The Oil Pollution Act authorizes certain federal agencies, states and Indian tribes, collectively known as the Natural Resource Trustees (Trustees) to evaluate the impacts of the Deepwater Horizon oil spill on natural resources.  The Trustees are responsible for studying the effects of the spill through a process known as Natural Resource Damage Assessment (NRDA).  As part of this process, scientists from each Trustee entity work together to identify potential injuries to natural resources resulting from the spill and to design studies that will be used to determine and measure spill-related injuries (or impacts) to natural resources and their human uses.  For the Deepwater Horizon spill, NRDA activities to date have been divided into categories that focus on specific organisms, habitats or uses.  These categories include, for example:

  • Birds
  • Marine Mammals and sea turtles
  • Fish and shellfish
  • Deep water habitat Intertidal and near shore subtidal habitats (inlcuding sea grasses, mud flats, coral reefs)
  • Shorline habitats (including salt marsh, beaches, mangroves)
  • Terrestrial animals
  • Human uses of natural resources (e.g., recreational fishing, boating, shoreline recreation, subsistence, cultural uses, etc.)

The first step in the NRDA process is known as the Preassessment Phase, Injury Assessment.  During this phase, the Trustees will implement studies to evaluate the extent, severity, and duration of impacts from the oil spill.  Some of these studies may need to go on for several years to fully assess the impacts to natural resources and determine the time needed for these resources to recover.  Throughout the Preassessment and Injury Assessment, the Trustees will also consider how natural resources harmed by the spill may be restored through Restoration Planning, the final phase of the NRDA process.  This phase will identify restoration actions which the Responsible Parties ("RPs"), including BP, will be required to pay for in order to fully compensate the public for the injuries to natural resources caused by the Deepwater Horizon oil spill.  This may be accomplished through the implementation by the RP of specific restoration projects or by the payment of money damages to the Trustees.  The projects, whether performed by the RP or the Trustees may include direct restoration or rehabilitation of the injured resources, or replacement or acquisition of resources equivalent to those injured.

The Trustees have and will continue to release study plans developed over the course of the spill.  The process for development of each plan reflects input and advice from experienced Trustee scientists and resource managers as well as leading experts from outside the Trustee entities, including scientists who specialize in studying oil spills and natural resources in the Gulf of Mexico.  The earliest approved plans are very brief as they were developed quickly to capture immediate, potentially perishable data during an evolving event.  The plans also reflect the different nature of resources, data requirements, and associated study methods and techniques.  Because study methods used for preassessment activities may also be applied in future injury assessment studies, some of the plans provide for both near term and longer term data collection or studies. As data from the studies become available, the Trustees may adapt study approaches or methods, or consider conducting additional studies, as needed, to ensure that the impacts of the oil spill can be fully identified and measured.  This iterative process is intended to obtain the highest quality scientific information available to determine how much harm to resources has occurred and how much restoration is required.

As permitted under the Oil Pollution Act's NRDA regulations, in some instances BP has been working cooperatively with the Trustees to collect preassessment data and to conduct NRDA activities.  The Trustees have afforded BP the opportunity to provide input to the Trustees in the development of preassessment study plans and many of the plans have been signed off on by representatives of Trustees and BP.  Cooperation facilitates the collection and sharing of reliable data, while allowing all parties to conduct their own analysis and interpretation of that data.  Trustees for the Deepwater Horizon oil spill include agencies or officials of the following:

  • State of Louisiana
  • State of Mississippi
  • State of Alabama
  • State of Florida
  • State of Texas
  • U.S. Department of the Interior, through the U.S. Fish and Wildlife Service, National Park Service, Bureau of Land Management, and Bureau of Indian Affairs 
  • U.S. Department of Commerce, through the National Oceanic and Atmospheric Administration

For more information about the NRDA process for the Deepwater Horizon Oil Spill, please visit the U.S. Fish and Wildlife Service's Environmental Contaminants website, the National Park Service's oil spill website or the National Oceanic and Atmospheric Administration's Damage Assessment, Remediation & Restoration Program website.

NRDAR Preassessment Workplans:

Field Plan for Cooperative Research Cruise to Document Biotic Effects of the Deepwater Horizon Oil Spill
May 4, 2010

Field Plan for Water-Column Profiling to Measure Dissolved-Phase Aromatic Hydrocarbons and Free Oil Droplets as a Function of Depth and Location Relative to the Subsurface Oil Release
May 7, 2010

Proposal to extend NRDA cruise "Water-Column Profiling to measure dissolved aromatic hydrocarbons and free oil droplets as a function of depth and location relative to the subsurface oil release"
May 10, 2010

NRDA plan for samples of opportunity in support of the Water Column injury
May 13, 2010

Aerial Surveys for assessing marine mammals and sea turtles in the region of the Mississippi Canyon 252 incident
May 15, 2010

Water Column Injury Ephemeral Data Collections:  Cruise 2:  Surface Water Sampling Plan, Deepwater Horizon Oil Spill (DWHOS)
May 21, 2010

NRDA plan for samples of opportunity in support of the Water Column baseline
May 24, 2010

Estimating Mortality of Birds Using Beached Bird Surveys in Louisiana for the Mississippi Canyon 252 Oil Spill (Bird Survey #1A-LA)
May 25, 2010

Water Column Injury Ephemeral Data Collections:  ADCP-Measured Currents Monitoring Plan, Deepwater Horizon Oil Spill (DWHOS)
May 26, 2010

Water Column Injury Ephemeral Data Collections:  Cruise 2:  Surface Water Sampling Plan, Deepwater Horizon Oil Spill (DWHOS), Amended
May 29, 2010

Water Column Injury Ephemeral Data Collections:  Cruise 3:  Surface Water Sampling Plan for Dispersant Treated Oil, Deepwater Horizon Oil Spill (DWHOS)
May 29, 2010

Proposal for NRDA Data collection for Deepwater Horizon Oil Spill, NOAA Vessel Gordon Gunter, Anticipated Cruise Date:  May 27 – June 4, 2010
June 5, 2010

Nearshore Water Column Injury Ephemeral Data Collections:  Submerged Oil Reconnaissance Plan, Deepwater Horizon Oil spill (DWHOS)
June 5, 2010

Work Plan for Aerial Surveys and Photographic Census for Birds in the Vicinity of the Deep Water Horizon (MSC 252) Oil Spill-Bird Study #2
June 7, 2010

Proposed Data Collection Plan to Assess Injury to West Indian Manatees from the Deepwater Horizon Oil Spill Outside of Florida
June 7, 2010

Proposed Data Collection Plan to Assess Injury to Florida Manatees from the Deepwater Horizon Oil Spill
June 7, 2010

Work Plan for Estimating Secretive Marsh Bird Mortality, Deepwater Horizon (MSC 252) Oil Spill, NRDA Bird Study #3
June 7, 2010

Water Column Injury Ephemeral Data Collections:  NRDA Cruise 4 – Jack Fritz 3 Water Sampling Plan, Deepwater Horizon Oil Spill (DWHOS)
June 11, 2010

Mississippi Canyon 252 Incident, Work Plan for the Collection of Data to Determine Impacts of the Deepwater Horizon Mississippi Canyon 252 Incident on Endangered and Protected Marine Mammals in the Northern Gulf
June 14, 2010

Work Plan for Estimating Oiling Rates Among Pelagic Birds Using Ship Based Surveys in the Vicinity of the Deepwater Horizon (MSC 252) Oil Spill (Bird Study #6)
June 24, 2010

Mississippi Canyon 252 Incident, NRDA Tier 1 for Deepwater Communities:  Work Plan and SOPs

June 27, 2010

Florida Keys Baseline Sampling Plan for Water and Sediment
June 29, 2010

Work Plan for Estimating Oiling and Mortality of Breeding Colonial Waterbirds from the Deepwater Horizon (MC252)Oil Spill (Bird Study #4)
July 10, 2010

Deepwater Horizon/MC252/BP, Shoreline/Vegetation NRDA Pre-assessment Data Collection Plan
July 12, 2010

NRDA Pre-Impact Sampling Plan for West Coast of Florida:  Hernando County through Collier County
July 23, 2010

Mississippi Canyon 252 (Deepwater Horizon) Texas Baseline Survey and Sampling Work Plan
August 2, 2010

Natural Resource Damage Assessment Work Plan for Determining Injury to the Piping Plover (Charadrius melodus) from the Deepwater Horizon (MC 252) Oil Spill, Bird Study #7
August 4, 2010