, NOAA
Viewed through binoculars, our very own “ghost ship.” This ship was actually 23 miles away at the time – over the visible horizon. Photo by Scott Broo, ENS/NOAA
Another phantom vessel – this one only six miles away, but appearing much closer. Photo by Casey Marwine, ENS/NOAA
A little bit of everything – ice, midnight sunsets, and some Arctic special effects. Photo by Scott Broo, ENS/NOAA

Ice pack recedes, Fairweather takes nearshore route

Good news! When NOAA Ship Fairweather started her Arctic reconnaissance survey, on August 1, there was some question about whether she would be able to complete the entire trackline. The icepack from Barrow to the Canadian border had not yet receded. Thanks to  satellite imagery and ice forecasts, we can see open water up to Barter Island, and then thin ice to Demarcation Point. Cmdr. Jim Crocker is now able to follow a nearshore route. They will survey closer to shore than the planned transit route – and acquire very useful hydrographic data!

We can’t wait to get the next blog update directly from the Fairweather

(For background, see NOAA Ship Fairweather conducting hydrographic reconnaissance survey of the Arctic.)

Update: Fairweather reconnaissance survey finds differences from chart depictions around Point Hope; scientists assess biological and chemical trends in Chukchi Sea

by Ensign Hadley Owen, NOAA, Junior Officer, NOAA Ship Fairweather (S-220)

1200 hours, August 12, 2012:  70°38.7’N  162°06.6’W, approximately 22 miles north of Icy Cape, Alaska’s North Slope

In 1963, the town of Point Hope (68° 21’N  166°46’W) – a small, ancient, and archeologically-significant Inupiaq community on Alaska’s North Slope that remains at present a largely native village – narrowly avoided the creation of an artificial harbor by underwater hydrogen bombs. Part of “Project Plowshare,” the planned creation of a deepwater harbor by thermonuclear power was intended to demonstrate the peaceful use of nuclear power for construction purposes. It was opposed by Native American communities, scientists in the state, and the Episcopalian church across the United States. The protest has been credited as one of the first government projects successfully challenged on the grounds of its potential environmental impact.

Point Hope is just one example of an Arctic Alaskan community for which an increased understanding of the regions oceans and near-coastal areas will prove relevant. From the bathymetry of the coastal region, to the chemical composition of its waters, and the characteristics of its benthic community, studies will document changes in the region due to increased exposure and vessel traffic. The NOAA Ship Fairweather’s current Arctic reconnaissance trip continues to offer that rare opportunity in environmental science – the establishment of “baseline” characteristics of a largely untouched region from which to monitor potentially imminent changes.

In 2008, the USCG Cutter Spar conducted a preliminary hydrographic survey around Point Hope (and other areas), which determined that strong currents in the area were contributing to large shifts in the coastal bathymetry (underwater topography). Sandy sediment and shallow depths, as well as the high level of coastal erosion, have resulted in a significantly changeable nature of the region’s seafloor. Point Hope was one area of interest for this summer’s investigation; on August 8, our ship-based reconnaissance survey of the spit of land’s projection into the ocean showed differences from the area’s charted depiction.

While NOAA’s Office of Coast Survey interest in updating our hydrographic understanding of this region of the Arctic has driven this voyage, we were happy to welcome in Kotzebue a trio of scientists whose work overlapped with and supplemented our own mission. Dr. Doug Dasher, an environmental scientist at the University of Alaska Fairbanks, has had an ongoing interest in Point Hope and related environmental radioactivity studies. He and Terri Lomax, from the Alaska Department of Environmental Conservation, are on board as part of a large-scale survey of biological and chemical trends in the waters of the Arctic Chukchi Sea. Under the Alaska Monitoring and Assessment Program (AKMAP), they are using a stratified random sampling plan over a large area to get the “big picture” of a marine area’s health. Their work supports the U.S. Environmental Protection Agency in their national Aquatic Resource Survey of the nation’s waters.

Also onboard is an aquatic toxicologist from NOAA’s National Center for Coastal Ocean Science (NCCOS), Dr. Ian Hartwell. His path crossed with Dr. Dasher’s several years back in Kachemak Bay on Alaska’s Kenai Peninsula (south of Anchorage), where they were both conducting similar research to their present study. Dr. Hartwell’s work is part of NCCOS’ Coastal Ocean Assessment, Status and Trends (COAST) Program, which conducts biological, physical, and chemical assessments of habitats affected – or potentially affected – by contaminants.

Together, they are paying particular interest to a 25 to 30 nautical mile corridor offshore in the Chukchi Sea. The corridor stretches between the Arctic Ocean’s deep-water oil leases, currently being researched and developed by international oil companies, and the largely subsistence native communities of Alaska’s North Slope. The forward-looking exploration of our Fairweather cruise meshes well with AKMAP’s and NCCOS’s goals of defining and describing the relatively untouched environment of the coastal North Slope. In light of increasing maritime traffic, AKMAP and NCCOS hope to monitor potential contamination and help to proactively address future environmental impact upon this still largely untouched Arctic region.

Finding WWII wrecks at sea, now and then

Coast Survey’s Vitad Pradith (right) offers instruction on the use of the magnetometer, prior to actual deployment. From left to right are team members Pasquale DeRosa, ship’s captain; John Wagner, maritime archaeologist; and Joseph Hoyt, maritime archaeologist.

How do ocean explorers know where to look when they investigate and document the historical secrets of the deep? Well, archaeological expeditions use a myriad of modern surveying technologies. Recently, when NOAA’s Monitor National Marine Sanctuary was investigating a World War II underwater battlefield site, they called on a surveying expert with NOAA’s Coast Survey to assist.

Vitad Pradith, a physical scientist with Coast Survey’s Navigation Services Division, joined a sanctuary team for a week, to provide ocean depth information for the marine archaeology site off North Carolina’s Outer Banks. Pradith and the sanctuary scientists onboard NOAA National Marine Sanctuary Vessel SRVx combined previous depth soundings with new data acquired by sonar to facilitate safe operations of an autonomous underwater vehicle looking for wreckage in depths exceeding 300 feet.

The team also prepared to follow up on items discovered during the 2011 Battle of the Atlantic Expedition. Pradith trained sanctuary archaeologists to use a magnetometer that will detect metal even if it is buried under the sea floor. With the magnetometer, teams can go back to previous contacts to investigate “items of interest” that were barely distinguishable with sonar. This particular sensor enables scientists to visually map the magnetic fields of the contacts to help discover vessels lost in battle.

COAST SURVEY AND THE ATLANTIC COAST DURING WORLD WAR II

This isn’t the first time that Coast Survey experts are involved in World War II wrecks on the Atlantic Coast. Following the attack on Pearl Harbor, the Coast and Geodetic Survey expanded rapidly and devoted virtually all of its resources to the successful prosecution of the war effort. They provided ships, personnel and, of course, charts.

“At the beginning of WWII, the C&GS annually produced about 800,000 nautical and aeronuatical charts, and related products,” explains Albert ‘Skip’ Theberge, a noted NOAA historian. “The comparable figures for the last year of the war were approximately 23 million publications. These included the normal suite of domestic nautical and aeronautical charts, but then the agency added aeronautical charts of foreign territories, target charts for aerial bombing, and other special charts.”

Two of those special charts, produced by the U.S. Coast and Geodetic Survey in 1942, were classified “restricted” — for purposes of anti-submarine warfare — until they were declassified in 1982. Bottom characteristics were mapped by the Woods Hole Oceanographic Institution for the National Research Defense Committee and overlaid on Coast and Geodetic Survey charts. The sunken ship locations, determined by C&GS, were also noted on the charts. See:

Theberge points out that “because of enemy submarine attacks, the Atlantic coast was strewn with shipwrecks that constituted major hazards to navigation. They were also mistaken for potential submarines ‒ thus the need to chart their location both for navigation and defense purposes.”

“In 1943 and 1945, USC&GS surveyors used a primitive sidescan system, coupled with an early marine magnetometer, camera system, and recording fathometer for locating and identifying wrecks,” he says. “The project’s primary objective was to develop methods for anti-submarine warfare but it also served as a model for modern hydrographic search methods.”

Fairweather in the Arctic – Log Entries, August 2 and August 5

Before we get to the Fairweather logs, we need to update the last post, NOAA Ship Fairweather zigzags her way to accurate and precised depth soundings. Cmdr. Crocker reports that the “normal” zigzagging won’t start until they head further north, starting near Point Hope. It was not planned for the trip to Kotzebue, and he would have run a straight course if he could have. This log by Ensign Hadley Owen explains why they zigzagged earlier than planned, as well as what they are doing for their first scientific project. We apologize for the error in the last post. -DF

Fairweather Log Entries, August 2 and August 5

by Ensign Hadley Owen, NOAA, Junior Officer, NOAA Ship Fairweather (S-220)

2400 hours, Thursday, August 02, 2012:  57°04.9’N  167°05.5’W, underway, Dutch Harbor to Kotzebue Sound

We left Dutch Harbor on the NOAA Ship Fairweather on August 1, to begin our 30-day reconnaissance trip bound for the Arctic. Our departure had been delayed until 1800 on Wednesday in order to let pass a 988 MB low-pressure system moving northeast through the Aleutians. Our initial plan was a straight line running generally west by north, on which we would acquire seafloor data using the ship’s hull-mounted multibeam echo sounder and a towed Klein 7180 long-range side scan sonar (a one-of-a-kind device designed to maximize the effectiveness of broad-scale fish habitat studies using acoustic “backscatter”). However, a persistent 8’ swell on the ship’s beam resulted in a more than 20-degree roll that kept many crewmembers in their beds and made useful data acquisition nearly impossible. Cmdr. James Crocker, commanding officer of the Fairweather, made the call to alter course in order to pass over the acquisition stations in a tacking motion – zigzagging our way north in order to minimize the effects of the swell on our ship’s data collection activities.

The first leg of our Arctic cruise is focusing on work conducted for NOAA’s National Marine Fisheries Service, and led on the Fairweather by Dr. Bob McConnaughey. He and his team of NOAA scientists and Navy technicians have been studying and mapping benthic regions in the eastern Bering Sea since 1996, addressing a congressional mandate to understand the habitat requirements of the nation’s managed fish and crab populations. Their recent work has focused on using a variety of sonars to identify seafloor properties that affect the distribution and abundance of fish, including the Fairweather’s multibeam echosounders (traditionally used for hydrographic surveying) and side scan sonars that can continuously survey a swath of seafloor up to a kilometer-wide, at a maximum speed of 12 knots. The project goal is to measure backscatter from the ocean’s bottom, rather than to simply produce images of it, and to use this information in combination with other environmental data and estimates of fish abundance from annual bottom trawl surveys to improve the team’s mathematical models that identify the habitat requirements of individual species.  At the same time, we are taking care to produce hydrographic-quality bathymetric data for updating nautical charts in areas with outdated or non-existent information – a great example of NOAA’s integrated ocean and coastal mapping strategy.

The NOAA team onboard Fairweather during the NMFS fish research project

The NMFS team’s broader interest in the Fairweather’s reconnaissance mission is to be at the forefront of activity documenting the areas that are opening up as the region’s ice-cover retreats. By this work, NOAA’s intention is to be well prepared to support fishery management decisions related to emerging uses: commercial fishing, large-scale shipping and navigation, and oil exploration interests. The team aims to document similarities and differences in the seafloor habitats found along the more than 1,000 km reconnaissance line extending from Dutch Harbor in the Aleutian Islands to the Kotzebue Sound area above the Arctic Circle. The data collected from the eastern Bering Sea, the northern Bering Sea and the Chukchi Sea will provide insights about possible outcomes if fish populations redistribute northward due to environmental change. It will also help us to understand the susceptibility of these areas to new forms of human disturbances.

Fairweather deploys the Klein side scan sonar

As of the end of Thursday, August 2, the seas have settled down and allowed the Fairweather to deploy the long-range side scan sonar and begin acquiring data. Depending on conditions, the sonar’s towfish will remain in the water until the northern end of the survey line near Kotzebue. In addition to backscatter data, the side scan sonar is also acquiring data about water column properties such as chlorophyll.

We are keeping a close eye on ice conditions for the latter part of our route. The current ice edge runs to Barrow, and will at present prevent us from completing the last leg of our track in the Beaufort Sea – along the north coast of Alaska and east to the Canadian border. However, any data obtained during this reconnaissance mission will initiate a new large-scale systematic study of the region’s benthic habitats, will provide new bathymetric data for nautical charts, and will ultimately create a foundation for appropriate management and safe navigation in the region’s future.

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1800 hours, Sunday, August 5, 2012:  67°00.8’N  165°35.5’W, heading east, Kotzebue Sound, north of the Arctic Circle

We have been transiting increasingly shallow water since we passed Nunivak Island. As the Klein 7180 operates best in depths greater than 20 fathoms, we were able to take advantage of improved weather and relatively calmer seas to bring the towfish on board yesterday morning.  However, data acquisition continues with the ship’s multibeam echo sounder.

At 1400 hours we crossed the Arctic Circle (66°33’N), heading northeast towards the town of Kotzebue. Dr. Bob and his crew will disembark the Fairweather early Monday morning and we will shift focus with a new team of scientists as we continue north. As we transit to our anchorage near the head of the Sound this evening, we will navigate using the newest chart (16161) of the area. NOAA produced Chart #16161 in May, using survey work conducted on the Fairweather last summer; it will be an inspiration for the work to come.

 

NOAA Ship Fairweather zigzags her way to accurate and precise depth soundings

The officers, scientists, and crew of the NOAA Ship Fairweather have started their 30-day Arctic reconnaissance survey, and you can watch their progress on NOAA’s ship tracker website.

The planned route of Fairweather’s reconnaissance survey, August 2012

The diagram on the right shows the corridor Fairweather will travel during this survey project. (Fairweather’s survey corridor is shown in green.) The ship will zigzag back and forth within that corridor, checking actual depth soundings against measurements acquired during the 20th century or even earlier. (See the vintage of the depth measurements in the Aug 1 blog post, Arctic reconnaissance survey checks old soundings to prioritize future surveys.)

By the way, completely surveying the green track line, in a normal full-bottom survey, would take 880 days! So you see why Fairweather commanding officer Cmdr. Jim Crocker is taking the ship on a reconnaissance survey, instead of “mowing the lawn” like survey ships do when they map out sections of the ocean or coastline in a grid pattern.

Taking sample measurements of the water depths during this reconnaissance is vitally important to NOAA’s mandate to provide the maritime industry with accurate and precise nautical charts. Coast Survey hydrographic teams have been measuring ocean depths in coastal Alaskan waters since the 1870s, and many of NOAA’s Alaskan nautical charts ‒ especially in the Arctic ‒ still rely on those depth measurements, many made with lead lines. Additionally, vast swaths of early Arctic measurement locations were based on celestial positioning.

By using modern geospatial technology, with advanced survey technologies, Fairweather will help ensure that both measurements and locations are precise.

The ancient Greek poet Homer said, “It was with a happy heart that the good Odysseus spread his sail to catch the wind and used his seamanship to keep his boat straight with the steering-oar.” We wish the good crew of the Fairweather happy hearts like the heroic Odysseus, but they’ll have to wait to keep their boat straight in future projects.

For this survey, zigzagging is just fine.

Arctic reconnaissance survey checks old soundings to prioritize future surveys

NOAA Ship Fairweather starts the Arctic reconnaissance survey on August 1, 2012

NOAA’s Office of Coast Survey, Alaska, and the nation’s economic vitality have been intertwined for 145 years. We strengthen that bond on August 1, as NOAA Ship Fairweather begins a reconnaissance survey to the northernmost tip of the Alaska’s Arctic coast. Fairweather will check soundings along a 1,500 nautical mile coastal corridor from Dutch Harbor, Alaska, to the Canadian border. (At least, we hope Fairweather can go all the way to the Canadian border… The ice cover is a little stubborn this summer, and may not recede sufficiently for safe passage. CMDR Jim Crocker, the ship’s commanding officer and chief scientist of the party, will keep us updated through the coming weeks. Watch this blog site for Fairweather updates!)

Regardless of whether ice interferes with the final northern leg of the survey, the sounding samples acquired by Fairweather throughout the reconnaissance will provide critical information needed to prioritize NOAA’s future survey projects in the Arctic.

COAST SURVEY TIES TO ALASKA GO BACK 145 YEARS

The U.S. Coast Survey, one of NOAA’s predecessor organizations, was instrumental in the U.S. decision to purchase Alaska. In 1867, Coast Surveyor George Davidson led the party making a geographical reconnaissance of Alaska, to assess the Russians’ offer to sell “Russian America” to the United States. He assured U.S. officials that Alaska would bring valuable resources to the nation, and we purchased Alaska for $7.2 million.

Coast Survey started its post-Davidson Alaska work in 1871, when Assistant William H. Dall led survey teams that took soundings, triangulated Alaskan coasts, and made astronomical observations. Dall’s teams provided the information for the first U.S. nautical charts of Alaskan harbors and coves. (See this chart of Sanborn Harbor, 1872, for example.) Coast Survey leadership, in their annual reports to Congress, foresaw that Alaska’s resource development would severely challenge the woefully inadequate transportation infrastructure at the time, and more hydrographic field parties were dispatched to Alaskan waters through the rest of the 19th century.

This illustration was produced by John Whiddon, Coast Survey, Marine Chart Division

As indicated in this image, which displays the vintage of the U.S. Coast & Geodetic Survey (“geodetic” was added to the agency name in 1878) and NOAA soundings along the Fairweather reconnaissance path, vast swathes of lead line measurements were collected more than a hundred years ago. Some of the small-scale charts in Alaskan waters use soundings from Captain Cook (1770s vintage) or even Vitus Bering (circa 1740). While it is difficult to pinpoint exact sources, some soundings could also come from British Admiralty charts or Russian Empire charts.

FAIRWEATHER RECONNAISSANCE WILL HELP PRIORITIZE FUTURE SURVEYS

Fast forward to this century. Modern ships navigating sea lanes in the Arctic should not be expected to trust ocean depth measurements reported by Captain Cook. A tanker, carrying millions of gallons of oil, should not be asked to rely on measurements made with lead lines, before modern technology allowed full bottom surveys. Unfortunately, that’s exactly what navigators have to do, in too many cases.

Coast Survey has made it a priority to update the nautical charts needed by commercial shippers, passenger vessels, and fishing fleets transiting the Alaskan coastline in every greater numbers. In June 2011, we issued the Arctic Nautical Charting Plan, a major effort to update Arctic nautical charts for the fairways, approaches, and ports along the Alaskan coast.

Before our cartographers can update the charts, however, they need up-to-date and accurate depth measurements. NOAA’s Office of Coast Survey is committed to getting that data.

Capturing the seafloor’s rich history while positioning America for the future

Coast Survey’s Navigation Response Team 4 is conducting a year-long survey of the sea floor in the Port of Houston and Galveston Bay navigational areas, re-measuring ocean depths and searching for dangers to navigation. Coast Survey will use the data to update future nautical charts to help mariners protect lives and increase shipping efficiencies. Recently, the team also found an opportunity where they could support marine archeological preservation.

Last week, the navigation team worked with federal and state partners who help us understand the rich history – and the secrets of human sorrows – lying on the seafloor. In collaboration with NOAA’s Flower Garden Banks National Marine Sanctuary and the Texas Historical Commission’s Marine Archeology Division, the navigation response team — with the State Marine Archeologist onboard —  re-mapped the location of two historically significant wrecks. (Some of the data was collected under an antiquities permit, as Texas requires for investigating historic shipwrecks in state waters.)

“With the often-shifting sediment around here, there are periods of covering and uncovering, so archeologists like to periodically map historically significant wrecks to see what’s changed,” explained Nick Forfinski, the navigation response team’s leader. “We were ‘in the neighborhood,’ surveying for maritime commerce, and we were able to obtain up-to-date images of the wrecks while we were here.”

The steamship City of Waco is one of the historical wrecks that Forfinski’s crew was asked to survey. The steamship burst into flames and sank on Nov. 8, 1875, and 56 people died. The sunken ship was ordered to be demolished in 1900, to protect navigation in the area.

“The collaboration between NOAA experts and the Texas Historical Commission brings a unique combination of expertise and resources to learning more about the hidden history in the Gulf of Mexico,” said Texas State Archeologist Pat Mercado-Allinger. “We are grateful to the NOAA Team for this opportunity to remap this historically important shipwreck.”

Forfinski’s team captured some fascinating images of the City of Waco, created from data they gathered during last week’s hydrographic survey.

CityOfWaco_Multibeam
This image was created from data acquired by NRT4’s multibeam echo sounder. NOAA hydrographic survey units use multibeam echo sounder systems to acquire full (and partial) bottom bathymetric coverage, to measure depths over critical items such as wrecks, obstructions, and dangers-to-navigation, and for general object detection.
CityOfWaco_Sidescan
This image was created from data acquired by NRT4’s side scan sonar. A side scan creates a “picture” of the ocean bottom. For example, objects that protrude from the bottom create a light area (strong return) and shadows from these objects are dark areas (little or no return), or vice versa, depending on operator preference.

Using hydrographic surveys for multiple purposes, like “piggybacking” wreck mapping on to a navigation safety project, makes for smart resource sharing. It positions America for the future while helping to preserve its past.

Survey discovers exposed natural gas pipeline south of Mobile Bay

Ocean floors are always changing. Coast Survey’s hydrographic surveys are intended to find and measure those changes. Often, we need to do more than that, as shown by a recent survey of the seafloor in Alabama coastal waters.

A Coast Survey contractor ‒ David Evans and Associates ‒ found a large high-pressure natural gas pipeline that had been uncovered and was lying exposed, as shown by this side scan sonar image. The exposed 36-inch diameter pipeline, pressured to 2,100 psi, posed a threat to navigation and the environment.

Side scan sonar of exposed pipeline

NOAA navigation manager Tim Osborn worked in concert with the contractor to report the danger to the Department of Interior Bureau of Ocean Energy Management (BOERME), and to the U.S. Coast Guard District 8 Headquarters Waterways Section. Tim and the contractor were able to provide precise positions, imagery, and other resources.

The Coast Guard is warning mariners to avoid the area.

The pipeline delivers over 1.3 billion cubic feet of natural gas per day to the 20 million residents of Florida. In addition to posing a threat to the marine environment, an accidental rupture of the pipe could cause a national economic impact in losing a huge supply of energy.

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Learn more about hydrographic surveys and side scan sonar.