Louisiana Deepwater Horizon Oil Spill – Natural Resource Damage Assessment 

Natural Resource 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 OPA 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.

NRDA is 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.

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”) will be required to pay for in order to fully compensate the public for the injuries to natural resources. This may be accomplished through the implementation by the RPs of specific restoration projects or by the payment of money damages to the Trustees for implementation of projects. The projects, whether performed by the RPs or the Trustees, may include direct restoration or rehabilitation of the injured resources, or replacement or acquisition of resources equivalent to those injured.

Click here to view Deepwater Horizon NRDA Data on DIVER, a source for data from Trustees and BP. Data is posted on DIVER as it becomes available.