Major Concepts in NRDAR

The purpose of a NRDAR is to restore natural resources injured as a result of oil spills or hazardous substance releases into the environment. In partnership with other affected State, Tribal, and Federal trustee agencies, DOI conducts damage assessments that provide the basis for determining the restoration needed to compensate for the public’s loss of natural resources.

Generally, studies are conducted to determine the injuries to natural resources that result from the spill or release, and/or from the response or remedial actions. Both the public and responsible parties are involved in the assessment process, and the recovered damages must be used for restoration of the injured resources.

Listed below are several major concepts that apply to the NRDAR process:

Injury - Natural resource "injury" is a measurable adverse change, either long- or short-term, in the chemical or physical quality or the viability of a natural resource resulting either directly or indirectly from exposure to a discharge of oil or release of a hazardous substance, or exposure to a product of reactions resulting from the discharge of oil or release of a hazardous substance (43 CFR § 11.14(v)). Injury also includes impairment of a natural resource service (15 CFR § 990.30) and impacts caused by response actions (43 CFR § 11.15(a)(1) and 15 CFR § 990.51(b)(2)(ii)).

Examples include: death, reproductive impairment, lost human or cultural use of the resource (such as e.g., fishing or consumption advisory).

Damages - Damages are the amount of money sought by the natural resource trustees as compensation for injury, destruction, or loss of natural resources (43 CFR § 11.14(l)). This includes the cost of restoring, rehabilitating, replacing, or acquiring the equivalent of, the damaged natural resources; the diminution in value of those natural resources pending restoration; plus the reasonable costs of assessing those damages (33 U.S.C. § 2706(d)(1)).

Examples include: Monetary (cash); restoration based (land purchase or easement).

Mitigation vs. Restoration - Often NRDAR restoration is discussed interchangeably with the term mitigation. However, mitigation has some other regulatory connotations (e.g., Clean Water Act Wetland Mitigation banks program) and is thought of as a process intended to offset known impacts to existing resources. NRDAR is a process used to evaluate unknown injuries to natural resource and restore those injured natural resources, and therefore NRDAR is not generally thought of as a mitigation process.

Public Involvement - It is very important to engage the public in the NRDAR process as the basic precept of NRDAR is to make the public whole for injuries to natural resources. Both CERCLA and OPA NRDAR regulations require public notification and review at important steps in the NRDAR process.

Under CERCLA (43 CFR Part 11), trustees are required to provide opportunities for public review on:

  • the Assessment Plan,
  • the Restoration and Compensation Determination Plan,
  • the Restoration Plan, and
  • significant modifications to the Restoration Plan.

Under OPA (15 CFR Part 990), trustees are required to provide opportunities for public review on:

  • the Notice of Intent to Conduct Restoration Planning, and
  • the Draft Restoration Plan.

Responsible Parties Engagement - Trustees must invite the responsible parties to participate in the natural resource damage assessment and the invitation to participate should be extended to known responsible parties as soon as practicable. Assessment of injuries may be a joint cooperative process or lead solely by the trustees however the final authority to make determinations regarding injury and restoration rest solely with the trustees.

Restoration - Any action, or combination of actions, to restore, rehabilitate, replace, or acquire the equivalent of injured natural resources and services. Restoration includes:

Primary restoration – any action, include natural recovery, that returns injured natural resources and services to baseline; and

Compensatory restoration – any action taken to compensate for interim losses of natural resources and services that occur from the date of the incident until recovery (15 CFR § 990.30). Compensatory restoration might include restoration of the injured resources to greater than the baseline condition; an action that provides additional services on-site; or an action that restores, rehabilitates, replaces, or is an acquisition of the equivalent resources or services off-site.


In summary, NRDAR is restoration-focused with the best results achieved if restoration is considered early in, and throughout, the process. NRDAR is also a cooperative process; getting to restoration requires a common vision and coordination with responsible parties, co-trustees, and the public. Lastly, NRDAR is a legal process, and the trustees must demonstrate causality between the release and the injury. The responsible party is then responsible for reasonable costs of assessment and restoration.

Initiation or Preassessment Phase 

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