NOAA's Response and Restoration Blog

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

Leave a comment

NOAA, Deepwater Horizon Trustees announce draft restoration plans for Gulf of Mexico following 2010 disaster

Bulldozers doing construction in a Gulf of Mexico marsh.

These efforts will restore wildlife and habitat in the Gulf by addressing the ecosystem injuries that resulted from the Deepwater Horizon incident. (NOAA)

NOAA and the other Deepwater Horizon Natural Resource Trustees today released 15-year comprehensive, integrated environmental ecosystem restoration plans for the Gulf of Mexico in response to the April 20, 2010 Deepwater Horizon oil rig explosion and spill.

Implementing the plan will cost up to $8.8 billion. The explosion killed 11 rig workers and the subsequent spill lasted 87 days and impacted both human and natural resources across the Gulf.

The Draft Deepwater Horizon Oil Spill Draft Programmatic Damage Assessment and Restoration Plan and Draft Programmatic Environmental Impact Statement allocates Natural Resource Damage Assessment  monies that are part of a comprehensive settlement agreement in principle  among BP, the U.S. Department of Justice on behalf of federal agencies, and the five affected Gulf States announced on July 2, 2015. The Department of Justice lodged today in U.S. District Court a consent decree as part of the more than $20 billion dollar settlement.

In the draft plan, the Trustees provide documentation detailing impacts from the Deepwater Horizon oil spill to:

  • wildlife, including fish, oysters, plankton, birds, sea turtles, and marine mammals across the Gulf
  • habitat, including marshes, beaches, floating seaweed habitats, water column, submerged aquatic vegetation, and ocean-bottom habitats
  • recreational activities including boating, fishing, and going to the beach

The Trustees determined that “overall, the ecological scope of impacts from the Deepwater Horizon spill was unprecedented, with injuries affecting a wide array of linked resources across the northern Gulf ecosystem.” As a result of the wide scope of impacts identified, the Trustees “have determined that the best method for addressing the injuries is a comprehensive, integrated, ecosystem restoration plan.”

Both the consent decree and the draft plan are available for 60 days of public comment. The Trustees will address public comment in adopting a final plan. For the consent decree, once public comment is taken into account the court will be asked to make it final.

Public comments on the draft plan will be accepted at eight public meetings to be held between October 19 and November 18 in each of the impacted states and in Washington, DC. Comments will also be accepted online and by mail sent to: U.S. Fish and Wildlife Service, P.O. Box 49567, Atlanta, GA 30345. The public comment period will end on December 4, 2015.

The Trustees are proposing to accept this settlement, which includes, among other components, an amount to address natural resource damages of $8.1 billion for restoration and up to $700 million for addressing unknown impacts or for adaptive management. These amounts include the $1 billion in early restoration funds which BP has already committed.

“NOAA scientists were on the scene from day one as the Deepwater spill and its impacts unfolded. NOAA and the Trustees have gathered thousands of samples and conducted millions of analyses to understand the impacts of this spill,” said Kathryn D. Sullivan, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator. “The scientific assessment concluded that there was grave injury to a wide range of natural resources and loss of the benefits they provide. Restoring the environment and compensating for the lost use of those resources is best achieved by a broad-based ecosystem approach to restore this vitally important part of our nation’s environmental, cultural and economic heritage.”

People in boat and in marsh assessing oiling impacts.

The draft plan has an array of restoration types that address a broad range of impacts at both regional and local scales. It allocates funds to meet five restoration goals, and 13 restoration types designed to meet these goals. (NOAA)

NOAA led the development of the 1,400 page draft damage assessment and restoration plan, with accompanying environmental impact statement, in coordination with all of the natural resource Trustees. The draft plan is designed to provide a programmatic analysis of the type and magnitude of the natural resources injuries that have been identified through a Natural Resource Damage Assessment conducted as required by the Oil Pollution Act of 1990 and a programmatic restoration plan to address those injuries. Alternative approaches to restoration are evaluated in the plan under the Oil Pollution Act and the National Environmental Policy Act.

Specific projects are not identified in this plan, but will be proposed in future project-specific restoration proposals. The Trustees will ensure that the public is involved in their development through public notice of proposed restoration plans, opportunities for public meetings, and consideration of all comments received.

The draft plan has an array of restoration types that address a broad range of impacts at both regional and local scales. It allocates funds to meet five restoration goals, and 13 restoration types designed to meet these goals.

The five overarching goals of the proposed plan are to:

  • restore and conserve habitat
  • restore water quality
  • replenish and protect living coastal and marine resources
  • provide and enhance human use recreational activities
  • provide for long term monitoring, adaptive management, and administrative oversight of restoration efforts.

The 13 proposed restoration activities are:

  1. Restoration of wetlands, coastal, and nearshore habitats
  2. Habitat projects on federally managed lands
  3. Nutrient reduction
  4. Water quality
  5. Fish and water column invertebrates
  6. Sturgeon
  7. Submerged aquatic vegetation
  8. Oysters
  9. Sea turtles
  10. Marine mammals
  11. Birds
  12. Low-light and deep seafloor communities
  13. Provide and enhance recreational opportunities

Together, these efforts will restore wildlife and habitat in the Gulf by addressing the ecosystem injuries that resulted from the Deepwater Horizon incident.

Once the plan is finally approved and the settlement is finalized, NOAA will continue to work with all of the Trustees to plan, approve, and implement restoration projects. NOAA will bring scientific  expertise and focus on addressing remedies for living marine resources — including fish, sturgeon, marine mammals, and sea turtles — as well as coastal habitats and water quality. NOAA scientists developed numerous scientific papers for the NRDA case including documentation of impacts to bottlenose dolphins, pelagic fish, sea turtles, benthic habitat and deep water corals.

The Deepwater Horizon Oil Spill Draft Programmatic Damage Assessment and Restoration Plan and Draft Programmatic Environmental Impact Statement is available for public review and comment through December 4. It is posted at and will be available at public repositories throughout the Gulf and at the meetings listed at

Leave a comment

Who Pays for Oil Spills?

This is a post by Kate Clark, Acting Chief of Staff with NOAA’s Office of Response and Restoration.

Oiled boom and marsh in Louisiana.

The Oil Pollution Act of 1990 states that those responsible for releasing oil and other hazardous materials pay for all costs associated with the cleanup operations, as well as the assessment of environmental impacts and necessary restoration. (U.S. Coast Guard)

After every major oil spill, one question comes up again and again: Who is going to pay for this mess?

While the American public and the environment pay the ultimate price (metaphorically speaking), the polluter most often foots the bill for cleanup, response, and restoration after oil spills.

In sum: You break it, you buy it. But our unspoiled coasts are priceless, and we would rather protect—or at least minimize impacts to—them as much as possible. Which means federal dollars are invested in ensuring top-notch experts are ready to act when oil spills do strike. (Stay tuned for more on that.)

So, Who Pays to Clean up an Oil Spill?

When an oil spill occurs, there are very clear rules about who pays for the direct response activities, the cost of assessing environmental damages, and implementing the necessary restoration.

The Oil Pollution Act of 1990, one legacy of the 1989 Exxon Valdez spill, spells out that those responsible for the pollution pay for all costs associated with the cleanup operations. However, similar to a car accident, insurance companies aren’t going to start writing checks without first looking at the circumstances.

But time is of the essence when oil hits the water, so oil companies and transporting vessels are required to have plans in place to respond immediately. In the rare instances when insurance companies investigate the details of legal (and hence, monetary) responsibility and hesitate to pay additional costs, the U.S. Coast Guard is able to set up an immediate source of funding for federal and state agencies and tribes who support the oil spill cleanup, which pays for their contributions to the response.

If the polluter is ultimately deemed liable for the spill, then they reimburse all expenses to the U.S. Coast Guard. Meaning the polluter pays for the cost of the oil spilled.

What About Restoration After Oil Spills?

Well, what about the environmental impacts left behind after the cleanup ends and everyone goes home? Does the American public pay to restore the animals and plants harmed by the spill?

Scientist leans over a boat to retrieve a dead Kemp's ridley sea turtle from the water.

It takes an average of four years to reach a settlement for environmental damages and then begin restoration after an oil spill. As a result, our job is not only to enforce pollution regulations but to ensure the right type and amount of restoration is achieved. (NOAA)

Nope. Again, the Oil Pollution Act states that parties that release hazardous materials and oil into the environment are responsible not only for the cost of cleaning up the release, but also for restoring any “injuries” (harm) to natural resources that result.

As the primary federal steward (“trustee”) for coastal animals and habitat, NOAA is responsible for ensuring the restoration of coastal resources in at least two specific cases.

First, for coastal resources harmed by releases of hazardous materials (e.g., oil and chemicals) and second, for national marine sanctuary resources harmed by physical impacts (e.g., when a ship grounds on coral reefs in a marine sanctuary).

But What if Polluters Don’t Have to Pay for Everything?

It is possible, though extremely rare, that a polluter can be found not to be liable (e.g., the pollution was caused by an act of war) or the polluter can reach its limit of liability under the law.

So, does the money for cleanup and restoration then come from American taxpayers?

Nope. In these cases, the costs are then covered by the Oil Spill Liability Trust Fund. This fund accrues from taxes on most domestically produced and imported oil. The oil companies, often those responsible for spills, are paying into this fund.

When a spill occurs, those involved in the response, cleanup, and damage assessment can access these funds if the polluter is unknown, unwilling, unable, or not liable for paying the spill’s full costs. For response activities, the fund will cover costs associated with preventing (in the case of a grounded ship that hasn’t released oil yet), minimizing, mitigating, or cleaning up an oil spill.

For natural resource damage assessment, the fund will cover costs associated with assessing an area’s natural resource damages, restoring the natural resources, and compensating the public for the lost use of the affected resources.

Of course, polluters aren’t always eager to accept liability, and accurately assessing environmental damages can take time. In fact, it takes an average of four years to reach a settlement for these damages and then begin restoration after an oil spill. As a result, our job is not only to enforce pollution regulations but to ensure the right type and amount of restoration is achieved.

That means, once again, dollars from polluters are essentially paying for oil spills.

So, the Public Doesn’t Pay for Anything?

Well, okay. The same as with your local fire department, public tax dollars are spent developing a highly trained group of professional emergency response and restoration experts. The more prepared we are to respond when an oil spill happens, the sooner a community can recover, environmentally and economically, from these unfortunate events.

When we aren’t providing direct support to an oil spill (or other marine pollution event), NOAA’s Office of Response and Restoration is hard at work training ourselves (and others) and developing tools and best practices for emergency response and assessment of impacts to natural resources.

Better Safe (and Prepared) Than Sorry

Oil spills can happen at any time of day and any time of year (including holidays). We have to be ready at any time to bring our scientific understanding of how oil behaves in the environment, where it might go, what it might impact, what can be done to address it, and what restoration may be needed.

And we think being prepared before a spill happens is a worthy investment.

Kate Clark is the Acting Chief of Staff for NOAA’s Office of Response and Restoration. For nearly 12 years she has responded to and conducted damage assessment for numerous environmental pollution events for NOAA’s Office of Response and Restoration. She has also managed NOAA’s Arctic policy portfolio and served as a senior analyst to the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.

Leave a comment

NOAA Is Supporting Oil Spill Response in Kentucky After Tugs Collide on Mississippi River

On the evening of September 2, 2015, two tug boats collided on the Mississippi River near Columbus, Kentucky, spilling slurry oil into the river.

Early reports, which later may be corrected, indicate an estimated 120,500 gallons of oil were released from a hole in the cargo tank of a barge being towed by the tug Dewey R during the collision. The spill and ensuing response closed the river between mile markers 938 and 922, south of Paducah, Kentucky, but the waterway was reopened to vessel traffic as of September 8.

At the request of the U.S. Coast Guard, NOAA’s Office of Response and Restoration is supporting the response and sending oil spill and data management experts to the scene of the spill. NOAA scientific support coordinators are providing a variety of information for the response, including river flow forecasts, chemistry of the spilled oil, a submerged oil assessment (because this heavier oil may sink), and other information to help determine where the spill will go and what can be done to protect our waterways and keep commerce moving.

The natural resource agencies also are beginning to assess potential impacts to natural resources, a first step to determining whether restoration is needed as a result of the spill.

Updates from NOAA about this oil spill may be available on IncidentNews.

What Is Slurry Oil?

Slurry oil is a residual oil resulting from the refining process and when spilled, most of it will sink or become suspended in the water column. A U.S. Coast Guard overflight the morning of September 3 revealed a floating sheen of oil four to five miles downstream of the discharge, which is not unexpected with this type of heavy oil.

Learn more about different types of oil and their behaviors when spilled and read about a 2005 slurry oil spill in the Gulf of Mexico.

How Is an Oil Spill in a River Different Than One in the Ocean?

From dams and density to muddy waters and vegetation, rivers offer a very different environment than the ocean during an oil spill.

Read more about the kinds of unique challenges we have to consider during an oil spill in a river.

More Information About Oil Spills

Find basic information related to oil spills, cleanup, impacts, and restoration, as well as NOAA’s role during and after oil spills.

Leave a comment

Podcast: What Was It Like Responding in the Aftermath of Hurricane Katrina?

On today’s episode of Diving Deeper, we remember one of the most devastating natural disasters to hit U.S. shores: Hurricane Katrina, which made landfall 10 years ago this week.

What was it like working in New Orleans and the surrounding area in the wake of such a storm?

In this podcast, we talk with Charlie Henry and Dave Wesley, two pollution responders from NOAA’s Office of Response and Restoration who were working in the area in the aftermath of not just one massive hurricane, but two, as Hurricane Rita swept across the Gulf Coast just a few short weeks later.

Hear about their experiences responding to these storms, find out which memories stand out the most for them, and reflect on the toll of working in a disaster zone:

Learn more about our work after Hurricanes Katrina and Rita, explore the progress made in the 10 years since, and see photos of the destruction these storms left across the heavily industrialized coast of the Gulf of Mexico.

Leave a comment

10 Years after Being Hit by Hurricane Katrina, Seeing an Oiled Marsh at the Center of an Experiment in Oil Cleanup

This is a post by Vicki Loe and Amy Merten of NOAA’s Office of Response and Restoration.

Oil tank damaged during Hurricane Katrina.

During Hurricane Katrina in 2005, one of the Chevron oil terminal’s storage tanks was severely damaged on top, possibly after being hit by something extremely large carried by the storm waters. (NOAA)

On August 29, 2005, not far from Chevron Pipe Line Company’s oil terminal in Buras, Louisiana, Hurricane Katrina made landfall. Knowing the storm was approaching, residents left the area, and Chevron shut down the crude oil terminal, evacuating all personnel.

The massive storm’s 144 mile per hour winds, 18 foot storm tide, and waves likely twice the height of the surge put the terminal under water. At some point during the storm, one of the terminal’s storage tanks was severely damaged on top, possibly after being hit by something extremely large carried by the storm waters. The tank released crude oil into an adjacent retention pond designed to catch leaking oil, which it did successfully.

However, just a few short weeks later, Hurricane Rita hit the same part of the Gulf and the same oil terminal. Much of the spilled oil was still being contained on the retention pond’s surface, and this second hurricane washed the oil into a nearby marsh.

A Double Impact

Built in 1963, Chevron’s facility in Buras is one of the largest crude oil distribution centers in the world and is located on a natural levee on the east bank of the Mississippi River. These back-to-back hurricanes destroyed infrastructure at the terminal as well as in the communities surrounding it. Helicopter was the only way to access the area in the weeks that followed.

Chevron wildlife biologist and environmental engineer Jim Myers witnessed the storms’ aftermath at the terminal. He described trees stripped of leaves, and mud and debris strewn everywhere, including power lines. Dead livestock were found lying on the terminal’s dock. And black oil was trapped in the marsh’s thick mesh of sedge and grass. This particular marsh is part of a large and valuable ecosystem where saltwater from the Gulf of Mexico and freshwater from the Mississippi River come together.

Even after using boom and skimmers to remove some oil, an estimated 4,000 gallons of oil remained in the 50 acre marsh on the back side of the terminal. Delicate and unstable, marshes are notoriously difficult places to deal with oil. The chaos of two hurricanes only complicated the situation.

Decision Time

Once the terminal’s substantial cleanup and repair activities began, an environmental team was assembled to consider options for dealing with the oiled marsh. Dr. Amy Merten and others from NOAA’s Office of Response and Restoration, Jim Myers and others from Chevron, and personnel from the U.S. Coast Guard, Louisiana Department of Wildlife and Fisheries, and U.S. Fish and Wildlife Service rounded out this team.

The team considered several options for treating the marsh, but one leapt to the top of the list: burning off the oil, a procedure known as in situ burn. In situ burning was the best option for several reasons: the density and amount of remaining oil, remote location, weather conditions, absence of normal wildlife populations after the storms, and the fact that the marsh was bound on three sides by canals, creating barriers for the fire. Also, for hundreds of years, the area had seen both natural burns (due to lightning strikes) and prescribed burns, with good results.

Yet this recommendation met some initial resistance. In situ burning was a more familiar practice for removing oil from the open ocean than from marshes, though its use in marshes had been well-reviewed in scientific studies. Still, in the midst of a hectic and widespread response following two hurricanes, burning oil out of marshes seemed like a potentially risky move at the time.

Furthermore, some responders working elsewhere followed conventional wisdom that the oil had been exposed to weathering processes for too long to burn successfully. However, the oil was so thick on the water’s surface and so protected from the elements by vegetation that the month-old oil behaved like freshly spilled oil, meaning it still contained enough of the right compounds to burn. The environmental team tested the oil to demonstrate it would burn before bringing the idea to those in charge of the post-hurricane pollution cleanup, the Unified Command.

Burn Notice

Left: Burning marsh. Right: Same view of green marsh 10 years later.

Similar views of the same marsh where the 2005 oil spill and subsequent burn occurred after Hurricanes Katrina and Rita. The view on the right is from August of 2015. (NOAA)

Fortunately, the leader of the Unified Command approved the carefully crafted plan to burn the oiled marsh. The burns took place on October 12 and 13, 2005, a month and a half after the spill. After dividing and cutting the affected marsh into a grid of six plots, responders burned two areas each day, leaving two plots unburned since they were negligibly oiled and did not have the right conditions to burn.

Lit with propane torches, the fire on the first day was dramatic, generating dense black smoke and burning for three hours, the result of burning the part of the marsh closest to the terminal, where the oil was thickest. The second fire generated less smoke but burned longer, for about four and half hours. Afterward, you could see how the burn’s footprint matched where different levels of oil had been.

Observations after the fact assured the environmental team that most (more than 90 percent) of the oil had been burned in the four treated areas. Small pockets of unburned oil were collected with sorbent pads, and any residual oil was left to degrade naturally. Within 24 hours of burning, traces of regrowth were visible in the marsh, and in less than a month, sedge grasses had grown to a height of one to two feet, according to Myers.

A Marsh Reborn

Healthy lush marsh vegetation at water's edge.

The marsh that was oiled after Hurricanes Katrina and Rita in 2005, and subsequently burned to remove the oil. This is how it looked in August of 2015, showing an abundance of diverse vegetation. (NOAA)

Ten years later, in August of 2015, I was curious to see how the marsh had come back. I had seen many photos of during and after the burn, and subsequent reports were that the endeavor had been a great success.

Knowing I would be in the New Orleans area on vacation, I was pleased to learn that Jim Myers would be willing to give me a tour of this marsh. I met him at the ferry dock to cross to the east side of the Mississippi River and the Chevron terminal.

We looked out over the marsh from an elevated platform behind the giant oil storage tanks. All you could see were lush grasses, clumps of low trees, and birds, birds, birds. Their calls were nonstop. We saw cattails uprooted next to flattened paths leading to the water’s edge, evidence of alligators creating trails from the water to areas for basking in the sun and of cows, muskrats, and feral hogs feeding on the cattails’ roots.

The water level was high, so rather than hike through the marsh, we traveled the circumference in a flat-bottomed boat. We saw many species of birds, as well as dragonflies, freely roaming cows, fish, and an alligator.

Today, the marsh is flourishing. I could see no difference between the areas that were oiled and burned 10 years ago and nearby areas that were untouched. In fact, monitoring following the burn [PDF] found that the marsh showed recovery across a number of measures within nine months.

This marsh represents one small part of a system of wetlands that has historically provided a buffer against the high waters of past storms. Since the 1840s, when it was settled, Buras, Louisiana, has survived being hit by at least five major hurricanes. But Hurricane Katrina was different.

Gradually, marshes across the northern Gulf of Mexico have been disappearing, enabling Hurricane Katrina’s floodwaters to overwhelm areas that have weathered previous storms. Ensuring existing marshes remain healthy will be one part of a good defense strategy against the next big hurricane. Given the successful recovery of this marsh after both an oil spill and in situ burn, we know that this technique will help prevent the further degradation of marshes in the Gulf.

See more photos of the damaged tank, the controlled burn to remove the oil, and the recovered marsh 10 years later.

Find more information about the involvement of NOAA’s Office of Response and Restoration after Hurricanes Katrina and Rita.

Amy Merten with kids from Kivalina, Alaska.Amy Merten is the Spatial Data Branch Chief in NOAA’s Office of Response and Restoration. Amy developed the concept for the online mapping tool ERMA (Environmental Response Mapping Application). ERMA was developed in collaboration with the University of New Hampshire. She expanded the ERMA team at NOAA to fill response and natural resource trustee responsibilities during the 2010 Deepwater Horizon oil spill. Amy oversees data management of the resulting oil spill damage assessment. She received her doctorate and master’s degrees from the University of Maryland.

Leave a comment

It Took More Than the Exxon Valdez Oil Spill to Pass the Historic Oil Pollution Act of 1990

Aerial view of Exxon Valdez tanker with boom and oil on water.

While the tanker Exxon Valdez spilled nearly 11 million gallons of oil into Alaskan waters, a trifecta of other sizable oil spills followed on its heels. These spills helped pave the way for passage of the Oil Pollution Act of 1990, which would vastly improve oil spill prevention, response, and restoration. (NOAA)

If you, like many, believe oil shouldn’t just be spilled without consequence into the ocean, then you, like us, should be grateful for a very important U.S. law known as the Oil Pollution Act of 1990.

Congress passed this legislation and President George H.W. Bush signed it into law 25 years ago on August 18, 1990, which was the summer after the tanker Exxon Valdez hit ground in Prince William Sound, Alaska. On March 24, 1989, this tanker unleashed almost 11 million gallons of oil into relatively pristine Alaskan waters.

The powerful images from this huge oil spill—streams of dark oil spreading over the water, birds and sea otters coated in oil, workers in shiny plastic suits trying to clean the rocky coastline—both shocked and galvanized the nation. They ultimately motivated the 101st Congress to investigate the causes of recent oil spills, develop guidelines to prevent and clean up pollution, and pass this valuable legislation.

Yet that monumental spill didn’t fully drive home just how inadequate the patchwork of existing federal, state, and local laws were at addressing oil spill prevention, cleanup, liability, and restoration. Nearly a year and a half passed between the Exxon Valdez oil spill and the enactment of the Oil Pollution Act. What happened in the mean time?

The summer of 1989 experienced a trifecta of oil spills that drained any resources left from the ongoing spill response in Alaska. In rapid succession and over the course of less than 24 hours, three other oil tankers poured their cargo into U.S. coastal waters. Between June 23 and 24, the T/V World Prodigy spilled 290,000 gallons of oil in Newport, Rhode Island; the T/V Presidente Rivera emptied 307,000 gallons of oil into the Delaware River; and the T/V Rachel B hit Tank Barge 2514, releasing 239,000 gallons of oil into Texas’s Houston Ship Channel.

But these were far from the only oil spills plaguing U.S. waters during that time. Between the summers of 1989 and 1990, a series of ship collisions, groundings, and pipeline leaks spilled an additional 8 million gallons along the United States coastline. And that doesn’t even include another million gallons of thick fuel oil released from a shore-side facility in the U.S. Virgin Islands after it was damaged by Hurricane Hugo.

Birds killed as a result of oil from the Exxon Valdez spill.

Thanks to the Oil Pollution Act, federal and state agencies can more easily evaluate the full environmental impacts of oil spills — and then enact restoration to make up for that harm. (Exxon Valdez Oil Spill Trustee Council)

Can you imagine—or perhaps remember—sitting at home watching the news and hearing again and again about yet another oil spill? And wondering what the government was going to do about it? Fortunately, in August of 1990, Congress voted unanimously to pass the Oil Pollution Act, which promised—and has largely delivered—significantly improved measures to prevent, prepare for, and respond to oil spills in U.S. waters.

Now, 25 years later, the shipping industry has undergone a makeover in oil spill prevention, preparedness, and response. A couple examples include the phasing out of tankers with easily punctured single hulls and new regulations for driving tankers that require the use of knowledgeable pilots, maneuverable tug escorts, and an appropriate number of people on the ship’s bridge during transit.

Oil spill response research also received a boost thanks to the Oil Pollution Act, which reopened a national research facility dedicated to this topic and shuttered just before the Exxon Valdez spill.

But perhaps one of the most important elements of this law required those responsible for oil spills to foot the bill for both cleaning up the oil and for economic and natural resource damages resulting from it.

This provision also requires oil companies to pay into the Oil Spill Liability Trust Fund, a fund theoretically created by Congress in 1986 but not given the necessary authorization until the Oil Pollution Act of 1990. This fund helps the U.S. Coast Guard—and indirectly, NOAA’s Office of Response and Restoration—pay for the upfront costs of responding to marine and coastal accidents that threaten to release hazardous materials such as oil and also of assessing the potential environmental and cultural impacts (and implementing restoration to make up for them).

This week we’re saying thank you to the Oil Pollution Act by highlighting some of its successes in restoring the environment after oil spills. You can join us on social media using the hashtag #Thanks2OilPollutionAct.

Leave a comment

How Is an Oil Spill in a River Different Than One in the Ocean?

Boat with boom next to oil mixed with river bank vegetation.

The often complex, vegetated banks of rivers can complicate cleaning up oil spills. (NOAA)

Liquid asphalt in the Ohio River. Slurry oil in the Gulf of Mexico. Diesel in an Alaskan stream. Each of these oil spills was very different from each other, partly because they involved very different types of oils.

But even if the same type of oil were spilled in each case, the results would be just as distinct because of where they occurred—one in a large inland river, one in the open ocean, and one in a small coastal creek.

In many cases, oil tends to float. But just because an oil floats in the saltwater of the Atlantic Ocean doesn’t mean it will float in the constantly moving freshwater of the Mississippi River.

But why does that happen? And what else can we expect to be different when oil spills into a river and not the ocean?

Don’t Be Dense … Blame Density

To answer the first question: When oil floats, it is generally because the oil is less dense than the water it was spilled into. The more salt is dissolved in water, the greater the water’s density. This means that saltwater is denser than freshwater. Very light oils, such as diesel, have low densities and would float in both the salty ocean and freshwater rivers.

However, very heavy oils may sink in a river (but perhaps not on the ocean), which is what happened when an Enbridge pipeline carrying a diluted form of oil from oil sands (tar sands) leaked into Michigan’s flooded Kalamazoo River in 2010. The lighter components of the oil quickly evaporated into the air, leaving the heavier components to drift in the water column and sink to the river bottom. That created a whole slew of new challenges as responders tried new methods of first finding and then cleaning up the difficult-to-access oil.

Going with the Flow

In rivers, going with the flow usually means going downstream. Except when it doesn’t. When might a river’s currents carry spilled oil upstream?

At the mouth of a river, where it meets the ocean, a large incoming tide can enter the river and overwhelm the normal downstream currents. That could potentially carry oil floating on the surface back upstream.

In open areas, such as on the ocean surface, both winds and currents have the potential to direct where spilled oil goes. And along most coasts, wind is what brings spilled oil onto shore.

In rivers, however, the downstream currents usually dominate the overall movement of oil while wind direction often determines which side of the river oil ends up on.

Locks and Other Blocks

Unlike the ocean, rivers sometimes feature structures such as dams, locks, and other barriers that block or slow down the free flow of water. During an oil spill on a river, these structures can also slow down the movement of oil.

That’s a helpful feature for responders who are trying to catch up to and clean up that oil. Frequently, dams and locks cause oil to pool up on the surface next to them. Some of the tools responders use to collect oil from these areas include skimmers, which are devices that remove thin layers of oil from the surface, and sorbent pads and booms, which are large squares and long tubes of special material that absorb oil but not water.

In fact, the banks of the river can constrain spilled oil as well. Because the oil can’t spread as far or thin as in open water, oil slicks can be thicker on rivers, and recovery efforts can be more effective.

One exception is the case of flow-over dams, known as weirs. The water passing over weirs can be very turbulent, causing oil to disperse into the water column. If it is very light oil and there’s not very much, that oil tends not to resurface and form another slick. But sheens may resurface with heavier oils that might be broken up going over a weir but later resurface as the water it is traveling in becomes calmer downstream.

Vegging Out

Oil rings on trees next to a river with boom.

Flooding on the Kalamazoo River in Michigan during the Enbridge pipeline oil spill left a ring of oil around trees and other vegetation after the river returned to its normal level. (NOAA)

Often, plants grow in rivers and line their banks, whereas many parts of the coast are open sandy or rocky beaches, which tend to be easier to clean oil off of than vegetation. (Salt marshes and mangroves being notable oceanic exceptions.) If oil gets past booms, the long floating barriers responders use to prevent the spread of oil, and leaves a coating on plants, then plant cleanup options generally include cutting, burning, treating with chemical shoreline cleaners, or flushing vegetation with low-pressure water.

Plant life actually became an issue during the oil sands spill in Michigan’s Kalamazoo River. Because this river was flooded at the time of the spill and later returned to its normal level, oil on the river surface actually became stranded in tree branches along the riverbanks.

Muddying the Waters

Another issue for oil spills in rivers is sediment. Rivers often carry a lot of sediment in their currents. (How do you think the Mississippi got its nickname “Big Muddy”?) That means when oil droplets drift into the water column of a river, the sediment has the potential to stick to the oil droplets. Eventually (depending on how strong-flowing and full of sediment a river is) some of the oil-sediment combination may settle out to the bottom of the river, usually near the river mouth as the water slows down and reaches the ocean.

One notable example is related to an oil spill that happened on the Mississippi River in New Orleans in 2008. The tanker Tintomara collided with Barge DM932, ripping it in half and releasing all of the heavy fuel oil it was carrying. Downstream of where the responders were cleaning up oil, the Army Corps of Engineers was dredging the sediments that build up at the mouth of the Mississippi and an oily sheen appeared in the collected sediment.

Responders suspected the oil from Barge DM932 had mixed with the river sediment and fell to the bottom further downstream as the river neared the Gulf of Mexico.

Learn more about oil spills in rivers at


Get every new post delivered to your Inbox.

Join 616 other followers