NRDA Overview

What Is Natural Resource Damage Assessment?

State and federal trustee agencies work cooperatively with local governments, local organizations, and the responsible party to assess ecological injuries and human use losses caused by spills. The goal of this process, known as natural resource damage assessment (NRDA) is to:

  • Quantify the injuries to wildlife, habitat, and lost human use of those resources.
  • Determine the amount of restoration necessary to restore the resources and compensate for the injuries and losses.
  • Develop an appropriate Restoration Plan.

Injuries are quantified by sampling environmental media (e.g., water, sediment, biota), tracking live and dead impacted wildlife, and collecting other empirical data following a spill or other deleterious event. Human use losses are documented, including lost opportunities for recreation such as diminished beach, boat, and fishing use in the spill area. In the case of a large spill event, injury and human use information will be collected by scientists and field observers representing government, academia, non-government organizations (NGOs), and the responsible party.

The trustee agencies will seek input on restoration project ideas to compensate for impacts to different resource types (e.g., bird losses, impacts to coastal habitats, losses of human recreational uses). Upon development of a Restoration Plan, trustees make a claim for funds from the responsible party to implement restoration projects designed to both restore and compensate for the injured resources and human use losses.

Frequently Asked Questions

Who Is Involved In Natural Resource Damage Assessment?

Assessing damage from spills is the responsibility of “natural resources trustees.” For example, the federal Oil Pollution Act (OPA 90) authorizes federal and state natural resource trustees and federally recognized Indian tribes to seek compensation for injuries to natural resources caused by an oil spill. In California, the Governor has designated the Resources Agency, including the Department of Fish and Wildlife, Office of Spill Prevention and Response as the lead state natural resource trustee for marine and inland oil spills. Federal trustees are likely to include representatives of the National Oceanic and Atmospheric Administration (NOAA), the U.S. Fish and Wildlife Service (USFWS), the National Park Service (NPS), and the Bureau of Land Management (BLM). The natural resource trustees may involve various contractors in the injury assessment, including private organizations, university staff, and NGOs. In most cases, the Responsible Party (RP) for the spill will work cooperatively with the natural resource trustees to implement and perform the NRDA.

What Is The Process?

    When a spill occurs that poses a threat to wildlife or habitat, CDFW biologists respond to evaluate the threat, assist with response operations, and document the injury.
    During and after a spill, data will be collected in order to evaluate the injury. Examples include macroinvertebrate surveys, water and sediment samples, and vegetation surveys. Following federal guidelines, this is often done cooperatively with the responsible party, as well as with fellow trustee agencies.
    Once the necessary data is collected, the injury is quantified in terms of the area of habitat impacted, the degree of the impact, and the time until recovery. Impacted animal populations may be evaluated separately, in terms of the number of individuals impacted and the time needed for population recovery.
    This process involves evaluating potential compensatory restoration projects and "scaling" them to the size of the injury. The cost of these projects becomes the measure of damages. See the resource valuation page for details.
    Once the damage claim is completed, CDFW and the other trustees attempt to reach a settlement with the responsible party. This is usually successful without going to court.
    After a case is settled, a trustee council is established to manage the funds and oversee the restoration work. The first step is to involve the public in project selection. Once a Restoration Plan is finalized, work may begin.


Michael Anderson
Phone: (916) 375-6672

Office of Spill Prevention and Response
Mailing: P.O. Box 944209, Sacramento, CA 94244-2090
(916) 375-8580 for OSPR Information

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(800) 852-7550 or (800) OILS-911

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