Natural Resource Damage Assessment (NRDA)


The purpose of a Natural Resource Damage Assessment (NRDA) is to assess the extent of injury to a natural resource and determine appropriate ways of restoring and compensating for damage to the environment. Under CERCLA 101(6) and 1001(20), natural resources are defined as: “land, fish, wildlife, biota, air, water, ground water, drinking water supplies, and other such resources.” In a NRDA, the functions or services provided by the contaminated resource are determined. The reduction in service levels as a result of the contamination are then quantified.

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Natural Resource Damage Assessment

The regulations used to conduct a NRDA are based on the nature of the release. If natural resources are damaged by a release of hazardous substances or a mixture of oil and hazardous substances, then the Department of the Interior (DOI) regulations apply.

DOI regulations provide a framework for two types of assessments, based on habitat. Type A evaluations apply to coastal and marine environments. In Type A assessments, a computer model is used to assess damages resulting from a chemical or oil spill to a marine environment. Type B assessments cover all other environments and utilize various approaches. Both types of assessments follow four sequential phases to assess damages:

  • Phase 1: Pre-Assessment Screen to determine if additional action is warranted
  • Phase 2: Assessment Plan to identify how potential damages will be evaluated
  • Phase 3: Assessment Implementation to gather the data necessary to quantify injuries and determine damages
  • Phase 4: Post-Assessment to report the results of the Assessment Implementation phase and propose restoration alternatives

In cases involving discharges of oil (except for any part of oil defined as a “hazardous substance” by CERCLA), the National Oceanic and Atmospheric Administration (NOAA) regulations are used to perform an assessment. NOAA outlines the following three phases under their protocols for conducting NRDAs.

  • Phase 1: Pre-Assessment Screen to determine appropriate jurisdiction and likelihood of environmental damage
  • Phase 2: Restoration Planning involving injury assessment and restoration selection
  • Phase 3: Restoration Implementation in which the final plan is presented to the responsible parties for implementation

EnviroScience’s experience with NRDA projects includes both terrestrial and aquatic environments. Our large staff of biologists possess an understanding of the NRDA planning and implementation process and have a wide array of technical expertise. Our environmental professionals respond rapidly and effectively to projects with a high-degree of technical and decision-making skill. EnviroScience’s technical expertise has allowed the company to complete environmental investigations throughout the United States and Canada, and our staff is familiar with federal environmental documentation processes at multiple levels.

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