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Louisiana Deepwater Horizon Oil Spill - Natural Resource Damage Assessment

Natural Resouce Damage Assessment Overview
Natural Resource Damage Assessment (NRDA) is a legal process under the Oil Pollution Act of 1990 (OPA) and the Louisiana Oil Spill Prevention and Response Act of 1991 (LOSPRA) whereby designated trustees represent the public to ensure that natural resources injured in an oil spill are restored.

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 an oil spill on natural resources. Trustees are charged with making the environment and the public whole for injuries to natural resources and services resulting from an incident involving a discharge of oil or substantial threat of a discharge of oil. Making the environment whole includes both restoring injured resources to the condition they would have been in but for the discharge as well as compensating for the temporal loss of natural resources, and the ecosystem services they provide, from the time of injury until the time they are fully restored.

The Natural Resource Trustees for the Deepwater Horizon Oil Spill are:

Federal Trustees State Trustees
The Department of Commerce
• National Oceanic and Atmospheric Administration

The Department of the Interior
• Fish and Wildlife Service
• National Park Service
• Bureau of Land Management
• Bureau of Indian Affairs

The Department of Defense
• Navy
• Coastal Protection and Restoration Authority, lead trustee
• Oil Spill Coordinator’s Office, lead administrative trustee
• Department of Environmental Quality
• Department of Wildlife and Fisheries
• Department of Natural Resources


NRDA is a often a cooperative process between the trustees and the responsible parties (RPs) to assess injuries resulting from an oil spill. State and federal NRDA regulations require the Trustees to invite RPs to participate in the assessment. Cooperation can facilitate the efficient collection and sharing of reliable data, while allowing all parties to conduct their own analysis and interpretation of that data.

Stages of NRDA

Preassessment Phase
The first step in the NRDA process is known as the Preassessment Phase. During this phase, the Trustees collect ephemeral data for the purpose of determining, among other things, whether injuries are occurring or are likely to occur, what resources may be injured, and whether it is appropriate to conduct a full injury assessment. This phase involves collecting information about how natural resources are exposed to the oil, what is likely to occur as a result of exposure, and over what period of time impacts are expected to occur. This phase may also include studies to document the condition of resources prior to exposure to the oil and to confirm the presence of oil from the Deepwater Horizon incident. 

Injury Assessment Phase
The next step in the process, which is based on the Trustees’ decision to conduct a full NRDA, is the Injury Assessment Phase. 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. 

Restoration Planning
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 that 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 for implementation of projects. 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.

 For more information about the NRDA process, click here.