Natural Resource Damage AssessmentsType A Procedures

SUMMARY: This final rule amends the regulations for assessing natural

resource damages under the Comprehensive Environmental Response,

Compensation, and Liability Act. Federal, State, and Indian tribe

natural resource trustees may use these regulations to obtain

compensation from potentially responsible parties for natural resource

injuries resulting from hazardous substance releases. Trustees obtain a

rebuttable presumption in litigation for damages, up to $100,000,

calculated in accordance with this rule. The rule does not change the

overall administrative process for conducting assessments but simply

revises an existing ``type A'' procedure for assessing natural resource

damages in coastal and marine environments and establishes a new type A

procedure for the Great Lakes.

EFFECTIVE DATE: The effective date of this final rule is June 6, 1996.

The incorporation by reference of certain documents listed in this rule

was approved by the Director of the Federal Register and is effective

June 6, 1996.

FOR FURTHER INFORMATION CONTACT: Mary Morton at (202) 208-3302 (for

questions about the rule language) or David Rosenberger at (202) 208-

3811 (for questions about the computer models). Interested parties may

obtain copies of the computer models and supporting documentation free

of charge from the Department through July 31, 1996, and thereafter for

a fee from the National Technical Information Service, 5285 Port Royal

Road, Springfield, VA 22161, ph: (703) 487-4650. The models are also on

the Internet at http://www.usgs.gov/doi/oepc/oepchome.html.

SUPPLEMENTARY INFORMATION: This preamble is organized as follows:

I. Background

A. Statutory Provisions

B. History of this Rulemaking

C. Oil Pollution Act Regulations

II. Relationship of Today's Final Rule to the Existing Regulations

A. Preassessment Phase

B. Assessment Plan Phase

C. Assessment Phase

D. Post-Assessment Phase

III. Nature of Type A Procedures

IV. Workings of the NRDAM/CME and NRDAM/GLE

A. Overview

B. Data Inputs and Modifications

C. Geographic Information System

D. Submodels

V. Use of the NRDAM/CME and NRDAM/GLE in Other Contexts

VI. Summary of Major Changes from the Proposed Rules

A. Rule Language

B. NRDAM/CME and NRDAM/GLE

VII. Response to Comments

A. General Comments

B. Technical Documents

C. Selection of Assessment Procedures

D. User-Supplied Information

E. Physical Fates

F. Species Distribution and Abundance

G. Toxicity and Mortality

H. Loss of Production

I. Catch and Bag Losses

J. Habitat Restoration

K. Assimilative Capacity Restoration

L. Restocking

M. Consideration of Costs and Benefits of Active Restoration

N. Damages for Fishing and Hunting Losses

O. Damages for Lost Wildlife Viewing

P. Damages for Beach and Boating Closures

Q. Judicial Review and the Rebuttable Presumption

I. Background

A. Statutory Provisions

The Department of the Interior (the Department) is amending the

regulations for assessing natural resource damages under the

Comprehensive Environmental Response, Compensation, and Liability Act,

as amended (42 U.S.C. 9601 et seq.) (CERCLA). CERCLA provides that

certain categories of persons, known as potentially responsible parties

(PRPs), are liable for natural resource damages resulting from a

release of a hazardous substance. CERCLA sec. 107(a). Natural resource

damages are monetary compensation for injury to, destruction of, or

loss of natural resources. CERCLA sec. 107(a)(4)(C).

Only those Federal, State, and Indian tribe officials designated as

natural resource trustees may recover natural resource damages. CERCLA

defines ``State'' to include:

The District of Columbia, the Commonwealth of Puerto Rico, Guam,

American Samoa, the United States Virgin Islands, the Commonwealth

of the Northern Marianas, and any other territory or possession over

which the United States has jurisdiction. CERCLA sec. 101(27).

Trustees must use all sums they recover in compensation for natural

resource injuries to restore, rehabilitate, replace, or acquire the

equivalent of the injured natural resources. CERCLA sec. 107(f)(1).

Trustee officials may also recover the reasonable costs of assessing

natural resource damages. Natural resource damages are distinct from

response costs. Response costs are the costs of actions taken under the

National Contingency Plan (40 CFR part 300) to remove threats to human

health and the environment caused by hazardous substance releases.

Today's final rule addresses only the assessment of natural resource

damages and is not intended for use in connection with response-related

activities, such as setting cleanup priorities.

CERCLA requires the President to promulgate regulations for the

assessment of natural resource damages resulting from hazardous

substance releases. CERCLA sec. 301(c). The President delegated the

responsibility for promulgating these regulations to the Department.

E.O. 12316, as amended by E.O. 12580. The regulations must identify the

``best available'' procedures for assessing natural resource damages.

CERCLA sec. 301(c)(2). CERCLA requires that the natural resource damage

assessment regulations include two types of assessment procedures.

``Type A'' procedures are ``standard procedures for simplified

assessments requiring minimal field observation.'' CERCLA sec.

301(c)(2)(A). ``Type B'' procedures are ``alternative protocols for

conducting assessments in individual cases.'' CERCLA sec. 301(c)(2)(B).

Federal and State trustees who perform assessments in accordance with

these regulations receive a rebuttable presumption in court. CERCLA

sec. 107(f)(2)(C). The Department must review the regulations, and

revise them as appropriate, every two years. CERCLA sec. 301(c)(3).

B. History of this Rulemaking

On March 20, 1987, the Department published a final rule

establishing a type A procedure for coastal and marine environments

that incorporated a computer model, known as the Natural Resource

Damage Assessment Model for Coastal and Marine Environments (NRDAM/

CME). 52 FR 9041. The Department indicated that it would consider

developing additional type A procedures as experience was gained with

the type A procedure for coastal and marine environments. Id. at 9057.

On June 2, 1988, the Department published an advance notice of proposed

rulemaking soliciting comment on the development of a type A procedure

for Great Lakes environments that would incorporate a computer model

called the Natural Resource Damage Assessment Model for Great Lakes

Environments (NRDAM/GLE). 53 FR 20143. A few months later,

[[Page 20561]]

the Department published an advance notice of proposed rulemaking

announcing the commencement of the statutorily required biennial review

of the type A procedure for coastal and marine environments. 54 FR 5093

(Feb. 1, 1989).

On July 14, 1989, the U.S. Court of Appeals for the District of

Columbia Circuit issued two decisions that affected these two pending

type A rulemakings. The Department had issued type B procedures on

August 1, 1986. 51 FR 27674. State, industry, and environmental group

petitioners challenged those procedures in State of Ohio v. United

States Department of the Interior (Ohio v. Interior), 880 F.2d 432

(D.C. Cir. 1989). The court in Ohio v. Interior upheld various aspects

of the type B procedures but ordered the Department to revise the type

B procedures to reflect the statutory preference for using restoration

costs as the measure of natural resource damages. The court used the

term ``restoration costs'' to encompass the cost of restoring,

rehabilitating, replacing, and/or acquiring the equivalent of the

injured natural resources. The court also ordered the Department to

revise the type B procedures to allow for the recovery of all reliably

calculated values lost to the public as a result of the injury to

natural resources.

State, industry, and environmental group petitioners also

challenged the original type A procedure for coastal and marine

environments in State of Colorado v. United States Department of the

Interior (Colorado v. Interior), 880 F.2d 481 (D.C. Cir. 1989). The

court in Colorado v. Interior upheld the Department's sequential

approach to developing type A procedures but urged the Department to

develop additional type A procedures to address as many different cases

as possible. The court also remanded the type A procedure for coastal

and marine environments, based on the reasoning in the Ohio v. Interior

decision, to permit the Department to allow for the calculation of

restoration costs. The original type A procedure for coastal and marine

environments calculated damages based solely on certain lost public

uses of the injured resources.

On September 22, 1989, the Department published an advance notice

of proposed rulemaking stating that it would revise the type A

procedure for coastal and marine environments in compliance with Ohio

v. Interior and Colorado v. Interior during the ongoing biennial

review. 54 FR 39013. The Department also announced that it would modify

the development of the type A procedure for Great Lakes environments to

conform with Ohio v. Interior and Colorado v. Interior. 54 FR 39015

(Sept. 22, 1989).

The Department published a notice of proposed rulemaking for the

type A procedure for Great Lakes environments on August 8, 1994. 59 FR

40319. The August 8, 1994, Federal Register notice also contained two

proposed amendments to the natural resource damage assessment

regulations that would affect all type A procedures. The Department

proposed to revise the conditions under which both type A and type B

procedures could be used in the same assessment, and to make explicit

the scope of judicial review of assessments performed using type A

procedures. The Department later extended the comment period on the

August 8, 1994, proposed rule through February 6, 1995. 59 FR 54877

(Nov. 2, 1994).

On December 8, 1994, the Department issued a notice of proposed

rulemaking for the modified type A procedure for coastal and marine

environments. 59 FR 63300. On February 7, 1995, the Department extended

the comment periods on both the proposed Great Lakes type A rule and

the proposed coastal and marine type A rule through July 6, 1995. 60 FR

7155 and 7156. The Department noted that, in light of the similarities

between the two proposed rules, it would consider the public comments

on the two rules concurrently. Id. at 7156 and 7157. Today's final rule

covers both the type A procedure for coastal and marine environments

and the type A procedure for Great Lakes environments.

C. Oil Pollution Act Regulations

Originally, trustees could use the Department's regulations to

assess natural resource damages resulting from either a hazardous

substance release under CERCLA or an oil or hazardous substance

discharge into navigable waters under the Clean Water Act (33 U.S.C.

1251 et seq.). However, the Oil Pollution Act of 1990 (OPA) amended the

natural resource damage provisions of the Clean Water Act. See 33

U.S.C. 1321, 2702(b)(2), and 2706(a). OPA authorized the National

Oceanic and Atmospheric Administration (NOAA) to develop new natural

resource damage assessment regulations for assessing natural resource

damages resulting from discharges, or threats of discharges, of oil

into navigable waters that, once final, would supersede the provisions

of the Department's regulations addressing oil. 33 U.S.C 2706(e)(1) and

2751(b). NOAA published a final OPA rule on January 5, 1996. 61 FR 439.

The Department began developing the type A procedures before the

enactment of OPA and, thus, originally included both hazardous

substances and oil in the NRDAM/CME and NRDAM/GLE algorithms and

databases. The Department has worked closely with NOAA during the

development of the type A procedures. During its rulemaking, NOAA

indicated it would allow use of the Department's type A procedures

under the OPA regulations. See 59 FR 1062, 1124-25 (Jan. 7, 1994); and

60 FR 39803, 39831 (Aug. 3, 1995).

NOAA's final rule states that trustees may use ``[m]odel-based

procedures, including type A procedures identified in 43 CFR part 11,

subpart D,'' provided that any such procedure meets the following

conditions:

(1) The procedure must be capable of providing assessment

information of use in determining the type and scale of restoration

appropriate for a particular injury;

(2) The additional cost of a more complex procedure must be

reasonably related to the expected increase in the quantity and/or

quality of relevant information provided by the more complex

procedure; and

(3) The procedure must be reliable and valid for the particular

incident. 61 FR at 503 (15 CFR 990.27).

Therefore, the Department has retained components relating to oil

in the final versions of the NRDAM/CME and NRDAM/GLE, while recognizing

that these components are without any direct regulatory effect. The

Department is also providing responses to comments it received on the

oil-related components of the type A models. However, the Department

wishes to emphasize that its regulations do not govern the assessment

of natural resource damages for oil discharges under OPA. Trustees who

wish to use the type A procedures and obtain a rebuttable presumption

for assessments of oil discharges must follow the process established

by NOAA's regulations.

Further, some of the language in the CERCLA rule varies from that

in the OPA rule. For example, today's final rule incorporates the

existing definition of ``reasonable cost'' at 43 CFR 11.14, from which

the definition in the OPA rule differs. See 61 FR at 504 (15 CFR

990.30). Section 11.35(b) of today's final rule, which requires

trustees to conduct type B procedures if the PRPs advance the

reasonable costs of using such procedures, differs from the OPA rule

conditions governing PRP requests for alternative assessment

procedures. See 61 FR at 501 (15 CFR 990.14(b)(6)). Also, Sec. 11.44(f)

of today's final rule

[[Page 20562]]

provides that if the models calculate damages in excess of $100,000,

then trustees who wish to obtain a rebuttable presumption must either:

(1) limit the portion of their claim calculated with the type A

procedure to $100,000; or (2) compute all damages using type B

procedures. The OPA rule, on the other hand, contains no dollar cut-off

for use of specific procedures. Because use of the type A procedures

for oil discharges is governed by the OPA rule, the Department defers

to NOAA on how such differences are to be resolved when the NRDAM/CME

and NRDAM/GLE are used for assessments of oil discharges.

II. Relationship of Today's Final Rule to the Existing Regulations

The existing regulations establish an administrative process for

conducting assessments. See 43 CFR part 11. The administrative process

covers all the steps trustees need to follow if they wish to obtain a

rebuttable presumption in litigation of their claim. However, trustees

have the authority to settle their damage claims at any time during the

administrative process and the Department continues to encourage

trustees and PRPs to pursue settlement. Furthermore, trustees are not

required to follow the regulations. If, however, trustees and PRPs fail

to reach a settlement and the case is litigated, trustees will only

obtain a rebuttable presumption if they performed their assessment in

accordance with the regulations.

The same general administrative process applies regardless of

whether type A or type B procedures are used. The process has four

phases: Preassessment, Assessment Plan, Assessment, and Post-

Assessment. During the Assessment Phase, trustees use type A and/or

type B procedures to perform the technical work needed for the actual

determination of damages.

Today's final rule does not change this overall administrative

process. The rule simply revises the type A procedures available for

use during the Assessment Phase and modifies the standards for using

both type A and type B procedures for the same release.

A. Preassessment Phase

Today's final rule does not affect the Preassessment Phase. The

Preassessment Phase consists of the activities that precede the actual

assessment. For example, upon detecting or receiving notification of a

release, trustees decide, based on a number of criteria, whether

further assessment actions are warranted. Trustees document this

decision in the Preassessment Screen Determination. For more

information on the Preassessment Phase, see subpart B of 43 CFR part

11.

B. Assessment Plan Phase

If trustees determine that additional assessment work is warranted,

they begin the Assessment Plan Phase. The Assessment Plan Phase

includes the preparation of a written Assessment Plan describing the

procedures trustees intend to use to determine damages. The trustees

must make the draft Assessment Plan available for public review and

comment.

The regulations provide two types of assessment procedures: type A

and type B. Type A procedures, such as those contained in today's final

rule, are simplified procedures requiring minimal field observation.

Type B procedures involve more detailed field studies. The Assessment

Plan documents whether trustees plan to use a type A procedure, type B

procedures, or both. Today's final rule revises the standards that

trustees must follow when selecting assessment procedures .

Section 11.34 of today's final rule identifies several conditions

that must be met before trustees can use a type A procedure and obtain

a rebuttable presumption. If the conditions are not met, then trustees

who elect to follow the regulations must use type B procedures to

assess all damages. If the conditions are met, then trustees must

decide whether to use a type A procedure, type B procedures, or both.

This decision is based on whether the benefits of the increased

accuracy provided by type B procedures would offset the anticipated

additional cost of using type B procedures, and whether the anticipated

damages would exceed the anticipated cost of using type B procedures.

Trustees may use both type A and type B procedures for the same

release if: (1) The type B procedures are cost-effective and can be

performed at a reasonable cost; (2) the type B procedures are used only

to determine damages for injuries or economic values of a type not

addressed by the type A procedure; and (3) there is no double recovery.

Section 11.36 of the final rule lists the categories of damages that

are included in the type A models and for which trustees may not

conduct supplemental type B studies. Trustees must document in the

Assessment Plan how they intend to prevent double recovery when they

use both type A and type B procedures.

Today's final rule also maintains the requirement that trustees use

type B procedures, even if they determine that use of a type A

procedure would be appropriate, whenever a PRP submits a written

request and justification for use of type B procedures and advances all

reasonable costs of using type B procedures within a time frame

acceptable to the trustees.

For more information on the Assessment Plan Phase, see Secs. 11.30

through 11.37 of today's final rule and subpart C of 43 CFR part 11.

C. Assessment Phase

During the Assessment Phase, trustees conduct the work described in

the Assessment Plan. The work consists of three steps: Injury

Determination; Quantification; and Damage Determination. In Injury

Determination, trustees determine whether any natural resources have

been injured. If trustees determine that resources have been injured,

they proceed to Quantification, in which they quantify the resulting

change in baseline conditions. ``Baseline'' conditions are the

conditions that would have existed had the release not occurred.

Finally, in Damage Determination, trustees calculate the monetary

compensation to be sought as damages for the natural resource injuries.

Damages include two components: (1) The cost of restoring,

rehabilitating, replacing, and/or acquiring the equivalent of the

injured natural resources; and (2) the economic value lost by the

public pending recovery of the resources (compensable value).

When trustees use type B procedures, they perform Injury

Determination, Quantification, and Damage Determination through

laboratory and field studies. The regulations provide a range of

alternative type B scientific and economic methodologies for conducting

such studies. For more information on use of type B procedures during

the Assessment Phase, see subpart E of 43 CFR part 11.

When trustees use a type A procedure, they perform Injury

Determination, Quantification, and Damage Determination through a

computer model. Today's type A procedure for coastal and marine

environments incorporates Version 2.4 of the NRDAM/CME. Today's type A

procedure for Great Lakes environments incorporates Version 1.4 of the

NRDAM/GLE.

Trustees must supply a number of data inputs to operate the NRDAM/

CME and the NRDAM/GLE. The rule also requires trustees to modify

certain data contained in the models if they have more reliable

information. Section 11.41 and Appendices II and III of the final rule

describe the required data inputs and modifications. After trustees

supply

[[Page 20563]]

the data inputs and modifications, the models themselves perform the

remaining calculations necessary to establish if there has been an

injury, quantify the extent of injury, select appropriate restoration

actions, and value economic losses. With the availability of these

computer models, trustees will now be able to pursue compensation for

cases in which the cost of detailed type B studies is prohibitive.

Trustees may not implement type B procedures until after the public

review period on the Assessment Plan. However, today's final rule

provides that trustees who use a type A procedure must perform a

preliminary application of the model before issuing the Assessment Plan

and then include the data inputs and the results of the preliminary

application in the publicly reviewed Plan. This requirement should

provide PRPs and other members of the public with a more meaningful

opportunity for comment. Performance of a preliminary application of

the models will also allow trustees to determine if type B procedures

are warranted in light of a new cap on the damages that can be claimed

through use of a type A procedure.

The rule now provides that if the preliminary application indicates

damages in excess of $100,000, then trustees who wish to obtain a

rebuttable presumption must decide whether to: (1) limit the portion of

their claim calculated with the type A procedure to $100,000; or (2)

compute all damages using type B procedures. The $100,000 limit applies

only to damages calculated by a type A procedure and does not limit

damages calculated through supplemental type B studies. This dollar

cut-off is based on the fairness of allowing trustees to receive a

rebuttable presumption for damages calculated by the NRDAM/CME or

NRDAM/GLE given the current level of experience with these models. The

cut-off is not based on reliability. The Department believes the NRDAM/

CME and NRDAM/GLE are capable of generating reliable damage estimates

at levels above $100,000. Therefore, although trustees cannot use the

models and obtain a rebuttable presumption above $100,000, the

Department believes the models are appropriate for use in other

contexts, such as settlement negotiations and litigation without the

rebuttable presumption.

After the close of the comment period on the Assessment Plan,

trustees must carefully review and substantively respond to all

comments they receive and must decide whether to continue using the

type A procedure. If they do decide to continue using the type A

procedure, they must make any necessary revisions to the user inputs,

and perform a final application of the model.

For more information on the Assessment Phase, see Secs. 11.40

through 11.44 of the final rule. For more information on how the NRDAM/

CME and the NRDAM/GLE perform Injury Determination, Quantification, and

Damage Determination, see Section IV of this preamble.

D. Post-Assessment Phase

Once the Assessment Phase is completed, trustees enter the Post-

Assessment Phase. Today's final rule does not substantively modify the

Post-Assessment Phase.

During the Post-Assessment Phase, trustees prepare a Report of

Assessment detailing the results of the Assessment Phase. When trustees

use a type A procedure, the Report will include the printed output of

the final model application. If a trustee is aware of reliable evidence

that a private party has recovered damages for commercial harvests lost

as a result of the release, the trustee must eliminate from the claim

any damages for such lost harvests included in the lost economic rent

calculated by the model. If a trustee is aware of reliable evidence

that the model application covers resources beyond his or her trustee

jurisdiction, the trustee must either: (1) have the other trustees who

do have jurisdiction over those resources join in the type A

assessment; or (2) eliminate any damages for those resources from the

claim.

Trustees present the Report of Assessment to the PRPs along with a

demand for damages and assessment costs. If a PRP does not agree to pay

within 60 days, the trustees may file suit. Federal and State trustees

receive a rebuttable presumption of correctness if they performed their

assessments in accordance with the Preassessment Phase, Assessment Plan

Phase, Assessment Phase, and Post-Assessment Phase requirements set

forth in the regulations. Once a court awards damages or the trustees

and PRPs have reached a settlement, trustees establish an account to

hold the recovered damages pending preparation of a Restoration Plan

describing how they intend to use the funds.

When trustees use a type A procedure, they are not restricted to

implementing the general restoration methods used by the model to

calculate the restoration cost component of the damage claim. Instead,

trustees have the discretion to spend recovered sums on other actions

to restore, rehabilitate, replace, and/or acquire the equivalent of the

injured resources.

Also, existing 43 CFR 11.93(d), which was not a subject of this

rulemaking, provides that trustees may apply several type A recoveries

to a single Restoration Plan, so long as the Plan is intended to

address the same or similar injuries as those identified in each

application of the type A procedure.

For more information on the Post-Assessment Phase, see subpart F of

43 CFR part 11.

III. Nature of Type A Procedures

The Department believes it is important that trustees, PRPs, and

the public clearly understand what the type A procedures are, as well

as what they are not, intended to provide. The NRDAM/CME and the NRDAM/

GLE are sophisticated computer models. These models incorporate a

significant level of site-specific detail about actual physical and

biological conditions in the geographic areas they encompass. The

language and legislative history of CERCLA suggest that Congress

envisioned type A procedures as look-up tables based on dollars per

gallon or unit of affected area. See, e.g., S. Rep. No. 96-848, 96th

Cong. 2d Sess. 86 (July 11, 1980). In requiring the development of two

types of assessment procedures--one simplified and the other more

complex and site-specific--Congress made a policy choice that trustees

be provided with a simplified, inexpensive mechanism for obtaining

recoveries in smaller cases. By envisioning a mechanism such as a look-

up table, Congress obviously recognized that trustees who use type A

procedures should not be required to develop--or be prejudiced for not

developing--the same degree of site-specific accuracy as might be

achieved using more expensive type B procedures. Nevertheless, in order

to increase accuracy, the Department has developed computer models that

enable the consideration of site-specific factors. For example, the

NRDAM/CME and NRDAM/GLE take into account physical variations among

geographic areas, differences in the toxicity and physical

characteristics of hazardous substances, seasonal and temperature

effects, and differences in the biological productivity of the spill

site. The Department believes that when applied correctly using

reliable input data, the NRDAM/CME and NRDAM/GLE are powerful, reliable

tools for assessing the injuries and compensable values they address.

However, as sophisticated and reliable as they are, the NRDAM/CME

and NRDAM/GLE do not, and were

[[Page 20564]]

never intended to, constitute automated type B procedures. The NRDAM/

CME and NRDAM/GLE are, after all, only models of selected aspects of

reality and, like all models, they are incapable of precisely capturing

reality in every case. Modeling always necessitates some simplifying

assumptions, and the modeling of something as complex as the effects of

hazardous substance spills on natural resources necessitates numerous

simplifying assumptions.

Section 11.34 of the final rule identifies a number of assumptions

the Department made during the development of the NRDAM/CME and NRDAM/

GLE. If these assumptions are not reasonable in a particular case,

trustees may not use the models and obtain a rebuttable presumption.

But even when these assumptions are reasonable, the models' damage

estimates will differ from the damages that type B procedures would

produce. However, Congress explicitly authorized the development of

simplified type A procedures that required less field work than type B

procedures and then explicitly granted a rebuttable presumption to

assessments performed using these type A procedures just as it granted

a rebuttable presumption to assessments performed using type B

procedures. Finally, the Department has retained in today's final rule

the safety valve that always allows PRPs to require trustees to use

type B procedures rather than a type A procedure if they advance all

reasonable costs of using such type B procedures within an acceptable

time frame.

The standard for evaluating the results of the NRDAM/CME or the

NRDAM/GLE in a particular case is not whether the model projections

conform precisely to field observations. Rather, the standard is

whether the overall damage figure calculated by the models is fair and

reasonable in light of the feasibility and cost of developing more

specific information using type B procedures. For example, if a spill

occurs in an area where biological conditions are relatively uniform

over a wide area, the fact that the NRDAM/CME or NRDAM/GLE project that

the surface trajectory would turn to the right when in fact it turned

to the left is not necessarily adequate grounds to reject wholesale the

results of the model.

IV. Workings of the NRDAM/CME and NRDAM/GLE

A. Overview

The NRDAM/CME and the NRDAM/GLE consist of integrated submodels and

databases that calculate natural resource damages based on certain

types of estimated restoration costs and compensable values. The NRDAM/

CME and the NRDAM/GLE are complex computer models; however, their use

is not restricted to computer specialists.

The NRDAM/CME was developed under contract to the Department by

Applied Science Associates, Inc., A.T. Kearney, Inc., and Hagler Bailly

Consulting, Inc. The NRDAM/GLE was developed under contract to the

Department by Applied Science Associates, Inc., and Hagler Bailly

Consulting, Inc.

``CERCLA Type A Natural Resource Damage Assessment Model for

Coastal and Marine Environments Technical Documentation,'' dated April

1996 (the NRDAM/CME technical document) describes the NRDAM/CME. Volume

I of the NRDAM/CME technical document discusses the content and

derivation of the NRDAM/CME submodels and databases. Volume II is a

user's manual. Volume III is a compilation of the chemical and

environmental databases used by the NRDAM/CME. Volume IV contains the

biological databases on the species life histories, species abundances,

and trophic-level production rates used by the NRDAM/CME. Volume V is a

compilation of the compensable values and restoration costs used by the

NRDAM/CME. Volume VI is a listing of the active source code for the

NRDAM/CME.

``CERCLA Type A Natural Resource Damage Assessment Model for Great

Lakes Environments Technical Documentation,'' dated April 1996 (the

NRDAM/GLE technical document) describes the NRDAM/GLE. Volume I of the

NRDAM/GLE technical document discusses the content and derivation of

the NRDAM/GLE submodels and databases. Volume II is a user's manual.

Volume III is a compilation of all the databases used by the NRDAM/GLE.

Volume IV is a listing of the active source code for the NRDAM/GLE.

Today's final rule incorporates by reference the NRDAM/CME, the

NRDAM/CME technical document, the NRDAM/GLE, and the NRDAM/GLE

technical document. Anyone can obtain computer diskettes containing the

models and technical documents from the National Technical Information

Service for a fee. The technical documents supplied on diskette are

formatted in WordPerfect 5.1. Some databases are formatted in

QuatroPro. Hard-bound copies of the technical documents are

also available. Also, to facilitate prompt distribution of the models,

the Department will be providing diskettes of the models and technical

documents free of charge until July 31, 1996.

The models have a menu-driven graphic display to assist users. The

minimum computer configuration required to use the models is:

IBM-compatible personal computer (PC) using MS-

DOS 3.3 or higher;

80386 processor or better with math co-processor;

1.4 megabyte 3.5 inch floppy disk drive;

4 megabytes of RAM with 540 kilobytes available;

Hard disk with 75 megabytes of available space;

VGA monitor; and

Microsoft-compatible mouse and mouse driver

software. For further information on installation of the models, see

Section 2, Volume II of the NRDAM/CME and NRDAM/GLE technical

documents.

B. Data Inputs and Modifications

The models' databases include most of the data used by the models

to determine injury and damages. However, the final rule requires

trustees to provide certain data inputs. The rule also requires

trustees to modify certain data contained in the models if they have

more reliable information. The required data inputs and modifications

are described in Sec. 11.41 and Appendices II and III.

Trustees may have direct knowledge of some of the required data

inputs. Additional information may be available from the On-Scene

Coordinator (OSC), who is responsible for managing response actions

following a release. The U.S. Coast Guard will normally be the OSC for

releases in coastal or marine environments or the Great Lakes. However,

trustees remain responsible for ensuring that all data inputs are

reliable.

C. Geographic Information System

The models incorporate a geographic information system (GIS) that

supplies geographically distributed information to the submodels. The

submodels divide space into series of rectangular grids. In the NRDAM/

CME, each grid contains 10,000 cells (100 x 100). In the NRDAM/GLE,

each grid contains 2,500 cells (50 x 50). The size of a specific grid

and, therefore, the interior cells, varies based on the physical

geometry of and the availability of natural resource information about

the particular geographic area. For example, the GIS uses smaller grids

for nearshore areas than for offshore areas. The models assign a

habitat type to each grid cell. The GIS draws the necessary

[[Page 20565]]

environmental and biotic data from the appropriate databases. The

models assume that conditions are uniform throughout a particular grid

cell.

For further information about the GIS and grid system, see Section

2, Volume I of the NRDAM/CME technical document; and Section 3.15,

Volume I of the NRDAM/GLE technical document.

D. Submodels

Both models include four linked submodels: a physical fates

submodel, a biological effects submodel, a restoration submodel, and a

compensable value submodel. The NRDAM/GLE also has a hydrodynamics

submodel.

1. Physical Fates Submodel

The physical fates submodel estimates the distribution of the

released substance on the water surface, along shorelines, in the water

column, and in sediments over time. The submodel uses an array of

computational ``particles'' to represent the released substance. A

variable fraction of the released substance is associated with each

particle. The submodel tracks the distribution of the particles in both

time and space as they move across a three-dimensional gridded

environment.

Modeled wind and current effects drive the movement of the

particles on the water surface and in the water column. In the NRDAM/

GLE, the hydrodynamics submodel simulates the wind-driven currents

occurring in the water column. In the NRDAM/CME, the physical fates

submodel simulates wind-driven currents in the upper water column and

employs user-supplied data inputs on background and tidal currents to

simulate movement in the upper and lower water column.

Drawing data about the physical and chemical properties of the

released substance from the chemical and toxicological database, the

submodel continues simulating the transport and fate of the substance

until all environmental exposure levels are below a specified

concentration (the acute toxicity threshold). The acute toxicity

threshold serves as a switch to turn off the physical fates submodel

and activate the biological effects submodel. The submodel creates a

time-series file of surface slick coverage, shoreline coverage, and

substance concentration levels in the water column and in bottom

sediments that is used by the biological effects submodel.

For further information on the physical fates submodel, see Section

3, Volume I of the NRDAM/CME and NRDAM/GLE technical documents. For

further information on the chemical and toxicological database, see

Section 7, Volume I, and Section 2, Volume III of the NRDAM/CME and

NRDAM/GLE technical documents.

2. Biological Effects Submodel

The biological effects submodel determines whether certain types of

natural resource injuries have resulted from the release and, if so,

quantifies those injuries. The biological effects submodel determines

and quantifies the following types of injury: (1) Direct mortality

resulting from short-term exposure to the released substance; (2)

direct loss of production resulting from short-term exposure to the

released substance; (3) indirect mortality resulting from food web

losses; and (4) indirect loss of production resulting from food web

losses. The biological database supplies data on habitat type and

species biomass to the biological effects submodel.

The biological effects submodel determines direct mortality of

fish, shellfish, and wildlife and direct loss of production for plants

and invertebrates by calculating exposure of different species to the

released substance. When performing these calculations, the biological

effects submodel uses the time series data generated by the physical

fates submodel concerning the distribution and concentration of the

released substance.

The biological effects submodel determines direct mortality of fish

and shellfish through use of an array of computational ``particles''

that move through the gridded environment. Each particle represents a

portion of the fish or shellfish populations potentially exposed to the

release. Each time a particle enters an area with dissolved water or

sediment concentrations of the spilled substance, the submodel

calculates the percentage mortality of the fish or shellfish population

represented by the particle. These calculations continue until

concentrations of the released substance fall below acute toxicity

thresholds.

The biological effects submodel uses similar procedures to

determine direct mortality of birds and mammals. However, the submodel

only determines direct mortality of birds and mammals when the released

substance forms a surface slick.

The biological effects submodel determines direct mortality of fish

and shellfish eggs and larvae through use of particle arrays that move

with the currents, as biologically appropriate. For plants and

invertebrates, the submodel determines direct loss of production based

on the assumption that such biota are uniformly distributed throughout

a particular habitat type within the model grids rather than through

use of particle arrays.

Once the biological effects submodel determines direct mortality

and direct loss of production , the submodel then calculates indirect

mortality and indirect loss of production for fish, shellfish, and

wildlife resulting from reductions in food resources. The submodel uses

a generalized food web model to determine the effect that direct loss

of plant production, invertebrates, and noncommercial fish and mammals

have on higher trophic-level fish, shellfish, and wildlife.

After determining injuries from both direct exposure and food web

losses, the biological effects submodel quantifies those injuries both

in terms of lost populations over time and, in the case of fish,

shellfish, and wildlife, fishing and hunting losses. The submodel also

computes fishing and hunting losses resulting from closures. The

compensable value submodel uses this information to determine

compensable value.

For further information on the biological effects submodel, see

Section 4, Volume I of the NRDAM/CME and NRDAM/GLE technical documents.

For further information on the biological database, see Section 6,

Volume I, and Volume IV of the NRDAM/CME technical document; and

Section 8, Volume I, and Section 3, Volume III of the NRDAM/GLE

technical document.

3. Restoration Submodel

The restoration submodel estimates the cost, if any, of restoring

the injured resources. The submodel first evaluates possible habitat

restoration and restocking actions. The submodel analyzes the costs and

benefits of any possible habitat restoration and restocking actions to

determine whether these forms of active restoration or natural recovery

should be assumed for purposes of the models' damage calculations. In

some cases, the submodel also determines the cost of restoring lost

assimilative capacity. The active restoration costs, if any, computed

by the restoration submodel comprise one component of the damage

figure; the other component, compensable value, is calculated by the

compensable value submodel.

For certain types of habitats, the restoration submodel evaluates

habitat restoration action. The submodel identifies those habitats for

which human intervention may potentially facilitate recovery. For each

such habitat in each affected area, the restoration submodel evaluates

the effect that a

[[Page 20566]]

particular active restoration alternative would have on the compensable

value calculated by the model. If the relevant active habitat

restoration alternative would result in a lower total compensable value

for a particular grid cell than reliance upon natural recovery, then

the restoration submodel computes the cost of performing that

alternative for that grid cell. The restoration cost database supplies

information on unit restoration costs to the restoration submodel. The

biological effects and compensable value submodels supply information

to the restoration submodel concerning the extent of injury and

compensable value with and without active habitat restoration. If the

active habitat restoration alternative would not result in a lower

total compensable value than reliance upon natural recovery, then the

restoration submodel does not compute any habitat restoration costs.

The restoration submodel evaluates the following types of active

habitat restoration alternatives against natural recovery:

For open water sediments: dredging and refilling with clean

material (shallow water); or capping (deep water);

For wetlands, macroalgal beds, and seagrass beds: replacement of

contaminated substrate and replanting (if sediments are toxic); or

replanting (if sediments are not toxic but mortality has occurred);

For invertebrate reefs (coral and mollusk): replacement of

contaminated substrate and reseeding (if sediments are toxic); or

reseeding (if sediments are not toxic but mortality has occurred);

and

For shorelines in coastal or marine environments: washing of

sand and gravel; replacement of mud; and chemical washing of rocky

shoreline.

The restoration submodel then considers restocking of fish and

wildlife. If stocks of the same age as the injured fish and wildlife

are available through captive breeding programs, then the submodel

computes the cost of restocking those species after the habitat has

recovered, either through natural recovery or active habitat

restoration. The restoration cost submodel supplies data on the

availability and cost of stocks to the restoration submodel.

If the relevant active habitat restoration alternative would reduce

compensable value or if restocking is possible, then the submodel

performs a cost-benefit test of these forms of active restoration. The

submodel compares the total costs of active habitat restoration and

restocking against the measured benefits of such restoration (i.e.,

compensable value assuming natural recovery minus compensable value

assuming active habitat restoration and restocking). If the costs

exceed ten times the measured benefits, then the submodel assumes, for

purposes of generating a damage figure, that natural recovery, rather

than active restoration, will be used to reestablish baseline

conditions. If the costs do not exceed the measured benefits by ten

times, then the submodel assumes, for purposes of generating a damage

figure, that habitat restoration and restocking actions will be

implemented.

Finally, for releases that generate a damage figure related to

mortality and loss of productivity, the restoration submodel also

calculates the cost of restoring the water's baseline ability to absorb

pollutants (assimilative capacity). In the case of such releases, the

restoration submodel determines the amount of the released substance

that would remain in the environment after environmental exposure

levels are below acute toxicity thresholds and after any habitat

restoration actions are completed. The submodel then computes the cost

of removing a contaminant mass with toxicity equivalent to the

remaining non-acutely toxic dispersed mass of the released substance

from other identified contaminated sites. When determining the amount

of contaminant mass to remove, the submodel adjusts for the relative

degradability of that contaminant compared to that of the spilled

substance. The restoration cost database supplies data on unit costs to

the restoration submodel.

The restoration submodel sums the costs of any selected types of

active restoration. The models combine this figure with the compensable

value figure computed by the compensable value submodel to form the

final damage figure.

For further information on the restoration submodel, see Section 5,

Volume I of the NRDAM/CME and NRDAM/GLE technical documents. For

further information on the restoration cost database, see Sections 5,

12, and 13, Volume I, and Sections 5 through 7, Volume V of the NRDAM/

CME technical document; and Section 9, Volume I and Section 5, Volume

III of the NRDAM/GLE technical document.

4. Compensable Value Submodel

Compensable value, as computed by the compensable value submodel,

is the sum of certain economic use values lost to the public pending

the reestablishment of baseline conditions through either natural

recovery or active restoration, as determined by the restoration

submodel. Only public losses are included in compensable value.

The submodel computes the following types of compensable values:

Lost economic rent for lost commercial harvests resulting from

any closures specified by the authorized official and/or from

population losses;

Lost recreational harvests resulting from any closures specified

by the trustee and/or from population losses;

In the NRDAM/CME, lost wildlife viewing, resulting from

population losses, by residents of the States bordering the

provinces in which the population losses occurred;

In the NRDAM/GLE, lost wildlife viewing, resulting from

population losses, by residents of local areas bordering the

provinces in which the population losses occurred; Lost beach

visitation due to closure; and

In the NRDAM/GLE, lost boating due to closure.

The submodel calculates compensable value for lost economic rent by

multiplying the total lost harvest of the species, as computed by the

biological effects submodel, by the commercial price per unit of

harvest, as supplied by the compensable value database. The rule

provides that if a trustee is aware of reliable evidence that a private

party has recovered damages for commercial harvests lost as a result of

the release, the trustee must eliminate from the claim any damages for

such lost harvests included in the lost economic rent calculated by the

model.

The submodel calculates compensable value for lost recreational

harvests by multiplying the total lost recreational harvest of the

species, as computed by the biological effects submodel, by the

marginal value of harvesting an additional animal, as supplied by the

compensable value database. The submodel computes damages only for

harvests lost due to populations losses or closures. The submodel does

not compute damages for lost quality of recreational fishing unrelated

to lost harvests or for lost trips due to de facto closures.

The compensable value submodel computes compensable value for a

specific range of lost wildlife viewing. First, the submodel only

calculates wildlife viewing damages resulting from population losses

and does not address damages resulting from closures. Second, the

submodel only calculates losses incurred by certain segments of the

wildlife viewing public. The models divide geographic areas into

provinces. The NRDAM/CME computes lost wildlife viewing only for

residents of States bordering the provinces in which the population

loss occurred. The NRDAM/GLE computes lost wildlife viewing only for

residents of local areas bordering the provinces in which the

population loss occurred. The submodel calculates damages by

multiplying the

[[Page 20567]]

number of viewing trips affected by the release by the per-animal

marginal viewing value for the animals killed.

The compensable value submodel computes compensable value for lost

beach visitation only if trustees specify that there has been a closure

of a beach. The submodel does not calculate damages for lost quality of

beach visitation or for lost beach visitation due to de facto closures.

If a closure is specified, the compensable value submodel calculates

compensable value by multiplying the length of beach closed per day and

the number of days closed, as supplied by trustees, by the per-day

value of trips to the closed length. The compensable value database

supplies data on the per-unit value of lost beach visitation.

The NRDAM/GLE computes compensable value for lost boating only if

trustees specify that there has been a closure of a boating area. The

model does not calculate damages for lost quality of boating or for

lost boating trips due to de facto closures. If a closure is specified,

the compensable value submodel calculates compensable value by

multiplying the geographic area closed per day and the number of days

closed, as supplied by trustees, by the per-day value of trips to the

closed area. The compensable value database supplies data on the per-

unit value of lost boating. The NRDAM/CME does not compute compensable

value for lost boating.

The per-unit values in the compensable value database are stated in

1991 dollars for the NRDAM/CME and 1990 dollars for the NRDAM/GLE. The

compensable value submodel uses the Gross National Product Implicit

Price Deflator, as supplied by trustees, to adjust per-unit values to

current dollars. The compensable value submodel discounts the value of

future losses using a three percent discount rate.

After applying the Gross National Product Implicit Price Deflator

and the discount rate, the compensable value submodel sums the lost

values to calculate a compensable value figure. This figure is added to

the restoration costs, if any, computed by the restoration submodel to

form the final damage figure calculated by the models.

The rule provides that if a trustee is aware of reliable evidence

that the model application covers resources beyond his or her

jurisdiction, the trustee must either: (1) Have the other trustees who

do have jurisdiction over those resources join in the type A

assessment; or (2) eliminate any damages for those resources from the

claim. Further, the rule provides that if the model output indicates

damages in excess of $100,000, then trustees who wish to obtain a

rebuttable presumption must either: (1) Limit the portion of their

claim calculated with the type A procedure to $100,000; or (2) compute

all damages using type B procedures.

For further information on the compensable value submodel, see

Sections 8 through 11, Volume I of the NRDAM/CME technical document;

and Section 6, Volume I of the NRDAM/GLE technical document. For

further information on the compensable value database, see Sections 8

through 11, Volume I, and Sections 1 through 4, Volume V of the NRDAM/

CME technical document; and Section 6, Volume I, and Section 4, Volume

III of the NRDAM/GLE technical document.

V. Use of the NRDAM/CME and NRDAM/GLE in Other Contexts

The Department is issuing today's final rule in compliance with the

statutory requirement to develop procedures for conducting simplified

assessments that are entitled to a rebuttable presumption. The

standards in today's final rule apply only when trustees use the type A

models to develop a damage figure and intend to obtain a rebuttable

presumption for that figure in litigation. Trustees who use the models

in other contexts, such as settlement negotiations or litigation

without the benefit of the rebuttable presumption, are not subject to

the rule standards. In these other contexts, trustees are free to make

modifications to the model databases beyond those permitted under the

rule and to use some, but not all, of the components of the models.

For example, trustees may wish to use the models to develop a

benchmark damage figure for settlement negotiations but may have more

up-to-date or more site-specific information on recreational fishing

values. In that case, trustees may choose to apply the models using

modified recreational fishing values, notwithstanding the rule

provisions concerning modification of the model databases. In other

situations, trustees may choose to rely on the models' predictions of

injury but perform their own analyses of restoration alternatives and

compensable values. Trustees may also choose to rely on the models'

damage calculations for some resources but for other resources

substitute their own damage calculations for other resources covered by

the models. The Department believes that although use of the type A

models in these ways would not be covered by today's rule and,

therefore, would not be entitled to a rebuttable presumption, such use

can produce reliable damage estimates if done properly.

VI. Summary of Major Changes from the Proposed Rules

The Department has made numerous changes in the rule language and

models based on the comments received. The Department discusses its

rationale for these changes in Section VII of this preamble.

A. Rule Language

The Department has made several major substantive changes to the

proposed rule language. With regard to the applicability of the type A

procedures, the Department has modified the conditions that must be met

before a trustee can use a type A procedure to obtain a rebuttable

presumption and has eliminated the provision that would have required

trustees to use the type A procedures in some circumstances. Instead of

delineating ``primary'' and ``secondary'' conditions for use as the

proposed rule did, the final rule now provides that if the conditions

for use of the models listed in Sec. 11.34 are met, then trustees

decide whether to use type A or type B procedures based on an

evaluation of the averaged data and simplifying assumptions listed in

the NRDAM/CME and NRDAM/GLE technical documents. The Department has

also more clearly delineated the conditions under which trustees can

use type B procedures to supplement a type A procedure and the process

for doing so.

With regard to operation of the NRDAM/CME and the NRDAM/GLE, the

rule now allows trustees to modify the habitat designations in the

models and still obtain a rebuttable presumption. The rule also

requires trustees to perform a preliminary application of the NRDAM/CME

or NRDAM/GLE and make the results available for public review before

performing a final application and presenting a demand to the PRP.

The final rule contains three new provisions that require trustees

in some cases to adjust the damage figure calculated by the models

before presenting a demand. First, the rule now provides that if

trustees are presented with evidence that private parties have obtained

recoveries for lost commercial harvests, they must eliminate any

damages for such lost harvests included in the lost economic rent

calculated by the model. Second, the rule provides that if a trustee is

aware of reliable evidence that the model application covers resources

beyond his or her trustee jurisdiction, the trustee must

[[Page 20568]]

either: (1) Have the other trustees who do have jurisdiction over those

resources join in the type A assessment; or (2) eliminate any damages

for those resources from the type A damage calculation. Third, the rule

provides that if the model output indicates damages in excess of

$100,000, then trustees who wish to obtain a rebuttable presumption

must either: (1) Limit the portion of their claim calculated with the

type A procedure to $100,000; or (2) compute all damages using type B

procedures.

The Department has also eliminated the proposed clarification of

the scope of review of a type A assessment in a natural resource damage

case.

Finally, as part of its regulatory reform efforts, the Department

has rewritten the final rule in plain English. The Department believes

this revision has made the rule significantly clearer and easier to

read.

The following is a section-by-section analysis of the final rule:

Subpart A--Introduction

Section 11.15 What Damages May a Trustee Recover?

The Department has rewritten the heading of this section to make it

easier to understand. The final rule language revising subsection

(a)(1) is unchanged from the August 1994 proposed rule. The final rule

eliminates the separate subsections referring to type A procedures,

type B procedures, or a combination of type A and B procedures in the

same assessment. Sections 11.34 through 11.36 include the criteria and

standards for selecting type A procedures, type B procedures, or a

combination, making additional detail in this introductory section

unnecessary.

Section 11.18 Incorporation by Reference

The final rule slightly revises and updates the proposed rule

language incorporating by reference the NRDAM/CME technical document,

and adding language incorporating by reference the NRDAM/GLE technical

document.

Section 11.19 Information Collection

The final rule retains the December 1994 proposed rule language to

remove and reserve this section.

Subpart C--Assessment Plan Phase

Section 11.30 What Does the Authorized Official do if an Assessment is

Warranted?

The final rule makes several revisions to this section that were

not included in the proposed rules, but which are necessary to conform

to other provisions in today's final rule. Existing subsection (a),

which applied to both type A and type B procedures, did not authorize

performance of any assessment methodologies until after the period of

public review and comment for the Assessment Plan. Section 11.42 of

today's final rule requires trustees to perform a preliminary

application of the NRDAM/CME or NRDAM/GLE before releasing the

Assessment Plan for public review and comment. Trustees who use type B

procedures, however, must still make the Assessment Plan available for

public review and comment before performing any of the procedures

contained in the Plan. See Sec. 11.32(c) of today's final rule. The

Department has revised the heading of the section and the language of

subsection (a) to make them easier to understand and to make this

conforming change. The Department has also modified subsection

(c)(1)(vi) to make a necessary conforming change cross-referencing

other rule provisions.

Section 11.31 What Does the Assessment Plan Include?

The final rule revises the heading and rule language to make the

section easier to understand. Subsection (a)(1) adopts as final the

language in the August 1994 proposed rule.

The Department has revised subsection (b) from the August 1994

proposed rule to make it clear that the Assessment Plan must include a

detailed explanation of how the trustee's decision to use a type A

procedure, type B procedures, or a combination, satisfies the

decisional standards contained in the rule.

Subsection (c) clarifies and corrects existing rule language, which

was garbled in 1988. Compare 53 FR 5174 (Feb. 22, 1988) with 51 FR at

27731. Although this language was not in the proposed rules, it is a

nonsubstantive change. Subsection (c)(1) has been modified to make a

necessary conforming change cross-referencing redesignated Sec. 11.37.

Subsection (d) revises the existing rule language to make it easier

to understand. Subpart D contains the requirements concerning

identification and documentation of information, and therefore it is

unnecessary to repeat them in subsection (d).

Section 11.32 How Does the Authorized Official Develop the Assessment

Plan?

The Department has revised the heading of this section to make it

easier to understand.

The final rule revises subsection (c) to make it easier to

understand and to make the same necessary conforming change described

in the discussion of Sec. 11.30.

The final rule language revising subsection (f) is slightly

reworded, but substantively the same as, the language in the August

1994 proposed rule. As explained in the August 1994 notice of proposed

rulemaking, this provision clarifies that the confirmation of exposure

requirement applies to type B, but not type A, procedures. Original

Secs. 11.34(a)(1), 11.31(c)(1), and 11.33(b)(4) already established

this distinction. Today's final rule language merely makes the rule

easier to understand.

Section 11.33 What Types of Assessment Procedures Are Available?

Today's final rule revises Sec. 11.33 to limit this section to

providing a brief description of the difference between type A and type

B procedures.

Section 11.34 When May the Authorized Official Use a Type A Procedure?

New Sec. 11.34 combines and revises changes that were proposed for

Sec. 11.33 in the August 1994 and December 1994 proposed rules. This

section now states the threshold conditions that must be present before

a trustee may use a type A procedure, many of which were included among

the ``primary'' conditions in the proposed rules.

Section 11.35 How Does the Authorized Official Decide Whether to Use

Type A or Type B Procedures?

New Sec. 11.35 further revises changes that were proposed for

Sec. 11.33. The section provides decisional criteria for the

determination whether to use type A or type B procedures, assuming that

the conditions in Sec. 11.34 are met. The final rule language requires

trustees to base the decision whether to use type A or type B

procedures on an evaluation of the data and assumptions in the type A

procedures, as described in the NRDAM/CME and NRDAM/GLE technical

documents. These assumptions include many of the ``secondary

conditions'' contained in the proposed rules.

Section 11.36 May the Authorized Official Use Both Type A and Type B

Procedures for the Same Release?

New Sec. 11.36 provides standards for when trustees may use both a

type A procedures and type B procedures for the same release. The

August and December 1994 proposed revisions to Sec. 11.33 included

similar modifications.

[[Page 20569]]

Today's final rule language provides clearer, more specific criteria,

and specifically identifies the categories of injury and compensable

value addressed by the type A procedures.

Subsection (d) addresses the issue of which type B procedures must

be followed when a trustee decides to combine a type A and type B

procedures in a single assessment.

Section 11.37 Must the Authorized Official Confirm Exposure Before

Implementing the Assessment Plan?

The Department has revised the heading of this section (formerly

Sec. 11.34) and has modified subsection (a) from the proposed rule to

make it easier to read. Subsection (a) clarifies the intent of the

existing rule that the confirmation of exposure requirement applies

only to type B procedures. Although former Sec. 11.34(a) did not

expressly distinguish between type B and type A procedures, former

Secs. 11.31(c)(1) and 11.33(b)(4) limited the confirmation of exposure

requirement to type B procedures.

Subpart D--Type A Procedures

Section 11.40 What Are Type A Procedures?

The Department has revised the heading of this section and the

language of subsection (a) to make them easier to read, to add

references to the type A procedures for Great Lakes environments, to

provide additional information about both type A procedures, and to

incorporate the requirement that a trustee must follow the procedures

in Secs. 11.41 through 11.44 when using either of the two type A

procedures. Today's final rule provides a more detailed description of

type A procedures than was contained in the August 1994 proposed

revision to Sec. 11.40.

Section 11.41 What Data Must the Authorized Official Supply?

This section identifies the data inputs and modifications that the

trustee must supply to use the NRDAM/CME or NRDAM/GLE. Today's final

rule modifies and simplifies proposed Sec. 11.42 (c) and (d) in the

August 1994 proposed rule, and proposed revisions to Sec. 11.41 in the

December 1994 proposed rule. The final rule language for Sec. 11.41 is

considerably shorter than that in the proposed rules, because the

format for data inputs and modifications is now contained in two new

appendices to the rule. The final rule now requires trustees to make

certain modifications to the model databases, including the habitat

designations, if they have reliable evidence that the databases are

incorrect.

Section 11.42 How Does the Authorized Official Apply the NRDAM/CME and

NRDAM/GLE?

This section contains a new procedure requiring trustees to perform

a preliminary application of the NRDAM/CME or NRDAM/GLE as part of the

process for deciding whether to use a type A procedure. If the trustee

decides to continue with a type A procedure, then the data inputs,

modifications, and results of the preliminary application become part

of the Assessment Plan.

Section 11.43 Can Interested Parties Review the Results of the

Preliminary Application?

This section requires trustees who decide to continue with a type A

procedure to develop an Assessment Plan, which must include the data

inputs, modifications, and results of the preliminary application. The

trustee must make the Assessment Plan available for public review and

comment.

Section 11.44 What Does the Authorized Official do After the Close of

the Comment Period?

Subsections (a) through (c) of this section state the procedural

and substantive requirements following public comment on the Assessment

Plan, which include performing a final application of the NRDAM/CME or

NRDAM/GLE and preparing a Report of Assessment. Subsection (d) includes

specific criteria to preclude double recovery for economic rent for

lost commercial harvests if a private party has already recovered for

the same damages. Subsection (e) resolves a potential problem arising

when trustees have not agreed in advance to use a type A procedure

jointly. Subsection (f) limits the damages that may be recovered by

trustees who use the NRDAM/CME or NRDAM/GLE and intend to obtain a

rebuttable presumption.

Subpart E--Type B Procedures

Section 11.73 Quantification Phase-Resource Recoverability Analysis

The Department has revised subsection (a) to make a necessary

conforming change to cross-reference redesignated Sec. 11.35 (now

Sec. 11.38).

Subpart F--Post-Assessment Phase

Section 11.90 What Documentation Must the Authorized Official Prepare

After Completing the Assessment?

The Department has revised the final rule from the August 1994

proposed rule to make the heading and rule language simpler and easier

to understand. The substantive effect of this provision is the same as

existing Sec. 11.90.

Section 11.91 How Does the Authorized Official Seek Recovery of the

Assessed Damages From the Potentially Responsible Party?

Today's final rule revises the heading of the section and the first

sentence of subsection (a) to make the rule language simpler and easier

to understand. The substantive effect of this provision is the same as

existing Sec. 11.91.

Appendices

The Department has added two new appendices to the rule. These

appendices specify the format for data inputs and modifications for the

NRDAM/CME and NRDAM/GLE.

B. NRDAM/CME and NRDAM/GLE

The Department has made several major substantive changes to the

NRDAM/CME and NRDAM/GLE computer code and databases. The Department has

revised the chemical database for both the NRDAM/CME and NRDAM/GLE to

incorporate an additional 24 oils and petroleum products. The

Environment Canada publication, ``A Catalogue of Crude Oil and Oil

Product Properties,'' and NOAA's ADIOS (Automated Data Inquiry for Oil

Spills) database provided the principal sources of information for

revision of the databases. The Department also deleted the following

hazardous substances from the database: pure metals, nontoxic

substances, and substances for which the toxicity threshold was less

than the water solubility. The Department deleted a total of 31

hazardous substances from the NRDAM/CME database and 32 hazardous

substances from the NRDAM/GLE database.

The Department has included an additive toxicity model for oil and

petroleum products in the biological effects submodel to address the

additive toxicity of the multiple substances in oil and petroleum

products. The additive toxicity model also addresses the effects of oil

weathering.

The Department has updated the wildlife viewing values contained in

both the NRDAM/CME and NRDAM/GLE economic databases based on

[[Page 20570]]

recent information available from the 1994 addendum to the 1991

National Survey of Fishing, Hunting, and Wildlife-Associated Recreation

developed by the U.S. Fish and Wildlife Service (FWS). Also, in the

NRDAM/CME, the Department revised the wildlife viewing values to

reflect the total population of the respective coastal states.

In the NRDAM/CME, the Department has modified the habitat grids to

provide a finer scale resolution. The Department changed the scale from

a 50 x 50 grid to a 100 x 100 grid. The Department has also upgraded

the Microsoft compiler to allow for use of 32-bit processing

and additional random access memory (RAM).

The Department has revised the east coast wetland habitats

represented in the NRDAM/CME grids for provinces 11, 12, and 13 (New

York and New Jersey) to incorporate more site-specific data provided by

commenters. See Section 3.4, Volume III of the NRDAM/CME technical

document.

In the NRDAM/CME, the Department has substantially revised wildlife

abundance data for provinces 40 through 51 (west coast and the Gulf of

Alaska) based on additional information and data provided by public

commenters.

The Department has added a habitat editor to the NRDAM/GLE user

interface consistent with that provided in the proposed NRDAM/CME.

The Department has included intertidal seagrass as an additional

habitat type in the NRDAM/CME. The intertidal seagrass habitat includes

those common habitats for tropical seagrass and eelgrass.

The Department has disaggregated the model output files for the

injury and damage calculations resulting from direct kills versus food

web and habitat losses, and from commercial versus recreational fishing

losses.

The Department has revised the active habitat restoration

alternatives evaluated for structured habitats (i.e., wetlands,

seagrass beds, macroalgal beds, and invertebrate reefs) to include not

only sediment replacement with replanting but also replanting alone.

The Department has eliminated the calculation of compensable value

for lost boating and subsistence losses from the NRDAM/CME.

The Department has revised the restoration submodel to include a

cost-benefit test for determining whether the measured benefits of

active habitat restoration and restocking, as compared to natural

recovery, are worth the additional costs.

Finally, the Department has revised the calculation of assimilative

capacity restoration costs to correct for the degradation rate of the

spilled substance and to limit the calculation of assimilative capacity

restoration costs to cases where biological injury has occurred and

produces compensable value.

VII. Response to Comments

The Department received numerous public comments on the proposed

type A procedures. The Department and NOAA also asked several

independent technical reviewers to examine the proposed NRDAM/CME. The

Department made the comments of these independent technical reviewers

available to the public and included them in the administrative record

for this rulemaking. See 60 FR 28773 (June 2, 1995). The Department

provides responses to both the public comments and the comments of the

independent technical reviewers below.

In addition to the issues discussed below, commenters addressed a

number of issues beyond the scope of this rulemaking. The Department

explicitly limited this rulemaking to four issues: the revision of the

existing type A procedure for coastal and marine environments; the

development of a new type A procedure for Great Lakes environments; the

conditions for combined use of type A and type B procedures; and the

scope of judicial review of assessments performed using type A

procedures. See 59 FR at 40319-20, 63300, and 63302. Nevertheless, some

commenters raised additional issues, including: whether trustees should

be allowed to pool natural resource damage recoveries to implement

regional restoration plans; the permissibility of using type A and type

B procedures for the same release; and whether lost economic rent and

the cost of restoring lost assimilative capacity are legally

permissible categories of damages. The Department has not evaluated,

and is not providing substantive responses to, comments on these issues

in this rulemaking.

Section 11.93(d) of the existing regulations, which was promulgated

in 1987, allows pooling of multiple type A recoveries to implement a

single restoration plan, so long as the plan is intended to address the

same or similar injuries as those identified in each application of the

type A procedure. See 52 FR at 9100. The Department neither reproposed,

revisited, nor solicited comment on Sec. 11.93(d) and merely cited it

in the preambles to the proposed rules by way of background. 59 FR at

40324 and 63305.

Section 11.15(a)(1)(iii) of the original type A rule, which was

promulgated in 1987, established that trustees could use both type A

and type B procedures for the same release under certain circumstances.

See 52 FR at 9095. The Department did not repropose, revisit, or

solicit comment on whether CERCLA allows trustees to combine type A and

type B procedures. The only issue raised and addressed in this

rulemaking was whether the Department should expand the authorization

for combined use of type A and type B procedures.

Finally, the Department did not repropose, revisit, or solicit

comment on its long-standing positions on the recoverability of damages

for lost economic rent and lost assimilative capacity. Both the

original type B rule and the original type A rule explicitly allowed

for the recovery of lost economic rent. See 43 CFR 11.83(c)(1); 51 FR

at 27749; and 52 FR at 9047. The Department has recognized the loss of

assimilative capacity as a legitimate category of natural resource

damages since the promulgation of the original type B procedures in

1986. 51 FR at 27716; see also 59 FR at 14273. The Department has begun

a biennial review of the type B procedures and will be considering the

issues of lost economic rent and lost assimilative capacity in that

context. See 59 FR 62749 (Oct. 19, 1994).

A. General Comments

Comment: Some commenters supported the concept of a reliable,

accurate, automated damage assessment procedure that would eliminate

the need for expensive tailor-made studies. However, other commenters

objected to the calculation of damages through what they considered to

be abstract application of theoretical, generic models. Some of these

commenters thought that many of the calculations of the NRDAM/CME and

NRDAM/GLE were based on unsubstantiated assumptions.

A number of commenters, including some of the independent technical

reviewers, questioned the Department's use of ``grand averages'' to

extrapolate data for a specific species, substance, or location, to

different species, substances, and locations. Commenters were

particularly concerned about the extrapolation of economic values made

in the compensable value submodel. For example, commenters noted that

some of the studies used to value recreational fishing in the NRDAM/CME

were based on freshwater fishing and commercial fishing. Commenters

also stated that many of the studies used outdated data and outdated or

unreliable

[[Page 20571]]

methodologies. For example, commenters noted that recreational hunting

values were derived from a 20-year old contingent valuation study. Some

commenters suggested specific criteria that they thought should be met

when performing benefits transfer (i.e., the extrapolation of economic

values derived from studies of one situation to another situation).

Response: CERCLA requires that type A procedures involve ``minimal

field observation'' and authorizes type A procedures to be based on

``units of discharge or units of affected area.'' CERCLA sec.

301(c)(2)(A). The Senate Report that accompanied the predecessor bill

to CERCLA provides the following indication of Congress' intent:

Natural resource damage assessments based on this type of

regulation [type A] should require as little fieldwork as possible,

and rely on a combination of habitat values, tables of values for

individual species, and previously conducted surveys and laboratory

studies, related to units of discharge or units of affected area. S.

Rep. No. 96-848 at 86.

This language indicates that Congress envisioned the development of

type A procedures that do not require the performance of any new

studies but instead use existing studies to provide generalized values

that can be applied in specific cases. Inherent in the concept of

developing unit values from existing studies is the notion of making

assumptions in the absence of empirical data and applying average

values across a range of nonidentical items. Therefore, the Department

believes that CERCLA authorizes it to make appropriate extrapolations

from existing data.

The science of natural resource damage assessment is still

evolving. The universe of relevant studies is still very small for many

crucial aspects of damage assessment. Existing data are particularly

limited as to the effects of small spills. Even when addressing the

limited range of scenarios covered by the NRDAM/CME and the NRDAM/GLE,

the Department faced significant challenges in bridging data gaps.

Although Congress did authorize the Department to make extrapolations

from existing data, the Department recognizes that any such

extrapolations must be reasonable. Thus, when developing the models,

the Department tried to make use of the most reliable information

available based on extensive reviews of published and unpublished

information and data; make only those assumptions that are necessary;

ensure that any assumptions that are made are reasonable; and identify

clearly all assumptions that were required for the development of

simplified procedures.

With regard to the compensable value submodel, the Department did

apply specific criteria during its selection of studies to use for

benefits transfer. The Department used only studies that: (1) Were

based on an extensive literature review and consultations with relevant

governmental agencies; (2) reasonably represented the natural resource

and public use under investigation; (3) contributed to a reasonable

representation of the different regions included in the models; (4)

were conducted by a recognized university-associated researcher or

established consulting firm; and (5) used appropriate valuation

methodologies. The Department believes that these criteria adequately

address all the concerns that the commenters' suggested criteria are

intended to address. The first three criteria assure that the resources

considered in the selected studies are as similar as possible to the

resources to be valued in the models. The fourth criterion assures that

the selected studies are scientifically sound. The fifth criterion

assures that the selected studies use appropriate valuation

methodologies.

Comment: One commenter suggested that the Department had developed

the models by selecting values from a few studies while ignoring

others. The commenter argued that the Department had failed to provide

adequate justification for the values it selected.

Response: The Department conducted extensive searches for available

information. Some data the Department identified were not used because

better or more applicable data were available. However, none of the

identified data was ignored. The Department believes that the NRDAM/CME

and NRDAM/GLE technical documents adequately explain and justify the

values in the models.

Comment: Some commenters thought that the proposed type A models

were so technically flawed that they did not meet the statutory

standard of ``best available procedures'' and, therefore, trustees

should not obtain a rebuttable presumption if they use the models.

These commenters urged the Department to abandon the models noting that

Colorado v. Interior does not require or authorize the Department to

issue a model that is unreliable. One commenter acknowledged that the

proposed revised NRDAM/CME appeared to be an improvement over the

original NRDAM/CME Version 1.2 issued in 1987. However, the commenter

thought the proposed revised model still contained too many flaws to

accomplish its intended purpose. Another commenter stated that the

damage figures produced by the models are nothing more than sheer

speculation and are not legally sufficient due to the compounding of

errors, uncertainties, biases, and overestimates.

Response: As discussed in more detail below, the Department has

carefully reviewed all comments it received on the proposed models and

rule language. Based on this review, the Department has made numerous

modifications to the models and the rule language. Where the Department

concluded that no changes were needed, the Department has explained its

reasoning. The Department believes that the final type A models, as

revised in response to comments, are best available procedures when

used in accordance with the standards and process set forth in today's

final rule. The models, with their state-of-the-art modeling and

extensive databases, represent a significant advancement beyond the

original NRDAM/CME issued in 1987. The final type A procedures provide

for reliable, cost-effective, simplified assessments that are entitled

to a rebuttable presumption.

Comment: Several commenters thought the Department had been overly

ambitious in attempting to develop models like the NRDAM/GLE and the

NRDAM/CME. Specifically, these commenters stated that the biological

effects submodel attempted to perform a task that is beyond the current

state of ecological modeling. The commenters contended that state-of-

the-art ecological modeling is not yet capable of producing accurate

quantitative determinations and is primarily useful only for making

qualitative predictions. The commenters also thought that the multiple

iterative calculations performed by the biological effects submodel did

not alleviate the problem but simply amounted to averaging of nonsense.

Response: The Department agrees that ecological models should

generally be used only for qualitative predictions. However, the

biological effects submodel in the NRDAM/GLE and the NRDAM/CME is not a

true ecological model in the sense suggested by commenters. Ecological

models evaluate the changes in ecosystem structure and function

resulting from disturbances. The biological effects submodel, on the

other hand, is a toxicological effects model. The biological effects

submodel simply calculates acute mortality and lost production and

projects these injuries forward as biota not present or used in future

years. The submodel need not, and does not attempt to, address the

higher-order ecological

[[Page 20572]]

changes in the structure and functions of biological systems as true

ecological models do.

The Department believes that the NRDAM/CME and NRDAM/GLE are

reasonable tools for assessing the injuries and compensable values that

they address and do not generate ``nonsense.'' Further, the use of

iterative calculations is designed to, and does, enhance the

reliability of damage estimates in particular cases. The biological

effects submodel uses several randomized algorithms for processes, such

as swimming by fish, that are considered random at the relevant spatial

and temporal scales. For each spill modeled, the submodel performs

multiple iterative runs and then selects the mean result. This approach

is a generally accepted method of modeling the most probable biological

effects for events that have an element of randomness.

Comment: Some commenters thought the proposed models were

fundamentally flawed because they used overly simplistic simulations of

movement of biota within a population. The commenters stated that these

simulations could not be improved because of the lack of basic data on

population movement.

Response: The Department believes that the NRDAM/CME and the NRDAM/

GLE use the best available procedure for simulating the movement of

biota and that this procedure is reliable for the purposes of a

simplified damage assessment. The Department acknowledges that the

directed movement of biota is not well understood quantitatively.

However, at the smallest scale, there is a random component to the

movements of animals within the habitats they occupy, and the NRDAM/CME

and NRDAM/GLE can and do model this component. The models do not

simulate within-season, between-habitat movements, except where

currents carry organisms across boundaries. However, the seasonal and

habitat-specific abundances included in the database do account for

inter-habitat movement between seasons.

Comment: Some commenters, including some of the independent

technical reviewers, thought that the Department should validate the

models against real-world data and perform sensitivity analyses. A few

commenters also thought the Department should calibrate the models.

Response: The Department has conducted extensive sensitivity

studies of both the NRDAM/CME and NRDAM/GLE. It is difficult to conduct

conclusive validation studies of the models due to the extreme lack of

data on the natural resource effects of small spills. In fact, although

more data exist for large spills, even those data are limited.

Nonetheless, the Department has used the data that are available to

conduct validation studies of the NRDAM/CME physical fates and

biological effects submodels and believes that these studies suggest

that the submodels provide reasonable estimates of the actual physical

fates and biological effects of spills. Even less data exist for spills

in the Great Lakes than for spills in coastal and marine environments.

However, since the NRDAM/GLE contains the same algorithms as the NRDAM/

CME, the Department believes the results of the validation studies of

the NRDAM/CME also support the NRDAM/GLE.

Because of the cost involved in performing site-specific type B

studies, trustees have rarely pursued damage claims for minor releases.

Therefore, virtually no data exist with which to validate the

restoration and compensable value submodels or determine the need for

calibrating the damage estimates produced by the models. In the absence

of such data, the Department has relied primarily on careful reviews of

the accuracy and reasonableness of the data and algorithms used in the

models. The Department believes that these reviews of the scientific

underpinnings of the models provide adequate support for the

reliability of the damage estimates produced by the models.

The Department further believes that the models are consistent with

congressional intent underlying the directive to produce procedures for

simplified assessments. The models are best available simplified

procedures. They produce reliable, fair, and reasonable results when

used for their intended purpose. The Department has clearly identified

the capabilities and limitations of the models and has allowed trustees

to select between type A and type B procedures based on specified

criteria. Finally, the Department has retained the provision allowing

PRPs to require trustees to use type B procedures if they advance the

reasonable cost of using such procedures within an acceptable time

frame.

Comment: One commenter stated that the NRDAM/GLE should be peer

reviewed in an open forum prior to promulgation.

Response: The Department believes that the NRDAM/GLE has been

adequately reviewed. The proposed model was made available for public

review and comment for eleven months. Also, the review of the proposed

NRDAM/CME by independent technical reviewers was directly relevant for

the NRDAM/GLE because the NRDAM/GLE incorporates the same basic

modeling as the NRDAM/CME.

Comment: Some of the independent technical reviewers claimed that

the proposed NRDAM/CME underestimated damages. In support of this

claim, these reviewers noted that when used to calculate damages for

certain actual releases, the model generated damage figures that were

usually at least an order of magnitude less than the figure for which

the parties settled.

Response: The Department believes that when the conditions set

forth in Sec. 11.34 are met, the models will generate reasonable and

appropriate damage figures for the injuries and losses these simplified

procedures address. The Department does not believe that historical

settlements provide an accurate or meaningful standard against which to

judge the reliability of damage figures generated by the NRDAM/GLE and

the NRDAM/CME. Although real-life case data on physical fates and

biological effects can, in some instances, provide useful comparisons

when evaluating the physical fates and biological effects submodels,

bottom-line settlement figures may differ from model damage figures for

a number of reasons that have nothing to do with reliability.

First, because of the cost involved in performing site-specific

type B studies, trustees have rarely pursued damage claims for minor

releases. Therefore, historical natural resource damage settlements

usually involve large spills. The type A models were designed for minor

releases and are based on various assumptions that often are not

reasonable in the case of large spills. Therefore, the restoration and

compensable value submodels would not have been applicable to the cases

in which natural resource damage settlements have been reached.

Second, it is difficult to determine the appropriate user inputs

for some of the actual cases, many of which are several years old. For

example, user-supplied information on beach, and fisheries closures can

significantly affect the total damage figure, yet data on the actual

extent of such closures are in some cases no longer available.

Third, the models do not purport to capture all, or even most, of

the ``real world'' or ``actual'' damages that could be determined if

the costs of a full on-site assessment were not a consideration.

Instead, the models use averaged values to calculate a specific subset

of the damages resulting from a release. When used for the minor

[[Page 20573]]

releases for which they are intended, the models yield reliable and

appropriate damage figures that are calculated at a reasonable cost.

Past natural resource damage settlement agreements have generally

identified a single damage figure that is not broken down by component.

In fact, most settlement agreements to date have not even listed which

types of injuries and losses the agreement is intended to address.

Therefore, it is usually impossible to determine if the model is even

calculating the same type of damages as those covered by the

settlement, let alone whether the calculation produces a damage figure

that matches the settlement figure. The larger--and more complicated--

the release, the greater the likelihood of a divergence between the

type A damage figures and the more site-specific damages that might be

calculated using type B procedures. The fact that such divergence

occurs, and even at times might appear ``extreme,'' does not suggest

unreliability or an inappropriate ``underestimation'' of damages by the

type A models. Rather, it only serves to illustrate the limited

function these procedures are intended to serve, and the reason they

are designed to be used for minor releases, for which the costs of type

B procedures cannot be justified when compared to the anticipated level

of damages.

Finally, settlements are the result of negotiation. The negotiation

process usually begins before either party has completed its assessment

work. Settlement negotiations are influenced by both parties'

perception of several factors extraneous to the assessment process.

These factors include: the transaction costs associated with delaying

settlement or terminating negotiations and litigating the case; the

strength of the liability portion of the case; the PRP's financial

condition; and the trustee's ability to fund a complete assessment. In

light of the influence of these factors in settlement negotiations and

the other difficulties in comparing settlement figures against model

calculations, the Department does not believe that variances between

model damage figures and historical settlements indicates anything

about the reliability of the models, when used as intended.

Comment: One of the independent technical reviewers questioned why

the damages calculated by the proposed NRDAM/CME do not agree with

those calculated by the original NRDAM/CME for the same spill.

Response: The new NRDAM/CME differs significantly from the 1987

version of the model due to modifications made in compliance with the

Colorado v. Interior remand as well as modeling and database

improvements made as a result of the biennial review. Among the most

significant differences, the original model assumed a generic study

area defined by the user with uniform depth, habitat, and environmental

conditions. Today's final NRDAM/CME allows for geographic resolution of

multiple habitats, depths, coastline, shore type, currents, ice cover

and other environmental condition. The new NRDAM/CME contains much

larger biological and economic databases, resolving many more species

categories and geographic regions. Also, the new NRDAM/CME contains a

restoration submodel and restoration cost database. The Department

believes that these and other changes have resulted in significant

improvements in the reliability of the calculations of the model.

Comment: One commenter stated that the models were unreliable

because NOAA used them to develop proposed OPA compensation formulas

that generated unrealistic damage figures.

Response: The Department does not believe that damage figures

produced by NOAA's proposed OPA compensation formulas are relevant to

the evaluation of either the proposed or final versions of the NRDAM/

GLE and NRDAM/CME. On January 7, 1994, NOAA proposed compensation

formulas for determining natural resource damages under OPA. 59 FR at

1176-77. These formulas were based on early developmental drafts of the

NRDAM/GLE and the NRDAM/CME that the Department made available to NOAA

in 1991. The Department has extensively modified both the NRDAM/CME and

NRDAM/GLE since 1991. For example, the Department has revised the

algorithms contained in the physical fates and biological effects

submodels; expanded and updated the biological databases; and revised

the chemical and economic databases. Section VI.B of this preamble

identifies other major changes that the Department made to the NRDAM/

CME and NRDAM/GLE as a result of public comments.

Comment: One commenter stated that the proposed NRDAM/CME

dramatically underestimated damages as compared to the compensation

table developed by the State of Washington under its natural resource

damage laws. The commenter expressed concern that PRPs may use the

NRDAM/CME to seek reductions in the State compensation table.

Response: The Department does not believe it is appropriate or

relevant to compare the results of type A model runs against the

figures in Washington's compensation table, because the type A models

and the State table are based on different approaches to damage

assessment. The Washington table establishes a pre-set, per-gallon

scale of damages. The type A models, on the other hand, estimate the

actual effects of the release and then generate a site-specific damage

figure based on the cost of restoring injured resources plus selected

public economic values lost pending recovery.

With regard to PRPs' potential use of the type A models to

undermine the Washington table, the Department would like to emphasize

that the type A models were developed specifically for use under

Federal law. State or tribal simplified procedures may take into

account costs, economic values, or other considerations not reflected

in the type A models. As such, the damages produced by the type A

models are not an appropriate point of comparison for evaluating State

or tribal procedures. The type A models in no way preempt State or

tribal procedures that are authorized under and designed to enforce

non-Federal laws.

Comment: Several commenters questioned the disparity between the

levels of sophistication of different components of the models. Some of

the independent technical reviewers noted that the compensable value

submodel, unlike the relatively complex physical fates and biological

effects submodels, essentially amounted to a look-up table. These

reviewers thought that the Department should develop a more dynamic

economics model. Other commenters thought that significant disparities

in complexity existed even within the physical fates and biological

effects submodels.

Response: The Department has attempted to incorporate the best

available procedures for modeling all components of the type A models.

The Department acknowledges that the levels of intricacy vary

throughout the models. These variances reflect the differing degrees of

current technology and scientific knowledge. Economic science has not

progressed to the point where there are general models of recreational

demand that can be readily applied to specific recreational activities

at specific locations. This is in distinct contrast to the biological

and physical sciences. The physical fates and biological effects

submodels are based on parameterizations of known and generally

accepted models of physical and biological processes.

Comment: One of the independent technical reviewers stated that the

models incorporate some biases that will result in underestimates of

damages and other biases that will result in

[[Page 20574]]

overestimates. The technical reviewer suggested that the models provide

a range of damage estimates that reflect consistent use of conservative

assumptions on one end and consistent use of liberal assumptions at the

other end. Another independent technical reviewer suggested that the

models be modified to perform an uncertainty analysis for each run.

Response: The Department believes it has adequately and

appropriately addressed the potential for bias in the NRDAM/CME and

NRDAM/GLE. The type A procedures are principally designed to establish

a process for trustees to follow if they wish to pursue a natural

resource damage claim and obtain a rebuttable presumption in court. In

a suit for damages, trustees will need to identify a specific claim.

Therefore, the Department has developed type A models that generate a

single damage figure rather than a range of possibilities.

Moreover, where commenters, or the Department itself, identified

specific potential biases in the proposed models, the Department

modified the models to correct for such biases to the extent possible.

Where the Department could not eliminate the potential for bias, it

identified the simplifying assumptions made in the models that produce

that potential. As discussed further below, those assumptions that

could result in significant overestimates of damages if they are not

reasonable in a particular case are listed in Sec. 11.34 as conditions

that must be met if the trustees expect to obtain a rebuttable

presumption. Those assumptions that are not likely to result in

significant overestimates of damages if they are not reasonable in a

particular case, and, in fact, may result in underestimates, are

explicitly identified in Section 1, Volume I of the NRDAM/CME and

NRDAM/GLE technical documents. Section 11.35(a) provides that if a type

A procedure is applicable, trustees must determine whether to use type

A or type B procedures based on an evaluation of those model

assumptions.

As discussed in Section III of this preamble, the type A models are

neither expected nor intended to produce damage estimates that

``match'' the results of more complex site-specific assessment

procedures. Therefore, the Department has concluded that a traditional

uncertainty analysis is not needed.

Comment: Several commenters thought the scope and complexity of the

proposed NRDAM/GLE and NRDAM/CME were too great. A few commenters

thought the models were so complex and difficult to use that operating

them was beyond the ability of untrained users. One commenter thought

the technical documents should clearly state the required user

qualifications. Several commenters, including some of the independent

technical reviewers, suggested improved user interfaces. Some of the

independent technical reviewers thought that additional user guidance

was needed; one suggested that the Department develop an animated

tutorial.

Response: While the Department acknowledges that the NRDAM/CME and

NRDAM/GLE are functionally very complex, it does not believe that they

require an undue level of expertise to operate. Users must simply be

able to: (1) Understand the conditions for use in Sec. 11.34; (2)

evaluate the models' simplifying assumptions listed in of Section 1,

Volume I the technical documents; (3) evaluate the averaged data

included in the models as described in Volumes III through IV of the

NRDAM/CME technical document and Volume III of the NRDAM/GLE technical

document; and (4) enter correctly the required user-supplied data as

described in Appendices II and III of the rule. Users who meet these

standards will obtain reliable results regardless of whether they have

a full understanding of all the models' components.

As discussed further below, the Department has revised the

regulatory conditions for use of the models to clarify a number of

points of confusion. Section 1, Volume I of the NRDAM/CME and NRDAM/GLE

technical documents now contains a clearer, simpler discussion of all

the major model assumptions of which users should be aware when

determining whether to use type A or type B procedures. The Department

has also rewritten the regulatory discussion of the user-supplied

information and moved that discussion into appendices in an attempt to

make it easier to read. Volume II of the technical documents includes a

revised discussion of how to develop and input the user-supplied data.

Finally, the models provide a graphic user interface that has been

revised to further simplify the task of the user. While additional

guidance might be helpful and may be developed in the future, the

Department believes that the current level of guidance is adequate to

allow non-expert users to operate the model correctly.

Comment: Some of the independent technical reviewers questioned why

the user interface was not consistent with Windows software.

Response: The Department chose to develop the user interface as a

stand-alone product that would not require licensing a copyrighted

product such as Windows software.

Comment: A few commenters complained about the speed of the

proposed models. Some commenters called upon the Department to upgrade

the computer platform required to run the models. The commenters

thought that such an upgrade would enable users to complete model runs

in hours rather than days and would allow the models to use more

detailed databases, thus increasing accuracy.

Response: In developing the type A models, the Department had to

strike a balance between the desire for the speed afforded by high-

powered computer equipment and the need to ensure that any type A

procedure developed is readily accessible to a wide array of potential

users. The Department believes it has struck the appropriate balance in

the PC environment.

It is evident from even a cursory review of the technical documents

that the models are very complex and perform millions of individual

calculations during a run. The Department has made every effort to

optimize the models for speed without compromising their accuracy or

applicability. Obviously, there continue to be advances in PC

technology. For the development of the type A models, it was necessary

for the Department to settle on a widely-available computer platform

and finalize the rule. While more recent technological developments

will allow these models to run faster on improved computer platforms,

the Department decided that maintaining the models for use on 386 PCs

would not compromise their function or purpose and would keep them

readily accessible to potential users.

Model run times are affected by the complexity of the spill (e.g.,

amount spilled, duration of the spill, and degradation rate of the

spilled substance) as much as the computer platform utilized.

Nonetheless, for minor spills, most runs are executed in a matter of

minutes rather than hours or days even on a 386 PC. The models will

take significantly less time to run on a 486 PC or a Pentium

PC, but the user is not precluded from using an older model of

computer.

Since the issuance of the proposed rule, the NRDAM/CME has been

moved to a 32-bit FORTRAN compiler. This move allowed the

Department to subdivide the habitat grids by a factor of four and

increase the number of computational particles used to represent

spilled material and biota. These changes should improve the accuracy

of the model. The area

[[Page 20575]]

modeled in the NRDAM/GLE is much smaller than that modeled in the

NRDAM/CME. Therefore, the Department concluded that these changes were

not needed in the NRDAM/GLE to increase speed or accuracy.

Comment: One of the independent technical reviewers stated that

when he attempted to replicate test runs on the proposed NRDAM/CME he

obtained different results.

Response: Users will obtain identical results if, but only if, they

use identical inputs. The Department designed the type A models so that

they will produce identical results, regardless of the make or model of

PC used, if the user-supplied inputs are identical. To accomplish this

result, the Department built a table of random numbers into the models'

code rather than have the models use the random number generating

features of the microprocessor.

Comment: Several commenters, including some of the independent

technical reviewers, suggested that the Department include additional

categories of damages in the type A models. Commenters recommended that

the Department add the following losses to the models: sublethal

biological effects; chronic biological effects; wetland losses; nonuse

losses (i.e., economic values that are not dependent on use of a

resource, such as the value of knowing a resource exists); de facto

beach, boating, and fisheries closures; reductions in the quality of

boating and beach recreation in the absence of closures; reductions in

the quality of recreational fishing unrelated to mortality or closures;

and ecosystem functional losses such as reductions in filtration,

mineral recycling, and decomposition. These commenters expressed

concern that if the models are not expanded to cover additional losses,

then type A assessments will consistently underestimate damages. They

noted that Ohio v. Interior and Colorado v. Interior instructed the

Department to allow for the recovery of all reliably calculated losses.

Commenters also thought that, in light of the cost of type B

procedures, it was disingenuous of the Department to state that

trustees could simply use type B procedures to calculate damages for

losses not included in the models.

Response: The Department has attempted to include in the models all

categories of loss and injury for which adequate, reliable information

exists in a format that enables the calculation of damages for the wide

range of substances, resources, and geographic areas covered by the

models. The Department acknowledges that the type A models do not

address all potential losses and injuries that might result from a

release and that, in some cases, losses not included in the models may

be significant. The Department further acknowledges that Ohio v.

Interior and Colorado v. Interior instructed the Department to allow

for the recovery of all reliably calculated values. The issue, then, is

reliability. The exclusion of certain categories of injury and loss

from the models was based on the Department's evaluation of whether

there was adequate reliable information to support their inclusion.

For example, the Department has considered the comments suggesting

the addition of nonuse losses, but continues to believe that the

addition of such values is not feasible at this time. As discussed in

the proposed NRDAM/CME technical document, most studies of nonuse

values do not report marginal nonuse values that would be required for

the type A models as they are presently designed. See Section 8.5.2,

Volume I of the proposed NRDAM/CME technical document. Furthermore,

these studies have tended to focus on the nonuse values of threatened

or endangered species. As a consequence, the bulk of available studies

are not directly applicable to the estimation of nonuse values that

would be lost as a result of the small spills addressed by the type A

models.

Furthermore, the final rule explicitly provides that where trustees

expect losses that are not addressed by the models, they may consider

using type B procedures in addition to a type A procedure, provided

that type B procedures are cost-effective, can be performed at a

reasonable cost, and do not result in double recovery. The Department

recognizes that type B procedures are likely to be significantly more

costly than type A procedures and, in some cases, trustees may not be

able to perform type B procedures and still satisfy the rule's

reasonable cost standard. Nevertheless, the Department does not believe

that the cost of performing type B procedures justifies the inclusion

in the models of losses for which there is an inadequate basis to

determine damages. During future biennial reviews, the Department will

reevaluate whether additional information has become available that

supports expansion of the categories of losses and injuries included in

the models.

Comment: One of the independent technical reviewers stated that

additional detail should only be added to the models if it influences

the final damage figure.

Response: The ultimate purpose of all the calculations made by the

type A models is the determination of a reliable damage figure.

Therefore, while reviewing the comments and deciding which changes to

make to the models, the Department has focused on whether the suggested

changes would significantly improve the reliability of the final damage

figure.

Comment: One commenter suggested that trustees be allowed to use

simplified procedures developed by States and receive a rebuttable

presumption under the CERCLA regulations. Another commenter requested

that the Department develop compensation tables for commonly released

hazardous substances.

Response: Some simplified State or tribal procedures may well be

appropriate for use under CERCLA. However, only a handful of coastal

States have developed such procedures. Further, these State procedures

have been developed under State laws, which may establish somewhat

different objectives and standards than CERCLA. The Department believes

it would need to evaluate carefully any particular State or tribal

procedure to determine its consistency with CERCLA's regulatory mandate

before allowing it to be used and accorded a rebuttable presumption

under these regulations. Therefore, the Department decided it was more

appropriate to develop its own simplified procedures for the coastal

and marine and Great Lakes environments.

The primary advantage of compensation tables appears to be their

ease of use. The Department believes that the NRDAM/CME and NRDAM/GLE

are simple enough to operate that compensation tables are not

necessary. Further, the Department believes that the models will

provide a level of site-specific accuracy beyond that which a

compensation table could offer.

Although the Department has decided not to incorporate compensation

tables or simplified State or tribal procedures in this rulemaking, the

Department has begun to evaluate the need for, and feasibility of,

additional type A procedures. See 60 FR 24604 (May 9, 1995). The

Department will further consider the use of simplified State procedures

and the development of compensation tables in that context.

B. Technical Documents

Comment: Some commenters stated that the Department had failed to

provide adequate documentation explaining how the proposed models

operated and why the Department made the choices it did when developing

[[Page 20576]]

different components of the proposed models. One commenter stated that

the scope and complexity of the models were too great and suggested

that a revised program be developed and accompanied by a simplified

synopsis of the technical assumptions and formulas presented in a

format more amenable to comment. Commenters cited case law requiring

agencies to provide a complete explanation and defense of models used

in the development of regulations. The commenters noted that the

Department's obligation to provide a full discussion of the type A

models was even greater because the models are used to determine

monetary liability of particular parties.

Response: The Department acknowledges its duty to provide an

adequate explanation and justification of the models and to provide the

public with a meaningful opportunity to review and comment on the

proposed models. The Department believes it has fulfilled this duty.

The proposed models were accompanied by lengthy and detailed

technical documents describing the content, workings, and development

of the models. The proposed NRDAM/CME technical document exceeded 2,400

pages in length; the proposed NRDAM/GLE technical document was almost

1,500 pages in length. Also, the preambles to the proposed rules

provided a roadmap to the technical documents, highlighting areas of

potential concern and identifying where various issues were discussed

in the technical documents. The Department made the proposed models and

technical documents available on diskette free of charge to anyone who

requested them.

To assist commenters in reviewing the models, the Department

equipped the proposed models with a user interface that included pull-

down menus, ``help'' screens, and graphic displays of the physical

environments and user-generated runs of the physical fates submodel.

The Department also incorporated pertinent calculations from the

physical fates, biological effects, restoration, and compensable value

submodels into the printed model output to enable reviewers to evaluate

the reliability of the models for incident-specific model applications.

The Department notes that the goal of developing models that

calculate compensatory damages for spills throughout the Great Lakes

and coastal and marine environments has necessitated a relatively high

level of complexity in modeling. The Department recognizes that with

models as complex as the NRDAM/CME and NRDAM/GLE some reviewers will

always want more information on specific elements while others will be

overwhelmed as the documentation becomes more extensive. Although the

Department never deliberately omitted any discussion it thought would

be of interest to reviewers, the Department did recognize that

providing too much information can be just as problematic as providing

too little. The Department has tried to be sensitive to the risk that

important information can become buried in a mountain of detail.

The Department extended the public comment period on the proposed

NRDAM/CME once and on the proposed NRDAM/GLE twice. The total comment

periods were seven months for the proposed NRDAM/CME and eleven months

for the proposed NRDAM/GLE. Those reviewers left with questions after

reviewing the models and technical documents were free to contact

Departmental staff at any time during the comment period.

Finally, the Department has provided additional discussion of

specific model aspects in the final versions of the NRDAM/CME and

NRDAM/GLE technical documents and in this preamble as a result of

specific public comments.

Comment: Several commenters, including some of the independent

technical reviewers, said that the technical documents were either

unclear or difficult to use. Others noted confusing table captions and

headings, inconsistencies, incorrect citations, and typographical

errors. One commenter suggested that major assumptions for each

submodel be placed in bold print at the beginning of each section. One

commenter recommended that the technical documents be amended to give

examples of when the models might underestimate or overestimate

damages.

Response: The Department has reviewed and revised the NRDAM/CME and

NRDAM/GLE technical documents to further clarify algorithms,

assumptions, and data sources. The Department has also checked the

documents for consistency, particularly with regard to terminology and

has fixed the noted typographical errors and incorrect citations.

Section 1, Volume I of the NRDAM/CME and NRDAM/GLE technical documents

now more clearly identifies all the major assumptions of which trustees

should be aware when deciding whether to use the models and describes

the likely results if the assumptions are not reasonable in a

particular case. Further, the discussion of each submodel in Volume I

of the technical documents now starts with a list of the assumptions

relevant to that submodel.

C. Selection of Assessment Procedures

Comment: The Department received numerous comments on the proposed

conditions for use of the type A models. The proposed rules identified

a set of primary conditions and a set of secondary conditions. Under

the proposed rules, if any primary condition were not met, trustees

would not have been allowed to use the type A procedure. If all primary

and all secondary conditions were met, trustees would have been

required to use the type A procedure for all damages. If all primary

conditions but only some secondary conditions were met, trustees could

have used a combination of type A and type B procedures.

Some commenters thought the proposed rules were overly prescriptive

in dictating which type of assessment procedures trustees may use.

These commenters argued that trustees should have greater discretion to

determine which procedures, type A, type B, or a combination, are

appropriate in a particular case. Commenters expressed concern that the

conditions regarding use of the type A procedures were vaguely defined

and would invite confrontation and litigation if they were imposed as

requirements. These commenters supported expansion of the authority to

use type A and type B procedures in combination, but thought the

proposed rules still did not provide adequate flexibility. These

commenters also stated that the type A procedures were particularly

useful when used with selective site-specific studies of impacts not

addressed in the type A models.

Other commenters, including one of the independent technical

reviewers, thought that the proposed rules gave trustees too much

discretion in selecting assessment procedures. Some of these commenters

thought that the conditions regarding use of the type A procedures

should be clearer and stricter. One of the independent technical

reviewers suggested that the Department recharacterize the assumptions

made by the models as limits of applicability. One commenter argued

that trustees be required to use a type A procedure unless they provide

scientific justification for using type B procedures. On the other

hand, some commenters expressed concern that the proposed rules would

allow excessive use of the type A procedures and suggested making the

primary conditions more restrictive.

Several commenters objected to the proposed provision allowing

combined

[[Page 20577]]

use of type A and type B procedures. The commenters argued that

Congress intended the type A and type B procedures to be mutually

exclusive. These commenters also thought that combined use of type A

and type B procedures would pose significant risks of double recovery

of damages and that the proposed rules failed to provide any guidance

on how to prevent such double recovery. One commenter stated that

combined use of type A and type B procedures was inconsistent with the

``average'' values justification for simplified procedures, since type

B procedures would be used to offset type A underestimates without any

corresponding offset of type A overestimates. Another commenter

expressed concern that if allowed to supplement type A assessments,

trustees would spend enormous sums assessing nonuse values for small

releases even though such releases are unlikely to produce any

meaningful nonuse losses. Some commenters stated that if the final rule

allowed use of type B procedures to supplement a type A assessment,

then such use should be limited to resources not included in the type A

procedure.

Response: The type A models are powerful tools for completing

assessments and beginning restoration as quickly and cost-effectively

as possible. The Department has sought to balance the utility of making

these tools available in the widest possible range of cases against the

potential dangers that they may produce unreliable results when

stretched beyond their limits or that they may result in double

recovery when inappropriately combined with type B procedures.

The Department has carefully reexamined both the proposed

conditions regarding use of the models as well as the additional major

simplifying assumptions incorporated into the models and described in

the technical documents. The Department has concluded that the

conditions for use of the models should recognize two different

categories of assumptions built into the models. The first category

encompasses those assumptions that could result in significant

overestimates of damages if they are not reasonable in a particular

case. The second category encompasses those assumptions that are not

likely to result in significant overestimates of damages if they are

not reasonable in a particular case and that may well result in

underestimates.

The Department believes it is inappropriate to grant a rebuttable

presumption to an assessment performed using the NRDAM/CME or NRDAM/GLE

if one of the assumptions in the first category is not reasonable in

the particular case. If an assumption in the second category is not

reasonable in a particular case, it may be appropriate for trustees to

use type B procedures to ensure that the public receives full

compensation for its losses. However, the Department believes trustees

in those cases should have the option of using the type A models when

the costs of type B procedures are not reasonable. The appropriateness

of the models in these cases will depend on site-specific factors. The

Department has concluded that it is more appropriate to allow trustees

to analyze these factors in the context of a particular case than to

establish inflexible, overly rigid standards.

Therefore, the Department has identified all the major model

assumptions and for each one determined into which of the two

categories they fall. Those assumptions in the first category are

identified in Sec. 11.34 of the final rule as conditions that must be

met if trustees intend to use the NRDAM/CME or NRDAM/GLE and obtain a

rebuttable presumption. These assumptions include most of the primary

conditions in the proposed rules.

The Department has identified the assumptions in the second

category and listed them, along with the other assumptions, in Section

1, Volume I of the NRDAM/CME and NRDAM/GLE technical documents. These

assumptions include many of the secondary conditions in the proposed

rule. Section 11.35(a) provides that if the conditions for use of a

type A procedure are met, the trustee must decide whether to use that

procedure or use type B procedures by weighing the difficulty of

collecting site-specific data against the suitability of these

additional assumptions as well as of the averaged data described in

Volumes III through IV of the NRDAM/CME technical document, and in

Volume III of the NRDAM/GLE technical document.

The Department has eliminated the proposed provision that would

have required trustees to use a type A procedure in some cases. That

requirement was originally motivated out of concern over potential

misuse of unnecessarily expensive and time-consuming type B procedures.

59 FR at 40322. Although the models are cost-effective, reliable tools

where applicable, the Department has concluded that trustees should not

be prevented from conducting site-specific work if they can do so at a

reasonable cost and if the additional costs of performing type B

procedures are warranted in light of the degree of additional precision

and accuracy that such procedures will provide.

The issue of the legal permissibility of allowing trustees to use

both type A and type B procedures for the same release is one that the

Department decided and resolved in 1987 and is beyond the scope of this

rulemaking. Today's final rule merely expands the use of supplemental

type B studies beyond resources not addressed by the type A procedure

to include compensable values and injuries of a type not addressed by

the type A procedure.

The Department acknowledges that combined use of type A and type B

procedures can, in some instances, pose potential double counting

problems. However, trustees should not be forced to choose between

forgoing compensation for a public loss not addressed by the type A

model on the one hand and funding a full-scale, time-consuming, labor-

intensive type B assessment of all injuries on the other hand. Instead,

the potential problems with combined use of type A and type B

procedures should be addressed through limitations designed to protect

against double recovery.

The final rule provides that trustees who use a type A procedure

may perform additional type B studies only for injuries or compensable

values of a type not addressed by the type A procedure. The secondary

conditions in the proposed rules have been recast to identify

explicitly the injuries and compensable values that are addressed in

the type A models and, therefore, may not be supplemented with type B

procedures.

Given the vast range of potential scenarios, it is infeasible to

develop a single, uniform formula for preventing double recovery.

Instead, Sec. 11.15(d) of the existing regulations prohibits double

recovery of damages. Also, Sec. 11.36(a)(2) of today's final rule

provides that trustees may only perform supplemental type B procedures

if such procedures will not result in double recovery. Further,

Sec. 11.36(c) requires trustees to provide an explanation in the

Assessment Plan of how they intend to avoid any double recovery in the

case of combined use of type A and type B procedures. PRPs and the

public will have an opportunity to review the trustees' strategy for

preventing double recovery when the Assessment Plan is made available

for public comment.

The Department agrees with the comment that the type A procedures

can be particularly useful when combined with selective studies of

impacts not addressed by the models. The Department would like to

ensure that

[[Page 20578]]

where combined use of type A and type B procedures is warranted,

trustees are freed from conducting duplicative assessment procedures.

Therefore, the Department has modified the final rule to clarify that

when using type B procedures for compensable values that are not

included in a type A procedure, but that result from injuries addressed

by the type A procedure, trustees need not conduct injury determination

and quantification all over again using type B procedures. Instead,

trustees may rely on the injury projections of the type A model and

simply use one of the type B valuation methodologies authorized by

Sec. 11.83 (a) and (c) to compute compensable value.

With regard to the concern about unwarranted type B studies of

nonuse values, aside from the implausibility of the scenario suggested

by the commenter, the Department notes that calculation of nonuse

values using type B procedures is under examination in a separate

rulemaking. See 59 FR 23097 (May 4, 1994). Therefore, this rulemaking

need not address this issue.

Finally, the Department believes it is appropriate to revise the

existing rule to allow supplemental use of type B procedures beyond

resources not addressed in the type A models. The public can experience

significant and distinct losses associated with the same resource. Ohio

v. Interior emphasized that the regulations should allow for the

recovery of all reliably calculated lost values. 432 F.2d at 464. The

Department sees no reason to impose an arbitrary distinction between

losses associated with different resources and losses associated with

the same resource so long as there is no double recovery.

Comment: One commenter suggested that trustees be allowed to use

supplemental type B procedures to determine damages for habitats that

are not accurately represented in the models.

Response: In cases where the models assign an incorrect habitat

designation for a specific area, trustees have the ability to correct

that designation and would not need to conduct supplemental type B

studies. In cases where releases affect habitats beyond the models'

level of spatial detail, trustees may perform supplemental type B

studies so long as such studies do not address injuries or compensable

values in the categories listed in Sec. 11.36(b) of the final rule. The

Department does not believe it is appropriate to expand this authority

to conduct supplemental type B studies and still obtain a rebuttable

presumption. When such small habitats are affected, the models will

nonetheless determine injury and damages for the geographic area in

which those habitats are located. If a trustee were to use one of the

models and then conduct supplemental type B studies of such a habitat,

the trustees would need to adjust the type A damage figure to eliminate

any damages calculated for the area over which the habitat is located.

The Department has concluded that in the context of a simplified

assessment, trustees who wish to obtain a rebuttable presumption should

be limited to conducting type B studies for the purposes of addressing

additional injuries and compensable values that are not included in the

model rather than substituting for damages already calculated by the

model.

Comment: A number of commenters thought that trustees should be

prohibited from using type A procedures unless all interested trustees

agree to a single joint assessment. These commenters stated that such a

provision was necessary to avoid the problems of double recovery and

improper allocation of damages among trustees. These commenters thought

that these problems were more significant for type A assessments than

for type B assessments because the type A models provide less detail

than type B procedures on the type and location of injured resources

and the damages associated with those resources.

Response: The Department acknowledges that the type A models pose a

unique problem when trustees do not act jointly. The type A models

generate a total damage figure for all affected resources. Therefore,

if a trustee acts independently and applies a type A model, the total

damage figure generated by the model might include damages for

resources that are not under that trustee's jurisdiction.

To address this problem, Sec. 11.42 now requires a trustee to

perform a preliminary application of the model before making the draft

Assessment Plan available for public review and comment. The trustee

must include a summary of the model application in the draft Assessment

Plan and make available a copy of the model output. The output of the

model does in fact identify the type and location of injured resources.

Section 11.31(a)(2) of the existing regulations requires trustees to

include in the Assessment Plan a statement of authority for asserting

trusteeship for those resources addressed in the Plan. Therefore, PRPs

and other interested members of the public will have an opportunity to

comment on whether any of the injured resources identified in the model

output are beyond the scope of the trustee's jurisdiction.

Also, Sec. 11.44(e) provides that if a trustee is aware of reliable

evidence that a type A application covers resources beyond his or her

trustee jurisdiction, the trustee must either: (1) Have the other

trustees who do have jurisdiction over those resources join in the type

A assessment; or (2) eliminate any damages for those resources from the

claim for damages.

Furthermore, the Department strongly encourages trustees to work

together to ensure that natural resource damage assessments remain

focused on restoring the injured resources rather than debating over

which trustee has jurisdiction over them. As noted by some of the

commenters, Sec. 11.32(a)(1) of the existing regulations requires a

trustee to notify all other interested trustees before beginning an

assessment and encourages all trustees to cooperate and coordinate.

Also, Sec. 11.15(d) of the existing regulations prohibits double

recovery of damages.

The issue of inter-trustee coordination extends beyond this

rulemaking to the overall administrative process for conducting all

assessments. The potential for overlapping claims exists whenever

trustees conduct separate assessments, regardless of whether type A or

type B procedures are used. The Department has initiated a biennial

review of the administrative process for conducting assessments. The

Department will be further examining the issue of inter-trustee

coordination during that review. 59 FR at 52752.

Comment: A few commenters stated that PRPs should be ensured a

meaningful opportunity to participate in the selection of assessment

procedures. These commenters requested that PRPs be given a chance to

review trustees' assumptions and reasoning. Commenters also expressed

support for cooperative trustee-PRP assessments.

Response: The Department agrees that PRPs should have an

opportunity to participate in selection of assessment procedures.

Section 11.32(a)(2)(iii)(A) of the existing regulations already

requires trustees to invite PRPs to participate in the development of

the type and scope of the assessment as well as the performance of the

assessment procedures. Today's final rule does not change that

requirement. Section 11.32(c) requires trustees to make their

Assessment Plans available for public review and comment. The proposed

rule required trustees to include in their Assessment Plans

documentation of their decision whether to use a type A procedure, type

B procedures, or both. Section 11.31(b) of today's final rule

[[Page 20579]]

now makes more explicit the trustees' duty to provide a detailed

explanation of their rationale for using a type A procedure, type B

procedures, or both. Also, Sec. 11.35(d) now clarifies that trustees

may change their decisions about the types of procedures they use based

on public comments.

Comment: Many commenters addressed specific proposed conditions for

use of the models. Some commenters questioned the condition regarding

whether the data in the models reasonably represented the spatial and

temporal distribution of affected biological resources. One commenter

suggested that this condition was inconsistent with the habitat editor.

Another commenter requested clarification of the term ``reasonably

represented.'' This commenter expressed concern that the condition

seemed to require trustees to collect baseline data, which would defeat

the intent of requiring minimal field observation in type A procedures.

Response: The Department has reexamined this proposed condition

regarding use of the models. The condition addressed two different

model assumptions. First, the condition addressed the assumption that

the release did not affect any small but important environments beyond

the level of spatial detail of the model. Second, the condition

addressed the assumption that species biomass is averaged spatially and

temporally. The Department has concluded that if the first assumption

is not reasonable in a particular case, then the model will most likely

underestimate, rather than overestimate, damages. Therefore, the

Department has eliminated this assumption from the conditions for use

listed in Sec. 11.34 of the final rule. Instead, the Department has

identified the assumption in the NRDAM/CME and NRDAM/GLE technical

documents as one of the factors for trustees to consider when deciding

whether to use type A or type B procedures, once they have established

that the conditions set forth in Sec. 11.34 are met. See Section 1,

Volume I of the NRDAM/CME and NRDAM/GLE technical documents. The

Department has clarified the second assumption, concerning species

biomass, and included it in Sec. 11.34 as a condition that must be met

if trustees intend to use the models and obtain a rebuttable

presumption.

The habitat editor does not conflict with either of these

assumptions. The final rule allows trustees to change the habitat

designation for an entire existing grid cell. However, the rule does

not allow trustees to redraw the boundaries of the grid cells or modify

the species biomass for a particular habitat. Even with correct habitat

designation, edited or through the built-in designation, the models may

not reflect small habitats or populations with densities that differ

from the seasonal average.

The Department acknowledges the confusion generated by the term

``reasonably represented.'' The term was not intended to require

trustees to conduct field surveys to collect baseline data. Instead, it

was designed to address cases where information already existed about

baseline conditions and such pre-existing information differed

significantly from the data in the model. Section 11.34(e) now simply

provides that a trustee may not use the models if he or she is aware of

reliable evidence that, for species expected to represent a significant

portion of the claim, the species biomass is significantly lower than

the species biomass assigned by the models.

Comment: A few commenters noted that the models may significantly

underestimate damages when the released substance causes chronic or

sublethal effects, when sensitive habitats or life stages are affected,

when animals aggregate for feeding or reproduction, or when long-term

effects, such as reproductive impairment or changes in food web

structure, are expected.

Response: The Department acknowledges that the type A models may

not accurately calculate total damages in the situations identified by

the commenters. However, the Department has included provisions in the

final rule to address these situations. Section 11.35(a) provides that

if a type A procedure is applicable, trustees must determine whether to

use type A or type B procedures based on an evaluation of the model

assumptions listed in Section 1, Volume I of the NRDAM/CME and NRDAM/

GLE technical documents. One of the listed assumptions is that there

are no affected environments beyond the spatial detail of the models.

This assumption will alert trustees to the potential for

underestimating damages where sensitive habitats are affected. Another

listed assumption is that species biomass is averaged spatially and

temporally. This assumption will alert trustees to the potential for

underestimating damages when animals aggregate. Finally, the rule

explicitly identifies the injuries addressed by the type A models;

therefore, trustees will have notice that they will need to perform

supplemental type B procedures if they wish to address chronic or

sublethal biological injuries.

Comment: Some commenters thought that trustees should be allowed to

use the models only if the release is a single event. These commenters

expressed concern that in the absence of such a requirement, trustees

could use a type A procedure to assess one release in a multi-release

incident and use type B procedures to assess the other releases. The

commenters thought that such a practice would result in double counting

because some of the injuries predicted for one release would already be

accounted for in the assessment of another release. These commenters

also thought that the rule should be rewritten to clarify that the type

A models can be applied only to releases of a single substance. The

commenters noted that without this change, similar double counting

problems could arise from multiple applications of the models.

Response: The Department has concluded that the model assumption

that the release is a single event need not be made a condition for use

of the models. Instead, Section 1, Volume I of the technical documents

notes that the models assume that each spill is an independent, short-

term event.

Section 11.15(d) of the existing regulations already prohibits

double recovery of damages. In the case of a multi-release incident, if

trustees choose to use a type A model for one release and then conduct

type B studies for the other releases, they will be required to ensure

that the type B procedures do not result in double recovery. The

Department acknowledges that in some cases it may be difficult for

trustees to satisfy this requirement. However, the Department believes

that in those multi-release cases where trustees can tailor their type

B studies to address only the effects of the releases not assessed by

the type A model, they should have the opportunity to do so.

With regard to releases of multiple substances, the rule now

provides that trustees must select and assess only one of the

substances that was released. See Appendices II and III. This

requirement will eliminate double counting problems. In fact, toxicity

of mixtures has been found to be additive or synergistic in aquatic

environments for a wide variety of substances. See Section 4, Volume I

of the NRDAM/CME technical document. Thus, this requirement may

actually result in underestimates of damages. However, the Department

believes that in cases of mixtures when the cost of using type B

procedures is not reasonable, trustees should have the option of using

a type A procedure rather than forgoing all compensation.

Comment: A few commenters addressed the use of the models for

[[Page 20580]]

substances not specifically identified in the database. Some commenters

supported giving trustees flexibility to use the models for such

substances provided that they identified a proxy that was included in

the database and documented the reasons why the use of that proxy was

appropriate. Other commenters expressed concern that allowing use of

proxies would add a significant range of discretion given the number of

different physical and chemical attributes that must be considered when

identifying a proxy. Some commenters, including one of the independent

technical reviewers, suggested that the Department expand the oil

database.

Response: The Department has concluded that allowing the use of

proxies for hazardous substances without significant guidance on

selection of such proxies would raise serious concerns about the

uniformity and reliability of the type A model results. Moreover,

developing guidance on selection of proxies would be impractical given

the extremely wide range of hazardous substances and the diversity of

their relevant attributes. Therefore, for chemical releases, trustees

may only use the models if the released material is one of the specific

chemicals listed in the database.

As discussed in Section I.C. of this preamble, use of the models

for oil discharges is governed by NOAA's OPA rule rather than by

today's final rule. However, the Department notes that it has expanded

the database to include 33 types of oils that cover a broad range of

chemical and physical characteristics.

Comment: Some commenters stated that trustees should be allowed to

use the type A models and obtain a rebuttable presumption for releases

that did not originate in, but later migrated into, a coastal or marine

or Great Lakes environment. These commenters argued that the type A

models could accommodate such releases. On the other hand, one

commenter thought that such use should not be allowed because there are

no data on conditions outside the boundaries of the type A models.

Response: The Department has concluded that the type A models can

produce reliable damage figures for releases that do not originate in,

but do migrate within, the boundaries of the models provided that the

user supplies appropriate data inputs. So long as the user supplies

data inputs that reflect conditions at the point that the substance

enters the model boundaries, the models are just as capable of

computing reliable damages as they would be if the release had actually

started at that point. In such cases, the models will start their

simulations at the point that the released substance enters water

within a geographic region represented in the models. The only

potential problem is that the models will not account for the effects

produced before the release entered the model boundaries, a

consideration that may support use of type B procedures in some cases.

However, the Department believes trustees should have the option of

using the models to assess such releases when the cost of performing

type B procedures to develop a more complete damage figure is not

reasonable.

Therefore, the rule allows trustees to use the models for releases

that occur outside the boundaries of the models so long as the user-

supplied inputs appropriately reflect conditions at the point that the

substance entered such waters rather than the point of the original

release. Appendices II and III specify that when using the models for

releases that originate on land or outside the model databases,

trustees must adjust the data inputs.

Comment: One commenter said that the definition of ``minor'' was

vague, but supported the Department's discussion of it and the proposal

to allow trustees discretion to define ``minor'' on a case-by-case

basis. Other commenters, including one of the independent technical

reviewers, thought that the Department should define ``minor.'' One

commenter suggested that the rule require trustees to justify their

determination of whether a release is minor with scientific

documentation. Another comment recommended the Department define

``minor'' based on spill size, prediction of affected area, or

resulting damage estimates.

Response: In light of Congressional intent to restrict use of type

A procedures to minor releases and after considerable analysis and

deliberation, the Department has decided to impose a specific dollar

cut-off for use of the models to obtain a rebuttable presumption. The

final rule provides that if the model output indicates damages in

excess of $100,000, then trustees who wish to obtain a rebuttable

presumption must either: (1) limit the portion of their claim

calculated with the type A procedure to $100,000; or (2) compute all

damages using type B procedures. The Department believes this provision

establishes an appropriate standard of fairness for allowing trustees

to receive a rebuttable presumption for damages calculated by the

NRDAM/CME or NRDAM/GLE given the current level of experience with these

models.

The language and legislative history of CERCLA indicate that

Congress intended the type A procedures as a tool for obtaining a

rebuttable presumption in cases of minor releases. Thus, the Department

included a provision in the proposed rules that prohibited trustees

from using the models to obtain a rebuttable presumption unless the

release was minor. The proposed rule provided no definition of

``minor,'' and the Department indicated in the preamble to the proposed

rules that it had been unable to develop a uniform standard for all

substances and areas encompassed by the models. See 59 FR at 40330 and

63313. However, after reviewing the comments, the Department has

concluded that given the significance of this term and the fact that

type A procedures were intended as simplified procedures requiring

limited analysis by trustees, it is appropriate to provide clear

guidance.

The Department evaluated a number of different approaches to

defining ``minor.'' First, the Department reviewed the language and

legislative history of CERCLA. The Senate Report that accompanied the

predecessor bill to CERCLA states:

[A] simplified type of regulation is necessary to effectively

deal with damage assessment in most ``minor'' releases of hazardous

materials * * *. The other type of regulations [type B] would be

employed in large or unusually damaging releases and would be used

to guide the site-specific damage assessment. S. Rep. No. 96-848 at

86.

However, nothing in the legislative history indicates what Congress

meant by ``minor.''

Next, the Department considered basing the definition on the

technical limitations of the NRDAM/CME and the NRDAM/GLE for modeling

large or highly toxic spills. However, sensitivity analyses of the

models failed to reveal any clear stages at which the model assumptions

became invalid.

The Department then considered relying upon existing standards

developed in other contexts of environmental law. The U.S. Coast Guard

has developed a volume-based system for classifying oil spills for

purposes of spill response. See 40 CFR 300.5 (minor discharge of oil is

one of less than 1,000 gallons to inland waters or 10,000 gallons to

coastal waters). The U.S. Environmental Protection Agency (EPA) is

responsible for developing a parallel rating system for hazardous

substance spill response. While EPA has developed a qualitative system,

this system does not provide the type of clear, quantitative limits

that the Department believes are needed in this context. See 40 CFR

300.5 (minor release of hazardous substance is one that poses minimal

threat to public

[[Page 20581]]

health or welfare of the U.S. or the environment).

Next, the Department considered basing a definition of minor on the

point at which type B procedures can no longer be performed at a

reasonable cost. However, because trustees have rarely pursued damage

claims for smaller spills, the Department was unable to develop

reliable estimates of the cost of conducting type B procedures in such

cases.

Therefore, the Department was left to make this policy decision

about the upper limit on applicability of type A procedures without the

benefit of clear empirical standards or legal precedents. The

Department has chosen to base this limit on its sense of when it is no

longer ``fair'' to allow trustees to obtain a rebuttable presumption

using the NRDAM/CME or NRDAM/GLE as opposed to performing type B

procedures. The Department believes that, given the current level of

experience with these models, $100,000 represents a reasonable cut-off

for their use. As more experience is gained with these models, the

Department will reconsider this cut-off in future biennial reviews.

Further, because this regulatory cut-off is based on considerations of

fairness rather than the inherent reliability of the models, the

Department wishes to emphasize that although use of the models to

calculate damages above $100,000 is not entitled to a rebuttable

presumption, such use may nonetheless be appropriate in other contexts,

such as settlement negotiations or litigation without the benefit of

the rebuttable presumption.

Finally, the Department recognizes that in some instances the

models may project damages in excess of $100,000, yet it may not be

reasonable to perform type B procedures. The Department believes that

trustees should be allowed the option of claiming damages up to

$100,000 in such cases instead of forgoing all compensation. Therefore,

the Department has eliminated the proposed rule condition that type A

procedures only be used for minor releases and instead imposed a cap on

the level of damages that trustees can claim through use of a type A

procedure and still obtain a rebuttable presumption.

Comment: Several commenters thought that the proposed condition

requiring uniform subsurface currents would render the NRDAM/CME

inapplicable to all spills in Massachusetts, New Hampshire, and Maine.

Response: The Department acknowledges that the condition regarding

subsurface currents may limit the applicability of the NRDAM/CME in

some circumstances but notes that it does not render the model

inapplicable to all locations where subsurface currents are not

uniform. The models use vertically averaged currents and assume that

the speed and direction of horizontal transport is uniform over depth

at a specific latitude and longitude. The models do include randomized

motion in the vertical dimension, but not directed motion. The

vertically averaged current is essentially a current that provides the

correct net transport averaged vertically. If the transport of the

released substance cannot be reasonably represented by a vertically

averaged current, then the NRDAM/CME's projections may not be reliable.

For example, substances with high densities, such as sulfuric acid, may

sink rapidly through the water column so that the principal mass is

transported in the direction of the subsurface current. However, in

many cases, such as when a substance remains at or near the surface or

sinks slowly, subsurface currents will not affect the fate of the

spilled substance. In these cases the model can reliably predict

damages. Therefore, the rule allows trustees to use the NRDAM/CME, even

if subsurface currents are not uniform, so long as they are not

expected to significantly affect the level and extent of injuries.

D. User-Supplied Information

Comment: Several commenters suggested changes to the proposed

models and rules that would require trustees to confirm injury. These

commenters asserted that the proposed models merely assume injury and

that the proposed rules inappropriately failed to require field

verification of this assumption. The commenters noted that CERCLA

limits recovery to damages that ``result from'' a release. These

commenters argued that this limitation requires that trustees conduct

field studies that prove that an injury actually occurred and that it

was caused by the release in question.

A number of commenters thought that Congress intended traditional

tort law standards of causation to apply to natural resource damage

cases and cited case law in support of this position. Some commenters

noted that Ohio v. Interior rejected a challenge to the Department's

strict acceptance criteria for determining injury under the type B

procedures and upheld the Department's interpretation that CERCLA

adopted traditional causation standards. 880 F.2d at 471. The

commenters stated that CERCLA does not create a different standard of

proof of causation when type A procedures, as opposed to type B

procedures, are used.

Several commenters observed that CERCLA calls for type A procedures

that involve ``minimal'' rather than ``no'' field observation. The

commenters thought that the Department was engaging in sheer

speculation when it asserted in the August 8, 1994, notice of proposed

rulemaking that requiring confirmation of injury in type A assessments

would be unduly burdensome. Finally, the commenters stated that none of

the steps that trustees must take before applying a type A model,

including the Preassessment Screen Determination, satisfy the required

standard of causation.

Response: The type A models do not ``assume'' that injury occurs.

Using both the information provided by the trustees and the biological

and environmental information about the spill site contained in the

model databases, the models perform millions of calculations to

determine whether or not the release has caused an injury. The models

project the distribution of the released substance over space and time,

track the changing toxicity of the substance over that space and time,

and simulate the movements of biota throughout the area around the

release. The models only conclude that injury has occurred if biota are

exposed to the released substance at concentrations and durations that

exceed acute toxicity thresholds. If such thresholds have not been

exceeded, the models conclude that there has been no injury. The models

can and have projected that no injury resulted from particular

releases. In such cases, the models determine that damages equal zero.

The issue is not whether the Department i

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