HAYS, Circuit Judge:
By Opinion No. 584, dated August 19, 1970, the Federal Power Commission granted a license to Consolidated Edison Company of New York, Inc., to construct, operate, and maintain a pumped storage project along the western shore of the Hudson River at Cornwall, New York. Eight parties1 have filed petitions pursuant to Section 313(b) of the Federal Power Act, 16 U.S.C. § 8251(b) (1964) seeking to set aside this order on various grounds. The issues raised by these petitions are both complex and important, involving, as they do, the conflict between the needs of a highly technological society and the increased awareness of environmental considerations.
The opinion and order of the Federal Power Commission presented here for review follow by five years the earlier remand by this court in Scenic Hudson Preservation Conference v. Federal Power Commission, 354 F.2d 608 (2d Cir. 1965), cert, denied sub nom., Consolidated Edison Co. of New York v. Scenic Hudson Preservation Conference, 384 U. S. 941, 86 S.Ct. 1462, 16 L.Ed.2d 540 (1966), in which the petitions challenged three 1965 orders of the Commission licensing the project and refusing to reopen proceedings and take additional evidence on various issues. In the intervening period extensive hearings have been held, two decisions have been rendered by a Hearing Examiner and the Commission has issued its own opinion.
The new proceedings have produced a project that is different in some ways from the project that was before this court in 1965.
The functional elements of the project remain the same. It is still to be the largest pumped storage plant in the world and its principal function, to provide energy for peak load periods, is unchanged. The proposed location is the same as that previously proposed, the Hudson River at approximately river mile 56.5, about 40 miles north of New York City at Storm King Mountain near Cornwall, New York, “an area of unique beauty and major historical significance.” Scenic Hudson, supra at 613. The project would consist, as did the earlier version, of an upper reservoir, a tunnel between the reservoir and the powerhouse, and the powerhouse itself, a pumping-[466]*466generation station located at the riverside containing eight reversible pump-turbine and motor generation units as well as switching gear and primary transmission lines. However, unlike the project presented in 1965, which provided for a powerhouse that was 80 per cent underground, the powerhouse now licensed by the Commission is to be entirely underground.
The upper reservoir would be situated approximately 10,000 feet south and west of the powerhouse in a natural mountain basin behind Storm King Mountain. When filled to its maximum elevation it would have a surface area of 240 acres. It would be formed and enclosed by five earth and rock dikes. The lower reservoir would be the Hudson River itself.
The capacity of the eight pumping-generating units in the powerhouse would be 2,000 megawatts, or 2,000,000 kilowatts.2 However, the project would be constructed in a manner which would permit enlargement to a maximum of 3,000 mw. Eight discharge tunnels from the reversible pump-turbine and motor generation units would convey water between each turbine and an open tailrace leading to the river. The tailrace with abutments at both ends would run 685 feet along the river. A fish protective device is to be located in front of the tailrace intake.
The third major facet of the project relates to transmission facilities. Submarine cable installations and spare pipes would transmit the energy generated in the powerhouse under the Hudson River and would continue underground on the east side of the river for approximately 1.6 miles to a point out of sight of the river. At this point overhead transmission would commence and would continue for approximately 9.2 miles through Putnam County to Con Edison’s existing Pleasant Valley-Millwood-Sprain Brook transmission right of way. Changes have been made in the proposed route and the towns of Cortlandt, Putnam Valley and Yorktown, which challenged the route before this court in 1965, no longer do so.
The project would function in the manner described in our earlier opinion. Scenic Hudson, supra at 612. The units in the powerhouse would use off-peak energy generated not at the project but at other facilities in the Con Ed system to pump water from the Hudson River to the upper reservoir. When needed for peak power production, that is, during hours of highest kilowatt demand, the units would reverse direction of rotation and provide power derived from the fall of the water released into the river from the upper reservoir. This power would then be transmitted through the transmission system described above. “The water in the upper reservoir may be regarded as the equivalent of stored electrical energy; in effect, Consolidated Edison wishes to create a huge storage battery at Cornwall.” Scenic Hudson, supra at 612.
A visitor’s information center and picnic and parking facilities, proposed in the original project for the powerhouse site, have been eliminated. In their place, a 57 acre, mile-long park is to be constructed along the riverfront. Additional recreational facilities are to be provided at a 36 acre scenic overlook inland from the project with access from the existing State Highway 9-W.
As an alternative the Commission has licensed the powerhouse aspect of the project at a location within Palisades Interstate Park, approximately one and one-half miles downstream from the Storm King Mountain site. Construction at the Palisades site is to be considered approved by the Commission only if construction at the Storm King Mountain site “shall be precluded on a petition to review this order.”
The petitions in this case are occasioned by the “grave concern” aroused among conservationist groups by the Storm King project. Scenic Hudson, supra at 612. The petitions allege lack of [467]*467compliance with the terms of our earlier remand, absence of substantial evidence to support the Commission’s findings, and failure to comply with statutory mandates. We find, however, that the Commission has fully complied with our earlier mandate and with the applicable statutes and that its findings are supported by substantial evidence. In view of the extensive powers delegated to the Commission and the limited scope of review entrusted to this court, it is our duty to deny the petitions.
I.
Congress has given the Federal Power Commission broad responsibility for the development of national policies in the area of electric power. In Section 4(e) of the Federal Power Act, 16 U.S.C. § 797(e) (1964), the Commission is authorized
“To issue licenses * * * for the purpose of constructing, operating, and maintaining dams, water conduits, res-servoirs, power houses, transmission lines or other project works necessary or convenient for the development and improvement of navigation and for the development, transmission, and utilization of power across, along, from, or in any of the streams or other bodies of water over which Congress has jurisdiction * *
There are statutory limitations on the issuance of such licenses. Section 10(a) of the Act, 16 U.S.C. § 803(a) (1964), requires
“That the project adopted * * * shall be such as in the judgment of the Commission will be best adapted to a comprehensive plan for improving or developing a waterway or waterways for the use or benefit of interstate or foreign commerce, for the improvement and utilization of waterpower development, and for other beneficial public uses, including recreational purposes * *
The Commission is now obliged also to consider the environmental factors covered by the National Environmental Policy Act, 42 U.S.C. §§ 4321 et seq. (§ 1970).
In the Federal Power Act Congress granted the Commission “sweeping authority and a specific planning responsibility.” The Act “was the outgrowth of a widely supported effort on the part of conservationists to secure the enactment of a complete scheme of national regulation which would promote the comprehensive development of the nation’s water resources.” Scenic Hudson, supra at 613 and authorities cited there.
The scope of review of the Commission’s exercise of its authority and responsibility is narrowly limited. The Act, § 313(b), provides that “[t]he finding of the Commission as to the facts, if supported by substantial evidence, shall be conclusive.” 16 U.S.C. § 8251(b). In assessing the factual contentions raised in the petitions, this court’s authority “is essentially narrow and circumscribed.” Permian Basin Area Rate Cases, 390 U.S. 747, 766, 88 S.Ct. 1344, 1360, 20 L.Ed.2d 312 (1968). The licensing of projects such as the Storm King plant and the evaluation of their environmental impact has been entrusted to “the informed judgment of the Commission, and not to the preferences of reviewing courts.” Id. at 767, 88 S.Ct. at 1360.
The statutory standard of substantial evidence is “something less than the weight of the evidence and the possibility of drawing two inconsistent conclusions from the evidence does not prevent an administrative agency’s finding from being supported by substantial evidence.” Consolo v. Federal Maritime Commission, 383 U.S. 607, 620, 86 S.Ct. 1018, 1026, 16 L.Ed.2d 131 (1966). In a recent case involving these principles of court review, the Supreme Court said:
“Insofar as the Court of Appeals’ opinion implies that there was not substantial evidence to support a finding of some benefits, it is clearly wrong. And insofar as the court’s opinion implies that the responsibilities assumed by Gainesville in combination with the benefits found to accrue to Florida Power were insufficient to constitute ‘compensation * * * reasonably due,’ the Court of Appeals overstepped [468]*468the role of the judiciary. Congress ordained that that determination should be made, in the first instance, by the Commission, and on the record made in this case, the Court of Appeals erred in not deferring to the Commission’s expert judgment.” Gainesville Utilities Department v. Florida Power Corp., 402 U.S. 515, 527, 91 S.Ct. 1592, 1599, 29 L.Ed.2d 74 (1971).
Petitioners would have us reject these familiar principles because, they argue, different standards ought to prevail with respect to issues arising in an environmental context.3 There is an effort to find a basis for this position in our earlier remand in Scenic Hudson and in cases which have taken a similar approach.4 See, e. g., Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 91 S.Ct. 814, 28 L.Ed.2d 136 (1971); Udall v. Federal Power Commission, 387 U.S. 428, 87 S.Ct. 1712, 18 L.Ed.2d 869 (1967); Zabel v. Tabb, 430 F.2d 199, 213 (5th Cir. 1970), cert, denied, 401 U.S. 910, 91 S.Ct. 873, 27 L.Ed.2d 808 (1971).
To read these cases as sanctioning a new standard of judicial review for findings on matters of environmental policy is to misconstrue both the holdings in the cases and the nature of our remand in Scenic Hudson. An element common to all these cases was the failure of an agency or other governmental authority to give adequate consideration to the environmental factors in the situations with which they were presented. In Citizens to Preserve Overton Park, Inc. v. Volpe, swpra, 401 U.S. at 416, 91 S. Ct. at 824, for example, the Court remanded the case to the district court to determine whether the Secretary of Transportation’s decision “was based on a consideration of the relevant factors.” The Court pointed out that “[ajlthough this inquiry into the facts is to be searching and careful, the ultimate standard of review is a narrow one. The court is not empowered to substitute its judgment for that of the agency.” Id. In Udall v. Federal Power Commission, supra, 387 U.S. at 450-451, 87 S.Ct. 1712, the remand to the Commission instructed it to explore the “neglected phases of the cases” and to make “an informed judgment on these phases of the cases.” The Court explicitly stated that it expressed “no opinion on the merits.” It added, “It is not our task to determine whether any dam at all should be built or whether if one is authorized it should be private or public.” Id. at 450, 87 S.Ct. at 1724.
In our opinion in Scenic Hudson, supra, remanding the 1965 orders of the Commission, we were careful to make it clear that we were raising no question of change in the basic standard of administrative review and that the purpose of our remand was only to require the proper performance of its functions by the Commission. We said:
“While the courts have no authority to concern themselves with the policies of the Commission, it is their duty to see to it that the Commission’s decisions receive that careful consideration which the statute contemplates.” Id. at 612 of 354 F.2d.
“This court cannot and should not attempt to substitute its judgment for that of the Commission. But we must decide whether the Commission has correctly discharged its duties. * * The Commission must see to it that the record is complete.” Id., at 620.
Where the Commission has considered all relevant factors, and where the challenged findings, based on such full consideration, are supported by substantial evidence, we will not allow our personal views as to the desirability of the result reached by the Commission to influence us in our decision. We now turn therefore to an examination of whether our remand has been complied [469]*469with, whether there is substantial evidence to support the Commission’s decisions on the issues remanded and other challenged issues, and whether the Commission has complied with all applicable statutory requirements.
II.
In our opinion remanding this proceeding to the Commission we directed the Commission to weigh a number of factors which we believed had not been given adequate consideration. Holding that “recreational purposes” in § 10(a) of the Act (16 U.S.C. § 803(a) (1964)) “encompasses the conservation of natural resources, the maintenance of natural beauty, and the preservation of historic sites,” we required the Commission “properly [to] weigh each [such] factor.” Scenic Hudson, supra, at 614. We held “that the Commission is under a statutory duty to give full consideration to alternative plans” (Id. at 617). We criticized the Commission’s refusal to receive “proffered information on fish protective devices and underground transmission facilities. * * * ” Id. at 620, and directed it to “take the whole fisheries question into consideration before deciding whether the Storm King project is to be licensed.” (Id. at 624). We ordered the Commission to weigh “the aesthetic advantages of underground transmission lines against the economic disadvantages” (Id. at 623). In sum the Commission was admonished to “reexamine all questions on which we have found the record insufficient and all related matters.” (Id. at 624).
On January 25, 1966, acting on our remand, the Commission ordered that further proceedings be commenced before a Hearing Examiner. In that order the Commission said:
“We do not understand the Court’s order as restricting any further proceedings to the specific matters on which it found the present record insufficient to support our previous determinations and we do not believe it would be in the public interest to do so. The record in the first two hearings in the proceeding will, of course, be part of the present hearing. But all parties will be free to offer timely presentations of evidence on all matters relevant to the question whether a license should be granted.”
The hearings were commenced on November 14, 1966 and with several brief recesses, were concluded on May 23, 1967. A motion of the State of Connecticut’s Board of Fisheries and Game to intervene was subsequently granted, and further hearings were held on the issue of the protection of fish. These hearings were closed on October 16, 1967. On August 6, 1968, the Hearing Examiner issued his Initial Decision recommending that Con Ed be granted a 50 year license for the project. On November 19, 1968, the proceedings were reopened in response to a petition by the City of New York to intervene and introduce evidence on possible hazards to its Catskill Aqueduct. At this proceeding, further evidence was taken on the alternative site in Palisades Interstate Park. The Hearing Examiner issued a Supplemental Initial Decision on December 23, 1969, which concluded that the project did not endanger the Aqueduct and that the alternative site was “not a proper and preferable alternative location for applicant’s projected project.” In all other respects, except for minor items,5 the Initial Decision remained unchanged.
The proceedings on remand involved 100 hearing days, the testimony of some sixty expert witnesses, and the introduction of 675 exhibits. The record comprises more than 19,000 pages. Both the Hearing Examiner and the Commissioners arranged with the parties to visit [470]*470the proposed site and the surrounding area before rendering their decisions.
On August 19, 1970, the Commission issued its decision. In its opinion the Commission reviewed the power needs of the area served by Con Ed and considered possible alternatives to the Storm King project in terms of reliability, cost, air and noise pollution, and overall environmental impact. Concluding that there was no satisfactory alternative, the Commission evaluated the environmental effects of the project itself. It held that the scenic impact would be minimal, that no historic site would be adversely affected, that the fish would be adequately protected and that the proposed park and scenic overlook would enhance recreational facilities. The Commission found that further undergrounding of transmission lines would result in unreliability in the delivery of power and would be too costly. The Commission determined that construction of the project would entail no appreciable hazard to the Aqueduct.6
We find that the proceedings of the Commission and its report meet the objections upon the basis of which we remanded the earlier determination. Examination of the Commission’s conclusions and the evidence on which the conclusions are based establishes that the Commission has complied with our instructions and that the evidence supporting the Commission’s conclusions amply meets the statutory requirement of substantiality.
A. “Alternative plans”
The Commission gave detailed and comprehensive consideration to alternatives. Its initial statement of the basic issues of the case before it and the manner of its subsequent dealing with those issues demonstrates that there is no sound basis for petitioners’ contention that the Commission’s approach was too narrow. The Commission said:
“The weighing of social values required by the concept of the public convenience and necessity in this case involves on the one hand the alleged greater and much needed reliability, economic savings, and anti-air pollution benefits which this project offers compared with any feasible alternative, and on the other hand the alleged aesthetic and environmental detriment the project would impose on an area of great scenic, natural and historic value.
Simply put, the issue is whether the project offers substantially more reliable electric service as well as cheaper electricity generated in a cleaner manner than any other feasible alternative and, if so, whether the project will create detrimental aesthetic and environmental conditions of such degree as to lead on balance to a judgment that the public convenience and necessity would be better served by denying the application herein.”
In deciding this issue the Commission proceeded to evaluate the needs of Con Ed and the probability that the proposed project would supply these needs in a more desirable way than would the possible alternatives.
The Con Ed system serves the densely populated area of New York City’s five boroughs and part of Westchester County. The electric load requirements that Con Ed must meet are constantly growing. The Commission found that in 1970 Con Ed’s capacity would be approximately 10,126 mw, plus 520 mw contracted from other utilities. However, much of the system is outdated and about 2,000 mw of its present capacity are due to be eliminated by 1978. And yet by 1979, Con Edison’s annual peak load 7 will be approximately 10,850 mw.
[471]*471Two factors were cited by the Commission as necessary to insure availability of the required amount of energy and to prevent major power failures, such as that which occurred in the northeast United States in 1965, as well as the lesser “brownouts” and “blackouts” which have become all too frequent in the New York area. The first of these two factors is the existence of adequate power facilities to meet the growing demand for electrical energy in the area served. The second is an adequate “reserve,” a part of which must be what is called a “spinning reserve.” 8 This “spinning reserve” is provided by units operating at less than full capacity but synchronized to the system so that the energy generated by them will all be immediately available to meet an increase in loads. It is this latter need that the Storm King project is designed to meet.
The Commission found that in order to prevent a major power failure the “spinning reserve” must be fully available within two minutes.9 The Commission expressed the opinion, based on the record before it, that “if Cornwall or a pumped storage equivalent with its very fast pick-up characteristics had been available the blackout of 1965 might have been avoided.”
The Commission examined in detail the possibility that there were alternatives more desirable than the Storm King project which would be capable of meeting these needs. Our earlier opinion required the Commission to consider the use of gas turbines. The Commission determined that using gas turbines alone would not be a feasible alternative to a pumped storage unit since the turbines would be less reliable and more expensive. Gas turbines, the Commission found, take between three minutes and ten seconds and four minutes to be brought to full operation from a cold start. Moreover, the Commission stated, unlike pumped storage units, gas turbines have a relatively low capacity for storage of rotational energy, and thus do not provide as substantial a cushioning effect in the event of a disturbance.
Gas turbines were found to be considerably more expensive to operate than pumped storage units. The Commission adopted the conclusion of a staff study that the operating costs of a pumped storage project would be at least $119,-000,000 less over a twenty-year period than the operating costs of gas turbines.10 It would cost about $38,000,000 less, the study estimated, to construct the pumped storage project than to provide the gas turbines.
The Commission also considered the possibilities of a project composed entirely of nuclear units but found that such an alternative would be inadequate for reasons which are fully developed in the report. The Commission was of the opinion that a nuclear-gas turbine combination 11
“suffers from the shortcomings inherent in its components, that is, unless the gas turbines are spinning they cannot be brought into operation soon enough to meet emergencies and the nuclear component has relatively slow response characteristics which when [472]*472combined with the forced outage reduces the reliability quotient of such a combination.”
“[T]he reliability quotient of a nuclear-gas turbine combination,” the Commission said, “is far less than Cornwall’s.”
The Commission estimated that construction of the nuclear-gas turbine alternative would cost |158,794,000 more than Cornwall. On the basis of these findings the Commission said:
“We do not accept the proposition put forth by Scenic Hudson that this extra cost is de minimis when spread among all of Con Ed’s customers. There are often good reasons why it is in the public interest to utilize a more expensive alternative. In appropriate cases the extra cost may even be substantial. But whether substantial or not, the extra cost must be justified by a showing that the alternative is in the public interest. There has been no showing that a combination nuclear-gas turbine alternative offers any advantages or indeed is even reasonably equivalent to Cornwall.”
The Commission also considered the feasibility of using power purchased from outside sources to supply Con Ed’s needs as an alternative to building the Storm King plant. It found that the maximum amount that could be assured would be slightly in excess of 1000 mw.12 Thus this alternative, the Commission held, would not provide sufficient power.
Petitioners do not suggest that interconnections alone could provide a feasible solution. Scenic Hudson proposed a combination of 810 mw of purchased power with gas turbines. However since the gas turbines in this combination would not be used to generate spinning reserves but to take on the load, the Commission found that this alternative would not serve the principal function for which the Storm King project is designed:
“In view of the assumption inherent in this suggestion by Scenic Hudson that the gas turbines would not operate as a spinning reserve, the spinning reserve would have to come from the purchase sources if this alternative is to be comparable to Cornwall. Accordingly this possibility cannot be deemed reliable, since such purchases would not be available in the event of a separation, the very time they would be most needed.”
The Commission also examined the possibility of alternative sites for a pumped storage project. As the Commission points out, none of the petitioners offered any evidence on possible alternative hydro-electric sites. However, both Con Ed and the Commission staff conducted extensive surveys to determine if such alternatives existed within a hundred mile radius of New York City. Detailed studies for five such sites showed that they would be more costly and less reliable than the Cornwall project. All of them would require the construction of long transmission lines. For example, the Bashbish site, in New England, would require a transmission system of between 32 and 56 miles, with attendant effects on the surrounding land, as compared to the 9.2 miles of overhead corridor planned for the Cornwall project.
In its examination of alternatives the Commission considered their effect on air pollution, noise pollution and the overall environmental situation. Nuclear energy was found by the Commission to be the method of generation of electric power involving the least pollution. However since nuclear energy by itself is inadequate for peaking purposes, the effect on air pollution must be measured with relation to gas turbines, operating either as part of a nuclear-gas turbine system or [473]*473operated partly loaded as spinning reserve. The Commission pointed out that the peaking energy generated at the Cornwall project is itself pollution free. Whatever pollution results from the operation of the project will be caused by the plants which supply the power for pumping the water into the reservoir. As the Commission said, “if the energy necessary to pump Cornwall comes from polluting power plants in New York City that would otherwise be idle, little or nothing would be gained in reducing the air pollution problem.” The Commission concluded, however, that “water for Cornwall will normally be pumped by use of electric energy from non-polluting sources * * The Commission believed that construction of the Cornwall project would permit a more rapid replacement of old relatively inefficient steam-electric plants with large nuclear plants. Even during the early years of the project’s operation, because pumping would take place during off-peak hours, i. e., at night, “clean-burning” natural gas would probably be available in amounts sufficient to meet a large part of the Cornwall requirements.
The Commission pointed out that proposed alternative methods of meeting Con Ed’s need for power, since they too require construction of new facilities, would have an overall impact on the physical environment similar to that to which the opponents of the Cornwall project are objecting.
“Still another approach to weighing ‘alternatives to the proposed action’ from an environmental standpoint is to compare the operational consequence to the environment of the Cornwall project with similar consequences which would result from any reasonable alternative project. We conclude that none of the most likely proposed alternatives, including an all-nuclear unit or the mixed nuclear and gas turbine combination, could be sited within 100 miles of New York City with any less physical impact on the environmental aspects of the affected area than the Cornwall project.”
B. “The conservation of natural resources, the maintenance of natural beauty, and the preservation of historic sites.”
The Commission gave extended consideration to the environmental aspect of our remand order. Testimony was taken from “a veritable ‘Who’s Who’ of conservation, each witness discussing a different facet of this esoteric and subjective matter.” The Commission said: “[O]ur conclusion that the license must issue does not rest upon any discounting of the case made by the intervenors relating to the natural beauty, historical significance, and spiritual qualities of the Storm King Mountain in its setting.” Its essential finding in this regard was that the Cornwall project, as modified by the Commission to make any structures not buried “as unobtrusive as ingenuity can make them,” constitutes “no real impairment of the environmental and scenic aspects of the Highlands.”
The original plan for the project provided for a powerhouse that would be 80 per cent underground. The project licensed by the Commission now calls for the powerhouse to be completely underground. While in an area visually part of Storm King Mountain, the powerhouse would not be under the mountain itself but in the Village of Cornwall “on a small river-bottom foothill.” Scenic Hudson’s witness Vincent J. Scully, professor of art and architecture at Yale University, although he was opposed to other features of the project, stated that the underground powerhouse itself did not “enter into the problem of visual relationship.” The external features of the powerhouse site would all be located below the cut of Storm King Highway on the mountain.13 The only features on the powerhouse site which would be aboveground would be the entrance to the underground plant, an access road, [474]*474and the tailrace. The Commission said that “the land surface above the power station will be planted and as much of the existing growth as possible preserved.”
The tailrace and abutments would be located at the river’s edge, in an area partially occupied at present by a decidedly unseenic railroad bridge. The tail-race would be 685 feet long, with a vertical rock cut rising from 10 to 32 feet above the river. At the east end of the tailrace the visible height of the cut would be at most 20 feet above the existing railroad bridge. At the west end, the cut would be completely obscured by the existing bridge. The Commission pointed out that the “planting of vines on the rock face behind the tailrace would further serve to amelioriate the view from the river.” With respect to the effect of the construction of the tail-race on the view of the mountain, the Commission said:
“The tailrace would be located where the river widens above the gorge and curves west by north, above the powerhouse. From the bank directly across the river the distance is 4000 feet. Because of the curved shoreline at that distance, at the river level there would be no direct view of the tail-race.”
The tailrace and the vertical cut would not, therefore, destroy a scenic, unspoiled view of the mountain. They would in large part be hidden from view by existing man-made structures or natural phenomena. The scenic impact of that part of the tailrace and cut that would be visible are to be evaluated not in terms of the number of square feet potentially visible but in terms of the entire visible panorama. The total area that would be occupied would be minuscule in proportion to the total area encompassed within a viewer’s peripheral vision. The Commission could reasonably find that with the river in the foreground and the mountain majestically rising 1343 feet behind, the tailrace and the vertical cut would not seriously impair the mountain’s scenic aspects.
The Commission found, in summary, that:
“Limiting the external features at the powerhouse site to the portal entrance, tailrace, and access road, totalling approximately 3 or 4 acres — out of Storm King’s total of over 400 acres — should reduce to a minimum the visual impact on the scenic vistas of Storm King Mountain or the Highland Gorge of the Hudson River and thereby preclude any material scenic impairment or detriment.”
The reservoir would not be on Storm King Mountain itself but behind the mountain from the river about two miles south and west of the powerhouse site, on lands owned in part by the Village of Cornwall and in part by Harvard University.14 It would not be visible from the river; its visibility from other points “varies in relation to the elevation and distance of the view.” From many of the points from which the reservoir can be seen various industrial developments can be seen as well.
The Commission found that, although the 240 acre reservoir will be larger than any of the other nearby bodies of water, “in the scale of the area it does not reasonably appear to dwarf the scene. Nor should it be materially different in appearance from ponds in the area and thus should not be deemed incongruous with the present character of the area.” 15
Finally with respect to the contention that the inside walls of mud, or rock fill, would be exposed as the reservoir rises and falls, the Commission found that the rock and earth comprising the dikes would not be out of character with the [475]*475rock and bare spots common in the Highlands and that “[t]he plantings and natural growth which would adhere to the exterior and possibly interior surfaces of the dikes would also serve to ameliorate any intrusion of the reservoir and dikes on the natural scene.”
The Commission’s criticisms led to the substantial modification of the recreational aspects of the project. Con Ed’s original proposal included an information center and recreation area to be located in the vicinity of the powerhouse site. These features were eliminated by the Commission. The Commission approved the construction of a riverfront park and a scenic overlook. The park is to be built on the rock excavated from the site of the power plant. It would be located in that part of the river to the north and west of the project adjacent to the shoreline. This 57 acre mile-long recreational facility, to be linked by two bridges to the Town of Cornwall to which it will be transferred upon completion, is to consist of play area, picnic sites, shelters, and sanitary facilities. The scenic overlook is to occupy a 36 acre tract abutting State Highway 9-W, and would also include picnic sites.16 The Commission found that the overlook would enable visitors to enjoy “the scenic vistas of the Hudson River” 17 and “will not seriously or substantially impinge on the scenic historic or environmental qualities of the area.”
The Commission heard extensive testimony on the effect of the project on historic sites in the area. There is no record that any event of historical significance took place at Cornwall or on Storm King Mountain. Constitution Island and West Point, and Forts Clinton and Montgomery, which are at Bear Mountain considerably below the project site, are the closest areas of historical importance. The project site is not visible from either Constitution Island or West Point. However, Constitution Island, which has the best preserved revolutionary fortification in the Highlands, will be visible from the proposed scenic overlook. None of the parties has offered any specific rebuttal to the Commission’s conclusion that “the project will not cause the destruction of any historical site.” 18
The thrust of petitioners’ arguments is that the principle of preservation of scenic beauty permits of no intrusion at all into this area and that, therefore, no power plant, no matter how innocuous, may be built. This is clearly a policy determination which, whatever may be our personal views, we do not have the power to impose on the Commission. The Commission has complied with the terms of our remand by giving careful [476]*476and thorough consideration to the impact of the project on the environment. The conclusions it has reached are supported by substantial evidence.
C. The “fisheries question.”
In our remand order, in addition to requiring further consideration of the overall environmental impact of the project, we specifically directed the Commission to “take the whole fisheries question into consideration before deciding whether the Storm King Project is to be licensed.” Scenic Hudson, supra at 624, of 354 F.2d. We had in mind the allegations of fishermen’s groups that the project threatened to destroy the eggs of the striped bass whose major spawning grounds, they maintained, are in the immediate vicinity of the project, and “that ‘no screening device presently feasible would adequately protect these early stages of fish life’ and that their loss would ultimately destroy the economically valuable fisheries.” Id.
The Commission took official notice of the report of the Hudson River Policy Committee entitled “Hudson River Fisheries Investigations 1965-1968,” which was based upon a study sponsored by the New York State Conservation Department and the United States Fish and Wildlife Service and conducted under the field direction of a technical advisor of the United States Bureau of Sport Fisheries.
The “Hudson River Fisheries Investigations” concluded that:
“ * * * the evidence indicates that there would not be any significant adverse effects to the striped bass and American shad fisheries of the Hudson River from a pumped storage generating plant at Cornwall, New York.”
The Policy Committee’s study lends strong support to the views presented by a number of witnesses at the hearings to the effect that the spawning grounds of striped bass extend from locations at river mile 35 to river mile 123, and that these spawning grounds are, in the Commission’s words, “not consistently more favorable in one location than another.” The Commission found “that bass spawn substantially in the Hudson River over an 80 mile reach, including the Cornwall area, and that no part thereof is distinguished as a major spawning area.”
The devices originally proposed to protect the fish have been redesigned to afford greater protection. Referring to the testimony of a fishery biologist from the Commission staff, the Commission said:
“ * * * that while the mortality rates of fish, fish eggs, and larvae inhabiting the water which will be drawn through the screen and the plant cannot be measured short of actual measurement during project operation, in his own opinion the losses to the fishery caused by the operation of the project would not significantly affect the Hudson River fishery resources.”
In order to compensate for the loss of fish resulting from the operation of the proposed plant, Con Ed proposed, and the Commission approved, construction of a fish hatchery.'
The Commission concluded:
“Witness Raney’s fear19 as to what might or could happen [is] counterbalanced by testimony based on sam[477]*477pling studies which relating egg producing capacity of the striped bass to volumes of water in plant operation indicates that the impact on Hudson fishery would not be substantial. Thus even if none of the fish and eggs at Cornwall survived, the total impact would be small. The evidence, however, is to the effect that no such disaster would befall the Cornwall segment. Eggs, larvae and fish entering the plant would have a survival rate in the area of 80 per cent. Further, hatchery operations elsewhere indicate the feasibility of an operation in the Hudson which would be capable of replacing any losses attributable to the project.”
D. The “aesthetic advantages of underground transmission lines against the economic disadvantages” and related routing problems.
In compliance with our mandate, the Commission investigated the possibility of constructing the transmission lines of the project entirely underground. The Commission weighed the obvious aesthetic advantage of underground transmission as against its economic and functional disadvantages.
The evidence shows that putting the transmission lines underground would cost substantially more than having them overhead. The Commission’s staff estimated that considering both construction and maintenance costs, underground lines would be approximately 16 times as expensive as overhead lines. The Commission explained that:
“The relative costs of undergrounding can be appreciated from the fact that the problems inherent in transmitting power underground at high voltages are not simply a matter of putting an overhead transmission line, which is merely a bare insulated piece of metal conductor, into a trench. The phenomena of heat buildup and condenser (or capacitance) effect require that underground cables be an entirely different species of equipment.”
The Commission cited a number of technological factors that result in higher labor and material costs for underground-ing. Underground cable requires a type of insulation which can be applied only by highly skilled labor. Transmission of power by underground lines presents problems which can be solved only by the installation of large magnet-type coils every 2 to 3 miles. Various other expensive techniques, such as intricate splicing, are needed to meet other problems presented by the electrical and thermal properties of underground lines.
The Commission found that there were functional disadvantages in underground cables. Although overhead lines have more outages, there can generally be immediate automatic reclosure with no disruption of service. Outages in underground cables, on the other hand, result in considerably greater disruption of service since the failure must be located, the damaged area excavated, and complicated repairs made.
The Commission, balancing the several factors which are involved, concluded:
“It is thus apparent that only for the most cogent reasons, as where no feasible alternative is possible or where the aesthetic detriment is so violent as to preclude any consideration of overhead transmission facilities, that undergrounding should be required.
Nor do we believe it is in the public interest to burden consumers with the cost of undergrounding cables unless it were necessary to prevent such destruction or serious damage.”
The transmission route which is now approved is different from the route challenged before this court in 1965. The new route is not the route preferred by Con Ed, but is a modified route developed by the Commission staff. Although it is 5 to 6 miles longer than the route proposed by Con Ed, it would require 4 miles less of transmission corridor because it uses a greater length of the existing Pleasant Valley-Millwood corridor. The alternative route was se[478]*478lected because “it will impinge less on the area through which it passes than would any other route.” The area traversed is “rough, wooded and hilly. More importantly, its valleys lie in a north-easterly direction and are oriented so as to provide the possibility of locating lines below crests.” The wooded nature of the area will provide natural screening. The Commission found that “the area will remain what it is now — scenic and pleasant, with open farmland and orchards and partly wooded with some brooks. To say that this will be seriously damaged or destroyed by an overhead transmission line is not consistent with reality.” 20
Since the Commission’s conclusions on this issue are based upon consideration of all relevant factors and are supported by substantial evidence, they cannot be rejected.
E. The Catskill Aqueduct
The issue of possible danger to New York City’s Catskill Aqueduct was not involved in the earlier proceeding. It is presented in the new application because of the change in the Cornwall project to provide for construction of the powerhouse completely underground. As a consequence of that change the powerhouse is to be located at its closest point a distance of about 140 feet from the Moodna Pressure Tunnel, a link in the Catskill Aqueduct system. The Catskill system is one of three systems that supply New York City with substantially all of its water. Twenty-odd communities in upstate counties also have the right to, and do tap the Catskill Aqueduct.
The city contends that the Cornwall project interferes with its control of the Catskill Aqueduct and is therefore precluded by Section 27 of the Federal Power Act, 16 U.S.C. § 821 (1964), which provides that:
“Nothing contained in this chapter shall be construed as affecting or intending to affect or in any way to interfere with the laws of the respective States relating to the control, appropriation, use, or distribution of water used in irrigation or for municipal or other uses, or any vested right acquired therein.”
The argument based on Section 27 is without merit. The license that the Commission has issued does not authorize Con Ed to divert any of the city’s water or to interfere with the tunnel. Moreover the “only purpose of section 27 is to preserve to holders of state-conferred water rights a right to compensation if those rights are taken or destroyed as an incident to the exercise by another, of a license granted by the Commission.” Portland General Electric Co. v. Federal Power Commission, 328 F.2d 165, 176, & n. 23 (9th Cir. 1964), citing City of Fresno v. California, 372 U.S. 627, 629-30, 83 S.Ct. 996, 10 L.Ed.2d 28 (1963) and Ivanhoe Irrigation District v. McCracken, 357 U.S. 275, 291, 78 S.Ct. 1174, 2 L.Ed.2d 1313 (1958), both of which involved the very similar language of Section 8 of the Reclamation Act of 1902, 43 U.S.C. § 383 (1964).21 Section 27 was not intended to give the city the power to veto Commission action.
[479]*479The Commission concluded that excavation of the powerhouse site would not cause damage to the Moodna Pressure Tunnel, that controlled blasting during construction would not endanger the Aqueduct and, generally, that “the probability of damage to the Aqueduct is remote.” We think that there is substantial evidence in the record to support the Commission’s determination.
The Commission found that the rock underlying the project “is a very large mass of dense uniform crystalline rock underlain by sedimental rock capable of sustaining great loads.” The city contends that, on the contrary, instability of the rock at the Aqueduct site can be deduced from a failure of the original Moodna Tunnel in 1913 and by the phenomenon of “popping rock” encountered in construction of the tunnel. However, the evidence shows that the failure of the original Moodna Tunnel was due to excessive water pressure and insufficient rock cover. The tunnel was corrected by construction of an alternate shaft and has operated for a period of over 50 years without untoward incident. The Commission found that “[t]he phenomenon of ‘popping rock’ occurs in rock of this area only at depths below 1,000 feet,” far below the depth proposed for the Cornwall project.
Although witnesses for the City testified that stress changes caused by the powerhouse excavation and by blasting might present hazards to the Aqueduct,22 other witnesses seriously disputed these contentions. Smith, a consulting geologist for Con Ed, testified, as the Commission said, “that he could conceive of no possible condition in this area which would make the proposed plan hazardous from a geological point of view.” Dr. Bartlett W. Paulding, Jr., Associate Professor and Acting Head of the Basic Engineering Department of the Colorado School of Mines, who was retained by Con Ed at the suggestion of the City, testified that the effect of excavations on the aqueduct would be insignificant. Dr. Paulding, whom the Commission described as “a geologist and geophysicist specializing in rock mechanics,” concluded, in the Commission’s words
“that the absence of adverse geological conditions, coupled with the results of a photoelastic analysis of the stress conditions around rectangular openings * * * indicate that the existing Catskill Aqueduct will not be endangered * * * during * * * excavation for the power plant.”
Similar testimony was offered by Charles P. Benziger who based his conclusion on low stress conditions at the site as shown by seismic tests in drilled holes at the point where the power station is to be located.
The Commission’s conclusion that blasting would pose at most a remote possibility of damage has ample 'support in [480]*480the record. The city’s own witness, Don Deere, testified that it was “possible, but unlikely that blasting, if restricted and properly controlled, will cause damage to the pressure tunnel.” Another of the city’s witnesses, Malcolm T. Wane, testified that the effects of blasting are somewhat conjectural. Con Ed’s witness Paulding testified that the Aqueduct would not be endangered if blasting charges were limited to 55 pounds per charge. The Commission’s conclusion that properly controlled blasting presented at most a “remote” danger is not seriously challenged by the city.
It is clear that the resolution of highly complex technological issues such as these was entrusted by Congress to the Commission and not to the courts. Where the Commission’s conclusions are supported by substantial evidence, the courts must accept them. It seems to us that it would be very difficult indeed to argue that the evidence supporting the Commission’s determination with respect to the Aqueduct is insubstantial. In fact the argument presented to us on this issue appears to be either that some higher burden of proof should be imposed with respect to the matter or that the city should be able to exercise what, in effect, amounts to a veto power. However, there is no authority whatever to support the imposition of any greater burden of proof than that provided in the statutory standard and “[s]uch a veto power easily could destroy the effectiveness of the federal act. It would subordinate to the control of the [city] the ‘comprehensive’ planning which the Act provides shall depend upon the judgment of the Federal Power Commission or other representatives of the Federal Government.” First Iowa Hydro-Electric Cooperative v. Federal Power Commission, 328 U.S. 152, 164, 66 S.Ct. 906, 912, 90 L.Ed. 1143 (1946) (footnote omitted).
III.
The only remaining concern is the allegation that the Commission failed to comply with certain statutory directives.
The first of these statutes is Section 10(a) of the Federal Power Act, 16 U.S.C. § 803(a) (1964 & Supp. 1971) which provides:
Ҥ 803. Conditions of license generally.
All licenses issued under sections 792, 793, 795-818, and 820-823 of this title shall be on the following conditions :
(a) That the project adopted * * * shall be such as in the judgment of the Commission will be best adapted to a comprehensive plan for improving or developing a waterway or waterways for the use or benefit of interstate or foreign commerce, for the improvement and utilization of waterpower development, and for other beneficial public uses, including recreational purposes; and if necessary in order to secure such plan the Commission shall have authority to require the modification of any project and of the plans and specifications of the project works before approval.”
This is the statute upon which, to a large extent, our earlier remand was based. In our opinion we said that the phrase “recreational purposes” “undoubtedly encompasses the conservation of natural resources, the maintenance of natural beauty, and the preservation of historic sites.” Scenic Hudson, supra at 614 of 354 F.2d. We directed the Commission to consider all of these factors in reaching its decision.
It is obvious that in finding compliance with our remand order, we also find compliance with the statute on which that order was based. As we have pointed out, the Commission has given careful and thorough consideration to “recreational purposes,” and, indeed, has used its “authority to require the modification of [the] project” in a number of aspects related to this end.
There is no real dispute as to other findings required by the statute. The Commission found that there would be no impediment to navigation, that use [481]*481of the Hudson River for electric generation by this project is “well adapted to development of the waterway for the use or benefit of interstate or foreign commerce,” and that the project will not interfere with any future program for the river since it will discharge no chemical, thermal or solid pollutants into the waterway. In short, the Commission has given full consideration to all of the statutory factors and has thus performed the “specific planning responsibility” entrusted to it by Congress in Section 10(a).
The petitioners also claim that the Commission has violated the National Environmental Policy Act, 42 U.S.C. § 4321 et seq. (Supp.1971). This Act was passed after the close of the hearing, but before the Commission’s decision.23 Its applicability to this proceeding is clear, and is conceded. See Zabel v. Tabb, 430 F.2d 199, 213 (5th Cir. 1970), cert, denied, 401 U.S. 910, 91 S.Ct. 873, 27 L.Ed. 2d 808 (1971). Section 101 “recognizing * * * the critical importance of restoring and maintaining environmental quality to the overall welfare and development of man” requires the federal government to
“(b) * * * use all practicable means, consistent with other essential considerations of national policy, to improve and coordinate Federal plans, functions, programs, and resources to the end that the Nation may—
(4) preserve important historic, cultural, and natural aspects of our national heritage, and maintain, whenever possible, an environment which supports diversity and variety of individual choice;
(5) achieve a balance between population and resource use which will permit high standards of living and a wide sharing of life’s amenities. * * * ” 42 U.S.C. § 4331 (Supp.1971).
Section 102 of the Act, 42 U.S.C. § 4332 (Supp.1971), requires agencies of the federal government to take certain prescribed measures.
The policy statement in Section 101 envisions the very type of full consideration and balancing of various factors which we, by our remand order, required the Commission to undertake. Like our remand, the Act does not require that a particular decision be reached but only that all factors be fully explored. The eventual decision still remains the duty of the responsible agency.
The Commission has complied with the specific directives contained in Section 102 of the Act. The hearings reflected the “systematic, interdisciplinary approach” required by that section. The Commission consulted with other agencies, as required by Section 102, including the Chief of Engineers, the Advisory Council on Historic Preservation, the Department of the Interior, the Atomic Energy Commission and a number of state and local groups that stand to be affected. The environmental statement required by Section 102(2) (C) of the Act, 42 U.S.C. § 4332(2) (C) (Supp. 1971) was submitted in the form of the Commission’s opinion. In view of the exhaustive environmental findings which occupy a substantial portion of the Commission’s opinion, and the Commission’s explicit conformance with the enumerated portions of the required statement, we conclude that full compliance with the National Environmental Policy has been demonstrated.
IV.
We do not consider that the five years of additional investigation which followed our remand were spent in vain. The petitioners performed a valuable service in that earlier case, and later before the Commission. By reason of their efforts the Commission has reevaluated the entire Cornwall project. The modifications in the project reflect a heightened awareness of the conflict between utilitarian and aesthetic needs. Whether the project as it now stands represents a perfect balance of these needs is not for this court to decide. Since the Commission has fully performed the duties and [482]*482responsibilities imposed upon it, it is our obligation to deny the petitions in all respects.