Full opinion text
KEARSE, Circuit Judge: These are appeals by state and federal defendants and a cross-appeal by plaintiffs Sierra Club, et al. (“Sierra Club”), from judgments of the United States District Court for the Southern District of New York, Thomas P. Griesa, Judge, upholding in part plaintiffs’ challenge to the federal defendants’ approval of Hudson River landfill in connection with a proposed New York City highway known as “Westway.” The court ruled that defendants United States Army Corps of Engineers (the “Corps”) and Federal Highway Administration (“FHWA”) had violated the National Environmental Policy Act, 42 U.S.C. § 4332 (1976) (“NEPA”), and that the Corps had violated the Clean Water Act, 33 U.S.C. § 1344 (Supp. V 1981), and § 10 of the Rivers and Harbors Appropriations Act of 1899, 33 U.S.C. § 403 (1976) (“Rivers and Harbors Act”), by making inadequate investigations and disclosures concerning the impact of the Westway landfill project on fisheries in the Hudson River. The court enjoined further construction of the project pending reconsideration by FHWA and the Corps in compliance with the statutes, ordered special record-keeping in connection with the reconsideration, and appointed a special master to supervise compliance. FHWA, the Corps, and defendant William C. Hennessy as Commissioner of the New York State Department of Transportation (“NYSDOT”) challenge various aspects of these rulings. In its cross-appeal Sierra Club seeks reversal of so much of the district court’s decision as found the Corps, in other respects, in compliance with NEPA, the Clean Water Act, and § 9 of the Rivers and Harbors Act. For the reasons below, we affirm the district court’s judgments except insofar as they (1) upheld plaintiffs’ claim that the Corps had violated § 10 of the Rivers and Harbors Act, (2) required FHWA and the Corps to include in a supplemental environmental impact statement current information on nonfisheries issues, (3) prohibited FHWA and the Corps from acting as joint lead agencies in preparing a supplemental environmental impact statement, and (4) appointed a special master. I. FACTS The background Of the present litigation is more fully set forth in two opinions of Judge Griesa, reported in Action for Rational Transit v. West Side Highway Project, 536 F.Supp. 1225 (S.D.N.Y.1982), see note 14 infra, and Sierra Club v. United States Army Corps of Engineers, 541 F.Supp. 1367 (S.D.N.Y.1982). Familiarity with both opinions is assumed. Except to the extent indicated, the following statement of facts reflects findings of the district court or evidence of record as to which we see no substantial dispute. A. Initiation of the Westway Project, the Draft EIS, and the Criticisms “Westway,” the currently proposed Manhattan highway intended to replace the southernmost portion of the deteriorating West Side Highway, had its origins in a 1971 agreement reached among New York City, New York State, and FHWA in connection with major revisions of the interstate highway system in the New York metropolitan region. The plan began to take shape in 1972, when the State and the City jointly established an administrative entity called the “West Side Highway Project” (the “Project”) under the jurisdiction of NYSDOT to plan the replacement for the West Side Highway. The Project was comprised almost entirely of outside consulting firms, the chief of which was Systems Design Concept, Inc. (“Sydec”), whose principal, Lowell K. Bridwell, was Executive Director of the Project from 1972 until 1981. Beginning in 1972, the Project spent many months developing policy statements and goals to use in planning the location and design of the replacement highway. At some point it became apparent that construction of the replacement highway would require preparation of an environmental impact statement (“EIS”) pursuant to § 102(2)(C) of NEPA, to describe the environmental consequences of the construction. The staff and consulting firms associated with the Project prepared, within their respective areas of expertise, draft sections of such a statement. Sydec assembled all of the sections in a single draft, and submitted it to NYSDOT and FHWA for review. On April 25,1974, a formal draft environmental impact statement (“DEIS”) was issued, signed by NYSDOT and FHWA, presenting five alternative plans for the replacement highway and analyzing the alternatives in terms of community needs and environmental concerns. The DEIS discussion of the replacement highway’s expected impact on fisheries in the Hudson River was based on a 1973 biological survey conducted by one of the Project’s consulting firms. It concluded that the interpier area was populated only by relatively few species of fish (tomcods) and invertebrates. In accordance with 40 C.F.R. § 1500.7(a) (1974), the DEIS was circulated for public comment. Most of the responses to the DEIS related to an alternative referred to as the “outboard” alternative, which included a proposal for the highway to be built on landfill between bulkhead and pierhead lines (the “interpier area”) on the river. Three federal agencies submitted comments to NYS-DOT. The National Marine Fisheries Service (“Fisheries Service”) informed NYS-DOT that it did “not believe that the statement provide[d] sufficient information to permit a valid assessment of probable environmental impacts,” particularly with respect to marine resources. The United States Federal Wildlife Service (“Wildlife Service”) and Environmental Protection Agency (“EPA”) also submitted comments which focused tangentially on marine impacts. Following issuance of the DEIS and the Project’s receipt of comments, city agencies, with Project support, reviewed the outboard alternative and recommended the construction of a modified version of that alternative. This recommendation was approved by the Governor and the Mayor on March 7, 1975, and Westway was the name given to the approved alternative. B. The Final EIS After publication of the DEIS, the Project reevaluated the alternatives and completed further engineering and environmental studies. The environmental studies included a Technical Report on Water Quality (“Water Report”) based on the same 1973 fisheries data that had been used to formulate the DEIS’s discussion of the project’s impact on fisheries. The Water Report stated that relatively few species of fish could tolerate the existing conditions of the interpier area and that, although the area might be used to a limited extent in migration, modern-day pollution made the area a “biological wasteland.” After receiving the comments on the DEIS, the Project staff reevaluated the outboard alternative and prepared a new document, as required by 40 C.F.R. § 1500.-7(a) (1974); see also NEPA § 102(2)(C), incorporating the comments and its responses to them, to become part of the final environmental impact statement. The final environmental impact statement (“FEIS” or “January 1977 EIS”) recommending Westway, signed by NYSDOT and FHWA, was issued on January 4, 1977. The FEIS analyzed the Westway alternative as it related to, inter alia, the quality of urban development, traffic patterns, air quality, noise, water quality, and the impact of the proposed landfill on the aquatic habitat of the interpier region. Noting that the interpier area was “biologically impoverished,” the FEIS stated that Westway would create an estuarine habitat in the interpier area that will closely resemble that of the main channel. The inter pier basins are presently almost devoid of macro organisms, and therefore the landfilling of the basins will cause a minimal loss of estuarine productivity for species other than micro organisms. Since the inshore area is biologically impoverished, the placement of landfill will have little impact on the overall productivity of the Hudson estuary. As noted earlier in this discussion, future dissolved oxygen levels throughout the Lower Hudson are expected to improve substantially with the complete implementation of wastewater treatment programs. This improvement will provide an attractive habitat for more diverse and numerous estuarine species in future years. Fluctuations in salinity along the Modified Outboard edge would be much less severe than the changes now occurring in the inter pier basins. The layering of fresh, brackish, and salt water which characterizes the main channel will also apply to the Modified Outboard shoreline. The rise and fall of these layers caused by tidal action will be gradual enough to permit shore migrations along the edge for species requiring a stable habitat. The preferable edge treatment for the Modified Outboard shore would be riprap because it can provide a greater variety of dwelling areas and can attract more species, both those resident along the edge and fishes which feed on these creatures. The Water Report, which had similarly described the interpier area as a “biological wasteland,” was appended to the FEIS. Like the DEIS, the FEIS had been drafted by Sydec, under the supervision of Brid-well, and had been reviewed by FHWA. FHWA administrators testified, however, that either they had been unaware of the Fisheries Service’s comment that the fisheries information in the DEIS was inadequate, or they had considered the matter unimportant in relation to other Westway concerns. On January 4, 1977, the day the FEIS was issued, FHWA approved federal funding for Westway. FHWA design and location approvals were issued soon thereafter. C. The Application for a Landfill Permit, the Federal Agencies’ Opposition, and the New Fisheries Data Because Westway would require landfill in the Hudson River, approval was required from the Army Corps of Engineers pursuant to § 404 of the Clean Water Act, and § 10 of the Rivers and Harbors Act. On April 7,1977, NYSDOT applied to the Corps for a permit. On April 22, 1977, the Corps issued a notice of public hearing on the application, thereby beginning the “public interest review” process required under the Clean' Water Act prior to a Corps decision on whether to issue the permit. See 33 C.F.R. § 320.4(a) (1981). The Corps notice also announced that FHWA was to be considered the “lead” federal agency in the project, see 40 C.F.R. § 1500.7(b) (1974), and that the FEIS that had already been published had been reviewed by the Corps and was adequate for Corps purposes. The public interest review procedures require the Corps decisionmakers to consult with, and give great weight to the views of> Fisheries Service and Wildlife Service, see 33 C.F.R. § 320.4(c) (1981), and to coordinate with EPA, see 33 C.F.R. § 323.5 (1981). Within the Corps, the initial decision would be made by the district engineer; objections by other federal agencies could lead to successive reviews by the division engineer, the chief of engineers, and the Assistant Secretary of the Army. See 33 C.F.R. § 325.8 (1981). Following the Corps’s April 22, 1977 notice, Fisheries Service, Wildlife Service, and EPA submitted to the Corps district engineer their objections to the issuance of the permit. Fisheries Service opposed the permit on the ground that the landfill would have a negative effect on the marine habitat. Wildlife Service opposed the permit on the ground that the marine habitat in the landfill area would become very active in the near future as a result of pollution control laws and that construction of Westway would therefore permanently preempt a potentially productive piscine population. EPA took the position that there were insufficient data available concerning the impact of the project on marine life and that, under applicable law, the permit therefore could not be issued. The district engineer did not respond to the three agencies’ objections, but instead forwarded them to the Project. The Project’s response, which took the form of a several-hundred-page document, dated May 16,1978, was submitted to the district engineer after review by FHWA; it (1) concluded that the predictions of a negative impact on the marine habitat were not well taken, because the Water Report demonstrated that the interpier area “functions neither as a nursery and migration area nor as a source of primary productivity to any extent”; (2) essentially repeated the conclusion of the FEIS that, even with the proposed landfill, the interpier area would be increasingly hospitable to numerous estuarine species; and (3) took the position that EPA’s stance was “fundamentally biased and prejudged,” and that its statement contained “sufficient inaccuracies, misinterpretations and misrepresentations” to render EPA’s opinion “meaningless.” Fisheries Service, Wildlife Service, and EPA found these responses unsatisfactory. Wildlife Service and EPA stated that the Project had provided no new information to change their views, and Fisheries Service suggested that the Project “may not fully appreciate estuarine processes.” The agencies conveyed these views to the district engineer during the summer of 1978. The district engineer also received letters of objection to the permit from New York City officials, private individuals, and various organizations. The district engineer forwarded these letters to FHWA, which took the position that the January 1977 EIS was completely adequate. In December 1978, however, EPA persuaded NYSDOT to make a further biological study of the interpier region. The Project commissioned the engineering firm of Lawler, Matulsky & Skelly (“Lawler”) for that purpose. The planned scope of the Lawler study was developed in consultation with Fisheries Service, Wildlife Service, and EPA. The Corps took no part in these discussions. In May 1979, shortly after the Lawler study had begun and six months before its scheduled completion, the Corps district engineer preliminarily approved the landfill permit. A formal document embodying the approval was issued in September 1979 on the basis of reports prepared in part by Linda Monte, a Corps biologist then at the district level, who later moved to the division level where she was also assigned to the Westway matter. Monte’s report discussed the effects of the proposal on aquatic environments and concluded that the Lawler data would not be necessary for a decision on the Westway permit and that no supplemental EIS (“SEIS”) was required. Because of the continuing objections of the Fisheries Service, Wildlife Service, and EPA to issuance of the permit, however, the district engineer’s decision was submitted for review by the division engineer. The review in the division engineer’s office resulted in a conclusion that the FEIS contained little useful information on the fisheries question, and the division engineer decided to await the results of the Lawler study before making his decision on the permit. By the end of 1979, the Lawler sampling had revealed significant numbers of fish in the interpier area, and the study was extended to cover the thirteen-month period from April 1979 through April 1980. Lawler regularly forwarded its sampling data to the Project. The Project, however, relayed only limited information about the results to FHWA and to Monte. The Corps division engineer requested the Lawler data in late 1979 and early 1980. The Project refused to provide them, however, on the ground that the Corps might be forced to reveal the data under the Freedom of Information Act, 5 U.S.C. § 552(a) (1976 & Supp. V 1981). Finally, in June 1980, the Project furnished copies of an early Lawler “progress report” to the division engineer’s office and EPA. This progress report included data only through November 1979, although several months’ later data had been collected and showed, for the most part, that the months of greatest abundance of fish in the interpier area had been October 1979 through April 1980. The Lawler progress report provoked the Corps in mid-August 1980 to request a meeting with the Project and FHWA to discuss “mitigation” measures to be taken, see 33 C.F.R. § 320.4(c), i.e., measures to minimize the loss of fisheries habitat or to compensate for its loss. By that time, the Project had received a draft copy of the final Lawler report, which it had forwarded to NYSDOT and FHWA, but not to the Corps. The mitigation meeting was held on August 13,1980, and it was agreed that the Project would develop mitigation concepts and that FHWA would consider funding the cost of mitigation. In late August 1980, EPA informed the Corps that it felt the Lawler data it had been given showed the landfill would result in a loss of habitat for certain species of fish, including white flounder, white perch, and striped bass. Attorneys for Sierra Club, who had obtained interim Lawler data, contended to the Corps that the data required a SEIS. The Corps sought the view of the FHWA as to whether a SEIS was required; FHWA in turn referred the matter to the Project and continued to express interest in the subject of mitigation. At a mitigation meeting on September 8, 1980, the first complete volume of the Lawler study was finally furnished to the Corps and to Fisheries Service, Wildlife Service, and EPA. The last three agencies persisted in their objections to the Corps’s issuance of the Westway permit. Nevertheless, on November 26, 1980, the division engineer informed the agencies that he had concluded that the landfill would not be detrimental to aquatic life in the interpier area, and that he would recommend issuance of the permit. The division engineer acquiesced in FHWA’s advice that no SEIS was necessary. He recommended to FHWA, however, that the Lawler report be filed with EPA as “supplemental information” to the FEIS and circulated to concerned agencies and interested public parties who had provided comments on the DEIS and the FEIS. Apparently this was never done. In late 1980 and early 1981, Fisheries Service, Wildlife Service, and EPA again requested review of the permitting decision, this time by the Corps chief of engineers, on the grounds of adverse, insufficiently mitigated impact on fishery resources. Fisheries Service expressed concern that the information on which the permitting process had relied was biased. On February 18, 1981, however, the Corps chief of engineers approved the landfill permit, and the objecting agencies decided not to appeal the decision to the Assistant Secretary of the Army. Fisheries Service stated that it lacked a “firm conviction” that the project would result in “severe, irreversible environmental degradation.” D. Proceedings in the District Court In March 1981, plaintiffs commenced the present suit against the Corps and NYS-DOT, attacking issuance of the landfill permit on several grounds. Their principal claim was that the January 1977 EIS was inadequate because of the insufficiency of its treatments of fisheries, the relationship of Westway to the development of the West Side of Manhattan, traffic and air quality impact, problems associated with toxic chemicals and flooding, alternatives to Westway, and the possibility of a funding shortfall. Plaintiffs contended that, by relying on the inadequate FEIS, the Corps had violated NEPA, the Clean Water Act, and § 10 of the Rivers and Harbors Act. The other grounds of plaintiffs’ challenge included the contention that the landfill permit should be voided because the landfill would be a “dike” within the meaning of § 9 of the Rivers and Harbors Act and hence would require the express authorization of Congress. The district court granted summary judgment dismissing all of the claims except those concerning the FEIS’s treatment of the fisheries issue, and held a bench trial as to the latter (“First Trial”). Following the trial, in a thorough opinion dated March 31, 1982, reported at 536 F.Supp. 1225, Judge Griesa found, inter alia, that striped bass is one of America’s most highly esteemed game and food fishes, attracting millions of fishermen, both sport and commercial, each year and commanding increasingly high prices in the market; and that the Hudson River is the second most important contributor of striped bass to the Atlantic Coast fishery, providing 18-32% of all the striped bass in the New York Bight and Long Island Sound. As contrasted with the FEIS’s characterization of the Hudson interpier area as a biological wasteland, the court found that that area in winter houses a concentration of juvenile striped bass. The court found that the Corp’s treatment of the fisheries issue failed to meet the requirements of NEPA. His opinion stated in part as follows: The most significant environmental impact requiring consideration by the Corps of Engineers was the impact of the proposed landfill on fishery resources. The Corps was under a duty to make reasonable effort to ascertain the facts, and then to set forth those facts in an environmental impact statement. Under the mandate of NEPA, the Corps was required to make a full disclosure of the information about fishery resources, and to give an opportunity for comment by interested parties. As part of this process, the Corps was required to make public the views of the federal agencies with jurisdiction and expertise on the subject of fisheries. The total failure of the Corps to comply with these obligations has been demonstrated beyond any question. At no point did the Corps make any effort of its own to ascertain the facts about marine life in the interpier area. It was content to rely upon the January 1977 EIS, despite warnings from EPA, [Fisheries Service] and [Wildlife Service] that the information in this statement about aquatic impacts was probably unreliable. After the [Lawler] report was obtained, at the instance of the other agencies, the invalidity of the conclusions in the January 1977 EIS regarding aquatic impact was proved. The interpier area was shown to be a highly significant and productive habitat for fish, including striped bass. The proposed landfill would have the impact of destroying this habitat. The Corps was obligated under NEPA to publicly disclose this information and this impact in an environmental impact statement. It did not do so. Instead, it acquiesced in the urgings of [NYSDOT] and the FHWA to withhold the information. Aside from public disclosure, the Corps had the obligation to develop a full and adequate environmental impact statement in order to ensure that its own deliberations took into account the relevant facts and the environmental impacts. The record in this case demonstrates the salutory [sic] nature of this legal requirement, and the total non-compliance by the Corps. The District Engineer’s recommendation was made without having any reliable fishery information whatever. The Division Engineer acted following receipt of the [Lawler] report, but obtained no appropriate technical assistance from the Corps’ own biologists or from the other federal agencies with expertise. The Chief of Engineers quickly affirmed what was done at the lower levels. This wholly inadequate procedure would have been avoided if the District Engineer had promptly instituted steps to prepare and promulgate an environmental impact statement as required by NEPA. Because of the failure of the Corps to comply with NEPA, its issuance of the Westway landfill permit was invalid and must be set aside. Id. at 1252-54. The court found that the Corps’s failures also violated the Clean Water Act and § 10 of the Rivers and Harbors Act. Id. at 1254. On April 14, 1982, the court entered a judgment in favor of the plaintiffs which granted the following principal relief: (1) voided the Westway landfill permit granted by the Corps; (2) ordered that, in the event NYSDOT applied for a new permit, the Corps was to undertake proceedings in accordance with NEPA, the Clean Water Act, and § 10 of the Rivers and Harbors Act, including (a) preparation of an adequate supplemental EIS with respect to the fisheries issues, (b) inclusion in the SEIS of current information on subjects other than fishery resources, (c) an independent evaluation of all fisheries data collected during the Lawler study, (d) after consultation with Fisheries Service, Wildlife Service, and EPA, the undertaking or contracting for such additional fisheries studies as the Corps concludes are necessary for its independent evaluation; and (3) enjoined any further Westway activities affecting the bed or waters of the Hudson River pending the Corps’s reconsideration. The court ordered the Corps to keep records of all activities in relation to any new application and its consideration thereof. (Judgment dated April 14, 1982 (“April Judgment”).) The court interpreted the April Judgment as requiring that the SEIS be prepared by the Corps itself, and not jointly by the Corps and FHWA. On April 13, 1982, at the suggestion of the district court, plaintiffs had moved to amend their complaint to add the United States Department of Transportation and FHWA, and officials of those agencies, as defendants to the present action. Plaintiffs contended (1) that the FHWA design, location, and funding approvals of Westway were invalid because the January 1977 EIS was misleading and incomplete, in violation of NEPA, and (2) that in any event, developments following the issuance of the FEIS, including the Lawler study, the adverse comments of Fisheries Service, Wildlife Service, and EPA, new proposals for alternatives to Westway, urban renewal on the West Side, increases in the cost of Westway, and increases in the estimated levels of traffic and air pollution resulting from the construction and operation of Westway, mandated preparation of a supplemental EIS on all of these issues. On April 20,1982, the district court granted the motion to add the new federal defendants, stating that it would be anomalous to enjoin the Corps from proceeding on the basis of the FEIS without also enjoining the agency that had signed the FEIS and was to fund the project. Following a trial with respect to the new federal defendants (“Second Trial”), the district court issued an opinion on June 30, 1982, reported at 541 F.Supp. 1367, ruling in favor of plaintiffs only on their claim that the FEIS was inadequate with respect to fisheries impacts. The court held that on this issue FHWA had failed to comply with NEPA, finding that the information in the January 1977 EIS regarding fisheries was untrue. The authors of the EIS knew, or should have known, that they had no basis for the presentation made on this subject. Subsequently, when the data from the fishery study became available, this [sic] data demonstrated positively the falsity of the EIS on the subject of fisheries. The FHWA was under a duty to file a supplemental environmental impact statement setting forth the facts. The FHWA wilfully refused to take the necessary corrective action. The evidence at the second hearing not only demonstrated the failure of the FHWA to fulfill its own obligations under NEPA, but also reinforced the evidence presented at the first hearing to the effect that the FHWA and [NYS-DOT] colluded in a successful effort to persuade the Corps of Engineers to refrain from issuing an environmental impact statement in connection with the landfill application. Id. at 1370. In particular as to the FEIS’s fisheries information the court found that FHWA and [NYSDOT] lacked a sufficient basis for making the assertions on the subject of fishery impact which are contained in the 1977 EIS.... [T]hey realized that the sampling which had been carried out in preparation for the January 1977 EIS was inadequate [and] that the reason the earlier study revealed virtually no fish in the interpier area was that the study was made at a time of year which was not representative and the sampling techniques were faulty. The court concludes that those responsible for preparing the fishery material in the January 1977 EIS knew, or should have known, of the lack of factual basis for what was stated. This does not mean that, as of 1977, there was any substantial body of information positively indicating that the in-terpier area was a fish habitat. The point is that the January 1977 EIS categorically asserted the opposite. There was no basis for such a presentation. Id. at 1371-72. Finally, the court concluded that [s]ince the January 1977 EIS did not make a true or adequate presentation on the subject of fisheries, the FHWA had the obligation to issue a correct supplemental EIS, something which it has never done. Even if one could say that the January 1977 EIS was justified on the basis of the information then existing, nevertheless the [Lawler] fisheries data constituted information of such importance on the subject of environmental impact that the FHWA was under a duty to issue a supplemental EIS. Such a duty of supplementation is implicit in NEPA.... It can hardly be doubted that the [Lawler] fisheries data constituted significant information relevant to environmental concerns and bearing on the impact of the proposed Westway project. The FHWA, in collaboration with [NYSDOT], acted in willful derogation of the requirements of law in failing to issue a corrective supplemental environmental impact statement. The FHWA fully recognized the serious nature of the environmental impact which had been revealed by the new fisheries data, but refrained from making the required public disclosure. Id. at 1382-83. On July 23, 1982, the court entered a judgment (“July Judgment”) enjoining FHWA from granting any approvals for Westway prior to preparation, either by the Corps with FHWA’s substantive approval or by FHWA itself, of a supplemental EIS as required by the April Judgment — i.e., one dealing adequately with fisheries issues and containing an undated treatment of nonfisheries issues. The court also ordered FHWA, as it had ordered the Corps, to keep records of all activities in connection with the reconsideration of Westway. In addition, the court appointed a special master to oversee compliance with its judgments. As set forth in the margin, the special master was given the authority to, inter alia, require FHWA and the Corps to submit detailed plans for their preparation of a supplemental EIS, and was given the power to review those plans and the agencies’ actions, summon officials to testify under oath, compel the production of documents and the answering of interrogatories under oath, compel the submission of compliance reports, make initial findings of compliance or noncompliance with the court’s orders, and report findings and make recommendations to the court. E. Issues and Prior Proceedings on the Present Appeal The parties present for our review several issues going to the merits of plaintiffs’ claims and to various aspects of the relief ordered by the district court. NYSDOT challenges principally the court’s decision on the merits, contending (1) that the court erred in finding that (a) the FEIS’s treatment of the fisheries issue was inadequate when the FEIS was issued, and (b) the subsequent Lawler data required the agencies to prepare a supplemental EIS, and (2) that the court erred in concluding, on the basis of these findings, that there had been violations of NEPA, the Clean Water Act, and the Rivers and Harbors Act. NYSDOT and the federal defendants contend that even if the court was correct in its conclusions that the federal statutes had been violated as to the fisheries question and that a supplemental EIS was required on that issue, the court erred in ordering that the SEIS include updated consideration of issues other than fisheries. In addition, the federal defendants contend that the court had no power to impose record-keeping requirements on the Corps and FHWA, to prohibit the Corps and FHWA from being joint lead agencies in the preparation of the SEIS, or to appoint a special master to control the federal agencies’ reconsideration. On its cross-appeal, Sierra Club contends principally that the district court erred in upholding the Corps’s 1981 reliance on the information in the 1977 FEIS with respect to nonfisheries issues, because (1) the Corps was required to base its permitting decision on an up-to-date EIS, and (2) the Corps was not entitled in any event to rely on the January 1977 EIS because it was prepared by NYSDOT, the permit applicant, rather than by a federal agency. In addition, plaintiffs renew their contention that the Westway landfill constitutes a “dike” requiring Congressional authorization under § 9 of the Rivers and Harbors Act. Following oral argument of the appeals, this panel, with Judge Oakes dissenting, granted the federal defendants’ motion for a stay of the district court’s judgments insofar as they appointed a special master and had the effect of determining that the Corps and FHWA could not act as joint lead agencies in preparation of a supplemental EIS. We declined, with Judge Mes-kill dissenting, to stay the court’s imposition of record-keeping requirements in connection with the agencies’ reconsiderations. We turn now to the merits of the various appeals. For the reasons below, we uphold the district court’s determinations (1) that FHWA and the Corps breached their duties under NEPA, (2) that the Corps violated the Clean Water Act by unquestioningly relying on a FEIS that was inadequate as to the issue of aquatic impact, and (3) that those violations warranted the invalidation of the landfill permit granted by the Corps and of the FEIS with respect to fisheries issues. ’ We conclude, however, that neither the reasons given by the district court nor those raised by plaintiffs in their cross-appeal justified the district court’s order that a supplemental EIS include material on issues other than fishery resources, and we therefore modify the judgments in this respect. Finally, we vacate the court’s appointment of a special master to oversee the preparation of a supplemental EIS and the ruling that FHWA and the Corps may not act as joint lead agencies in its preparation, but we uphold the requirement that those agencies maintain adequate records to permit appropriate judicial review of their decisions reached after reconsideration. II. THE MERITS A. NEPA As the Supreme Court has stated repeatedly, although NEPA established “ ‘significant substantive goals for the Nation,’ ” the balancing of the substantive environmental issues is consigned to the judgment of the executive agencies involved, and the judicially reviewable duties that are imposed on the agencies are “ ‘essentially procedural.’ ” Strycker’s Bay Neighborhood Council, Inc. v. Karlen, 444 U.S. 223, 227, 100 S.Ct. 497, 499, 62 L.Ed.2d 433 (1980) (quoting Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U.S. 519, 558, 98 S.Ct. 1197, 1219, 55 L.Ed.2d 460 (1978) (“ Vermont Yankee ”)). “The only role for a court is to insure that the agency has taken a ‘hard look’ at environmental consequences; it cannot ‘interject itself within the area of discretion of the executive as to the choice of the action to be taken.’ ” Kleppe v. Sierra Club, 427 U.S. 390, 410 n. 21, 96 S.Ct. 2718, 2730 n. 21, 49 L.Ed.2d 576 (1976) (quoting Natural Resources Defense Council, Inc. v. Morton, 458 F.2d 827, 838 (D.C.Cir.1972)). The primary function of an environmental impact statement under NEPA is “ ‘to insure a fully informed and well-considered decision,’ [although] not necessarily ‘a decision the judges of the Court of Appeals or of this Court would have reached had they been members of the decisionmaking unit of the agency.’ ” Strycker’s Bay Neighborhood Council, Inc. v. Karlen, supra, 444 U.S. at 227, 100 S.Ct. at 499 (quoting Vermont Yankee, supra, 435 U.S. at 558, 98 S.Ct. at 1219); see also Monroe County Conservation Council, Inc. v. Volpe, 472 F.2d 693, 697 (2d Cir.1972). In order to fulfill its role, the EIS must set forth sufficient information for the general public to make ah informed evaluation, see id.; Natural Resources Defense Council, Inc. v. Callaway, 524 F.2d 79, 93 (2d Cir.1973), and for the decisionmaker to “consider fully the environmental factors involved and to make a reasoned decision after balancing the risks of harm to the environment against the benefits to be derived from the proposed action.” County of Suffolk v. Secretary of Interior, 562 F.2d 1368, 1375 (2d Cir.1977) (“County of Suffolk”), cert. denied, 434 U.S. 1064, 98 S.Ct. 1238, 55 L.Ed.2d 764 (1978). In so doing, the EIS insures the integrity of the process of decision by giving assurance that stubborn problems or serious criticisms have not been “swept under the rug.” Silva v. Lynn, 482 F.2d 1282, 1285 (1st Cir.1973). The “ ‘detailed statement’ ” required by § 102(2)(C) of NEPA thus “is the outward sign that environmental values and consequences have been considered during the planning stage of agency actions.” Andrus v. Sierra Club, 442 U.S. 347, 350, 99 S.Ct. 2335, 2337, 60 L.Ed.2d 943 (1979). Given the role of the EIS and the narrow scope of permissible judicial review, the court may not rule an EIS inadequate if the agency has made an adequate compilation of relevant information, has analyzed it reasonably, has not ignored pertinent data, and has made disclosures to the public. County of Suffolk, supra, 562 F.2d at 1383. We have described the district court’s function as follows: The district court does not sit as a super-agency empowered to substitute its scientific expertise or testimony presented to it de novo for the evidence received and considered by the agency which prepared the EIS. Environmental Defense Fund v. Froehlke, 368 F.Supp. 231, 240 (W.D. Mo.1973), aff’d, 497 F.2d 1340 (8th Cir.1974) . The court’s task is merely “to determine whether the EIS was compiled in objective good faith and whether the resulting statement would permit a decisionmaker to fully consider and balance the environmental factors.” Sierra Club v. Morton, 510 F.2d [813, 819 (5th Cir.1975) ]. “The court is not empowered to substitute its judgment for that of the agency.” Scenic Hudson Preservation Conference v. FPC, 453 F.2d 463, 468 (2d Cir.1971) cert. denied, 407 U.S. 926, 92 S.Ct. 2453, 32 L.Ed.2d 813 (1972), quoting Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 416, 91 S.Ct. 814, 28 L.Ed.2d 136 (1971). This is particularly true when it comes to evaluating the factual conclusions of the EIS. If the agency’s conclusions have a “substantial basis in fact,” FPC v. Florida Power & Light Co., 404 U.S. 453, 463, 92 S.Ct. 637, 643, 30 L.Ed.2d 600 (1972), and if the EIS has set forth responsible opposing scientific views, Committee for Nuclear Responsibility v. Seaborg, 149 U.S.App.D.C. 380, 463 F.2d 783 (1971), it is not for the district court to resolve conflicting scientific options. Id. If the district judge finds that the agency did not make a reasonably adequate compilation of relevant information and that the EIS sets forth statements that are materially false or inaccurate, he may properly find that the EIS does not satisfy the requirements of NEPA, in that it cannot provide the basis for an informed evaluation or a reasoned decision. Further, the court may properly be skeptical as to whether an EIS’s conclusions have a substantial basis in fact if the responsible agency has apparently ignored the conflicting views of other agencies having pertinent expertise. Silva v. Lynn, supra, 482 F.2d at 1285: [WJhere comments from responsible experts or sister agencies disclose new or conflicting data or opinions that cause concern that the agency may not have fully evaluated the project and its alternatives, these comments may not simply be ignored. There must be good faith, reasoned analysis in response. See also County of Suffolk, supra, 562 F.2d at 1383: “Where evidence presented to the preparing agency is ignored or otherwise inadequately dealt with, serious questions may arise about the author’s efforts to compile a complete statement.” In the present case the district court’s rulings on the merits of plaintiffs’ NEPA claims were consonant with the proper scope of its review and the proper view of the obligations imposed on FHWA and the Corps. With respect to the fisheries issues, the court found, inter alia, that the FEIS contained false statements depicting the interpier region as “biologically impoverished” and as a “biological wasteland,” when in fact the interpier area in winter harbored a concentration of juvenile striped bass. The court found that the FEIS statements regarding aquatic impact had not been compiled in “objective good faith.” Notwithstanding NYSDOT’s contention that “the FEIS set forth the relevant facts that were known about the interpier area and the surrounding Hudson estuary at the time it was prepared ...,” (NYSDOT brief on appeal at 24), the court’s findings to the contrary are amply supported by the record. For example, after the DEIS was issued, the Project received critical comments regarding fisheries impact from Fisheries Service, Wildlife Service, and EPA to the effect that the fish life had been underestimated and that the information provided was inadequate. Although the FEIS purported to respond to these comments, no new studies were performed, no additional information was collected, no further inquiry was made; and the FEIS essentially reiterated or adopted the statements in the DEIS. Employees of the Project and FHWA testified that they knew before getting any data from the Lawler study that the Project’s 1973 sampling had been faulty in both timing and technique and that these flaws were the reason the earlier study had revealed virtually no fish in the interpier area. Yet the Water Report, prepared in the wake of comments to the DEIS and appended to the FEIS, simply relied on the 1973 data. Bridwell, who was responsible for the preparation of the FEIS’s fisheries discussion testified that he was aware that the Water Report had not attempted to make any thorough or investigative inquiry into the existence of fish in the interpier area. He stated that the Water Report had attempted to verify only the existing literature on fish life in that area. It is not clear that even this academic study was performed: the Water Report neither identified any existing literature on the subject nor stated that there was no such literature; Bridwell himself was unaware of whether any literature existed. The evidence at trial suggested that there was no literature upon which the Report could have based its conclusion that the interpier area was biologically impoverished. Initial responsibility for the inaccurate characterization of the interpier area as a biological wasteland must be attributed to Sydec which the court found authored the FEIS and which was under the jurisdiction of NYSDOT. 541 F.Supp. at 1371. NEPA did not prohibit FHWA’s reliance on NYS-DOT for preparation of the FEIS, see NEPA § 102(2)(D), 42 U.S.C. § 4332(2)(D) (added by Pub.L. No. 94-83, 89 Stat. 424 (1975)), but it did require FHWA to make its own independent evaluation of the FEIS, § 102(2)(D)(iii), 42 U.S.C. § 4332(2)(D)(iii). There was no evidence that FHWA made any independent evaluation whatever of the fisheries issues. There was no proof that it had sought to learn what comments had been received on the DEIS from other federal agencies with expertise in special environmental subjects. FHWA officials testified that they could not recall whether they had reviewed the pointed criticisms of Fisheries Services. They stated that they may simply have ignored these criticisms as unimportant in relation to other Westway concerns. While it would indeed have been within FHWA’s discretion to make a substantive determination that an adverse impact on fisheries did not outweigh the benefits to be gained, this was not the evaluation that was made. Rather, FHWA ignored criticisms pointing out that FHWA lacked “sufficient information to permit a valid assessment” of marine impact. In short, we concur in the district court’s view that the FEIS did not reasonably adequately compile relevant information with respect to fisheries impact. The evidence as to the cavalier manner in which the Project had reached its conclusion that the interpier area was a biological wasteland, and as to FHWA’s failure to make an independent evaluation or to react in any way to sister agencies’ pointed comments that the draft EIS did not provide adequate information for a reasoned assessment of impact on fisheries, easily supports the district court’s findings (1) that the FEIS’s fisheries conclusions lacked a “substantial basis in fact,” and (2) that a decisionmaker relying on the January 1977 EIS could not have fully considered and balanced the environmental factors. In the circumstances, we agree that FHWA’s issuance of the FEIS, and the Corps’s reliance on the FEIS, violated NEPA. B. The Clean Water Act The district court’s ruling that the Corps violated § 404 of the Clean Water Act, 33 U.S.C. § 1344, is also supported by the record. The obligations imposed on the Corps by the Clean Water Act differ somewhat from those imposed by NEPA. In particular, although the Clean Water Act requires public hearings and consideration of the “public interest” before the Corps decides whether to issue a permit, see 33 C. F.R. § 320.4, it does not itself require the same types of environmental disclosures that are required by NEPA. Rather, in order to satisfy the Clean Water Act, the Corps primarily must give public notice, conduct hearings, make its own assessment of the impacts of the proposed project, and create a reasoned administrative record for its decision. See River Defense Committee v. Thierman, 380 F.Supp. 91, 95 (S.D.N.Y.1974). In reviewing the validity of a decision by the Corps to issue a permit under the Clean Water Act, a court should, as provided by the Administrative Procedure Act (“APA”), uphold the decision unless it is “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A) (1976); see Nofelco Realty Corp. v. United States, 521 F.Supp. 458, 462 (S.D.N.Y.1974); cf. Taylor v. District Engineer, 567 F.2d 1332, 1336 (5th Cir.1978). Where the Corps may rely on an EIS previously issued by a sister agency, see 40 C.F.R. § 1500.7; 40 C.F.R. § 1506.3 (1982), the determination of whether a Corps permitting decision was arbitrary and capricious depends not only on the information disclosed by that EIS, but also on information disclosed by later studies and information conveyed to the Corps. See Nofelco Realty Corp. v. United States, supra; see also Camp v. Pitts, 411 U.S. 138, 142, 93 S.Ct. 1241, 1244, 36 L.Ed.2d 106 (1973); Joseph G. Moretti, Inc. v. Hoffman, 526 F.2d 1311 (5th Cir.1976). The district court’s findings suggest that the Corps’s decision was arbitrary 'and capricious. The court found every level of the Corp’s review process woefully inadequate. It found that although the district engineer did not make his decision to approve the permit application until some 2V2 years after the application was filed, the decision “was made without having any reliable fishery information whatever.” 536 F.Supp. at 1253. Similarly, the court found that the division engineer’s decision was based on so little information that it could “only be explained as resulting from an almost fixed predetermination to grant the Westway landfill permit.” Id. at 1248. It found the chief of engineer’s decision virtually a rubber stamp of the decisions of his subordinates: “It is clear that [the chief of engineers] sought to expedite the matter, and saw no reason to ‘second guess’ the decision of the Division Engineer.” Id. at 1251. These findings are supported by the record. NYSDOT’s application for a permit was filed in April 1977 and formally approved by the district engineer in September 1979. There was no evidence that in the interval the Corps did anything whatever to conduct its own investigation into the fisheries questions on which it was to pass. It had announced that the FEIS was adequate for its purposes barely two weeks after receiving NYSDOT’s application, hardly an indication that any critical thought had been brought to bear on the fisheries issues. The Corps then received criticisms from Fisheries Service, Wildlife Service, and EPA, indicating that there were serious inadequacies in the information provided by the SEIS. It was required to give “great weight” to the views of Fisheries Service and Wildlife Service, 33 C.F.R. § 320.4(c); yet it merely passed them on to the Project and was not moved to conduct any inquiry of its own. Nor, apparently, was it interested in helping to shape the Lawler study that EPA finally prevailed upon NYSDOT to commission. Indeed, knowing that the Lawler study was underway, the district engineer decided to approve the permit without waiting for the results of the study. The division engineer’s decision was at least equally flawed. By the time that decision was rendered, the Lawler report had been received, and it confirmed the criticisms of the objecting federal agencies and revealed the inaccuracy of the FEIS’s conclusion that the interpier area was a biological wasteland. Nonetheless, the division engineer, like the district engineer, merely forwarded all federal agency criticisms of the FEIS to NYSDOT and FHWA, and had no independent Corps study made of the questions raised. At the chief of engineers level there may have been some effort by a Corps biologist to review independently the Lawler data, but this hardly sufficed to meet the Corp’s obligation under the Clean Water Act to make a reasoned decision: it resulted only in a two-page memorandum that the record does not reveal was even reviewed by the decisionmakers. Thus the record discloses that at every level of review the Corps simply ignored the views of sister agencies that were, by law, to be accorded “great weight.” The evi-denee amply warranted the district court’s finding that the Corps never made a serious attempt to discover, or to make a decision based on, reliable fisheries information. In the face of the Lawler report and the other federal agencies’ criticisms, the Corps’s unquestioning reliance on the FEIS must be regarded as arbitrary and capricious. We affirm the court’s ruling that the Corps violated the Clean Water Act. C. The Rivers and Harbors Act 1. Section 10 Section 10 of the Rivers and Harbors Act, see note 5 supra, prohibits the creation of any obstruction in navigable waters without affirmative authorization by Congress and makes such an obstruction unlawful without the prior approval of the Corps chief of engineers and authorization by the Secretary of the Army. The district court ruled that the Corps’s failures, inter alia, to investigate, develop adequate information, and make accurate public disclosures as to the fisheries issues constituted a violation of this provision. Whatever the validity of this conclusion, however, we reverse the judgment insofar as it upheld the § 10 claim since the Supreme Court has ruled that § 10 of the Rivers and Harbors Act does not provide a private right of action. California v. Sierra Club, 451 U.S. 287, 101 S.Ct. 1775, 68 L.Ed.2d 101 (1981). 2. Section 9 Section 9 of the Rivers and Harbors Act prohibits, inter alia, construction of dikes in navigable waters absent the prior approval of the Corps chief of engineers and the Secretary of the Army and the consent of Congress. Plaintiffs contended that defendants violated, or perhaps were about to violate, § 9 because Congressional consent had not been obtained for the proposed Hudson River landfill. The district court dismissed this claim as a matter of law prior to trial, without specifying its reasons. Whether or not the Westway landfill would be a dike within the meaning of § 9 as plaintiffs contend, we affirm the dismissal because we conclude that § 9 does not provide a private right of action. Using the Cort v. Ash, 422 U.S. 66, 78, 95 S.Ct. 2080, 2088, 45 L.Ed.2d 26 (1975), analysis as employed by the Supreme Court with respect to § 10 in California v. Sierra Club, supra, we see no grounds for con-eluding that § 9 was designed to create a private right of action. There is no basis for inferring that § 9 was enacted for the “especial benefit” of any class of individuals, nor that plaintiffs would be within such a class if there were one. As is the case with § 10, § 9 “states no more than a general proscription of certain activities; it does not unmistakably focus on any particular class of beneficiaries whose welfare Congress intended to further.” Id.,- 451 U.S. at 294, 101 S.Ct. at 1779. In the absence of any apparent intent on the part of Congress to create a private right of action to enforce § 9, we affirm the district court’s dismissal of plaintiff’s § 9 claim. III. RELIEF A. The Requirement of a Supplemental EIS on Fisheries Issues The principal relief ordered by the district court was an injunction against any further Westway activities affecting the bed or waters of the Hudson River unless and until a supplemental EIS has been prepared by the Corps containing adequate and accurate information with respect to the fisheries issues. Subject to the modification set forth in Part III.C.2. infra, as to who may author the SEIS, we regard this relief as well within the proper scope of the district court’s discretion in the circumstances of the present case. As discussed in Part II.A. supra, the record revealed that the authors of the FEIS had not made an adequate compilation of fisheries data, had not compiled information in objective good faith, had paid no heed to the experts’ warnings that they lacked needed information, and hence had reached the erroneous conclusion that the interpier area was a biological wasteland. This baseless and erroneous factual conclusion then became a false premise in the decisionmak-ers’ evaluations of the overall environmental impact of Westway and their balancing of the expected benefits of the proposed action against the risks of harm to the environment. Thus, the January 1977 EIS provided no valid “outward sign that environmental values and consequences [had] been considered” with respect to fisheries issues, Andrus v. Sierra Club, supra, 442 U.S. at 350, 99 S.Ct. at 2337, and hence furnished no assurance that the Westway approvals had been given on a reasoned basis. Enforcement of NEPA requires that the responsible agencies be compelled to prepare a new EIS on those issues, based on adequately compiled information, analyzed in a reasonable fashion. Only if such a document is forthcoming can the public be appropriately informed and have any confidence that the decisionmakers have in fact considered the relevant factors and not merely swept difficult problems under the rug. Accordingly, we uphold the district court’s requirement that before Westway landfill may proceed, FHWA or the Corps must prepare a new EIS on fisheries issues. Whether the new statement be called an amended EIS as in Silva v. Lynn, supra, or a supplemental EIS, as in the judgments below, NEPA requires no less. Our ruling on this point is not, however, an expansive one. We do not intend to suggest that inaccuracies in an EIS will always, or even usually, warrant a court’s ordering the preparation of a supplemental EIS. Had the January 1977 EIS contained a reasoned analysis of fisheries data reasonably adequately compiled, and merely drawn an erroneous factual conclusion, we would not believe it proper to order FHWA or the Corps to prepare a SEIS. See Hanly v. Kleindienst, 471 F.2d 823 (2d Cir.1972), cert. denied, 412 U.S. 908, 93 S.Ct. 2290, 36 L.Ed.2d 974 (1973). Or had reasonable investigative efforts resulted in less accurate data than later became available, the determination as to whether the later data warranted preparation of a SEIS, see 33 C.F.R. § 230.11(b) (1981); see also 33 C.F.R. § 209.410(g)(1) (1977); see also Part III.B. infra, would be a matter committed to the discretion of the responsible agencies, not to the judgment of the court. See Warm Springs Dam Task Force v. Gribble, 621 F.2d 1017, 1024 (9th Cir.1980) (it is for the agency to “evaluate [new information] and make a reasoned determination whether it is of such significance as to require implementation of formal NEPA filing procedures”). Nor do we express any view as to whether the decisionmakers’ overall evaluation of the benefits and detriments of West-way was “wrong.” We hold simply that a decision made in reliance on false information, developed without an effort in objective good faith to obtain accurate information, cannot be accepted as a “reasoned” decision. B. The Requirement of a Supplemental EIS on Nonfisheries Issues As indicated in Part I.D. above, the district court rejected plaintiffs’ contentions that the January 1977 EIS was inadequate in its treatments of nonfisheries issues such as air and noise pollution, flooding, funding, and the like, and hence declined to find that FHWA and the Corps had violated NEPA and the Clean Water Act with respect to these issues. 536 F.Supp. at 1234. Nonetheless, in its April and July Judgments, the court ordered that before the Westway landfills could proceed, the Corps must prepare a SEIS containing current information on subjects other than fisheries impacts. Information was required as to such matters as current cost estimates, substantial new developments as to alternatives, and current plans for the selection of real estate and commercial developers. We conclude that this requirement was not justified either on the ground relied on by the district court, to wit, that the FEIS was probably out-of-date, or on the alternative ground urged by plaintiffs, i.e., that the FEIS was prepared by an author on whom the Corps was not entitled to rely. 1. The Passage of Time In an opinion dated August 5, 1982 (“August 5 Opinion”), denying the motion of FHWA and the Corps for elimination of the requirement that the SEIS include current nonfisheries information, the court gave the following reasons for requiring such information: The provision in the April 14 Judgment regarding non-fisheries information is based upon the obvious fact that certain important information contained in the EIS filed five years ago in 1977 is probably seriously out-of-date — such as information about cost estimates, the availability and value of certain alternatives, and other similar factors. The Judgment requires that the supplemental EIS provide current information on such subjects. This requirement is not something gratuitous on the part of the Court. It follows, as an inevitable necessity, from the fact that the Corps of Engineers is required to reconsider the whole range of relevant factors bearing upon the landfill permit application, that this range of factors must include current information on items such as costs and alternatives, and that the currently issued supplemental EIS must reflect the significant factors which are being considered by the Corps. All of this follows from the rulings of the Court, and must be included in the in-junctive relief. August 5 Opinion at 6 (emphasis in original). We disagree. Since the requirement that the SEIS include nonfisheries information was not justified by the violations found by the court, it was not a proper exercise of the court’s discretion within the framework of NEPA or the regulations thereunder. We note at the outset that supplemental nonfisheries information was not required as a remedy for any violation of NEPA. As to the nonfisheries questions, the court found no failure to compile adequate data, no failure to make a reasoned analysis of the data compiled, no disregard of any pertinent data, and no failure to disclose the relevant data to the public. In short, as to nonfisheries matters it found no failure by any party to proceed on a good faith basis, and hence no nonfisheries violation of NEPA or any other statute. As the bad faith and inadequacies found by the court concer