Full opinion text
OPINION BERZON, Circuit Judge: We consider challenges to the decision of the Secretary of the Interior to withdraw from new uranium mining claims, for up to twenty years, over one million acres of land near Grand Canyon National Park. Determining the appropriate balance between safeguarding an iconic American natural wonder and permitting extraction of a critically important mineral is at the heart of the present dispute. The fission of uranium atoms into smaller component parts releases a huge amount of energy—enough to sustain a nuclear chain reaction, as scientists discovered in the first half of the last century. The design and construction of nuclear reactors and weaponry followed. In the ensuing years, uranium became, at times, highly valuable, though prices rose and fell dramatically in response to swings in demand. Uranium also entered the cultural lexicon. In 1947, large quantities of uranium were discovered in Arizona near Grand Canyon National Park, a treasured natural wonder and World Heritage Site—called, by John Wesley Powell, “the most sublime spectacle in nature.” John Wesley Powell, Canyons of the Colorado 394 (1895). Northern Arizona saw limited uranium mining until a spike in uranium prices in the late 1970s led to a uranium mining surge in the 1980s and 1990s, when six new mines opened. But the mining boom did not last. With the collapse of the Soviet Union and consequent decommissioning of large numbers of nuclear warheads, demand for uranium dropped dramatically in the 1990s. Uranium production in much of northern Arizona stopped. Prices spiked again in 2007, and renewed interest in mining operations in the 'region followed. With that resurgence came concerns about the environmental impact of the extraction of radioactive materials such as uranium. Reflecting those ■ concerns, then-United States Secretary of the Interior (“the Secretary”)- Kenneth L. Salazar published a Notice of Intent in the Federal Register to withdraw from new uranium mining claims, for a period of up to twenty- years, a tract of nearly one million acres of federally owned public land. See Federal Land Policy and Management Act of 1976 (“FLPMA”) § 204(c), 43 U.S.C. § 1714 (authorizing the Secretary to make, revoke, or modify such withdrawals subject to certain conditions). After an extended study period, the Secretary issued a Record of Decision (“ROD”) in January 2012 announcing, the withdrawal of 1,006,546 acres. Several entities and one private individual opposed to the withdrawal challenged the Secretary’s decision in four separate actions filed in the District of Arizona. Parties interested in supporting the withdrawal moved to intervene, including four environmental groups and the Havasupai Tribe. The district court, in two well-crafted opinions, rejected the various challenges to the withdrawal. I. Background We begin with a brief history of-the political and legislative backdrop against which FLPMA was enacted in 1976. .The Property Clause of the U.S. Constitution vests in Congress the “power to , dispose of and make all needful rules and regulations respecting ... property belonging to the United States,” including federally owned public lands. U.S. Const,, Art. IV, § 3,, cl. 2. Congress has long used its authority under the Property Clause to permit the purchase of mining rights and exploration on federal lands, most notably in the General Mining Act of 1872, 30 U.S.C. §§ 22-54. Under .that Act, “all valuable mineral deposits in lands belonging to the United States, both surveyed and un-surveyed, shall be free and open to exploration and purchase.” 30 U.S.C. § 22. From early on, the executive branch has asserted and exercised the authority to withdraw federally owned lands from claims for mineral extraction. See United States v. Midwest Oil Co., 236 U.S. 459, 469-72, 35 S.Ct. 309, 59 L.Ed. 673 (1915). As Midwest Oil recognized, although Congress had delegated no “express statutory authority”- to withdraw previously available land from mineral exploitation, the executive branch had made a “multitude” of temporary such withdrawals, and Congress had “uniformly and repeatedly acquiesced in the practice." Id. at 469-71, 35 S.Ct. 309. That -acquiescence, Midwest Oil held, constituted an “implied grant of power” from Congress to. the executive permitting withdrawal of public lands from mineral extraction claims. Id. at 475, 35 S.Ct. 309. For decades after Midwest Oil, Congress did little to restrain the .executive’s withdrawal authority, and the executive branch made liberal use of it. After World War II, however, demand for the commercial use of public land increased considerably. To address that increased demand) Congress in 1964 established the Public Land Law Review Commission (“PLLRC”), composed of several members of Congress and presidential appointees, to conduct a comprehensive review of federal land law and policy and propose suggestions for more efficient administration' of public lands. After several years of study the PLLRC issued a report-making 137 specific recommendations to Congress concerning the use and governance of public lands. PLLRC, One Third of the Nation’s Land ix-x, 9 (1970) (hereinafter “PLLRC Report”). The PLLRC Report observed that the roles of Congress and the ' executive branch with respect to public land use had “never been carefully defined,” and recommended that Congress pass new legislation specifying the precise authorities delegated to the executive for land management, including withdrawals. Id. at 43, 44, 54-55. The Report also recommended that “large scale limited or single use withdrawals of a permanent or indefinite term” should be within Congress’s exclusive control, while “[a]ll other withdrawal authority should- be expressly delegated with statutory guidelines to insure proper justification for proposed -withdrawals, provide for public participation in their consideration, and establish criteria for Executive action.” ' Id. at 54 (emphasis added). The Report, did not recommend a legislative veto over any withdrawal authority delegated to the executive. In response to the PLLRC’s recommendations, Congress in- 1976 • enacted FLPMA. FLPMA declares as the policy of the United States that “Congress exercise its constitutional authority to withdraw or otherwise designate or dedicate Federal lands for specified purposes and that Congress delineate the extent to which the Executive may withdraw lands without legislative action,” 43 U.S.C. § 1701(a)(4); that “in administering public land statutes and exercising discretionary authority granted by them, the Secretary be required to establish comprehensive rules and regulations after considering the views of the general public[,] and to structure adjudication procedures to assure adequate third party participation, objective administrative review'of initial decisions, and expeditious decisionmaking,” 43 U.S.C. § 1701(a)(5); that “goals and objectives be established by law as guidelines for public land use planning, and that management be on the basis of multiple use and sustained yield unless otherwise specified by law,” 43 U.S.C. § 1701(a)(7); and that “the public lands be managed in a manner that will protect the quality of scientific, scenic, historical, ecological, environmental, air and atmospheric, ■ water resource, and archeological values; [in a manner] that, where appropriate, will preserve and protect certain public lands in their natural condition; [in a manner] that will provide food and habitat for fish and wildlife and domestic animals; and [in a manner] that will provide for outdoor recreation and human occupancy and use,” 43 U.S.C. § 1701(a)(8). As relevant here, FLPMA eliminates the implied executive branch withdrawal authority recognized in Midwest Oil, and substitutes express, limited authority. See Pub. L. 94-579, § 704, Oct. 21, 1976, 90 Stat. 2743, 2792. It reserves to Congress the power to take certain land management actions, such as making or revoking permanent withdrawals of tracts of 5,000 acres or more (“large-tract” withdrawals) from mineral extraction. 43 U.S.C. § 17J4(c), (j). And it delegates to the Secretary of the Interior the power to make withdrawals of tracts smaller than 5,000 acres (“small-tract” withdrawals), whether temporary or permanent, 43 U.S.C. § 1714(d), and to make temporary withdrawals of large-tract parcels of 5,000 acres or more, 43 U.S.C. § 1714(c). For all withdrawals, whether small- or large-tract, FLPMA requires that the Secretary publish notice of the proposed withdrawal in the Federal Register; afford an opportunity for public hearing and comment; and obtain consent to the withdrawal from any other department or agency involved in the administration of the lands proposed for withdrawal. 43 U.S.C. § 1714(b), (h), (i). The statute also bars the Secretary from further delegating his or her withdrawal authority to any individual outside the Department of the Interior, or to any individual within the Department who was not appointed by the President and confirmed by the Senate. 43 U.S.C. § 1714(a). FLPMA circumscribes the Secretary’s temporary large-tract withdrawal authority in three ways relevant here. First, the Secretary may make large-tract withdrawals lasting no longer than twenty years. Second, no later than the effective date of any withdrawal, the Secretary must furnish a detailed report to Congress addressing twelve specific reporting requirements. 43 U.S.C. § 1714(c)(2). Third, FLPMA provides that Congress retains legislative veto power over any large-tract withdrawal. 43 U.S.C. § 1714(c)(1). FLPMA also contains a severability clause: “If any provision of this Act or the application thereof is held invalid, the remainder of the Act and the application thereof shall not be affected thereby.” FLPMA § 707, 90 Stat. at 2794, (codified at notes to 48 U.S.C. § 1701). Congress has never exercised its authority under FLPMA to veto a large-tract withdrawal. In 1983, the Supreme Court in I.N.S. v. Chadha, 462 U.S. 919, 959, 103 S.Ct. 2764, 77 L.Ed.2d 317 (1983), declared one variety of legislative veto provision unconstitutional. Since Chadha, Congress has not amended FLPMA to limit the Secretary’s withdrawal authority further. A. The Northern Arizona Withdrawal Uranium, often found within “breccia pipes”—cylinder-shaped deposits of broken sedimentary rock stretching thousands of feet underground—was first discovered near Grand Canyon National Park in 1947. Only limited uranium mining occurred in Northern Arizona until uranium prices increased in the late 1970s. After that, in the 1980s and 1990s, miners extracted 1,471,-942 tons of uranium from six new mines. A second spike in the price of uranium in 2007 generated renewed interest in mining operations near the Grand Canyon, manifested in the submission of thousands of new claims. The large volume of new claims sparked concerns about the potential environmental impact of increased uranium mining on the Grand Canyon watershed. Uranium mining has been associated with uranium and arsenic contamination in water supplies, which may affect plant and animal growth, survival, and reproduction, and which may increase the incidence of kidney damage and cancer in humans. See, e.g., National Primary Drinking Water Regulations, Radionuclides, 65 Fed. Reg. 76,708 (Dec, 7, 2000). In response to local concerns, Arizona Congressman Raul Grijalva introduced legislation in March 2008 seeking permanently to withdraw over one million acres of federal land abutting Grand Canyon National Park, on the northern side (North Parcel), northeastern side (East Parcel), and southern side (South Parcel) of the Park. Rep. Grijalva’s proposed legislation was not enacted. In 2009, Secretary Salazar published a Notice of Intent in the Federal Register declaring that he proposed to withdraw from new uranium mining claims an area nearly identical to that covered by the Grijalva bill. Notice of Proposed Withdrawal and Opportunity for Public Meeting, 74 Fed. Reg. 35,887 (July 21, 2009). In compliance with FLPMA’s command, the Secretary stipulated that any agency action would be “subject to valid existing rights.” Id.; FLPMA § 701(h), 90 Stat. at 2786 (codified at notes to 43 U.S.C. § 1701). The Notice of Intent had the immediate effect of withdrawing the land from new uranium mining claims for two years while the agency studied the anticipated impact of the proposed withdrawal. 74 Fed. Reg. at 35,887. In fulfillment of the Interior’s obligation under the National Environmental Policy Act (“NEPA”), 42 U.S.C. § 4332, the Bureau of Land Management (“BLM”), an agency within the Department of the Interior, prepared an Environmental Impact Statement (“EIS”) examining the potential environmental impact of the withdrawal. The EIS declared that the underlying purpose of the withdrawal was protecting the “Grand Canyon watershed from adverse effects of ... mineral exploration and mining” other than those “stemming from valid existing rights.” 74 Fed. Reg. at 43,152-53. To inform the EIS, BLM requested a full report from the United States Geological Survey (“USGS”) analyzing soil, sediment, and water samples in the proposed withdrawal area. ■In response, USGS prepared Scientific Investigations Report 2010-5025 (the “USGS Report”). To prepare its report, USGS examined 1,014 water samples from 428 different sites. It found that 70 samples “exceeded the primary or secondary' maximum containment levels” for certain ions and trace elements, including uranium and other heavy metals. The agency also analyzed soil and sediment samples from six sites north of the Grand Canyon, including reclaimed uranium mines, approved mining sites where mining had been suspended, and exploratory sites (sites where there had been drilling but not mining).. Consistently high concentrations of uranium and arsenic were discovered at these sites. Water samples from fifteen springs and five wells contained’ dissolved uranium levels beyond the maximum allowed by the Environmental Protection Agency (“EPA”) for drinking water. The USGS Report observed that fractures, faults, sinkholes, and breccia pipes occurred throughout the region and were potential pathways for contaminants, including uranium and arsenic, to migrate through groundwater. The Report acknowledged, however, that the available data , on these pathways was “sparse .., and often limited,” and that more investigation would be required fully to understand groundwater flow paths and the potential impact of uranium mining. BLM relied heavily on the USGS Report in preparing fits EIS. It used the findings of the USGS Report, as well as additional data gathered during its own two-year study, to assess the risk to five different water resources. These resources included springs and wells connected to perched aquifers; springs and wells connected to the Redwall-Muav aquifer (“R-aquifer”), the main deep aquifer within the Grand Canyon watershed;' and surface waters. BLM issued a draft EIS in February' of 2011; the draft EIS remained open for public comment for, 75 days. Interior received over' -296,339 comment submittals, from which it.extracted over 1,400 substantively distinct comments. See Notice of Availability of the Northern Arizona Proposed Withdrawal Final Environmental Impact Statement, 76 Fed. Reg. 66,747, 66,748 (Oct. 27, 2011). After reviewing these comments, Interior submitted its final EIS on October 27,2011. In addition to its public comment process, Interior designated several affected counties in Arizona and Utah (“the Counties”) as cooperating agencies, and solicited their input. Based in part on the Counties’ public comments on the draft EIS, Interior requested further, analysis of the anticipated economic effect of the withdrawal and consulted with county representatives. Interior also' organized five meetings with cooperating agencies, including the Counties, as well as two public meetings in the region. The final EIS and ROD discussed four different withdrawal alternatives. Alternative A was .to take no action at all, allowing new mining. claims and .development to proceed unhindered. Alternative B was to withdraw the full tract of roughly one million acres from new mining claims. Alternative C was to withdraw a substantially smaller tract of roughly 650,000 acres, which would have excluded 120,000 acres in the North Parcel. outside the Grand Canyon watershed, as well as 80,000 additional acres in the North Parcel where groundwater is believed to flow away from Grand Canyon National Park. Alternative D was to withdraw an even smaller area, roughly 300,000 acres. The USGS Report, final EIS, and ROD all acknowledged substantial uncertainty regarding water quality and quantity in the arpa, the possible impact of additional mining on perched and deep aquifers (including the R-aquifer), and the- effect of radionuclide exposure on plants, animals, and humans. The USGS Report, for example, recognized that “[a] more ’thorough investigation of water chemistry in the Grand Canyon region is required to better understand groundwater flow paths, travel times, and contributions from mining activities, particularly on the north side of the Colorado River, The hydrologic processes that control the distribution and mobilization of natural uranium in this hydrogeo-logic setting are poorly understood.” The ROD concluded, however, that there was sufficient data regarding dissolved uranium concentrations in the USGS Report to “inform a reasoned choice,” so the missing information was not essential to its decision. ■After weighing the data available, the ROD took a measured approach. It observed that a “twenty-year withdrawal will allow for additional data to be gathered and more thorough investigation of groundwater flow paths, travel times, and radionuclide contributions from mining.” Because of the uncertainty regarding the movement, of groundwater in the region, the ROD explained, Interior could not risk contamination of springs feeding'into the Colorado River. The ROD went on to explain that “the potential impacts estimated in the EIS due to the uncertainties of subsurface water movement, radionuclide migration, and biological toxicological pathways result in low probability of impacts, but potential high risk. The EIS indicates that the likelihood of a serious impact may be low, but should such an event occur, significant.” The final EIS and ROD also stated justifications for the withdrawal other than the risk of groundwater contamination. The ROD noted that “mining within the sacred and traditional places of tribal peoples may degrade the values of those lands to the tribes that use them,” that certain tribes believe “repeated wounding of the earth can kill their deities,” and that “damage to traditional cultural and sacred places is irreversible,” The ROD also observed that even if the proposed area were withdrawn in its entirety, eleven new mines could be developed during the twenty-year withdrawal period under valid existing rights. Given this potential for development of new mines, the expected rate of mining development over the ensuing twenty years would roughly match the rate of development at the time of the withdrawal. Any economic impact on local communities would thus not be severe. While recognizing that the level of mining that would go forward in the area during the withdrawal period -itself posed a risk of harm, the ROD concluded that additional mining presented a significant added threat to environmental safety and could endanger wildlife and human health. Finally, the agency stated that the “unique resources” within Northern Arizona, including the Colorado River, the Grand Canyon, and the “unique landscapes” of the region, support a “cautious and careful approach.” The ROD observed that “[w]hile the lands are withdrawn, studies can be initiated to help shed light on many of the uncertainties identified by USGS in [the USGS Report] and by BLM in the EIS.” B. This Litigation After the ROD issued, mining companies and local governments concerned about the economic impact of the withdrawal filed suit challenging the Secretary’s action. These parties (collectively “Plaintiffs” or “Appellants”) filed four separate suits, one or more of which maintained (1) that section 204(c)(1) of FLPMA, 43 U.S.C. § 1714, which confers on- the Secretary of the Interior the authority to make temporary large-tract withdrawals, contains an unconstitutional legislative veto provision not severable from the remainder of the subsection; (2) that the Secretary’s withdrawal was arbitrary and capricious, inconsistent with the administrative record, or otherwise not in accordance with FLPMA; (3) that the Secretary failed to comply with NEPA in approving the withdrawal; (4) that the withdrawal violated the Establishment Clause of the First Amendment; and (5) that the United States Forest Service acted arbitrarily and capriciously, or contrary to law, in granting its consent to the withdrawal. After the four cases were consolidated into a single action, Plaintiffs moved for summary judgment on the ground that the legislative veto provision within FLPMA was both unconstitutional and not severa-ble. As a result, Plaintiffs argued, there was no longer any statutory basis for the Secretary’s twenty-year large-tract withdrawal authority. Denying the motion, the district court held the legislative veto provision unconstitutional, but severable, leaving the Secretary’s challenged withdrawal authority intact. Yount v. Salazar, 933 F.Supp.2d 1215, 1243 (D. Ariz. 2013). After discovery, the parties all cross-moved for summary judgment. The district court granted summary judgment to Interior and Grand Canyon Trust, upholding the withdrawal against each of the plaintiffs’ challenges. The evidence in the record, particularly the USGS Report, final EIS, and ROD, supported the agency’s withdrawal decision, the district court concluded, and the agency did not exceed its statutory authority under FLPMA or NEPA. The district court also rejected the plaintiffs’ Establishment Clause challenge and their claim that Interior’s consultation with local counties and treatment of information gaps were inadequate under NEPA. This appeal followed. II. FLPMA’s Legislative Veto Provision The Supreme Court ruled definitively in Chadha that Congress may invalidate an agency’s exercise of lawfully delegated power in one way only: through bicameral passage of legislation followed by presentment to the President. 462 U.S. at 953-55, 103 S.Ct. 2764. FLPMA provides that Congress may invalidate a large-tract withdrawal announced by the Secretary by passing a concurrent resolution disapproving of the withdrawal within 90 days of the withdrawal’s effective date; the statute does not require presentment to the President. 43 U.S.C. § 1714(c)(1). We have little difficulty concluding that the legislative veto provision violates the presentment requirement, a conclusion with which all parties agree. Unlike in Chadha, the statutory legislative veto was not exercised by Congress in this case. Appellants maintain— and the government does not disavow— that the severability issue is nonetheless properly before us, as the Secretary’s withdrawal authority is at issue, and that authority would fall if the legislative veto were not severable from Congress’s broader delegation of power to the executive. Although not raised by the parties, there is an argument that because Congress did not invoke the legislative veto, the provision did not injure Appellants even if constitutionally invalid, and so the Appellants lack standing to challenge either it or the withdrawal provision’s continuing validity. Lujan v. Defs. of Wildlife, 504 U.S. 555, 560, 112 S.Ct. 2130, 119 L.Ed.2d 351 (1992); see, e.g., United States v. City of Yonkers, 592 F.Supp. 570, 576 (S.D.N.Y. 1984). That is, once the veto deadline passed, one could view the situation as if there were no veto available, in which case severability would, not piatter. Nonetheless, we conclude that Appellants do have standing to raise the sever-ability issue. We are presented here with an unresolvable ambiguity as to whether Congress declined to exercise its veto based on the merits of the Secretary’s withdrawal or based on the veto’s constitutional infirmity. Appellants’ merits argument is that the withdrawal authority would not exist at all without the veto provision in place, exercised or not. Appellants’ alleged injury—primarily, the inability to perfect new mining claims—is traceable to the exercise of that authority, and if their merits argument succeeded, could be redressed by invalidating the Secretary’s withdrawal authority. Chadha, 462 U.S. at 936, 103 S.Ct. 2764. We therefore turn to that merits argument. Invalid portions of a federal statute are to be severed “ ‘[u]nless it is evident that the Legislature would not have enacted those provisions which are within its power, independently of that which is not.’ ” Chadha, 462 U.S. at 931-32, 103 S.Ct. 2764 (quoting Buckley v. Valeo, 424 U.S. 1, 108, 96 S.Ct. 612, 46 L.Ed.2d 659 (1976)). “Generally speaking, when confronting a constitutional flaw in a statute, we try to limit the solution to the problem, severing any problematic portions while leaving the remainder intact.” Free Enter. Fund v. Pub. Co. Accounting Oversight Bd., 561 U.S. 477, 508, 130 S.Ct. 3138, 177 L.Ed.2d 706 (2010) (citation and internal quotation marks omitted). We must retain any portion of á statuté which is (1) “constitutionally valid,” (2) “capable of functioning independently” from any unconstitutional provision, and (3) “consistent with Congress’ basic objectives in enacting the statute.” United States v. Booker, 543 U.S. 220, 258-59, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005) (citation' and internal quotation marks omitted). This general principle applies with greater force when, as here, the statute in question contains a severability clause. “[T]he inclusion of such a clause creates a presumption that Congress did not intend the validity of the statute in question to depend on the validity of the constitutionally offensive provision.” Alaska Airlines, Inc. v. Brock, 480 U.S. 678, 686, 107 S.Ct. 1476, 94 L.Ed.2d 661 (1987). That presumption can be overcome only by “strong evidence” that Congress intended the entire relevant portion of the statute to depend upon the unconstitutional provision. Id. That the offending portion of FLPMA is a legislative veto provision further strengthens the severability presumption. There is an obvious substitute for the1 legislative veto: the ordinary process of legislation. Nothing (except the need to muster sufficient'votes) prevents Congress from revoking a large-tract withdrawal by passing legislation vacating the withdrawal, presenting the proposed legislation to the President, and (if necessary) overriding the President’s veto. Notably, none of the Appellants have cited any case holding that a legislative veto provision could not be'severed where the statute in question contained a severability clause, nor have we found one. Moreover, the language and structure of ■ FLPMA and the legislative history underlying the statute do not provide the requisite “strong evidence*” that the Secretary’s authority to make large-tract withdrawals rises and falls with Congress’s veto power over those withdrawals. To the contrary, the limited delegation of large-tract withdrawal authority is fully “consistent with Congress’ basic objectives” in enacting FLPMA even if there is no legislative veto option. Booker, 543 U.S. at 259, 125 S.Ct. 738. First, Congress in FLPMA imposed significant limitations on the Secretary’s withdrawal authority and provided for congressional oversight over executive withdrawals by means other than the legislative veto. For example, Congress reserved to itself the exclusive authority to make permanent large-tract withdrawals, limiting the Secretary’s large-tract withdrawals to no more than twenty years. 43 U.S.C. § 1714(c)(1). Although large-tract withdrawals can be renewed after the twenty-year term expires, the twenty-year term ensures that the renewal decision would necessarily have to be made by a different presidential administration and, almost surely, a different Secretary of the Interi- or. Congress in FLPMA also limited the Secretary’s power to delegate withdrawal authority to subordinates, restricting that delegation to officers appointed by the President and confirmed by the Senate. 43 U.S.C. § 1714(a). And for large-tract withdrawals, FLPMA requires not only that the Secretary provide timely notice to Congress (enabling Congress to address the proposed withdrawal legislatively if it so chooses), but mandates that the Secretary issue a detailed report addressing twelve specific issues .of concern. 43 U.S.C. § 1714(c)(2). The statute also delineates spécifíc requirements for public hearings concerning proposed withdrawals and requires publication in the Federal Register of such proposals. 43 U.S.C. § 1714(b), (h). The plethora of constraints on-the Secretary’s large-tract withdrawal authority—all of which remain in place—confirms that the legislative veto provision was only one of many provisions enacted to advance Congress’s broad oversight of the Secretary’s withdrawal decisions. Severing the legislative veto provision would leave the remaining limitations, and opportunity for congressional oversight and involvement, in place. The legislative history underlying FLPMA confirms this conclusion. As the district court observed, the PLLRC Report, on which Congress relied in passing FLPMA, was “equally concerned with enabling the Executive to act through controlled delegation as it was with preserving Congress’s reserved powers.” Yount, 933 F.Supp.2d at 1223. For example, the Report recommended, without mention of a legislative veto, that Congress “delineate] specific delegation of authority to the Executive as to the types of withdrawals and set asides that may be effected without legislative action.” PLLRC Report, at 2. And the Report recommended that all withdrawal authority other than “large scale limited or single use withdrawals of a permanent or indefinite term” be “expressly delegated.” Id. at 55. Similarly, the House Réport identified among the primary objectives of the legislation both establishing “procedures to facilitate Congressional oversight of public land operations entrusted to the Secretary of the Interior,” and endowing BLM with “sufficient authority to enable it to carry out the goals and objectives established by law for the public lands under its jurisdiction.” H.R. Rep. 94-1163, at 2 (1976). The House Report discussed the legislative veto only in the context of several other mechanisms for congressional oversight and limitations on the Secretary’s authority: the notice and reporting requirements, the limits on delegation, the consent requirement, the hearing requirement, and the temporal limitation. Id. at 9-10. Nor does the Conference Report suggest that the legislative veto was an essential component of the legislation. That Report referenced the legislative veto only in the context of delineating where the House bill (ultimately adopted) diverged from the Senate bill. And although several Members of Congress emphasized in their floor statements the importance of the bill’s oversight provisions during the floor debates, many other members, including several who voted for the legislation, expected the legislative veto to prove overly burdensome for Congress. At best, the legislative history of FLPMA is inconclusive as to whether a majority of the House would have opposed delegating large-tract withdrawal authority without the legislative veto. As with most legislation, FLPMA’s legislative veto provision represented a compromise between groups of lawmakers with divergent and sometimes competing interests. It is possible—perhaps even likely—that had Congress known in 1976 that the legislative veto provision was unconstitutional, a somewhat different legislative bargain would have been struck. Congress might, for example, have shortened the twenty-year term for temporary withdrawals, or decreased the acreage required to trigger FLPMA’s large-tract withdrawal provisions. But the question before us is not whether Congress would have drafted the statute differently in the absence of the unconstitutional provision. The question is whether “the statute’s text or historical context makes it evident that Congress ... would have preferred no statute at all.” Hamad v. Gates, 732 F.3d 990, 1001 (9th Cir. 2013) (internal quotation marks omitted); see Free Enter. Fund, 561 U.S. at 481, 130 S.Ct. 3138; Alaska Airlines, 480 U.S. at 685-86, 107 S.Ct. 1476. Given the recognized desire for executive authority-over withdrawals of federal lands from new mining claims—and given Congress’s preference regarding survival of that authority, as expressed in the severability clause—there is no indication, let alone “strong evidence,” Alaska Airlines, 480 U.S. at 686, 107 S.Ct. 1476, that Congress would have preferred “no statute at all” to a version with the legislative veto provision severed. As in Chadha, “[ajlthough it may be that Congress was reluctant to delegate final authority ..., such reluctance is not sufficient to overcome the presumption of severability raised by [a severability clause].” 462 U.S. at 932, 103 S.Ct. 2764. Notably, given FLPMA’s notice and report provision, Congress has the opportunity to pass timely and informed legislation reversing any withdrawal—legislation that would then be submitted for presidential approval (or veto, followed by a potential override). Since the passage of FLPMA, the Secretary has exercised large-tract withdrawal authority 82 times without Congress ever attempting to override that authority. See Interior-SER 637-38. Nor, since Chadha was decided more than three decades ago, has Congress amended the relevant section of the statute to enhance congressional oversight or limit the Secretary’s withdrawal authority. That history further undermines the Appellants’ contention that the legislative veto was an essential and indispensable component of FLPMA without which Congress would never have delegated large-tract withdrawal authority. Appellants make one final, technical argument in support of severability: They observe that the legislative veto provision is contained entirely within the subsection of the statute delegating large-tract withdrawal authority to the Secretary, section 204(c)(1) of FLPMA Appellants propose that the legislative veto and the delegation of large-tract withdrawal authority are therefore part of the same “provision.” As the statute’s severability clause mandates severance of any unconstitutional “provision,” Appellants contend, the entirety of section 204(e)(1) must be severed. Not so. There is no support for the proposition that a statutory subsection, like section 204(c)(1), is the smallest unit that can be characterized as a “provision” subject to a severability clause. And no reason occurs to us why a sentence within a subsection is not a “provision” of the statute. See Black’s Law Dictionary 1420 (10th ed. 2014) (defining “provision” as “clause”). Indeed, courts have severed legislative vetoes within single sentences. See Alabama Power Co. v. U.S. Dep’t of Energy, 307 F.3d 1300,1306-08 (11th Cir. 2002) (severing a dependent clause containing a legislative veto from a statutory subsection because that clause was an unconstitutional “provision”). Were we to accept Appellants’ argument, the result would be to require courts to sever more of a statute that contains a severability clause referring to a “provision” than one that does not. Absent a clear command, we cannot imagine that Congress intended such a peculiar result. We therefore hold that the unconstitutional legislative veto embedded in section 204(c)(1) of FLPMA is severable from'the lárge-tract withdrawal authority delegated to the Secretary in that same subsection. Invalidating'the legislative veto provision does not affect the Secretary’s withdrawal authority. ■ III. FLPMA A. Appellants’ FLPMA Claims We turn next to the merits of the FLPMA claims. We review challenges to agency actions such as those here under the Administrative Procedure Act (“APA”), 5 U.S.C. § 706. Under the APÁ, a reviewing court may set aside only agency actions that are “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with the law.” 5 U.S.C. § 706(2)(A). “This standard of review is “highly deferential, presuming the agency action to be valid .and affirming the agency action if a reasonable basis exists for its decision.” Nw. Ecosystem Alliance v. U.S. Fish & Wildlife Serv., 476 F.3d 1136, 1140 (9th Cir. 2007) (internal quotation marks omitted). A court may not “substitute its judgment for that of the agency,” Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 416, 91 S.Ct. 814, 28 L.Ed.2d 136 (1971), abrogated on other grounds by Califano v. Sanders, 430 U.S. 99, 105, 97 S.Ct. 980, 51 L.Ed.2d 192 (1977), and an agency’s interpretation of its organic statute, as well as of its own regulations, is entitled to deference. Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 844, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984); Auer v. Robbins, 519 U.S. 452, 461-63, 117 S.Ct. 905, 137 L.Ed.2d 79 (1997). The ROD listed four rationales for the withdrawal: (1) It would protect water resources in the Grand Canyon watershed and the Colorado River from possible contamination; (2) it would preserve cultural and tribal resources throughout the withdrawn area; (3) it would protect natural resources, including wildlife and wilderness areas; and (4) because existing claims could still be mined, the economic benefits of uranium mining could still be realized by local communities. Appellants challenge each of the Secretary’s rationales for the withdrawal, but focus on the first. Appellants contend that the final'EIS and ROD exaggerated the risk of water contamination from uranium mining in the affected area, and that' the administrative record suggests that existing laws and regulations were sufficient to achieve the aim of water protection. 1. Potential Impact on Water Resources The crux of Appellants’ FLPMA argument is that the scientific evidence in the record does not justify the Secretary’s decision to withdraw this large tract of land to protect water resources. In support, Appellants characterize several segments of the final EIS, ROD, and administrative record as indicating that the risk of groundwater contamination from uranium mining was low and the scientific rationale for the withdrawal weak. Congress defined the Secretary’s “withdrawal” power as the power to withhold federal lands from mining or settlement, “in order to maintain other public values in the area or reserv[e] the area for a particular public purpose or program.” 43 U.S.C. § 1702CÍ). The terms “public values” and “public purpose” are not' defined in the statute. Congress’s stated objectives in enacting FLPMA provide clues to the meaning of those words. Congress’s objectives included ensuring that “the public lands [would] be managed in a manner that [would] protect the quality of scientific, scenic, historical, ecological, environmental, air and atmospheric, water resource, and archeological values; that, where appropriate, [would] preserve and protect certain public lands in their natural condition; that [would] provide food and habitat for fish and wildlife and domestic animals; and that [would] provide for outdoor Recreation and human occupancy and use.” 43 U.S.C. § 1701(a)(8). That broad language encompasses the Secretary’s justifications for the withdrawal here challenged. The USGS Report and the final EIS establish that Interior did have evidence that additional uranium mining could present a risk of contamination, The USGS Report analyzed over 1,000 water samples from 428 different locations within the region, and found that 70 sites exceeded the EPA’s primary or secondary heavy metal contaminant levels. Samples from fifteen springs and five wells indicated uranium concentrations exceeding the EPA’s maximum contaminant levels.. The USGS Report acknowledged that the evidence was “inconclusive” regarding a connection between those findings and mining activity, but could not rule out such a connection. The final EIS and ROD further indicate that the full-withdrawal alternative was expected to reduce substantially the potential environmental impact from continued mining operations. The final EIS concluded that under Alternative A (“no action”) the projected water quality impact to R-aquifer springs was “none to moderate” in the entirety of the North Parcel and East Parcel, and “none to major” for part of the South Parcel; the anticipated impact was “none tó negligible” only for two springs in the South Parcel. The potential impact on surface water quality was assessed as at least “negligible to moderate” in all three parcels under Alternative A. Under Alternative B (the full withdrawal), the final EIS assessed the risk to 'water quality as “negligible to moderate” only for surface waters in the North Parcel, and “none to major” only for R-aquifer wells in the South Parcel. The final EIS, the USGS Report, and the ROD acknowledge considerable uncertainty regarding whether and how mining contributes to groundwater contamination in the Grand Canyon watershed. The USGS Report, for example, found that “[t]he hydrologic processes that control the distribution and mobilization of natural uranium in this hydrogeologic setting are poorly understood,” and that available information regarding • any correlation between mining and groundwater contamination was “limited and inconclusive.” Both the final EIS and the ROD recognized that the risk to water quality in the R-aquifer was likely low, but that significant uncertainty existed regarding travel times and hydrogeologic conditions within particular breccia pipes. In both documents, Interior observed that the Bureau would benefit from continued study, which a temporary withdrawal would allow. But after acknowledging the uncertainties and need for further study, the ROD concluded that unfettered mining presented a small but significant risk of dangerous groundwater contamination—a risk that would be substantially mitigated by the withdrawal. The final EIS supports this conclusion. Some analysts within the Department of the Interior disagreed. They believed the scientific data presented- in the EIS insufficient to justify the withdrawal. But the existence of internal disagreements regarding the potential risk of contamination does not render the agency’s ultimate.decision arbitrary and capricious. Scientific conclusions reached by the agency need not reflect the unanimous opinion of its experts. “[A] diversity of opinion by local or lower-level agency representatives will not preclude the agency from reaching a contrary decision, so long as the decision is not arbitrary and capricious and is otherwise supported by the record.” Wild-Earth Guardians v. Nat’l Park Serv., 703 F.3d 1178, 1186-87 (10th Cir. 2013); see also Nat’l Ass’n of Home Builders v. Defs. of Wildlife, 551 U.S. 644, 658-59, 127 S.Ct. 2518, 168 L.Ed.2d 467 (2007). Again, we must uphold the agency’s choice so long as it is “supported by reasoned analysis.” Ecology Ctr. v. Castaneda, 574 F.3d 652, 665 (9th Cir. 2009). The record demonstrates that the Secretary conducted a carefully reasoned analysis, considered the available scientific data, weighed diverse opinions from Interior experts and public commenters, recognized the limitations of the available scientific evidence, and concluded that a cautious approach was necessary to forestall even a low probability of contamination in excess of EPA thresholds—thresholds developed in response to serious concerns about human health. See 65 Fed. Reg. 76,708. The Secretary stressed that the withdrawal was not permanent, affording the opportunity to collect additional data about the hydraulic patterns in the area and the impact of uranium mines on water resources. We cannot say that the withdrawal decision was arbitrary, capricious, or not in accordance with the law. 2. Cultural and Tribal Resources Appellants next contend that the Secretary lacked the authority to withdraw such a large tract of land for the purpose of protecting cultural or tribal resources, and that even if it had the authority, it acted arbitrarily and capriciously in exercising it. We do not agree with either proposition. FLPMA permits the Secretary to premise a withdrawal of public lands from new mining claims on the protection of cultural and tribal resources. The congressional policy statement included in FLPMA contemplates that Interior will manage public lands in part for the protection of “historical” and “archaeological” values. 43 U.S.C. § 1701(a)(8). Consistent with that mandate, Interior’s regulations require that an EIS, prepared in compliance with NEPA, include a full report on “the identification of cultural resources” possibly impacted by agency action. 43 C.F.R. § 2310.3-2(b)(3)(I). Appellants argue that the withdrawal was overbroad because it was not “based on particular sites or sacred areas,” but rather covers a large tract of federal land that includes multiple sites. But the final EIS explained that the withdrawn area as a whole is of profound significance and importance to Native American tribes. The entirety of the North and East Parcels falls within the traditional territory of the Southern Paiute, while the Southern Parcel is a traditional use area for the Navajo, the Hopi, the Hualapai and the Havasupai tribes. Many tribes, including the Hopi, view the whole territory as sacred and regard any drilling and mining as inflicting irreparable harm. Moreover, the final EIS also identified a host of specific sites, trails, hunting areas, springs, and camps which are of traditional importance to several tribes and are cultural and archeological treasures in their own right. Nothing in FLPMA or our case law indicates that the Secretary may not withdraw large tracts of land in the interest of preserving cultural and tribal resources. Nor is there any reason to believe that a withdrawal must be restricted to narrow carveouts tracing the perimeter of discrete cultural and historical sites, as opposed to a larger area containing multiple such sites. Courts have previously upheld large-tract withdrawals justified in part by the protection of tribal resources and “areas of traditional religious importance to Native Americans.” See, e.g., Mount Royal Joint Venture v. Kempthorne, 477 F.3d 745, 752 (D.C. Cir. 2007). 3. Other Resources Appellants also challenge the Secretary’s third reason for the withdrawal: to protect “other resources,” including visual resources and wildlife. This challenge fails as well. The record supports the conclusion that there would be a significant impact on visual resources and a risk of significant harm to wildlife absent the'withdrawal. The final EIS concluded that if new mining claims proliferated, the impact on visual resources would range from minor to major, depending on the area, but would likely be “moderate” overall. The ROD found that mining-related emissions, dust, and haze would be dramatically higher absent the withdrawal, with, a consequent risk to air quality and visibility. Although some of the effects of increased uranium mining— such as the effects of increased, levels of radionuclides on wildlife—were unknown or difficult to project, the final EIS concluded that the relative impact of mining on wildlife would be “significantly less” -if the proposed area were withdrawn. Fewer roads and power lines would be built, and trucking would be significantly decreased. And the final EIS explained that even a minimal degree of water contamination could have considerable impact on aquatic species. 4. Economic Benefits Appellants propose that Interior violated both FLPMA and NEPA by miscalculating the amount of uranium in the withdrawn area and thus failed accurately to weigh the economic impact of the withdrawal. Specifically, Appellants argue that the USGS Report used outdated information from a 1990 USGS study, and that BLM failed to account for “hidden” breccia pipes (pipes hot exposed above ground) in its analysis of the economic impact of precluding new mining claims, Appellants proffer their own analyses-of the quantity of uranium in the withdrawn area, which they project to be five times larger than the USGS Report’s estimate of 162,964 tons. These challenges fail for several reasons. First, Appellants offer no basis for concluding that the methodology of the 1990 Report was unsound. Further, the 2010 USGS Report did not in fact incorporate the 1990 Report wholesale. It incorporated some of the findings of the 1990 Report, but made several adjustments and recalculations in a peer-reviewed update. The 2010 Report also relied on several peer-reviewed papers published before and after the 1990 Report, including one authored by an expert, Karen Wenrich, who opposed the withdrawal. Additionally, BLM reviewed and reasonably responded to Appellants’ proposed alternative calculations, made in comments on the proposed withdrawal. The agency concluded that the alternative proposals had not been sufficiently developed or peer-reviewed and so declined to accord them significant weight. With regard to Appellants’ contention that BLM failed to account for “hidden” bréccia pipes in its economic analysis, BLM stated in response to NMA’s public comments that those pipes were in fact incorporated into BLM’s numerical estimates. In sum, the agency’s findings regarding the quantity of uranium in the withdrawn area were not arbitrary or capricious, as the agency relied on peer-reviewed data and reasonably explained why it did not adopt Appellants’ alternative'version. B. Boundaries Opening up another front, Appellants maintain that two subsections of the withdrawn area—roughly 120,000 acres in the western section of the North Parcel; which are part of the Virgin River watershed rather than the Grand Canyon watershed,- and an additional 80,000 acres in the northeast section of the North Parcel, where groundwater is believed to flow away from the Colorado River and Grand Canyon National Park—should not have been included even if the withdrawal was otherwise proper (which, of course, they dispute). Observing that the withdrawn area has essentially the same boundaries included in Rep. Grijalva’s unsuccessful legislation, Appellants contend that the Secretary did not make an independent determination that withdrawal of those discrete areas was merited. Inclusion of those 200,000 acres, Appellants maintain, is inconsistent with both (1) the stated purpose of the withdrawal as expressed in the BLM’s 2009 application for the withdrawal (to protect “the Grand Canyon watershed”), and (2) the guidance of Interior manuals directing that withdrawals “bé kept to a minimum consistent with the demonstrated needs of the applicants.” Department of the Interior, 603 DM 1.1(A) (Aug. 1, 2005). The principal flaw in this partial challenge is that protection of the Grand Canyon watershed was not the only basis for the withdrawal. As the district court noted, the three other bases for the withdrawal are fully applicable to the disputed 200,000 acres. In particular, in including the North Parcel in the withdrawal area, Interior relied not just on water or air contamination, but also on the anticipated impact mining would have on wildlife, cultural, tribal, and visual resources.' For example, BLM observed in the final EIS that the “no action” alternative could increase wildlife mortality and reduce viability—particularly across the North Parcel—due to “noise and visual intrusions,” the development of new roads and power lines, and “chemical and radiation hazards.” The Anal EIS also observed that several tribes considered some or all of the North Parcel an ancestral homeland with significant cultural value. The entire North Parcel overlaps with Southern Paiute band territories, which, according to a University of Arizona ethnographic report commissioned by Grand Canyon National Park and cited in the final EIS, “remain important in the cultural life and history of Southern Paiute tribes.” Alternative C would not have •withdrawn areas “with isolated or low concentrations of [biological] resources” that could be adversely affected by mineral exploration and development, such as the area outside the Grand Canyon watershed. But the final EIS considered and rejected Alternative C because it still risked a number of adverse consequences. Interior anticipated a harmful impact to wildlife under Alternative C—though of a lesser magnitude—as well as a “very high” potential for disturbance “of places of cultural importance to American Indians within the North Parcel.” Full withdrawal had “the greatest potential of all alternatives ... to not change the existing wilderness characteristics.” The upshot is that arguments concerning the disputed 200,000 acres (and Alternative C) are myopically—and, so, incorrectly-—focused solely on an asserted disconnect between that area and the Grand Canyon watershed. The Department of the Interior’s assigned role is administering public lands in a manner “that will protect the quality of scientific, scenic, historical, ecological, environmental, air and atmospheric, water resource, and archeological values.” 43 U.S.C. § 1701(a)(8). That responsibility goes well beyond particular groundwater areas or watersheds. The Secretary appropriately included the full North Parcel in the withdrawal area after considering all relevant environmental and cultural impacts; The decision to do so was not arbitrary and capricious. Importantly, we note also that although Interior’s analysts concluded that the hydrological basis for withdrawing the disputed 200,000 acres was not especially strong, they also observed that, within that acreage, underground fault zones conveyed some groundwater “south toward the Grand Canyon.” Interior’s cautious assessment of the possible impact of any groundwater contamination in the North Parcel reflected the agency’s recognition that the hydrology of the North Parcel was not particularly well studied or understood. C. Multiple-Use Mandates Somewhat opaquely, Appellants raise yet another challenge to the Secretary’s withdrawal decision—that it contravened the principle that land management under FLPMA “be on the basis of multiple use and sustained yield.” 43 U.S.C. § 1701(a)(7). This argument lacks merit. FLPMA defines “multiple use” as “the management of the public lands and their various resource values so that they are utilized in the combination that will best meet the present and future needs of the American people,” and specifically contemplates “the use of some land for less than all of the resources” and the long-term preservation of “natural scenic, scientific and historical values.” 43 U.S.C. § 1702(c). Accordingly, FLPMA cautions the Secretary to give consideration to “the relative values' of the resources and not necessarily to the combination of uses that will give the greatest economic return or the greatest unit output.” Id. As the Supreme Court has observed, “multiple use” is a “deceptively simple term that describes the enormously complicated task of striking a balance among the many competing uses to which land can be put.” Norton v. S. Utah Wilderness Alliance, 542 U.S. 55, 58, 124 S.Ct. 2373, 159 L.Ed.2d 137 (2004). It does not, as Appellants suggest, require the agency to promote one use above others. Nor does it preclude the agency from taking a cau tious approach to assure preservation of natural and cultural resources. The agency must weigh competing interests and, where necessary, make judgments about incompatible uses; a particular parcel need not be put to all feasible uses or to any particular use. See New Mexico ex rel. Richardson v. Bureau of Land Mgmt., 565 F.3d 683, 710 (10th Cir. 2009). Consequently, the principle of multiple use confers broad discretion on an implementing agency to evaluate the potential economic benefits of mining against the long-term preservation of valuable natural, cultural, or scenic resources. Here, Interior engaged in a careful and reasoned balancing of the potential economic benefits- of additional mining against the possible risks to environmental and cultural resources. This approach was fully consonant with the multiple-use principle. D. Sufficiency of Existing Laws and Regulations Launching yet another line of attack, Metamin and AEMA maintain that the Interior did not adequately consider whether existing laws and regulations were sufficient to protect the resources identified in the ROD, undermining the justification for the withdrawal. Alternatively, and to some degree in contradiction, Metamin and AEMA represent that Interi- or found existing laws and regulations sufficient but did not draw the proper conclusion—that withdrawal was unjustified. Neither argument is persuasive. The final EIS repeatedly acknowledged that some applicable laws and regulations mitigate the impact of uranium mining on environmental, cultural, and visual resources, as well as wildlife and human health. But the final EIS does not suggest that simply enforcing existing laws and regulations would suffice to meet the purposes of the withdrawal. For example, the final EIS examined the relative impacts of Alternative A (wherein the agency would take no action and existing laws and regulations would be left in place) and Alternative B (the full withdrawal) at great length. The final EIS concluded that the potential negative impact on water resources would be significantly greater under Alternative A, a comparison that expressly accounted for the applicable regulatory schemes. With respect to cultural and tribal resources, the final EIS concluded that (1) under the existing regulatory regimes, “it may not be possible to reduce all such adverse effects in the long term, especially impacts to the character, association and feeling of the setting”; (2) mitigation of the expected damage to tribal resources, in particular, “may be difficult or impossible in many cases”; and (3) “the preferred mitigation method is avoidance.” Limiting the withdrawal to 600,000 acres—still a sizeable area—would, the final EIS concluded, have resulted in a “very high” impact on cultural and tribal resources. With respect to wildlife and visual resources, the final EIS’s comparison of Alternatives A and B demonstrated that the existing regulatory scheme would be “significantly” less effective without the withdrawal, and that taking no action would result in a moderate impact on those resources. In short, the final EIS did take existing legal regimes into account but reasonably concluded that they were inadequate to meet the purposes of the withdrawal. IV. The Establishment Clause Appellant Gregory Yount alone challenges the Secretary’s withdrawal as violating the Establishment Clause of the First Amendment. The Secretary observed in the ROD that uranium mining “within the sacred and traditional places of tribal peoples may degrade the values of those lands to the tribes that use them.” According to Yount, precluding new mining claims on federal land out of concern that the area has sacred meaning to Indian tribes violates the Establishment Clause. In general, state action does not violate the Establishment Clause if it (1) has a secular purpose, (2) does not have a principal or primary effect of advancing or inhibiting religion, and (3) does not foster excessive government entanglement with religion. Lemon v. Kurtzman, 403 U.S. 602, 612-13, 91 S.Ct. 2105