This case is a companion to Robertson v. Methow Valley Citizens Council, ante, p. 332. It arises out of a controversial decision to construct a dam at Elk Creek in the Rogue River Basin in southwest Oregon. In addition to the question whether an Environmental Impact Statement (EIS) prepared pursuant to the National Environmental Policy Act of 1969 (NEPA), 83 Stat. 852, 42 U. S. C. § 4321 et seq., must contain a complete mitigation plan and a "worst case analysis," which we answered in Robertson, it presents the question whether information developed after the completion of the EIS requires that a supplemental EIS be prepared before construction of the dam may continue.
In the 1930's in response to recurring floods in the Rogue River Basin, federal and state agencies began planning a major project to control the water supply in the Basin.
Plans for the Elk Creek Dam describe a 238-foot-high concrete structure that will control the run-off from 132 square miles of the 135-square-mile Elk Creek watershed. When full, the artificial lake behind the dam will cover 1,290 acres of land, will have an 18-mile shoreline, and will hold 101,000 acre-feet of water. The dam will cost approximately $100 million to construct and will produce annual benefits of almost $5 million. It will be operated in coordination with the nearby Lost Creek Dam, where the control center for both dams will be located. Its "multiport" structure, which will permit discharge of water from any of five levels, makes it possible to regulate, within limits, the temperature, turbidity,
In 1971, the Corps completed its EIS for the Elk Creek portion of the three-dam project and began development by acquiring 26,000 acres of land and relocating residents, a county road, and utilities. Acknowledging incomplete information, the EIS recommended that further studies concerning the project's likely effect on turbidity be developed. The results of these studies were discussed in a draft supplemental EIS completed in 1975. However, at the request of the Governor of Oregon, further work on the project was suspended,
Because the Rogue River is one of the Nation's premier fishing grounds, the FEISS paid special heed to the effects the dam might have on water quality, fish production, and angling. In its chapter on the environmental effects of the proposed project, the FEISS explained that water quality studies were prepared in 1974 and in 1979 and that "[w]ater temperature and turbidity have received the most attention." FEISS 33. Using computer simulation models, the 1974 study predicted that the Elk Creek Dam might, at times, increase the temperature of the Rogue River by one to two degrees Fahrenheit and its turbidity by one to three JTU's.
Other adverse effects described by the FEISS include the displacement of wildlife population — including 100 black-tailed deer and 17 elk — and the loss of forest land and vegetation resulting from the inundation of 1,290 acres of land with the creation of the artificial lake. Id., at 26, 38, 46. Most significantly, it is perfectly clear that the dam itself would interfere with the migration and spawning of a large number
On February 19, 1982, after reviewing the FEISS, the Corps' Division Engineer made a formal decision to proceed with construction of the Elk Creek Dam, "subject to the approval of funds by the United States Congress." App. to Pet. for Cert. 53a. In his decision, he identified the mitigation measures that had already been taken with respect to the loss of anadromous fish spawning habitat, as well as those that would "most likely" be taken to compensate for the loss of other wildlife habitat. Id., at 56a-57a. He concluded that the benefits that would be realized from the project "out-weigh the economic and environmental costs" and that completion would serve "the overall public interest." Id., at 58a. In August 1985, Congress appropriated the necessary funds.
In October 1985, four Oregon nonprofit corporations
After conducting a hearing on respondents' motion for a preliminary injunction, the District Judge denied relief on each of the NEPA claims.
The new information relied upon by respondents is found in two documents. The first, an internal memorandum prepared by two Oregon Department of Fish and Wildlife (ODFW) biologists based upon a draft ODFW study, suggested that the dam will adversely affect downstream fishing, and the second, a soil survey prepared by the United States Soil Conservation Service (SCS), contained information that might be taken to indicate greater downstream turbidity than did the FEISS. As to both documents, the District Judge concluded that the Corps acted reasonably in relying on the opinions of independent and Corps experts discounting the significance of the new information. Id., at 1567-1568. At the conclusion of his opinion, the District Judge directed that the motion for preliminary relief be consolidated with trial on the merits pursuant to Federal Rule of Civil Procedure 65(a)(2), and thus denied respondents' claim for a permanent injunction as well.
The Court of Appeals reversed. 832 F.2d 1489 (CA9 1987). Applying the same "reasonableness" standard of review employed by the District Court, the Court of Appeals reached a contrary conclusion, holding that the Corps had not adequately evaluated the cumulative environmental impact of the entire project. Id., at 1497. Since the Corps did not seek review of that holding, we do not discuss it. The court also held that the FEISS was defective because it did not include a complete mitigation plan and because it did not contain a "worst case analysis." Id., at 1493-1494, 1496-1497. These holdings were erroneous for the reasons stated in our opinion in Robertson v. Methow Valley Citizens Council,
The subject of postdecision supplemental environmental impact statements is not expressly addressed in NEPA.
This reading of the statute is supported by Council on Environmental Quality (CEQ) and Corps regulations, both of which make plain that at times supplementation is required. The CEQ regulations, which we have held are entitled to substantial deference, see Robertson, ante, at 355-356; Andrus v. Sierra Club, 442 U.S. 347, 358 (1979), impose a duty on all federal agencies to prepare supplements to either draft or final EIS's if there "are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action or its impacts."
The parties are in essential agreement concerning the standard that governs an agency's decision whether to prepare a supplemental EIS. They agree that an agency should apply a "rule of reason," and the cases they cite in support of this standard explicate this rule in the same basic terms. These cases make clear that an agency need not supplement an EIS every time new information comes to light after the EIS is finalized.
Respondents contend that the determination whether the new information suffices to establish a "significant" effect is either a question of law or, at a minimum, a question of ultimate fact and, as such, "deserves no deference" on review. Brief for Respondents 29. Apparently, respondents maintain that the question for review centers on the legal meaning of the term "significant" or, in the alternative, the predominantly legal question whether established and uncontested historical facts presented by the administrative record satisfy this standard. Characterizing the dispute in this manner, they posit that strict review is appropriate under the "in accordance with law" clause of § 706(2)(A) or the "without observance of procedure required by law" provision of § 706 (2)(D). We disagree.
The question presented for review in this case is a classic example of a factual dispute the resolution of which implicates substantial agency expertise. Respondents' claim that the Corps' decision not to file a second supplemental EIS should be set aside primarily rests on the contentions that the new information undermines conclusions contained in the FEISS, that the conclusions contained in the ODFW memorandum and the SCS survey are accurate, and that the Corps' expert review of the new information was incomplete, inconclusive,
Respondents' argument that significant new information required the preparation of a second supplemental EIS rests on two written documents. The first of the documents is the so-called "Cramer Memorandum," an intraoffice memorandum prepared on February 21, 1985, by two scientists employed by ODFW. See Cramer Memorandum 3a.
The significance of the Cramer Memorandum and the SCS survey is subject to some doubt. Before respondents commenced this litigation in October 1985, no one had suggested that either document constituted the kind of new information that made it necessary or appropriate to supplement the FEISS. Indeed, the record indicates that the Corps was not provided with a copy of the Cramer Memorandum until after
The Court of Appeals attached special significance to two concerns discussed in the Cramer Memorandum: the danger that an increase in water temperature downstream during fall and early winter will cause an early emergence and thus reduce survival of spring chinook fry and the danger that the dam will cause high fish mortality from an epizootic disease. Both concerns were based partly on fact and partly on speculation.
With respect to the first, the Cramer Memorandum reported that the authors of the draft ODFW study had found that warming of the Rogue River caused by the Lost Creek Dam had reduced the survival of spring chinook fry; however, the extent of that reduction was not stated, nor did the memorandum estimate the extent of warming to be expected due to closure of the Elk Creek Dam. Instead, the memorandum estimated that an increase of only one degree centigrade in river temperature in January would decrease survival of spring chinook "from by 60-80%." Cramer Memorandum 3a. The authors of the memorandum concluded that because the Elk Creek Dam is likely to increase the temperature of the Rogue River, further evaluation of this effect should be completed "before ODFW sets its final position on this project." Ibid.
With respect to the second concern emphasized by the Court of Appeals, the Cramer Memorandum reported the fact that "an unprecedented 76% of the fall chinook in 1979 and 32% in 1980 were estimated to have died before spawning" and then speculated that the Lost Creek Dam, which had been completed in 1977, was a contributing cause of this unusual mortality.
The Court of Appeals also expressed concern that the SCS survey, by demonstrating that the soil content in the Elk Creek watershed is different than assumed in the FEISS, suggested a greater turbidity potential than indicated in the FEISS. 832 F. 2d, at 1495. In addition, the court observed that ODFW scientists believe that logging and road building in the Elk Creek watershed has caused increased soil disturbance resulting in higher turbidity than forecast by the FEISS. Ibid. As to this latter point, the SIR simply concluded that although turbidity may have increased in the early 1980's due to logging, "watershed recovery appears to have occurred to reduce the turbidity levels back to those of the 1970's." SIR 12a. The implications of the SCS soil survey are of even less concern. As discussed in the FEISS, water quality studies were conducted in 1974 and 1979 using computer simulation models. FEISS 33. The 1974 study indicated that turbidity in the Rogue River would increase by no more than one to three JTU's as a result of the Elk Creek Dam, and the 1979 study verified this result. Ibid. These studies used water samples taken from Elk Creek near the proposed dam site and from near the Lost Creek Dam, and thus did not simply rely on soil composition maps in drawing their conclusions. Id., at 18-19, 21-22, 33-34. Although the SIR did not expressly comment on the SCS survey, in light of the in-depth 1974 and 1979 studies, its conclusion that "the turbidity effects are not expected to differ from those described in the 1980 EISS" surely provided a legitimate reason
There is little doubt that if all of the information contained in the Cramer Memorandum and SCS survey was both new and accurate, the Corps would have been required to prepare a second supplemental EIS. It is also clear that, regardless of its eventual assessment of the significance of this information, the Corps had a duty to take a hard look at the proffered evidence. However, having done so and having determined based on careful scientific analysis that the new information was of exaggerated importance, the Corps acted within the dictates of NEPA in concluding that supplementation was unnecessary. Even if another decisionmaker might have reached a contrary result, it was surely not "a clear error of judgment" for the Corps to have found that the new and accurate information contained in the documents was not significant and that the significant information was not new and accurate. As the SIR demonstrates, the Corps conducted a reasoned evaluation of the relevant information and reached a decision that, although perhaps disputable, was not "arbitrary or capricious."
The judgment of the Court of Appeals is accordingly reversed, and the case is remanded for further proceedings consistent with this opinion.
It is so ordered.
"Lying within the southwest corner of Oregon, the Rogue River Basin drains a 5,060 square mile area in Jackson, Josephine, Coos, and Klamath Counties, as well as small portions of Del Norte and Siskiyou Counties in California . . . . Rogue River passes through vastly different environmental settings in the course of its journey from its upper reaches near Crater Lake to the Pacific Ocean at Gold Beach, Oregon. The climatological factors and other characteristics of the basin are such that floods are frequently experienced." U. S. Army Corps of Engineers, Portland District, Elk Creek Lake Environmental Impact Statement, Supplement No. 1, p. 1 (Dec. 1980) (hereinafter FEISS).
"Much of the heavy suspended materials will settle out in Elk Creek reservoir so no downstream effect of siltation is expected. Average annual downstream turbidity will be the same with or without the project.
"No major adverse effect on fish production in the Rogue River is expected as a result of the changes in the turbidity regime as a result of the Elk Creek project. Minor effects on production can be expected in the reach of Elk Creek between the project and its confluence with the Rogue River during normal years when turbidity will be higher than without the project. However, the project will also provide periods when turbidity will be lower than without the project. The multi-level withdrawal capability which will be built into the Elk Creek project will provide the ability to minimize turbidity effects on fish production." Ibid.
"Increases in magnitude and extended duration of turbidity in the Rogue River are expected to result from operation of Elk Creek Dam. These increases could affect angling for salmonids in the Rogue because the ability of fish to see lures or flies is impaired by turbidity. Fly-fishing for resident trout and summer steelhead would be the most vulnerable to effects of turbidity. The fly-fishing season runs from late July into October. According to Rogue River guides and [Oregon Department of Fish and Wildlife] biologists, fly-fishing success declines at a turbidity level of 10 JTU or greater. Other fishing methods are not productive when turbidity exceeds 20 JTU. It is possible that fisheries at other times, such as in the winter, will be affected for short periods. It is not expected that outflow from Lost Creek and Elk Creek Dams would, under the worst conditions, ever cause turbidity in the Rogue River to exceed 13 JTUs during late summer and early fall." Id., at 36.
A "salmonid" is a soft-finned, elongated fish that has an upturned final vertebrae. See Webster's Third International Dictionary 2004 (1981). Salmon and trout are two common salmonids. Ibid.
"Cole M. Rivers Fish Hatchery was constructed to mitigate the loss of anadromous fish-spawning habitat in Elk Creek, Applegate River, and the upper Rogue River, as well as to provide rainbow trout and kokanee for stocking in the reservoirs as mitigation for lost trout production. The hatchery is located about 0.2 miles downstream of Lost Creek Dam. It has a design capacity of 355.000 pounds of salmon and steelhead and 71,000 pounds of trout and kokanee. Production for Elk Creek would utilize approximately 14 percent of the total design capacity . . . ." FEISS 35.
"The Congress authorizes and directs that, to the fullest extent possible. . . (2) all agencies of the Federal Government shall —
"(C) include in every recommendation or report on proposals for legislation and other major Federal actions significantly affecting the quality of the human environment, a detailed statement by the responsible official on —
"(i) the environmental impact of the proposed action,
"(ii) any adverse environmental effects which cannot be avoided should the proposal be implemented,
"(iii) alternatives to the proposed action,
"(iv) the relationship between local short-term uses of man's environment and the maintenance and enhancement of long-term productivity, and
"(v) any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented." 83 Stat. 853, 42 U. S. C. § 4332.
The term "action forcing" was introduced during the Senate's consideration of NEPA, see Kleppe v. Sierra Club, 427 U.S. 390, 409, n. 18 (1976), and refers to the notion that preparation of an EIS ensures that the environmental goals set out in NEPA are "infused into the ongoing programs and actions of the Federal Government," 115 Cong. Rec. 40416 (1969) (remarks of Sen. Jackson). See also 40 CFR § 1500.1(a) (1987) ("Section 102(2) contains `action-forcing' provisions to make sure that federal agencies act according to the letter and spirit of the Act").
"(1) Shall prepare supplements to either draft or final environmental impact statements if:
"(i) The agency makes substantial changes in the proposed action that are relevant to environmental concerns; or
"(ii) There are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action or its impacts.
"(2) May also prepare supplements when the agency determines that the purposes of the Act will be furthered by doing so." 40 CFR § 1502.9(c) (1987).
"Supplements. A Supplement to the draft or final EIS on file will be prepared whenever significant impacts resulting from changes in the proposed plan or new significant impact information, criteria or circumstances relevant to environmental considerations impact on the recommended plan or proposed action as discussed in 40 CFR 1502.9(c). A supplement to a draft EIS will be prepared, filed and circulated in the same manner as a draft EIS . . . . A supplement to a final EIS will be prepared and filed first as a draft supplement and then as a final supplement. . . ." 33 CFR § 230.11(b) (1987).
" `Administrative consideration of evidence . . . always creates a gap between the time the record is closed and the time the administrative decision is promulgated. . . . If upon the coming down of the order litigants might demand rehearing as a matter of law because some new circumstance has arisen, some new trend has been observed, or some new fact discovered, there would be little hope that the administrative process could ever be consummated in an order that would not be subject to reopening.' " Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U.S. 519, 554-555 (1978) (quoting ICC v. Jersey City, 322 U.S. 503, 514 (1944)). See also Northern Lines Merger Cases, 396 U.S. 491, 521 (1970) (same).
" `Significantly' as used in NEPA requires considerations of both context and intensity:
"(a) Context. This means that the significance of an action must be analyzed in several contexts such as society as a whole (human, national), the affected region, the affected interests, and the locality. Significance varies with the setting of the proposed action. . . .
"(b) Intensity. This refers to the severity of impact. . . . The following should be considered in evaluation of intensity:
"(1) Impacts that may be both beneficial and adverse. A significant effect may exist even if the Federal agency believes that on balance the effect will be beneficial.
"(2) The degree to which the proposed action affects public health or safety.
"(3) Unique characteristics of the geographic area such as proximity to historic or cultural resources, park lands, prime farmlands, wetlands, wild and scenic rivers, or ecologically critical areas.
"(4) The degree to which the effects on the quality of the human environment are likely to be highly controversial.
"(5) The degree to which the possible effects on the human environment are highly uncertain or involve unique or unknown risks.
"(6) The degree to which the action may establish a precedent for future actions with significant effects or represents a decision in principle about future consideration.
"(7) Whether the action is related to other actions with individually insignificant but cumulatively significant impacts. . . .
"(8) The degree to which the action may adversely affect districts, sites, highways, structures, or objects listed in or eligible for listing in the National Register of Historic Places or may cause loss or destruction of significant scientific, cultural, or historic resources.
"(9) The degree to which the action may adversely affect an endangered or threatened species or its habitat . . . .
"(10) Whether the action threatens a violation of Federal, State, or local law . . . ." 40 CFR § 1508.27 (1987).
"hold unlawful and set aside agency action, findings, and conclusions found to be —
"(A) arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law;
"(B) contrary to constitutional right, power, privilege, or immunity;
"(C) in excess of statutory jurisdiction, authority, or limitations, or short of statutory right;
"(D) without observance of procedure required by law;
"(E) unsupported by substantial evidence in a case subject to sections 556 and 557 of this title or otherwise reviewed on the record of any agency hearing provided by statute; or
"(F) unwarranted by the facts to the extent that the facts are subject to trial de novo by the reviewing court.
"In making the foregoing determinations, the court shall review the whole record or those parts of it cited by a party, and due account shall be taken of the rule of prejudicial error."
It is uncontested that the present controversy is not controlled by §§ 706(2)(E) or 706(2)(F), which primarily apply in cases involving either agency rulemaking or adjudication. Nor is there a claim that the Corps exceeded its constitutional authority under § 706(2)(B) or its statutory authority under § 706(2)(C).
"Whenever it is clearly understood that an EIS supplement is not necessary but where [it] is only necessary to provide supplemental information to a point of concern discussed in the final EIS . . . a supplemental information report will be prepared and filed with EPA." 33 CFR § 230.11(d) (1987).
"The experimental reduction in outflow temperatures last October and November, in conjunction with other factors, appears to have improved survival to the fry stage. We had the lowest number on record of wild fish spawning, yet this spring we had the second highest abundance of spring chinook fry on record. The low density of spawners, the absence of floods last winter, and the low incubation temperatures all contributed to the high survival of chinook eggs. We do not know yet what the river temperatures last October-November would have been without the dam, but release temperatures were lower than previous years since dam closure." Letter from Dr. John R. Donaldson of August 15, 1985, Admin. Record, Doc. No. 109.
"We have not determined the actual cause of the epizootics in 1979 and 1980, but we suspect that Lost Creek Dam contributed to them because no such mortality of fall chinook had been documented previously." Cramer Memorandum 4a.
As Judge Wallace noted in his dissenting opinion, the Cramer Memorandum did not address the possibility that diseased hatchery fish, rather than the Lost Creek Dam, caused the 1979 and 1980 epizootics. See 832 F.2d 1489, 1501 (CA9 1987) (opinion concurring in part and dissenting in part).
"Harry, the spring chinook runs on the Rogue are at an all-time low point. Anglers are becoming increasingly frustrated and upset about low runs, shortened seasons and smaller bag limits. They are also becoming more vocal. We feel the agency stands to lose much of its credibility if we continue to support Elk Creek Dam after knowing what has occurred to the adult spring chinook returns following completion of Lost Creek Dam. The Commission should be made aware of this new information and the possible consequences if they continue to hold to the middle of the road." Cramer Memorandum 5a.