NOAA's Response and Restoration Blog

An inside look at the science of cleaning up and fixing the mess of marine pollution


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Improving Currents Predictions for Washington Waters Will Help Efforts to Prevent and Respond to Oil Spills

Front of a kayak pushing through floating wood in the Strait of Juan de Fuca.

Kayakers and oil spill responders alike will appreciate the updated currents predictions NOAA is producing from a survey of Washington’s Puget Sound, San Juan Islands, and Strait of Juan de Fuca. (Courtesy of Amy MacFadyen)

This is a post by Amy MacFadyen, NOAA oceanographer and modeler in the Office of Response and Restoration’s Emergency Response Division.

As a sea kayaking enthusiast who enjoys paddling the waters of Washington’s Puget Sound, I need to have up-to-date information about the currents I’m passing through. Accurate predictions of the strong tidal currents in the sound are critical to safe navigation, and kayak trips in particular need to be timed carefully to ensure safe passage of certain regions.

As a NOAA oceanographer and modeler, I also depend on accurate information about ocean currents to predict where spilled pollutants may travel in the marine environment.

Sound Information

These are two reasons I was excited to learn that NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) is performing a scientific survey of currents in the marine waters of the Puget Sound, the San Juan Islands, and the Strait of Juan de Fuca. They began in the south sound in the summer of 2015, deploying almost 50 devices known as Acoustic Doppler Current Profilers to measure ocean currents at various depths throughout the water column.

Work is getting underway this summer to continue gathering data. The observations collected during this survey will enable NOAA to provide improved tidal current predictions to commercial and recreational mariners. But these updated predictions will also help my line of work with oil spill response.

When oil spills occur at sea, NOAA’s Office of Response and Restoration provides scientific support to the Coast Guard, including predictions of the movement and fate of the oil. Accurate predictions of the oil trajectory may help responders protect sensitive shorelines and direct cleanup operations.

Spills Closer to Home

U.S. Coast Survey nautical chart of Washington's Puget Sound in 1867.

A U.S. Coast Survey nautical chart showing the complex channels of Puget Sound when Washington was just a territory in 1867. (NOAA)

In the last few years, I’ve modeled oil movement for numerous spills and traveled on scene to assist in the oil spill response.

Seeing oil on the water and shorelines of places ranging from Santa Barbara, California, to Matagorda Island, Texas, I can’t help but think about both the possibility of a spill closer to my home in Puget Sound and our ability to model the movement of the oil there.

When oil spills in the marine environment, it spreads quickly, forming thin slicks on the ocean surface that are transported by winds and currents.

Puget Sound is a glacially carved fjord system of interconnected marine waterways and deep basins separated by shallower regions called sills.

Tidal currents in these narrow, silled connection channels can reach fairly swift speeds of up to 5-6 mph, whereas in the deep basins the currents are much slower (typically less than 1-2 mph).

Accurate predictions of currents within the sound will be critical to forecasting oil movement. Today’s predictions for this region rely on limited amounts of data gathered from the 1930s-1960s. Thanks to both these current surveys and modern technological advances, we can expect significant progress in the accuracy of these predictions.

The information collected on the NOAA current surveys will also be used to support the creation of an Operational Forecast System for Puget Sound, a numerical model which will provide short-term forecasts of water level, currents, water temperature, and salinity—information that is critical to oil spill trajectory forecasting.

Making Safer Moves

A fuel barge in Puget Sound on a cloudy day.

With the methods for transporting oil through Washington rapidly shifting and the number of vessels carrying oil increasing, the risks for oil spills are changing as well. Here, a fuel barge passes through Puget Sound. (NOAA)

More accurate current and water level predictions are good for oil spill modeling, but they are even better for oil spill prevention by making navigating through our waterways safer.

Until fairly recently, 90% of the oil moving through Washington (mainly to and from refineries) traveled by ship. But by 2014, that number dropped to less than 60%, with rail and pipelines making up the difference.

Because the methods for transporting oil through Washington are shifting, the risks for oil spills shift as well. However, even with the recent increase in crude oil being delivered by train, the number of vessels transporting oil through state waters has gone up as well, increasing the risk of a large oil spill in Puget Sound.

With such a dynamic oil transportation system and last December’s repeal of a decades-long ban on exporting U.S. crude oil, the Washington Department of Ecology has decided to update its vessel traffic risk assessment for the Puget Sound. Results from the risk assessment will ultimately be used to inform spill prevention measures and help us become even better prepared to respond to a spill.

The takeaway? Both state and federal agencies are working to make Washington waters safer.

Amy MacFadyenAmy MacFadyen is a physical oceanographer at the Emergency Response Division of the Office of Response and Restoration (NOAA). The Emergency Response Division provides scientific support for oil and chemical spill response — a key part of which is trajectory forecasting to predict the movement of spills. During the Deepwater Horizon oil spill in the Gulf of Mexico, Amy helped provide daily trajectories to the incident command. Before moving to NOAA, Amy was at the University of Washington, first as a graduate student, then as a postdoctoral researcher. Her research examined transport of harmful algal blooms from offshore initiation sites to the Washington coast.


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NOAA Supporting Spill Response in the Green Canyon Oil Reserve Area of the Gulf of Mexico

Vessels skim oil from the surface of the Gulf of Mexico.

Vessels conduct skimming operations, May 14, 2016, in response to an estimated 88,200 gallons of crude oil discharged from a segment of flow line at the Glider Field approximately 90 miles south of Timbalier Island, Louisiana. As of May 15, the vessels have removed a combined total of more than 51,000 gallons of oily-water mixture since the discharge on May 12, 2016. (U.S. Coast Guard)

NOAA’s Office of Response and Restoration is supporting the U.S. Coast Guard response to an oil spill in the Green Canyon oil reserve area in the Gulf of Mexico. We are providing oil spill trajectory analysis and information on natural resources potentially at risk from the oil. The NOAA Scientific Support Coordinator has been on-scene.

The spill occurred at approximately 11:00 a.m. on May 12, 2016 when 2,100 barrels (88,200 gallons) of oil was discharged from a Shell subsea well-head flow line at the Glider Field. Since then, the source has been secured and the pipeline is no longer leaking. The U.S. Coast Guard reports that the spill happened approximately 90 miles south of Timbalier Island, Louisiana.

We are providing scientific support, including consulting with natural resource trustees and environmental compliance requirements, identifying natural resources at risk, coordinating overflight reports, modeling the spill’s trajectory, and coordinating spatial data needs, such as displaying response data in a “common operational picture.” The reported oil trajectory is in a westerly direction with no expected shoreline impact at this time.

For more details, refer to the May 15 U.S. Coast Guard press release or the May 15 Shell Gulf of Mexico Response press release.


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How Does NOAA Model Oil Spills?

Dark oil drifts near the populated shores of Berkeley and Emerville, California.

After the cargo ship M/V Cosco Busan struck the San Francisco-Oakland Bay Bridge in 2007, NOAA oceanographers modeled how wind, waves, tides, and weather would carry the ship’s fuel oil across San Francisco Bay. Here, dark oil drifts near the shores of Berkeley and Emerville, California, on November 9, 2007. (NOAA)

One foggy morning in 2007, a cargo ship was gliding across the gray waters of San Francisco Bay when it ran into trouble, quite literally. This ship, the M/V Cosco Busan, struck the Bay Bridge, tearing a hundred-foot-long gash in its hull and releasing 53,000 gallons of thick, sticky fuel oil into the bay.

When such an oil spill, or even the threat of a spill, happens in coastal waters, the U.S. Coast Guard asks the oceanographers at NOAA’s Office of Response and Restoration for an oil spill trajectory.

Watch as NOAA’s Ocean Service breaks down what an oil spill trajectory is in a one-minute video, giving a peek at how we model the oil’s path during a spill.

Using a specialized NOAA computer model, called GNOME, our oceanographers forecast the movement of spilled oil on the water surface. With the help of data for winds, tides, weather, and ocean currents, they model where the oil is most likely to travel and how quickly it may come ashore or threaten vulnerable coastal resources, such as endangered seabirds or a busy shipping lane.

During the Deepwater Horizon oil spill, we produced dozens of oil spill trajectory maps, starting on April 21 and ending August 23, 2010, when aerial surveys and satellite analyses eventually showed no recoverable oil in the spill area. You can download the trajectory maps from that spill.

Swirls of oil on the surface of San Francisco Bay west of the Golden Gate Bridge.

Specially trained observers fly over oil spills to gather information that is fed back into NOAA’s trajectory model to improve the next forecast of where the oil is going. (NOAA)

Learn more about how we model and respond to oil spills:

Attempting to Answer One Question Over and Over Again: Where Will the Oil Go?

“Over the duration of a typical spill, we’ll revise and reissue our forecast maps on a daily basis. These maps include our best prediction of where the oil might go and the regions of highest oil coverage, as well as what is known as a “confidence boundary.” This is a line encircling not just our best predictions for oil coverage but also a broader area on the map reflecting the full possible range in our forecasts [PDF].

Our oceanographers include this confidence boundary on the forecast maps to indicate that there is a chance that oil could be located anywhere inside its borders, depending on actual conditions for wind, weather, and currents.”

A Bird’s Eye View: Looking for Oil Spills from the Sky

“Aerial overflights are surveys from airplanes or helicopters which help responders find oil slicks as they move and break up across a potentially wide expanse of water … Overflights give snapshots of where the oil is located and how it is behaving at a specific date and time, which we use to compare to our oceanographic models. By visually confirming an oil slick’s location, we can provide even more accurate forecasts of where the oil is expected to go, which is a key component of response operations.”

Five Key Questions NOAA Scientists Ask During Oil Spills

“Responders can potentially clean up what is on top of the water but recovering oil droplets from the water column is practically impossible. This is why it is so important to spill responders to receive accurate predictions of the movement of the surface slicks so they can quickly implement cleanup or prevention strategies.”


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Supporting the Response to a Platform Fire and Oil Spill in Bayou Sorrel, Louisiana

Fire burns in one of several oil tanks on a platform in a bayou.

The Coast Guard, with state and local partners, is responding to an oil production platform fire in Bayou Sorrel, Louisiana, March 15, 2016. One of the tanks reportedly collapsed, releasing an unknown amount of crude oil into a canal. (U.S. Coast Guard)

On the morning of March 15, 2016, the U.S. Coast Guard requested assistance from NOAA‘s Office of Response and Restoration for an oil production platform fire near Berry Lake in Bayou Sorrel, Louisiana.

While crews were working to dismantle the platform, one of the oil storage tanks caught fire. No injuries have been reported. The U.S. Coast Guard is leading the response with state and local agencies.

The platform and one of its storage tanks burned throughout the day on March 15 before the tank partially collapsed, releasing crude oil into a canal. Most of the oil released from the tank continued to burn on the water surface and was consumed.

Responders contained the remaining oil and burn residue in the canal with boom.

Fire-fighting vessel sprays water on an oil tank on a platform in a bayou.

Response crews extinguished the fire on the oil production platform and will continue to monitor the scene in Bayou Sorrel, Louisiana. (U.S. Coast Guard)

A second tank on the platform subsequently caught fire but has been extinguished. The two storage tanks had a maximum capacity of more than 33,000 gallons of crude oil.

We are assisting the Coast Guard’s response by coordinating local weather forecast support, modeling the potential trajectory of spills of oil or burn residue, and outlining the wildlife and habitats that could be at risk in the area. A NOAA Scientific Support Coordinator has reported to the response to provide further help and assess potential impacts of the oil spill.

Bayou Sorrel is predominantly composed of seasonally flooded, forested wetlands with some patches of freshwater marshes and open canals. While oil is unlikely to penetrate flooded or water-saturated soils, it will readily coat and become mixed with floating debris such as branches and leaves.

A variety of birds, particularly diving and wading birds and waterfowl, may be present in the area and might be at risk of coming into contact with oil, which can coat their feathers, be ingested, or inhaled. In addition, fish and invertebrates such as crawfish may be present or spawning in the marshy habitats surrounding the oil platform, and alligators and small-to-medium-sized mammals including mink and river otters may be nearby.

In 2013, NOAA provided on-site technical support for an oil spill from a pipeline in Bayou Sorrel and helped coordinate a controlled burn of the spilled oil in the area’s flooded, wooded swamps. Additionally, we assisted with other oil spills in this area in 2015, 2007, and 1988.

Look for more information about the current oil spill and fire here and at the U.S. Coast Guard’s media site.


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During the Chaos of Oil Spills, Seeking a System to Test Potential Solutions

This is a post by Ed Levine of NOAA’s Office of Response and Restoration.

Response workers load oil containment boom onto a supply ship in Louisiana.

NOAA helped develop a systematic approach to vetting new and non-traditional spill response products and techniques during the fast-paced atmosphere of an oil spill. We helped implement this system during the 2010 Deepwater Horizon oil spill to evaluate the tens of thousands of ideas proposed during the spill. (U.S. Coast Guard)

In the pre-dawn hours of January 7, 1994, the tank barge Morris J Berman ran aground near San Juan, Puerto Rico, damaging coral and spilling more than 800,000 gallons of a thick, black fuel oil. Strong winds and waves battered the barge as it continued to leak and created dangerous conditions for spill responders.

During the hectic but organized spill response that followed [PDF] the barge’s grounding, a number of vendors appeared at the command post with spill cleanup products which they assured responders would fix everything. This scenario had played out at many earlier oil spills, and nearly every time, these peddled products were treated differently, at various times sidelined, ignored, tested, or put to use.

It’s not unexpected for the initial situation at any emergency response—be it medical, natural disaster, fire, or oil spill—to be chaotic. Responders are dealing with limited resources, expertise, and information at the very beginning.

As the situation progresses, additional help, information, and experts typically arrive to make things more manageable. Usually, in the middle of all this, people are trying to be helpful, or make a buck, and sometimes both.

At the spill response in Puerto Rico, the responders formed an official ad hoc group charged with cataloging and evaluating each new suggested cleanup product or technology. The group involved local government agencies, NOAA, and the U.S. Coast Guard. It began to develop a systematic approach to what had typically been a widely varying process at previous oil spills.

The methodology the group developed for this case was rough and quickly implemented for the situation at hand. Over the course of the several months required to deal with the damaged barge and oil spill, the ad hoc group tested several, though not all, of the potential cleanup products.

Approaching Order

A few years later, another group took this process a step further through the Regional Response Team III, a state-federal entity for response policy, planning, and coordination for West Virginia, Maryland, Delaware, Pennsylvania, Virginia, and the District of Columbia.

This working group set out to develop a more organized and systematic way to deal with alternative oil spill response techniques and technologies, those which aren’t typically used during oil spill responses. After many months of working collaboratively, this multi-agency working group, which included me and other colleagues in NOAA’s Office of Response and Restoration, produced the approach known as the Alternative Response Tools Evaluation System (ARTES).

This system allows a special response team to rapidly evaluate a proposed response tool and provide feedback in the form of a recommendation to the on-scene coordinator, who directs spill responses for a specified area. This coordinator then can make an informed decision on the use of the proposed tool.

artes-process-flow-chart_noaa_720

The Alternative Response Tools Evaluation System (ARTES) process is designed for use both before and after a spill. “OSC” stands for on-scene coordinator, the person who directs a spill response, and “RRT” stands for Regional Response Team, the multi-agency group charged with spill response policy, planning, and coordination for different regions of the United States.

The ARTES process is designed for two uses. First, it can be used to assess a product’s appropriateness for use during a specific incident, under specific circumstances, such as a diesel spill resulting from a damaged tug boat on the Mississippi River. Second, the process can serve as a pre-evaluation tool during pre-spill planning to identify conditions when a proposed product would be most effective.

One advantage of the ARTES process is that it provides a management system for addressing the numerous proposals submitted by vendors and others during a spill. Subjecting all proposals to the same degree of evaluation also ensures that vendors are considered on a “level playing field.”

Although developed for one geographic region, the ARTES process quickly became adopted by others around the country and has been included in numerous local and regional response plans.

Once the ARTES process was codified, several products including an oil solidifier and a bioremediation agent underwent regional pre-spill evaluations. Personally, I was involved in several of those evaluations as well as one during an actual spill.

A Flood of Oil … and Ideas

A super tanker ship with a large slit in the bow anchored in the Gulf of Mexico.

The super tanker “A Whale” after testing during the Deepwater Horizon oil spill. The skimming slits on its bow are being sealed because it was not able to perform as designed. This vessel design was one of more than 80,000 proposals for surface oil spill response submitted during the spill. (NOAA)

Another defining moment for the ARTES process came in 2010 during the Deepwater Horizon oil spill. Within the first week of the spill, the unified command, the multi-agency organization which coordinates the response and includes those responsible for the spill, was inundated with suggestions to cap the leaking well and clean up the oil released into the Gulf of Mexico.

At one of the morning coordination meetings, the BP incident commander shared his frustration in keeping up with the deluge of offers. He asked if anyone had a suggestion for dealing with all of them. My hand shot up immediately.

After the meeting I spoke with leaders from both BP and the U.S. Coast Guard and described the ARTES process to them. They gave me the go-ahead to implement it. Boy, did I not know what we were in for!

As the days went by, the number of submissions kept growing, and growing, and growing. What started out as a one-person responsibility—recording submissions by phone and email—was soon taken over by a larger group staffed by the Coast Guard and California Office of Spill Prevention and Response and which eventually grew into a special unit of the response.

A dedicated website was created to receive product proposals and ideas, separate them into either a spill response or well capping method, track their progress through the evaluation system, and report the final decision to archive the idea, test it, or put it to use during the spill.

People who submitted ideas were able to track submissions and remain apprised of each one’s progress. Eventually, 123,000 individual ideas were submitted and tracked, 470 made the initial cut, 100 were formally evaluated, and about 30 were implemented during response field operations. Of the original 123,000 submissions, there were 80,000 subsurface and 43,000 surface oil spill response ideas.

One of the many proposals for cleaning up the oil took the form of the ship A Whale. It was a super tanker with a large slit in the bow at the waterline that was meant to serve as a huge skimmer, pulling oil off the ocean surface. Unfortunately, testing revealed that it didn’t work.

Some other examples of submissions included sand-cleaning machines and a barge designed to be an oil skimming and storage device (nicknamed the “Bubba Barge”) that actually did work. On the other hand, popular proposals such as human hair, feathers, and pool “noodles” didn’t perform very well.

Even under the weight of this incredible outpouring of proposals, the ARTES process held up, offering a great example of how far pre-planning can go.

Ed Levine.

Ed Levine is the Response Operations Supervisor – East for NOAA’s Office of Response and Restoration, managing Scientific Support Coordinators from Maine to Texas.

 


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How Do We Use Satellite Data During Oil Spills?

This is a post by NOAA’s George Graettinger with Amy MacFadyen.

A view of the Deepwater Horizon oil spill from NASA's Terra Satellites.

A view of the Deepwater Horizon oil spill from NASA’s Terra Satellites on May 24, 2010. When oil slicks are visible in satellite images, it is because they have changed how the water reflects light, either by making the sun’s reflection brighter or by dampening the scattering of sunlight, which makes the oily area darker. (NASA)

Did you know satellites measure many properties of the Earth’s oceans from space? Remote sensing technology uses various types of sensors and cameras on satellites and aircraft to gather data about the natural world from a distance. These sensors provide information about winds, ocean currents and tides, sea surface height, and a lot more.

NOAA’s Office of Response and Restoration is taking advantage of all that data collection by collaborating with NOAA’s Satellite and Information Service to put this environmental intelligence to work during disasters such as oil spills and hurricanes. Remote sensing technology adds another tool to our toolbox as we assess and respond to the environmental impacts of these types of disasters.

In these cases, which tend to be larger or longer-term oil spills, NOAA Satellites analyzes earth and ocean data from a variety of sensors and provides us with data products such as images and maps. We’re then able to take that information from NOAA Satellites and apply it to purposes ranging from detecting oil slicks to determining how an oil spill might be impacting a species or shoreline.

Slick Technology

During an oil spill, observers trained to identify oil from the air go out in helicopters and planes to report an oil slick’s exact location, shape, size, color, and orientation at a given time. Analogous to this “remote sensing” done by the human eye, satellite sensors can help us define the extent of an oil slick on the ocean surface and create a target area where our aerial observers should start looking for oil.

In the case of a large oil spill over a sizable area such as the Gulf of Mexico, this is very important because we can’t afford the time to go out in helicopters and look everywhere or sometimes weather conditions may make it unsafe to do so.

The three blue shapes represent the NOAA oil spill trajectory for May 17, 2010, showing potential levels of oiling during the Deepwater Horizon oil spill. The green outline represents the aerial footprint or oil extent for the same day, which comes from the NOAA satellite program. All of these shapes appear on a NASA MODIS Terra Satellite background image, as shown in our online response mapping program ERMA.

The three blue shapes represent the NOAA oil spill trajectory for May 17, 2010, showing potential levels of oiling during the Deepwater Horizon oil spill. The green outline represents the aerial footprint or oil extent for the same day, which comes from the NOAA satellite program. All of these shapes appear on a NASA MODIS Terra Satellite background image, as shown in our online response mapping program ERMA. (NOAA)

Satellite remote sensing typically provides the aerial footprint or outline of the surface oil (the surface oiling extent). However, oil slicks are patchy and vary in the thickness of the oil, which means having the outline of the slick is useful, but we still need our observers to give us more detailed information. That said, we’re starting to be able to use remote sensing to delineate not just the extent but also the thickest parts of the slicks.

Armed with information about where spilled oil may be thickest allows us to prioritize these areas for cleanup action. This “actionable oil” is in a condition that can be collected (via skimmers), dispersed, or burned as part of the cleanup process.

You can see how we mapped the surface oiling extent during the Deepwater Horizon spill based on data analyses from NOAA Satellites into our online response mapping program ERMA.

A Model for the Future

A common use of remotely sensed data in our work is with our oil spill models. Reports of a slick’s extent from both satellite sensors and aerial observers, who report additional information about constantly changing oil slicks, helps our oceanographers improve the forecasts of where the oil will be tomorrow.

Just as weather forecasters continually incorporate real-time observations into their models to improve accuracy, our oceanographers update oil spill trajectory models with the latest overflights and observations of the surface oiling extent (the area where oil is at a given moment). These forecasts offer critical information that the Coast Guard uses to prioritize spill response and cleanup activities.

A Sense of Impact

Oil at the water's surface in a boat wake.

The 2010 Deepwater Horizon oil spill provided us with a number of new opportunities to work with remotely sensed data. One use was detecting the outline of oil slicks on the ocean surface. (NOAA)

Over the course of an oil spill, knowing the surface oiling extent and where that oil is going is important for identifying what natural resources are potentially in harm’s way and should be protected during the spill response.

In addition, the data analyses from remote sensing technology directly support our ability to determine how natural resources, whether salt marshes or dolphins, are exposed to spilled oil. Both where an oil slick is and how often it is there will affect the degree of potential harm suffered by sensitive species and habitats over time.

In recent years, we’ve been learning how to better use the remote sensing data collected by satellite and aircraft to look at how, where, and for how long coastal and marine life and habitats are impacted by oil spills and then relate this oil exposure to actual harm to these resources.

Large amounts of oil that stay in the same place for a long time have the potential to cause a lot more harm. For example, dolphins in a certain impacted area might breathe fumes from oil and ingest oil from food and water for weeks or months at a time. Without remotely sensed data, it would be nearly impossible to accomplish this task of tying the exact location and timing of oil exposure to environmental harm.

Remote Opportunities

The 2010 Deepwater Horizon oil spill provided us with a number of new opportunities to work with remotely sensed data. For example, we used this technology to examine the large scale features of the circulation patterns in the Gulf of Mexico, such as the fast-moving Loop Current and associated eddies. The Loop Current is a warm ocean current that flows northward between Cuba and Mexico’s Yucatán Peninsula, moves north into the Gulf of Mexico, then loops east and south before exiting through the Florida Straits and ultimately joining the Gulf Stream.

During this oil spill, there were concerns that if the oil slick entered the Loop Current, it could be transported far beyond the Gulf to the Caribbean or up the U.S. East Coast (it did not). NOAA used information from satellite data to monitory closely the position of the slick with respect to the Loop Current throughout the Deepwater Horizon oil spill.

Our partnership with NOAA’s Satellite and Information Service has been a fruitful one, which we expect to grow even more in the future as technology develops further. In January, NOAA Satellites launched the Jason-3 satellite, which will continue to collect critical sea surface height data, adding to a satellite data record going back to 1992. One way these data will be used is in helping track the development of hurricanes, which in turn can cause oil spills.

We hope ongoing collaboration across NOAA will further prepare us for the future and whatever it holds.


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Accidents on a Flooded Lower Mississippi River Keep NOAA Busy with a Rash of Spills

Damaged barge on the Mississippi River.

A barge carrying slurry oil being pushed by the towing vessel Amy Francis hit the Natchez-Vidalia Bridge, Jan. 21, 2016. The barge reportedly has a maximum potential of more than 1 million gallons of slurry oil on board. (U.S. Coast Guard)

This is a post by the Office of Response and Restoration’s Donna Roberts.

Did you know that oil spills occur every day in U.S. waters? Rivers bustling with ship traffic, such as the Mississippi, are no exception to this rule.

In the past few weeks, we’ve been involved with quite a few accidents involving vessels carrying oil and chemicals on the Lower Mississippi River.

These river accidents coincided with high water and swift currents. Despite safeguards for vessel traffic put in place by the U.S. Coast Guard, the river conditions resulted in ships colliding, hitting bridges and ground, and breaking away from their towing vessels. One unlucky railroad bridge in Vicksburg, Mississippi, has been hit by vessels five times already this year.

Even now, the NOAA River Forecast Center reports that the Lower Mississippi is experiencing moderate flood conditions. It’s difficult to navigate a river with a tow of barges at any flow—and extremely challenging when the flow is high and fast. In spite of everyone’s best efforts, under conditions like these, accidents can and do still happen, and investigations are ongoing into the precise causes.

Luckily, most of the incidents that have occurred were relatively minor, resulted in no injuries to vessel crews, and all spills received immediate responses from state and federal agencies. Still, when oil or chemicals spill into rivers, we know that they differ from spills in the ocean or along coasts, and therefore present different challenges for spill responders.

Here are just a few of the dozen or so spills and near-spills we know of and which have been keeping our spill modelers, chemists, and Scientific Support Coordinators busy over the past few weeks.

January 21, 2016: A barge being towed by the UTV Amy Frances struck the Natchez Bridge, where Highway 84 crosses over the Lower Mississippi River between Mississippi and Louisiana, in the vicinity of Mile Marker 363. As a result, two of the barge’s tanks were damaged, spilling slurry oil, which our chemical lab confirmed was denser than water. That means this oil sinks.

In the wake of this oil spill, one of our Scientific Support Coordinators helped survey the river to detect sunken oil. Given the river’s very fast and turbulent water at the time, we think any oil released from the damaged tanks was immediately broken into small droplets and carried downstream while also sinking below the river surface. Any oil that reached the bottom was probably mixed with or buried by the sand moving downstream near the river bottom. This is because rivers that move a lot of water also move a lot of sediment.

In addition, we provided information on the expected fate and effects of the barge’s spilled slurry oil and on the animals and habitats that could be at risk.

Workers on a river edge pump oil from a damaged barge.

Response crews remove oil from the damaged MM-46 barge, Jan. 23, 2016, on the Mississippi River. Crews estimate that approximately 76,000 gallons of clarified oil mixture is still unaccounted for. Crews continue to take soundings of the damaged barge tank to determine the amount spilled while assessment teams work to locate missing product. (U.S. Coast Guard)

January 25, 2016: Just a few days later, the Coast Guard called on us for advice related to a barge containing liquid urea ammonium nitrate (liquid fertilizer), which sank south of Valewood, Mississippi, at Mile Marker 501 on the Mississippi River. Side-scan sonar indicates the barge is upside-down on the river bottom, approximately 80 feet down.

Given the position and water pressure, we believe the chemical cargo stored on the barge was likely released into the river. The chemical is heavier than water and will mix quickly into the water column. Because elevated levels of ammonia can affect aquatic life, our focus was on predicting and tracking where the chemical would go downriver and what would happen to it. Salvage efforts for the barge itself continue.

January 26, 2016: The next day, two vessel tows collided upriver of New Orleans, Louisiana, near Mile Marker 130 on the Lower Mississippi River. The collision capsized one of two barges carrying caustic soda, or sodium hydroxide. We provided the Coast Guard with an initial chemical hazard assessment for this chemical, which is a strong base. The release of a large enough quantity of sodium hydroxide could raise the pH of the water around it, posing a risk to local fish and other aquatic life nearby. The barge is secure, but righting it is difficult in the swift currents. No pollution release has been reported to date.

Science for Spills of All Kinds

During these kinds of spills, we have to be ready to provide the same round-the-clock, science-based support to the Coast Guard and other agencies as big spills like the Deepwater Horizon in the Gulf of Mexico.

For example, if a chemical has spilled into a river, we need to know where it’s going to go, what’s going to happen to it, and what, if any, species will be harmed by it. To help answer the “where’s it going?” question, our response specialists use the spill trajectory tool, GNOME, to predict the possible route the pollutant might follow.

To better understand the pollutant and its possible effects, we use software tools such as CAMEO Chemicals to provide information about the chemical’s properties, toxicity, and behavior as it is diluted by the river water. Our Chemical Aquatic Fate and Effects (CAFE) database contains information on the effects of thousands of chemicals, oils, and dispersants on aquatic life.

The Mississippi River and its floodplain are home to a diverse population of living things. On the Lower Mississippi, there may be as many as 60 separate species of mussel. To protect vulnerable species, we use our Environmental Sensitivity Index maps and data to report what animals or habitats could be at risk, particularly those that are threatened or endangered. Keeping responders and the public safe and minimizing environmental harm are two of our top priorities during any spill, no matter the size.

Donna Roberts

Donna Roberts

Donna Roberts is a writer for the Emergency Response Division of NOAA’s Office of Response and Restoration (OR&R). Her work supports the OR&R website and the Environmental Sensitivity Index mapping program.

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