Opinion for the Court filed by District Judge JOHN H. PRATT.
JOHN H. PRATT, District Judge:This petition challenges the validity of orders1 by the Federal Energy Regulatory Commission (hereinafter “Commission”) approving an amendment to the license of the Department of Lighting of the City of Seattle (hereinafter “City”) for the Skagit River Project No. 553 in Washington State. Application for the amendment was made to the Federal Power Commission2 on December 17, 1970, more than 9 years ago. The orders under review raised the height of the present Ross Dam by 121 feet, thereby increasing the peaking capacity and energy output of the Ross Power Plant. The petitioners, all intervenors before the Commission, consist of three separate groups: the Swinomish Tribal CommunLy, Upper Skagit Tribe and Sauk-Suiattle Tribe, et al. (hereinafter “Tribes”), the North Cascades Conservation Council, et al. (hereinafter (“American Intervenors”) and the Run Out Skagit Spoilers Committee (R.O.S.S. Committee), et al. (hereinafter “Canadian Intervenors”). The principal intervenor3 on the side of the respondent Commission is City, a large municipally owned electric utility serving a total population of approximately 750,000 persons. The issues have been fully briefed and argued and for the reasons set forth hereafter, we affirm the orders of the Commission and dismiss the petition.
HISTORICAL BACKGROUND
The Skagit River rises in British Columbia, flows south across the international boundary and then west to its outlet in Puget Sound. Prior to 1920, when the Federal Water Power Act4 was passed, which required federal licensing of all hydro-electric projects on navigable waters of the United States, City had constructed the Gorge development on the Upper Skagit, consisting of a concrete arch dam with a capacity of 175 MW (megawatts). In 1927, City in Project No. 553 was licensed by the Commission to construct a second development at Diablo, upstream from Gorge, and consisting of a concrete arch dam with a capacity of 159 MW. This license for Project No. 553 was for a 50 year period and covered three Skagit River dams and power plants, known in order proceeding upstream as Gorge, Diablo and Ross. Ross, the largest, was proposed for construction in four stages as power needs required. It contemplated an ultimate reservoir elevation of 1725 feet above mean sea level. Stages 1 and 2 were authorized in 1937 and 1942. Stage 3, by virtue of several Commission orders, the latest being 1967, raised the water surface of the Ross reservoir to 1602.5 feet, the present level.
The fourth and final stage for increasing the height of the Ross Dam for which application to the Commission was made in 1970, would raise the water surface in the reservoir (hereinafter sometimes Ross Lake) to 1725 feet. The orders now under review concern the Commission’s approval of such construction (hereinafter High Ross).
*44STATEMENT OF FACTS
The purpose of the High Ross amendment is to meet the growing energy needs of the Seattle area, served by City, its electric utility, and to provide sources of power important to the Pacific Northwest Power Pool. City’s present resources are insufficient to serve both peak and base energy demands and this shortage has had to be made up by purchases from the Bonneville Power Administration (BPA). City and other preference customers have already received notice from BPA that by 1983 BPA will not be able to meet the demands caused by preference customer growth. It does not appear to be seriously contested that City is confronted with prospects of an acute energy shortage and must act to increase its existing supplies.5
The present development at the Ross Dam consists of a dam with a current height elevation of 1615 feet above sea level and a powerhouse with four generating units with a capacity of 252 MW. The present height of Ross Lake, the reservoir, is 1602.5 feet and the Lake presently covers a surface area of 11,700 acres.
The proposed High Ross amendment, by adding 122V2 feet to the existing structure, would increase the present generating capacity of the Ross development from 252 MW to 525 MW, an increase of 273 MW. This enlargement of capacity will result from the increase in the hydraulic or pressure head available to rotate the hydro-electric turbines which will result from the greater storage capacity of Ross Lake. Raising the present Ross Dam to permit a reservoir elevation of 1725 feet, which is 122V2 feet above the present elevation of 1602.5 feet, will make available an additional 292,000 kilowatts of peaking capacity and 30,000 kilowatts of firm energy. At the same time, Ross Lake will inundate an additional 8320 acres, 4720 in Canada and 3600 in the United States.
Because the reservoir at the maximum elevation of 1602.5 presently extends into Canada about one mile covering 480 acres and because the proposed construction of High Ross will further increase the surface area of the reservoir, Canadian interests have been implicated since Project No. 553 was originally authorized in 1927.
The Canadian-American Waters Treaty of 1909, 36 Stat. 2448, established an International Joint Commission (hereinafter IJC) over waters flowing across the international boundary. Article IV of the Treaty prohibits construction of dams on one side of the boundary which would raise the natural water level on the other, unless approved by the IJC. City received IJC approval for High Ross in 1942, conditioned on City’s execution of a compensation agreement with the Province of British Columbia regarding the flooding of provincial lands. Work commenced on the initial stages of the Ross Dam and in 1947 the passage by the Province of the Skagit Valley Lands Act, authorized City to flood lands in the Province, subject to payment to be agreed upon. This resulted in a series of annual agreements, which covered inundation caused by the Ross reservoir to elevation 1602.5, the operating level of the third stage. In 1967, the Province and City executed a 99 year rental agreement to cover all lands in Canada flooded as the result of raising the surface of the Ross reservoir to elevation 1725. IJC approved this agreement, noting that the condition of its 1942 approval of High Ross had been met. Since 1967, City has been making annual rental payments of $34,566 as well as paying annual property taxes levied by the Province. The 1967 agreement permits the Province, at its option, to take such payments in electrical energy, which option has thus far not been exercised. To sum up, the present reservoir at elevation 1602.5 has a maximum surface of 11,700 acres, 480 acres of which are in Canada. High Ross with an elevation of 1725 will flood an additional 8320 acres, 4720 of which are in Canada. The present reservoir extends one mile into *45Canada; the enlarged reservoir will extend seven miles into Canada.
To complete this factual recitation, it is appropriate to single out the specific Acts of Congress passed by the same Congress on October 2, 1968 and having a direct bearing on the present proposal. (1) Section 5(a)(24) of the Wild and Scenic Rivers Act (hereinafter WSRA), 16 U.S.C. § 1276(a)(24) designated portions of the Skagit River approximately 11 miles below City’s Gorge development for potential addition to the Wild and Scenic Rivers System established by the Act. During the Commission’s consideration of High Ross, the lower Skagit was a “study river.” The provisions of Section 7(b) of the WSRA have a bearing on the Commission’s exercise of jurisdiction.6 (2) The North Cascades Park Legislation established a diverse recreational complex comprising 1,642,000 acres in the North Cascades Mountains. A portion includes the headwater drainage of the Skagit River Basin. At the core are some 107 000 acres designated as the Ross Lake National Recreational Area. .This area was specifically reserved to FPC jurisdiction because of City’s planned further power developments. As Secretary of Interior testified in support of the North Cascades legislation:7
The Ross Lake reservoir built by the City of Seattle was one of the early hydro projects built in the Northwest. This is going to be a vital access area to a new national park.
The basic reasons supporting a natural recreation area are to permit a future raising of Ross Lake and more diversified and intense recreational use of this area than is normally the custom within a national park.
It is fair to say that the proposed amendment to High Ross is the culmination of a project licensed more than 50 years ago and was in the mind of Congress prior to the formal application made by City in 1970.
PROCEEDINGS BEFORE THE COMMISSION
The 1970 application for approval of High Ross was given proper public notice and copies were distributed to federal, state and local agencies for review and comment, as was a draft environmental impact statement (hereinafter DEIS) prepared by the Commission staff and released in October, 1973. Hearings lasting 67 days took place during the period in the Seattle area and here in Washington, D.C. from April, 1974 to March, 1975, The hearing transcript of almost 10,000 pages included the testimony of 73 witnesses. Over 300 exhibits and 48 Items by Reference were admitted into evidence. The petitioning American intervenors and Canadian intervenors participated fully throughout the course of the hearings. On February 4, 1976, the presiding Administrative Law Judge (hereinafter ALJ) issued his Initial Decision which recommended approval of the City’s application subject to numerous protective provisions. The matter then went before the Commission.
On October 4,1976, while the Commission was giving consideration to exceptions to the Initial Decision of the AU, the petitioners Swinomish Tribal Community, Upper Skagit Tribe and Sauk-Suiattle Tribe sought for the first time to participate in the Commission’s proceedings by filing a petition to intervene. They volunteered that they had no desire “to reopen the record to submit evidence” and that “they will take the record as they find it.”8 The *46ALJ’s Initial Decision was affirmed and adopted by the Commission on July 5, 1977 in Order No. 808 which order granted the Tribes’ motion to intervene upon the basis that the record would not be reopened.
All of the present petitioners asked for a rehearing and the Secretary of Interior, whose department had previously provided letters of comment on public access and recreation facilities (all ordered by the Commission) petitioned for the first time to intervene and simultaneously asked for a rehearing, a stay of Commission’s order pending an examination of the impact on downstream fishery resources or, alternatively, for a 45 day stay to formulate conditions relating to fishery resources for inclusion in the license. On September 16,1977, the 45 day stay was granted to Interior.
On March 9, 1978, the Tribes moved to dismiss the City’s application for the High Ross amendment, on the ground that the 50 year license for Project No. 553 granted in 1927 expired by its own terms on October 28, 1977. This motion was denied by the Commission. During this period Interior submitted certain recommended license conditions relating to stream flow in the downstream Skagit.
On August 2, 1978, the Commission issued Opinion No. 808-A denying rehearing of Opinion No. 808 and denying reopening. At the same time it instituted a separate proceeding to consider Interior’s proposed license conditions. The present petitions to review Commission’s actions are now before this Court.
THE ISSUES
The issues raised by petitioners are as follows:9
1.Whether the expiration of the original license on October 28, 1977 affected the power of the Commission to complete action on the High Ross amendment. (Tribes).
2. Whether the Commission is required under § 4(e) of the FPA, 16 U.S.C. § 797(e), to include, as part of the license amendment, conditions relating to downstream flows submitted by Interior and, since this issue was not argued on rehearing, whether it may now be raised on appeal. (Tribes).
3. Whether the Commission’s orders are consistent with § 7(b) of the WRSA, 16 U.S.C. § 1728(b), without first having reviewed a determination from the Secretary of Agriculture that the scenic, recreational, fish and wildlife values of the Skagit River commencing more than ten miles downstream from the Gorge dam would be adversely affected. (American intervenors).
4. Whether the Commission acted properly in instituting a separate proceeding to consider the matter of downstream flow releases. (American intervenors and Tribes).
5. Whether in approving an amendment to the license for hydroelectric Project No. 553, which permitted an increase in the height of Ross Dam, the Commission fully complied with the requirements of NEPA:
(a) by adequately considering the environmental impact on lands in Canada (Canadian intervenors).
(b) by adequately considering alternatives. (American intervenors).
We turn now to a consideration of these issues in the order listed above.
1. The Expiration of the Original License as Affecting the Validity of the High Ross Amendment
The Tribes argue that the “annual license”10 issued under § 15(a) of the Federal Power Act, 16 U.S.C. § 808(a) (herein*47after FPA), in the interim between the expiration of a license and a decision on an application for its renewal, cannot be amended. Their principal argument is that § 15(a) itself states that annual licenses are to be issued “under the terms and conditions of the original license . . . .” Id. Because the Tribes and the Secretary of Interior filed motions for reconsideration and a 45 day stay was granted by the Commission before the amendment became final and subject to judicial review, and because the initial 50 year term of the original license expired before that stay lapsed and before those motions were denied, the Tribes claim that § 15(a) prevents the addition to Ross Dam from being approved, i. e., that the Ross addition may be considered only in the pending relicensing proceeding. We reject this argument as lacking merit for three reasons: First, but for the Tribes’ and the Secretary of Interi- or’s motions for a stay and for reconsideration, the license amendment clearly would have been made final before the 50 year initial license term. Second, § 15(a) licenses are designed simply “to prevent a possible hiatus in the operation of a project . . .” Lac Courte Oreilles Band v. FPC, 510 F.2d 198, 206 and n.29 (D.C.Cir.1975), and not to force the licensee back to square one in an amendment proceeding which is on the edge of completion after being seven years in process. Third, § 9(b) of the Administrative Procedure Act, 5 U.S.C. § 558(c) (1976), provides that when a licensee files an application to renew “a license with reference to an activity of a continuing nature,” that license “does not expire until the application has been finally determined by the agency.” In such circumstances, the expiration date is tolled. City filed a timely application to renew its license for Project No. 553; thus, under § 9(b) City’s 50 year license in a sense has not effectively expired.
2. and 3. The Issues Concerning Compliance with § 4(e) of the FPA and § 7(b) of the WSRA
Both of these issues arise out of the present downstream conditions below the Gorge Dam and the Commission’s statutory obligations under § 4(e) of the FPA and § 7(b) of the WSRA. It is acknowledged by all parties that the irregular water flows have caused injury to the spawning of anadromous fish and to the Indian Tribes which depend on them for sustenance and their commercial livelihood. When downstream flows are substantially lowered over a short period of time, anadromous fish fry are left stranded on sandbars and gravel bottoms and die. The problem was addressed, at least in part, more than 30 years ago when City and the Washington State Department of Fisheries in 1947 entered into an agreement which required a minimum discharge from the Gorge Dam of 1,000 cubic feet per second or the natural river flow, whichever is less. The particular interest of the Tribes who fish in the Skagit River stems from their rights under the 1859 Treaty of Point Elliott11 between United States and certain Indian tribes 12 in Washington Territory and the decision of the Federal courts in United States v. State of Washington, 384 F.Supp. 312 (W.D.Wash. 1974), aff’d and remanded, 520 F.2d 676 *48(9th Cir. 1975) interpreting the Treaty. It is worth noting that the Treaty does not guarantee the tribes “any constant quantity of fish, but merely equal access to fishing grounds” in common with all citizens of the [Washington] territory. The Treaty thus does not provide an independent basis for arguing that the flow of the river is required to be maintained at any particular level and gives additional support to considering the matter in a separate proceeding.
The statutory provisions which form the basis for these two issues, read as follows: Federal Power Act, § 3(2), 16 U.S.C. § 796(2) in pertinent part:
(2) ‘reservations’ means national forest, tribal lands embraced within Indian reservations, military reservations, and other lands and interests in lands owned by the United States, and withdrawn, reserved, or withheld from private appropriation and disposal under the public land laws;
Federal Power Act, § 4(e), 16 U.S.C. § 797(e) in pertinent part:
Provided, That licenses shall be issued within any reservation only after a finding by the Commission that the license will not interfere or be inconsistent with the purpose for which such reservation was created or acquired, and shall be subject to and contain such conditions as the Secretary of the department under whose supervision such reservation falls shall deem necessary for the adequate protection and utilization of such reservations. (Emphasis supplied).
Federal Power Act, § 10(a), 16 U.S.C. § 803(a):
(a) That the project adopted, including the maps, plans, and specifications, shall be such as in the judgment of the Commission will be best adopted 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 water-power 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. (Emphasis supplied). The Wild and Scenic Rivers Act, § 7(b), 16 U.S.C. § 1278(b) in pertinent part: Construction projects on rivers designated for potential addition to system— (b) The Federal Power Commission shall not license the construction of any dam, water conduit, reservoir, powerhouse, transmission line, or other project works under the Federal Power Act, as amended, on or directly affecting any river which is listed in section 1276(a) of this title, and no department or agency of the United States shall assist by loan, grant, license, or otherwise in the construction of any water resources project that would have a direct and adverse effect on the values for which such river might be designated, as determined by the Secretary responsible for its study or approval —(Emphasis supplied).
Section 5(a)(24) of The Wild and Scenic Rivers Act, 16 U.S.C. § 1276(a)(24) designated portions of the Skagit River System approximately 11 miles below City’s Ross, Diablo and Gorge developments for potential addition to the Wild and Scenic Rivers System established by the Act. During the Commission’s consideration of High Ross, the Lower Skagit was a “study river” and the above cited provisions of § 7(b) applied to the Commission’s exercise of its jurisdiction. Section 7(a) which is applicable to rivers already designated as part of the natural wild and scenic rivers system likewise prohibits the licensing of construction projects having “a direct and adverse effect on the values for' which such river was established, as determined by the Secretary charged with its administration.” Section 7(a) goes on to read:
Nothing contained in the foregoing sentence shall preclude the licensing of, or assistance to, developments below or above a wild, scenic or recreational river area or on any stream tributary thereto which will not invade the area or reason*49ably diminish the scenic, recreational, and fish and wildlife values present in the area on October 2, 1968. (emphasis supplied)
The Secretary of the Interior or, where national forest lands are involved, the Secretary of Agriculture, are secretaries having jurisdiction to make determinations under the WSRA prior to licensing.
This brief reference to the applicable statutes serves to highlight matters concerning the primary jurisdiction13 of the Commission to approve the High Ross amendment. In presenting the issues of the Commission’s compliance with the specific statutory mandates of § 4(e) of FPA and § 7(b) of the WSRA, there are also raised difficult questions of statutory interpretation as well as policy questions concerning the participation of several executive departments in accommodating the public interest in the production of energy and in the conservation and protection of our natural resources.
On December 3,1979 and following argument before the court on the various petitions to review the Commission’s orders, the Secretaries of the Interior and Agriculture were given time to file a joint brief as amici curiae raising the question “whether, in the context of this case, this Court need to resolve certain issues regarding the respective areas of jurisdiction and authority as between the Commission and the executive departments” under the WSRA and the FPA “where those issues are currently being considered in Commission proceedings in which the appropriate executives are participating.” Amici Brief, p. 3. In summary, both departments, without taking a position on the merits of the Commission’s orders, urge that we need not consider the issues presented by § 4(e) and § 7(b) in the present proceeding because the matter of downstream impacts is now the subject of two separate proceedings in which both departments have intervened, i. e., the separate proceeding ordered in Order No. 808-A and the proceeding to consider the renewal of the permit for Project No. 553 in which proceedings the jurisdiction of both departments to impose conditions will be an important issue.
Both the FERC and City support the position of the amici for substantially the same reasons. As to the § 4(e) issue, both assert that the review provisions of § 313(b) foreclose our consideration of this issue because it was not raised by the Tribes on rehearing and Interior has sought no review in this proceeding. Section 313 of the FPA provides the general framework for rehearings before the Commission and for court review of Commission orders. More specifically, § 313(b) provides in pertinent part:
No objection to the order of the Commission shall be considered by the Court unless such objection shall have been before the Commission in the application for rehearing unless there is reasonable ground for failure to do so.
The record is devoid of any claim which would excuse the failure to raise the § 4(e) issue upon rehearing. Instead, we are being asked to rule on a question having an important bearing on the Commission’s authority without such question being first addressed to the Commission. This we decline to do. It is clear, therefore, that we should not now reach out to consider a matter which the plain wording alone of the statute forbids our doing.
As to the § 7(b) issue, both FERC and City point out that the Commission found that High Ross will have no impact on downstream flows and will not diminish fish and wildlife values and that Interior and Agriculture, while insisting on their *50right to impose conditions, have not sought review of said findings and therefore are bound thereby. On a more practical level, Commission staff on July 20, 1979 met in Seattle with the parties to discuss issues concerning downstream flows. As a result, the staff reported that “progress was made toward an agreement that would provide controlled flows downstream from Gorge Dam while the parties conduct cooperatively the fishery and power studies necessary to compile an adequate factual record as the basis for deciding on the long term solution to the issues.” Report of Commission Staff to Parties, August 29, 1979, Attachment 6 to City’s Response to Amici Brief. In short, the § 7(b) issue, whatever is present validity before this court, may very well become a non-issue in the two separate proceedings pending before the Commission.
In response, the Tribes insist that we must decide the § 4(e) question and dismiss the Interior and Agriculture positions as “inexplicable,” characterizing the separate proceedings as “a colossal waste of time.” The American and Canadian intervenors in a more detailed response assert that the § 7(b) claims are based on issues of law which can be decided on the present record. Admitting that Interior and Agriculture failed to present their positions before the Commission (as well as failing to ask review of the Commission’s orders), they suggest that we decide this legal issue without reference to the position of the two executive departments and, as an alternative, invite further briefing on this issue to ascertain such position. It seems to us that the § 7(b) issue can only be decided in the context of a full factual record reflecting not only the legal position of Interior and Agriculture but also the precise conditions which the two departments claim authority to impose under § 7(b). They also claim that Interior and Agriculture, in asking us to pass up a decision on the § 4(e) issue, did not seek to avoid a decision by this court that the Commission’s alleged failure to develop a comprehensive plan, which considers the matter of downstream flows and their effect on the economic benefits of High Ross, violates § 10(a) as well as NEPA. At bottom, these intervenors fear that approval of High Ross, before the proper downstream flows are determined in separate proceedings, will permit City to proceed with construction and will prevent the Commission from making a decision increasing downstream flows because such an increase would undermine the economic justification for High Ross. In other words, the ability of intervenors to prevail ultimately, particularly in the matter of increasing downstream flows, would be seriously prejudiced.
Despite the superficial appeal of intervenors’ argument we cannot agree. Aside from the failure of the Tribes to pursue the § 4(e) issue at a rehearing and the inaction of Interior and Agriculture in failing to ask for a review of the Commission’s finding that High Ross will have no effect on downstream flows below Gorge, we are faced with a formal request from Interior and Agriculture that we need not reach these two issues in the context of this case. Implicit in this request is the recognition that §§ 4(e) and 7(b) raise basic questions concerning the respective areas of jurisdiction and authority as between the executive departments and the Commission which cannot be presently decided on the present record. The request further emphasizes that this record will be implemented in two separate proceedings, in which Interior and Agriculture have intervened and will present their respective positions. Under these circumstances, we believe that prudential considerations as well as interests of judicial economy require that we abstain from treatment of the §§ 4(e) and 7(b) issues in this review. This leads us to the next issue raised by the Tribes and American and Canadian intervenors.
4. The Propriety of the Commission’s Action in Instituting a Separate Proceeding to Consider the Matter of Downstream Flow Releases
It is the position of the intervenors that the Commission should have reopened the record to consider “evidence as to the effects of the proposed minimum flow re*51quirements on power production from Ross Dam and recreational opportunities there. R 17105.” American Intervenors Brief, p. 30. The Commission refused to reopen the record and initiated a separate proceeding to consider the matter of downstream flows. Intervenors claim that the downstream flow issue should have been considered and decided in the present proceeding and, in effect, that Commission acted improperly in deferring this matter for consideration in a separate proceeding.
The record shows that after Opinion No. 808 was issued (July 5, 1977) and three years after the record was closed, Interior proposed that certain minimum flow requirements be attached to City’s license. The American intervenors at this point moved to reopen the record to consider Interior’s proposals. In Opinion No. 808-A, the Commission denied the request to reopen because, having found that High Ross will have no effect on downstream flows, it concluded that “the question of flow releases is not an issue in this proceeding.” R 16964. At the same time, it recognized that the matter of downstream flows was a continuing problem and the possible necessity and appropriateness of the Interior’s proposed conditions.14 Accordingly, it set the matter down for consideration in a separate proceeding.
Given the fact that Interior’s proposals had been filed seven years after the proceeding was commenced and more than three years after the record was closed and having found that the matter of downstream flows would not be affected by the construction of High Ross, the Commission determined to approve the amendment, at the same time ordering a separate proceeding.
It is well-settled that administrative agencies enjoy a broad discretion in the manner of carrying out their statutory functions and responsibilities. As the Supreme Court recently said in Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519, 543 — 4, 98 S.Ct. 1197, 1211, 55 L.Ed.2d 460 (1978):
Absent constitutional constraints or extremely compelling circumstances the “administrative agencies ‘should be free to fashion their own rules of procedure and to pursue methods of inquiry capable of permitting them to discharge their multitudinous duties.’ ” (citations omitted). Indeed, our cases could hardly be more explicit in this regard.
See also FPC v. Transcontinental Gas Pipe Line Corp., 423 U.S. 326, 333, 96 S.Ct. 579, 583, 46 L.Ed.2d 533 (1976).
In the factual context of this case, the Commission’s action in instituting a separate proceeding to consider the matter of downstream flow releases was well within the agency’s discretion. Intervenors’ position to the contrary is without substance.
5. The Issues Concerning Compliance With the Requirements of the National Environmental Policy Act (NEPA)
American and Canadian intervenors, both being represented by the same counsel, attack the Commission’s action for failure to meet the requirements of NEPA. The Canadian intervenor’s principal interest is in the preservation of 4720 acres extending over approximately seven miles in the Upper Skagit River Valley in Canada which the construction of High Ross would flood. The American intervenors, while concerned with the inundation of five miles of the Big Beaver Valley in the United States, concentrate on the failure of the Commission to give adequate consideration to the matter of other alternatives, particularly that of a lower dam at Ross. We now consider each of these challenges.
A. The Impact in Canada
When City applied in 1970 for the amendment to permit construction of High Ross, *52the United States and Canada requested the IJC to investigate and report on the environmental effects in Canada resulting from raising the level of Ross Lake and to make such recommendations to the Commission as were appropriate for the protection of the environment in Canada. The IJC report,15 consisting of 191 pages, gave thought to the method of analysis concerning the numerous aspects of this assignment and the procedure to be followed. It stated at the outset of its report (pp. 10-11):
It was clear that the nature of the environmental and ecological consequences could be established in terms of the impact of the proposed reservoir on various components of the environment — land, water, flora and fauna. But forecasting these effects would provide no guidance as to their importance or significance. To report on the scope and impact of the consequences, further dimensions were added to the inquiry. These reflect both the amount and value of human uses associated with the environment. To compare the uses which would be possible ‘with’ and ‘without’ High Ross Reservoir, the amount and value of each use was estimated and the difference in total value of uses supported by the Valley was taken as an indication of the scope or impact of the consequences of the reservoir.
The IJC report considers in detail the potential effects of the flooding to be caused by High Ross and the possible protection and enhancement of the Valley. In so doing, it evaluated the area resources, physiography, plant ecology, wildlife and fisheries and recreation and compared the possible uses “with” and “without” High Ross. Pointing out that this area is one of great natural beauty and “worthy of special attention” and conceding that the enlarged reservoir would have an important environmental impact, the IJC nevertheless concluded that the overall detrimental effect in Canada of the proposal would not be substantial (pp. 28-29):
The present characteristics of the environment would be changed, but the new environment would retain many of the former characteristics. Those who appreciate and use the Valley in its present state would inevitably suffer somewhat, although other people would find the new environment at least as pleasant. Measured either by the amount of use, or weighted by dollar values, the overall impact of changes in the total environment is not significantly large.
The Commission staff prepared and released a draft environmental impact statement (DEIS) in October, 1973, to which it attached as an Appendix the IJC report concerning the Canadian environmental impact. After analyzing the comments on the DEIS, the staff released its final EIS (FEIS) in March, 1974 which cross-referenced the IJC report. Thereafter in April, 1974, the lengthy hearings were commenced which were concluded in March, 1975. At these hearings, the EIS and IJC reports were made a part of the record as were other studies submitted on the record which analyzed the Canadian impact of High Ross. The Commission in considering this question of Canadian impacts was not limited to the FEIS alone. It could and did consider the subsequent testimony and exhibits introduced during 67 days of hearings. Greene County Planning Board v. FPC, 455 F.2d 412 (2d Cir. 1972), cert. denied 409 U.S. 849, 93 S.Ct. 56, 34 L.Ed.2d 90 (1972). More than a dozen of these witnesses focused on the matter of Canadian impacts. It was entirely appropriate to incorporate the IJC report as a part of the EIS. Inman Park Restoration, Inc. v. UMTA, 414 F.Supp. 99, 120 (N.D.Ga.1976), aff’d sub nom. Save our Sycamore v. MARTA, 576 F.2d 573 (5th Cir. 1978). To insist that the EIS must be prepared and considered in vacuo is to exalt procedural form over substance. To suggest the need of a supplemental EIS focusing specifically on the Canadian impact has an equally hollow ring. In 1974, such a *53motion by the American intervenors was denied without prejudice to being refiled should the parties “be able to demonstrate the existence of environmental impacts which are not covered by the final EIS and the IJC report.” Apparently none of the petitioners saw fit to renew such a motion.
That these impacts concerned the Commission is reflected in the numerous conditions, imposed by the Commission in Opinion No. 808, which relate to the project’s Canadian impacts, i. e., Article 54 (clearing of reservoir area in consultation with Canadian and Province agencies), Article 56 (Ross-Skagit fishery above the dam, requiring consultation with the British Columbia Fish and Wildlife Branch), Article 57 (wildlife resources and habitat, including preparation of a comprehensive plan), Article 58 (long range wildlife study) and Article 68 (recreational development in the Skagit Valley in Canada).
We can only conclude that both the ALJ and Commission gave careful consideration to the upstream effects of the larger reservoir on wildlife, fish and recreation both in the United States and Canada and took a “hard look” at these consequences. The record clearly shows that these effects were adequately evaluated in compliance with NEPA. The arguments of the Canadian intervenors that the Commission failed to do so are without merit.16
B. The Consideration of Alternatives
NEPA’s requirement that the agency’s “detailed statement” address alternatives to a proposed action “has been aptly characterized as ‘the linchpin of the entire impact statement.’ ” Alaska v. Andrus, 580 F.2d 465, 474 (D.C.Cir.1978), vacated in part sub nom. Western Oil & Gas Assn. v. Alaska, 439 U.S. 922, 99 S.Ct. 303, 58 L.Ed.2d 315 (1978). The consideration of such alternatives in sufficient detail is required under the Federal Power Act as the basis for a determination that a project will be “in the public interest.”
The American intervenors claim that the Commission failed to consider or consider adequately important alternatives in violation of the requirements of NEPA and the FPA. They have concentrated on three specific aspects in which they assert that Commission’s consideration does not meet the test of adequacy.
1. Construction of a lower dam
These intervenors argue that the added capacity for the project would be roughly the same at elevations 1725 or 1675. This, of course, is technically correct, because 525 MW of capacity would be produced at either elevation. They also point out that a lower dam and lower reservoir would cause less environmental damage by saving from inundation 3900 acres (out of 4720 acres) in the Skagit Valley in Canada and all or most of the Big Beaver Valley.
This alternative was not considered in the final EIS (R 10670-84). Apparently, American intervenors did not see fit to raise this subject by way of comment (R 10791-10820) and did so only in briefs to the Commission after the record was closed. The alternative of dams of lower elevations was mentioned in the comments from the Department of Interior, which comments, although received too late for analysis, were included in the EIS (R 10857). It received its first attention one year later during the testimony of American intervenors’ witness Teasley who was called on rebuttal during the closing days of the hearings “to discuss the economic implications of raising Ross dam.” (R 8600). The Initial Decision of the ALJ *54issued on February 4,1976 while addressing a number of alternatives to High Ross in considerable detail appears not to have directly considered the alternative to the 1675 elevation (R 16311-19). The ALJ concluded his consideration of alternative by stating (R 16318-19):
The above arguments of the intervenors are not convincing. The City needs the peaking capability of High Ross which is not as cheaply obtainable elsewhere. It is the value of High Ross’ peaking capability which makes it less expensive than any other peaking source combined with a based-load facility.
Intervenors failed to support their contentions to the contrary. The testimony of City and Staff show that proposed High Ross Dam is the most economic alternative for the City to obtain that ‘amount of power for its system. A review of the environmental impacts of all the more expensive alternatives indicates that they would have adverse effects in quantity and quality at least as significant if not more so than High Ross. Accordingly, Intervenors’ argument about the cost comparison is hereby rejected.
In Opinion No. 808, the Commission briefly discussed the 1675 elevation alternative and referred to it as a variation on the “No Action” alternative discussed in the EIS (R 16966-7). The EIS had disposed of the “No Action” alternative by stating (R 10676-7):
If an order approving the construction of the High Ross development is not issued by the Federal Power Commission, the Applicant and the Pacific Northwest would need to provide power from other sources to meet requirements as previously described. The Pacific Northwest Utilities Conference Committee’s West Group Forecast shows an annual firm load growth for the area during the 10-year period (July 1973-June, 1983) of approximately 5.8 percent for peak load and 5.4 percent for energy. High Ross project output amounts to 3.6 percent of the 10-year period incremental peak demand and 1.5 percent of the incremental energy.
In Opinion No. 808-A, the Commission concluded its discussion of this alternative with the following (R 17144-5):.
American Intervenors and R.O.S.S. continue to argue that the Commission has not fully explored alternatives to High Ross. American Intervenors say that the record is devoid of testimony or studies regarding the effects of raising the reservoir to 1675 feet of elevation, or any other alternate elevation between the present height and 1725 feet. They cite Aeschliman v. NRC, 547 F.2d 622, 628 (CADC 1976), in which the court said that where an intervenors’ comments on a draft EIS raises a colorable alternative not considered already, the Commission must undertake its own preliminary investigation of the proffered alternative to determine whether it is worthy of detailed consideration in the EIS, and the Commission must explain the basis for each conclusion that further consideration of a suggested alternative is unwarranted. The court said, however, that the preliminary investigation of an alternative need not be nearly as detailed as that required of alternatives which are considered in the Environmental Impact Statement (EIS), and that often a short explanation will suffice.
As discussed in Opinion No. 808, a Ross Dam at 1675 feet will not deliver the power available at 1725 feet and that appears to by why no study was made of the environmental impact of this or alternative levels. Further consideration of this variation of the City’s proposal is unwarranted. Contour maps in the record indicate that along most of the shoreline, because of the steep slopes, the fifty foot difference would not greatly affect the amount of the land flooded at the head of Beaver Canyon or at the northern end of the Canadian Skagit.17
*55In considering the validity of the Commission’s conclusion that “further consideration of this variation on City’s proposal is unwarranted,” we must accept the fact that City has an unchallenged need for additional energy. The annual firm load growth for the Northwest area for the 10 year period (July, 1973-June, 1983) has been shown to be 5.8% for peak load and 5.4% for energy and that the High Ross annual incremental output of 329,900,000 KWH of energy amounts to 3.6% of the incremental peak demand and 1.5% of the incremental energy. Pacific Northwest Conference Committee’s West Group Forecast. “Firm energy” is energy available at any time, even under adverse conditions; “peaking capacity” is the ability to supply energy during the hours of the highest daily, weekly, or seasonal loads. It is true that the total capacity of 525 MW would be produced at elevation 1675 as well as 1725. The additional capacity of both elevations results from the increased water pressure on the turbines caused by the higher water surface elevation of the reservoir. However, High Ross could maintain this capacity during a maximum drawdown of 56.2 feet to 1669 feet, where capacity would decrease by 5 MW. On the other hand, with an elevation of 1675 feet, the same maximum drawdown would lower the reservoir some 75 feet or less then the present maximum height of 1602.5 feet. More important, the 525 MW capacity at 1675 feet almost immediately would begin to decline to 450 MW. Low Ross’ decline in capacity would occur when Seattle usually has its highest loads and requires maximum peaking capacity. High Ross would convert the present project with an elevation of 1602.5 feet from one of variable capability to one of almost constant capability. The Commission properly concluded that a 1675 foot dam would not produce the dependable power available from High Ross and therefore would not be appropriate.
In summary, the Commission considered and rejected elevation 1675 as a reasonable alternative. It determined that the environmental differences resulting from the two elevations were minimal, that the differences in energy capacity were substantial, and that, for these reasons, extensive consideration of this alternative was unwarranted. We agree.
2. Delay in Construction
This alternative must fail because of the admitted power needs of City. It was considered by the ALJ and rejected (R 16338). Rather, the attention of the parties has focused on other alternatives available to meet the energy demands which were conceded by all. The alternative of delay was never in serious contention for this reason.18 With the passage of approximately nine years since City’s application was filed, the argument for further delay in construction has lost whatever validity it may once have had.
3. Alternative Power Sources
The EIS considered in detail various alternative types of electric power generation. These included combustion turbine, combined-cycle (combustion and steam turbines), base load oil fired, base load nuclear steam-electric plants, conventional hydroelectric plants and purchased power. The annual cost of the incremental energy from High Ross was estimated and compared with the costs of such energy produced by other sources of energy. The beneficial and detrimental environmental effects were carefully considered for each alternative. (R 10670-81). In addition, the EIS considered and rejected the pumped storage alternative as not realistic and, admitting the desirability of electrical energy conservation practices and their long range impor*56tanee, concluded that they would not eliminate the steady growth in energy demand and the need to expand capacity (R 10681-83). At the hearings, testimony indicated the permanent savings to be realized from City’s existing conservation program to be 1%. (R 6806).
Testimony further indicated that rate manipulation would have little effect on demand, demand being inelastic because the price of City’s electricity was so low that doubling of price would not affect consumption. (R 16967).
The ALJ reviewed the EIS study and, as stated previously (p. 28 supra), found that “it is the value of High Ross’ peaking capacity which makes it less expensive than any other peaking source combined with a base facility” and that “A review of the environmental impacts of all the more expensive alternatives indicates that they would have adverse effects in quantity and quality at least as significant if not more so than High Ross.” (R 16318-9). The Commission agreed and in Opinion No. 808-A summarized its position. (R 17145):
As to other alternatives, the purchase of power from the Bonneville Power Administration is subject to what we consider to be an unassured sufficiency of capacity, and certainly energy, existing in the Pacific Northwest.19 Other alternatives, such as steam and nuclear generation, are more expensive and as the FEIS points out, as well as supporting testimony, are subject to their own environmental problems. It is clear that the disadvantages of a fossil fuel or nuclear plant such as stack emissions, water heating, land clearing, mining, and loss of wildlife and recreation in the area cannot be mathematically compared with the disadvantages of High Ross. This is a matter of judgment. In our opinion, since the Ross Dam is already in place, it is likely that raising it would produce less impact on the environment than construction of a fossil-fuel or nuclear plant.
To conclude this aspect of our discussion, § 102(2)(C) of NEPA, 42 U.S.C. § 4332(2)(C) requires, “to the fullest extent possible,” the preparation of an EIS for “other major Federal actions significantly affecting the quality of the human environment.” The purpose of such a statement is to enable the decision maker to take a “hard look” at the environmental consequences and to provide the public and Congress with information concerning the environmental issues involved. In this case Commission staff prepared a draft EIS and sent copies of the same to the parties and numerous interested groups for comment. A final EIS reflecting these comments was prepared and made public. The bulk of the long record, including testimony, exhibits and studies, was directed to, and focused on, the environmental impacts of High Ross as compared with alternatives to such construction. Such alternatives were considered and analyzed in detail on the basis of an exhaustive record and a decision rendered. We are satisfied that the procedural requirements of NEPA were complied with.
With such a record of procedural conformity, our function as a court of review is a limited one. We are guided by the most recent instruction of the Supreme Court that we are confined to the sole question of whether the Commission considered the environmental consequences of its decision. The court stated in pertinent language:
In Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519, 558, [98 S.Ct. 1197, 1219, 55 L.Ed.2d 460] (1978), we stated that NEPA, while establishing ‘significant substantive goals for the Nation,’ imposes upon agencies duties that are ‘essentially procedural.’ As we stress in that case, NEPA was designed ‘to in*57sure a fully-informed and well-considered decision,’ but 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.’ Vermont, Yankee cuts sharply against the Court of Appeals’ conclusion that an agency, in selecting a course of action, must elevate environmental concerns over other appropriate considerations. On the contrary, once an agency has made a decision subject to NEPA’s procedural requirements, the only role for a court is to insure that the agency has considered the 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). See also FPC v. Transcontinental Gas Pipeline Corp., 423 U.S. 326, 96 S.Ct. 579, 46 L.Ed.2d 533 (1976). (footnote omitted).
In the present case there is no doubt that HUD considered the environmental consequences of its decision to redesignate the proposed site for low-income housing. NEPA requires no more. The judgment of the Court of Appeals is therefore reversed.
Strycker’s Bay Neighborhood Council, et al. v. Karlen (3 cases), 444 U.S. 223, 100 S.Ct. 497, 62 L.Ed.2d 433 (1980).
In short, no arbitrary action having been claimed or shown and having found that the Commission fully considered the environmental consequences of its decision, we cannot interject ourselves “within the area of discretion of the executive as to the choice of the action to be taken.” On this record, we cannot substitute our judgment for that of the Commission.
For all of the foregoing, the Commission’s decisions in Opinions No. 800 and No. 800-A are
Affirmed.
. Opinion No. 808 issued July 5, 1977 and Opinion No. 808-A issued August 2, 1977.
. The functions of the Federal Power Commission (FPC) were taken over by the Federal Energy Regulatory Agency (FERC) on October 1, 1978 pursuant to Department of Energy Act, 42 U.S.C. § 7172. The term “Commission” is used interchangeably to refer to the FPC on actions prior to October 1, 1978 and to the FERC thereafter.
. Other named intervenors are three departments of the State of Washington, i. &, the Department of Ecology, the Department of Fisheries and the Department of Game. Of these three departments, only the Department of Ecology filed a brief herein, in which it asserted that the procedural requirements of the National Environment Policy Act (hereinafter NEPA) had been complied with and urged affirmance of the Commission’s orders.
. 41 Stat. 1063, as amended, now Part I of the Federal Power Act, 16 U.S.C. §§ 79a, et seq. as amended.
. The Commission specifically found: “We therefore find that there is a regional need for High Ross power and a need for the power on the system of the City of Seattle.” Order No. 808, p. 19.
.Commission argues that the legislative history indicates that the Congress did not intend the WSRA to prevent the construction of High Ross. It quotes the Conference report in describing the purpose of an amendment to § 7 (Commission Brief, pp. 48-9):
Section 7: This section is amended to make clear that water developments above or below a wild, scenic or recreational river area which do not “unreasonably” diminish its values are not prohibited. In this connection, reference is made to the Skagit River.
1968 U.S.Code Cong. & Admin.News, p. 3854.
. Hearings on S. 1321 before the Subcommittee on Parks and Recreation of the Senate Com. on Interior and Insular Affairs, 90th Cong., 1st Sess., at 12 (1967).
. The Tribes’ petition to intervene also noted that they were in the process of preparing evi*46dence to support their claim of impairment to the downstream fishing rights caused by Project No. 553, which they planned to present in the separate relicensing proceedings which were to follow the expiration date of City’s original 50 year license granted in 1927.
. Petitioners or petitions raising a particular issue indicated in parenthesis.
. Such a license was issued in this case at the time City’s 50 year license expired in October, 1977.
. Art. V of the Treaty, 12 Stat. 927, provides: The right of taking fish at usual and accustomed grounds and stations is further secured to said Indians in common with all citizens of the Territory, and of erecting temporary houses for the purpose of curing, together with the privilege of hunting and gathering roots and berries on open and unclaimed lands. Provided, however, that they shall not take shell-fish from any beds staked or cultivated by citizens.
. The Upper Skagit and Sauk-Suiattle Tribes were parties to the Treaty. The Swinomish Reservation is apparently not a separate tribe but a tribal reservation which many tribes, including a majority of the Sauk-Suiattle and some of the Skagit Tribes, presently occupy. In modern times, there are about 30 Sauk-Suiattle Indians, who fish for their personal use but not commercially. Similarly, there are about 30 Upper Skagit Indians interested primarily in subsistence fishing. Their “usual and accustomed fishing places” include “numerous areas along the Skagit River, extending from about Mt. Vernon upstream to Gorge Dam.” United States v. State of Washington, 384 F.Supp. 312, 376, 379.
. Our use of the term “primary jurisdiction” reflects our understanding of the entire statutory scheme which places on the Commission the obligation to see to it “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 . . EPA, § 10(a), 16 U.S.C. § 803(a). It is the Commission’s position that its mandate under this provision requires it “to exercise its judgment in determining the extent to which it will include a Secretary’s proposed conditions in a license.” Opinion No. 36, Escondido Mutual Water Co., Project No. 176, (issued Feb. 26, 1979) slip op. pp. 95-108.
. In refusing to reopen, the Commission found: “That is not to say that Interior and the Tribes do not raise substantial points with respect to a higher rate flow below the Gorge Dam, but it is clear that increasing the height of the Ross Dam will not affect the flow regime. (R 17152). (emphasis supplied).
. The IJC report is entitled “Environmental and Ecological Consequences in Canada of Raising Ross Lake in Skagit Valley to Elevation 1725.”
. We are aware that the Canadian Parliament by unanimous resolution has expressed its opposition to the flooding of the Skagit Valley and that the Canadian government has addressed two letters to the State Department expressing this opposition. This opposition does not deprive the. IJC of its jurisdiction under the treaty and the State Department has indicated that it saw “no reason why the [Commission] should not proceed expeditiously to exercise its domestic regulatory responsibilities in this case.” (R 16873). Also, under the British North America Act 1867, 4 Halsbury’s Statutes of England, 205 (3rd ed.), the “management ... of public lands belonging to the province,” is made a subject of exclusive provincial legislation. Id., 92(5).
. American intervenors have claimed that a lower dam with elevation 1675 would save 3900 acres from inundation. City argues that because of the steep slopes shown on the con*55tour maps, only some 1900 acres would be saved from flooding and therefore that the environmental consequences of a dam at either elevation were not as significant as American intervenors claim. Brief of Intervenor City, p. 31.
. The comments on the DEIS do not mention delay as an alternative (R 10685-97) and American intervenors apparently did not argue delay in construction as an alternative prior to this appeal.
. In dismissing the purchase of BPA power as a “proper alternative” to High Ross, the ALJ pointed out that BPA power is more expensive (using any reasonable discount rate) and that supplying such power to City would require BPA to deprive other customers, who as a consequence would be required to expand their facilities and meet their own environment problems. He stated that “Pacific Northwest will have a deficit of peaking power through the next 20 years even with High Ross and all the peaking power BPA can obtain by adding units to federal dams.” (R 16314).