Full opinion text
MEMORANDUM OPINION JAMES E. BOASBERG, United States District Judge Designed to transport oil from the Bakken oil fields in North Dakota to a storage hub in southern Illinois, the Dakota Access Pipeline (DAPL) has also borne substantial controversy-in its wake. Most significant has been the opposition from Indian tribes .whose reservations lie in close proximity to the pipeline’s crossing of the Missouri River at Lake Oahe. To block Dakota Access LLC’s construction of that last segment and its operation of DAPL, the Standing Rock. Sioux Tribe filed this suit in July 2016, and the Cheyenne River Sioux Tribe intervened shortly thereafter. The Tribes have since mounted two substantial legal challenges to DAPL, neither of which yielded success. The .first contended that the grading and clearing of land for the pipeline threatened sites of cultural and historical significance, and that the U.S. Army Corps of Engineers had flouted its duty to engage in tribal consultations pursuant to the National Historic Preservation Act. See Standing Rock Sioux Tribe v. U.S. Army Corps of Eng’rs (Standing Rock I), 205 F.Supp.3d 4, 7 (D.D.C. 2016). The second maintained that the presence of oil in the pipeline under Lake Oahe would desecrate, sapred wafers and make it impossible for the Tribes to freely exercise their religious beliefs, thus violating the Religious Freedom Restoration Act. See Standing Rock Sioux Tribe v. U.S. Army Corps of Eng’rs (Standing Rock II), No. 16-1534, 239 F.Supp.3d 77, 80-81, 2017 WL 908538, at *1 (D.D.C. Mar. 7,2017). 'Now that the Court has rejected these two lines of attack, Standing Rock and Cheyenne River here take their third shot, this time zeroing in DAPL’s environmental impact. They seek summary judgment on several counts related to the Corps’ alleged failure to comply with the National Environmental Policy Act. In particular, the. Tribes believe that the Corps did not sufficiently consider the pipeline’s environmental effects before granting permits to Dakota Access to construct and operate DAPL under Lake Oahe, a federally regulated waterway. This volley meets with some degree of success. Although the Corps substantially complied with NEPA in many areas, the Court agrees that it did not adequately consider the impacts of an oil spill on fishing rights, hunting rights, or environmental justice, or the degree to which the pipeline’s effects are likely to be highly controversial. To remedy those violations, the Corps will have to reconsider those sections of its environmental analysis upon remand by the Court. Whether Dakota Access must cease pipeline operations during that remand presents a separate question of the appropriate remedy, which will be the subject of further briefing. Table of Contents I. Background... 112 A. NEPA. ..112 B. Factual History... 114 C. Litigation... 116 1. Filing of Suit... 116 2. Further Consideration... 117 3. A New Administration... 119 II. Legal Standard... 121 III. Analysis ■ of Standing Rock’s Claims... 122 A.Decision Not to Prepare EIS... 122 1.Hard Look/Convincing Case... 123 a. Extent of Record... 123 b. Spill-Risk Analysis... 125 c. Impacts Analysis Re: Treaty Rights... 130 2. Alternatives... 134 3. Environmental Justice... 136 B. Decision to Grant the Easement. . .140 1. Policy Change... 141 2. Trust Responsibilities... 143 C. NWP12...145 D. Remedy... 147 IV. Analysis of Cheyenne River’s Claims... 148 A. Section 408 Decision... 148 1. . Impairment.. .148 2. Injurious to Public Interest... 150 3. Other Arguments... 150 B. Easement Decision... 152 1. Section 185(b)(1)... 152 2. Section 185(h)(2)... 153 3. Section 185(x)... 154 C. Trust Responsibilities... 155 D. Consultation.. .155 V. Conclusion.. ,160 I. Background To familiarize the reader with the background information relevant to its analysis, the Court first briefly sets out the National Environmental Policy Act’s statutory framework and then separately discusses the factual history and litigation to date. A. NEPA The National Environmental Policy Act, the statute under which the majority of the Tribes’ claims are brought, has two aims: it “places upon an agency the obligation to consider every significant aspect of the environmental impact of a proposed action,” and “it ensures that the agency will inform the public that it has indeed considered environmental concerns in its decisionmaking process.” Baltimore Gas & Elec. Co. v. Natural Res. Def. Council, Inc., 462 U.S. 87, 97, 103 S.Ct. 2246, 76 L.Ed.2d 437 (1983) (citation omitted). NEPA’s requirements are “procedural,” requiring “agencies to imbue their de-cisionmaking, through the use of certain procedures, with our country’s commitment to environmental salubrity.” Citizens Against Burlington, Inc. v. Busey, 938 F.2d 190, 193-94 (D.C. Cir. 1991). Importantly, “NEPA does not mandate particular consequences,” id. at 194, and courts are discouraged from substituting their own policy judgments for that of the agency. See N. Slope Borough v. Andrus, 642 F.2d 589, 599 (D.C. Cir. 1980); see also Marsh v. Or. Nat. Res. Council, 490 U.S. 360, 378, 109 S.Ct. 1851, 104 L.Ed.2d 377 (1989). “NEPA merely prohibits uninformed — rather than unwise — agency action.” Robertson v. Methow Valley Citizens Council, 490 U.S. 332, 351, 109 S.Ct. 1835, 104 L.Ed.2d 351 (1989). Agency actions with adverse environmental effects can thus be NEPA compliant where “the agency has considered those effects and determined that competing policy values outweigh those costs.” Ohio Valley Envtl. Coal. v. Aracoma Coal Co., 556 F.3d 177, 191 (4th Cir. 2009) (citations omitted). Under NEPA, an agency must prepare an Environmental Impact Statement for any proposed major federal action “significantly affecting the quality of the human environment.” 42 U.S.C. § 4332(2)(C). An EIS must detail the environmental impact of the proposed action, any unavoidable adverse effects, alternatives to the proposed action, the relationship between short-term uses of the environment and long-term productivity, and any irreversible commitments of resources. Id. To determine whether an agency must prepare an EIS, it first drafts an Environmental Assessment. See 40 C.F.R. § 1501.4(b). An EA is a “concise public document” that “[b]riefly provide[s] sufficient evidence and analysis for determining whether to prepare an environmental impact statement or a finding of no significant impact.” Id. § 1508.9(a). The EA must discuss the need for the proposal, the alternatives, the environmental impacts of the proposed action and alternatives, and the agencies and’ persons consulted. Id. § 1508.9(b). If, after preparing an EA, the agency determines that an EIS is not necessary, it must prepare a Finding of No Significant Impact (FONSI) setting forth the reasons why the action will not have any significant impact on the environment. Id. §§ 1501.4(e), 1508.13; cf. Grand Canyon Trust v. FAA, 290 F.3d 339, 340 (D.C. Cir. 2002) (“If any ‘significant’ environmental impacts might result from the proposed agency action then an EIS must be prepared before agency action is taken.”) (quoting Sierra Club v. Peterson, 717 F.2d 1409, 1415 (D.C. Cir. 1983)). If the action will not have such impact because' of the agency’s commitment to ensure the performance of mitigation measures, the agency prepares a Mitigated FONSI. See Council on Environmental Quality, Appropriate Use of Mitigation and Monitoring and Clarifying the Appropriate Use of Mitigated Findings of No Significant Impact 2, 7 (2011), https://energy.gov/sites/prod/ files/NEPA-CE Q_Mitigation_and_Monitoring_Guidance_14Jan2011.pdf. Mitigation includes “[ajvoiding an impact by not taking a certain action”; “[m]inimizing an impact by limiting the degree or magnitude of the action”; “Rectifying an impact by repairing, rehabilitating, or restoring the affected environment”; “Reducing or eliminating an impact over time, through preservation and maintenance operations”; and “Rompensating for an impact by replacing or providing substitute resources or environments.” Id. at 4-5. As will be explained below; the Corps here prepared an EA and a Mitigated FONSI. The central question this Opinion answers is whether that was sufficient. B. -Factual History ■ As those who have followed this litigation and the concomitant public debate well know, DAPL,is a nearly 1,200-mile pipeline designed .to move more than half a million gallons of crude oil from North Dakota . to Illinois every. day. Standing Rock I, 205 F.Supp.3d at 7. Although no government approval is necessary for oil pipelines traversing private lands, it is required for those segments that cross federally regulated waters. Id. DAPL crosses such waterways at hundreds of discrete places along, its route, including, most prominently, at Lake Oahe. Id, Created by the Corps in 1958 via a dam constructed on the Missouri River, Lake Oahe is a reservoir that'spans Northland South Dakota and borders the Standing Rock and Cheyenne River Sioux Reservations to the east. Id. at 13; ECF No. 172-1 (Environmental Assessment) , at 35, ,75; ECF No/ 97-1 (CRST* Second Amended Complaint), ¶ 29. DAPL crosses, the Lake 0.55 miles north of the Standing Rock Reservation and 73 miles north of the Cheyenne River Reservation. See Standing Rock II, 239 F.Supp.3d at 80-81, 2017 WL 908538, at *1; EA at 75. For orientation purposes, the southern border of the former Reservation also acts as the northern border .of the latter. See ECF No. 117-5 (Map of Current Sioux Reservations). . • Lake Oahe holds special significance -for the Standing Rock and Cheyenne River Sioux Tribes.^ Its creation necessitated the taking of approximately 56,000 acres of some of “the best land” from. Standing Rock’s Reservation, as. well as 104,420 acres of Cheyenne River’s trust lands.. See Act of Sept. 2,1958, Pub. L. No. 85-915, 72 S.tat. 1762; S. Rep. No. 102-267, at 188 (1992); Standing Rock II, 239 F.Supp.3d at 97-99, 2017 WL 908538, at *16 (citing South Dakota v. Bourland, 508 U.S. 679, 683, 113 S.Ct. 2309, 124 L.Ed.2d 606 (1993)). Today, Standing Rock members rely on Lake Oahe’s waters to service “homes, a hospital, clinics, schools, businesses and government buildings throughout the Reservation” and- to support agriculture and industrial activities. See ECF No. 117 (SRST MSJ) at 4. The Lake is also., the primary source of water for the Cheyenne River Reservation. See CRST Second Amend. Compl., ¶2. Both Tribes consider the waters to be “sacred” and “central to .[their] practice of religion.” SRST MSJ at 4; see Standing Rock II, 239 F.Supp.3d at 85-87, 88-89, 2017 WL 908538, at *6, 8. Dakota Access notified the Corps of its intent to construct a portion of DAPL under-Lake Oahe in June 2014, see ECF No. 183-1 (Email from Monica Howard, Dir. Envtl. Sci., Dakota Access, to Jason Renschler, Project Manager, Corps, June 23, 2014);- and first sought the Corps’--approval to do so'in October 2014. See ECF No. 159-1, Exh. A' (Letter from Monica Howard to Brent Cossette, Nat. Resource Specialist, Corps, Oct. 21, 2014). Specifically, the Company needed three authorizations, from, the Corps: (1) verification that its activities satisfied the terms and conditions of Nationwide Permit 12; (2) permission under the Rivers and Harbors Act, 33 U.S.C.- § 408; and (3) a real-estate, easement under the Mineral Leasing Act, 30 U.S.C. § 185. See ECF No. 172-6 (Memorandum from John Henderson, Omaha District Commander & Engineer, Corps, Dec, 3, 2016), ¶ 4. The Court has previously discussed some of the details, of these permitting schemes, see Standing Rock I, 205 F.Supp.3d at 10-12, and will not repeat them here. In December 2015, the Corps published and sought public comment on a- Draft Environmental Assessment that evaluated the environmental effects of DAPL’s proposed crossing of Lake Oahe and concluded that “construction of the proposed Project [was] not expected to have any significant direct, indirect, or cumulative impacts on the environment.” ECF No. 6-19 (Draft EA) at 1; see EA at 1, Standing Rock promptly submitted comments touching on a range of concerns, including that the Draft EA failed to adequately address potential harm from the pipeline’s construction and operations to the Lake’s water and the Tribe’s rights thereto; did not acknowledge the pipeline’s proximity to the Reservation; insufficiently analyzed the risks of an oil spill; and did not properly address environmental-justice considerations. See ECF No. 159-1, Exh. C (SRST Comments on Draft EA, Jan. 8, 2016) at 9 — Í7; id., Exh. D (SRST Suppl. Comments on Draft EÁ, Mar. 24, 2016) at 2-3. The Tribe, accordingly, asked that the Corps prepare an Environmental Impact Statement to assess the pipeline’s effects, a request it had also made prior to the Draft EAs release. See ECF No. 209-6 (Notes for Feb. 18-19, 2016, Tribal Meeting) at 51; ECF No. 209-9 at 33-34 (Letter from Waste Win Young, Tribal Historic Preservation Officer, Standing Rock Sioux Tribe, to Martha Chieply, Omaha District Regulatory Branch, Corps, Feb. 25, 2015). Cheyenne River expressed similar views. See ECF No. 185-1, Exh. II (Letter from Steve Vance, Tribal Historic Preservation Officer, Cheyenne River Sioux Tribe, to Richard Harnois, Sr. Field Archaeologist, Corps, May 2, 2016); ECF No. 183-19 (Letter from Steve Vance to John Henderson, May 19, 2016); ECF No. 183-20 (Letter from Harold Frazier, Chairman, Cheyenne River Sioux Tribe, June 3, 2016). Other federal agencies also weighed in on the Draft EA. Like the Tribes, the Department of the Interior requested that the Corps prepare an' EIS, a step it believed necessary given DAPL’s “potential impact on trust resources” — la, 800,000 acres of land held in trust for the Tribe by Interior, as well as waters on which the Tribe and its members depend for drinking' and other purposes — should' a leak or spill occur. See ECF No. 209-7 at 21 (Letter from Lawrence Roberts, Acting Assistant Secretary for Indian Affairs, Dep’t of Interior, to Brent Cossette, Mar. 29, 2016). Interior criticized the Corps for, inter alia, “not adequately justifying] or otherwise supporting] its conclusion that’ there would be no significant impacts upon the surrounding environment and community” and not assigning a level of intensity to those potential adverse impacts that were acknowledged. Id. The Environmental Protection Agency similarly expressed concern that the Draft EA “lack[ed] sufficient analysis of direct and indirect impacts to water resources,” did not adequately address “the measures that will be required to assure that impacts from construction and operation of the pipeline are not significant,” and did “not identify the related effects from the entire project segment.” ECF No. 209-16 at 184 (Retter from Philip Strobel, Director of NEPA Compliance & Review Program, EPA, to Brent Cossette, Jan. 8, 2016). Although the EPA did not believe that the Draft EA “would support a FON-SI,” it did not call for the Corps to prepare an EIS; instead, it suggested that “information and mitigation could be added to the EA in order to support a mitigated FONSI.” Id. at 187. After “becomfing] aware of the proximity” of DAPL to Standing Rock’s Reservation, the EPA supplemented its comments. See ECF No. 209-8 at 123 (Letter from Philip Strobel.to Brent Cossette, Mar. 11, 2016). It recommended that the Corps revise the Draft EA and provide a second public-comment period “to assess potential impacts to drinking water and the Standing Rock Sioux Tribe,” as well as “additional concerns regarding environmental justice and emergency response actions to spills/leaks.” Id. Notably, the EPA took some issue with the Draft EA’s spill analysis, stating that although it indicated only a minimal spill risk associated with the project, based.on its “experience in spill response,” a break or leak could significantly affect water resources. Id. at 124. Given DAPL’s proposed capacity of 13,100 to 16,600 gallons per minute of crude oil and the proximity of drinking-water intakes to the Oahe crossing, the agency explained, “There would be very little time to determine if a spill or leak affecting surface waters is occurring, to notify water treatment plants and to have treatment plant staff on site to shut down the water intakes.” Id. at 125. Finally, the EPA urged the Corps to expand its analysis for purposes of assessing environmental-justice considerations from “the area of construction disturbance” to “the impacts of the proposed project,” and to look at route alternatives. Id. at 126; see also ECF No. 209-9 at 209 (Email “Quick Summary of Conference Call with EPA,” Feb. 25, 2016) (“EPA concerned over the lack of Environmental justice — Tribal interests have not been addressed sufficiently.”). On July 25, 2016, about eight months after releasing the Draft EA, the Corps published its Final EA and a Mitigated Finding of No Significant Impact. See EA; ECF No. 172-2 (FONSI). The Final EA— like the Draft EA — was prepared by Dakota Access with involvement from the Corps, as is permitted, when certain conditions are met, by Council on Environmental Quality regulations. See EA at 1; Draft EA at 1; 40 C.F.R. § 1506.5(a)-(b). The Mitigated FONSI explained that the Corps had “coordinated closely with Dakota Access to avoid, mitigate and minimize potential impacts of the Proposed Action” — largely via horizontal directional drilling (HDD) technology — and that the Company was required to comply with a set of mitigation measures set out in the EA. See FONSI at 3. Given those measures and its evaluation of DAPL’s “anticipated environmental, economic, cultural, ... social^ and] ... cumulative effects,” the Corps concluded that the crossing at Lake Oahe would not “significantly affect the quality of the human environment,” and preparation of an EIS was therefore not required. Id. at 6. The Corps, accordingly, verified that the pipeline activities satisfied the terms and conditions of NWP 12 and granted permission under Section 408 of the Rivers and Harbors Act for DAPL’s placement at Lake Oahe. See ECF No. 209-9 at 149-53 (NWP 12 Permit); ECF No. 209-10 at 54 (Section 408 Permit). The parties disagree as to whether the Corps also at that time granted an easement pursuant to the Mineral Leasing Act, 30 U.S.C. § 185. See ECF Nos. 57, 66, 73. For purposes of this Opinion — and consistent with its understanding throughout the litigation — the Court will assume that it did not. Without such easement, Dakota Access could not construct the pipeline under the Lake. C. Litigation 1. Filing of Suit While factual backgrounds to lawsuits are often considerably more involved than the litigation itself, that is not' the case here. In part, that is because this action (as well as the 2016 election) generated significant further maneuvers. To begin, two days after the release of the EA on July 25, 2016, Standing Rock filed this suit against the Corps for declaratory and in-junctive relief pursuant to the National Historic Preservation Act, National Environmental Policy Act, Clean Water Act, and the Rivers and Harbors Act. See ECF No. 1 (Complaint), ¶¶ 128-212. Dakota Access successfully moved to intervene in support of the Corps on August 5, see ECF No. 7, and the Cheyenne River Sioux Tribe intervened as a Plaintiff on August 10. See ECF No. 11. Cheyenne River then filed its own Complaint, see ECF No. 11-12, which it later amended on September 8. See ECF No. 37. Like Standing Rock’s Complaint, Cheyenne River’s pleadings stated claims under the NHPA, NEPA, CWA, and RHA, as well as for breach of trust responsibility and violations of the Flood Control Act and the Administrative Procedure Act. Id. at 38-56. The Tribes initially sought a preliminary injunction based solely on the NHPA, contending principally that the clearing and grading of land along the pipeline route desecrated sites sacred to them. On September 9, "2016, immediately after this Court issued its Opinion denying that motion, see Standing Rock I, 205 F.Supp.3d at 7, the Departments of Justice, the Interior, and the Army issued a joint statement explaining that, because “important issues raised by the Standing Rock Sioux Tribe and other tribal nations and their members regarding the Dakota Access pipeline” remained, “construction of the pipeline on Army Corps land bordering or under Lake Oahe [would] not go forward” until the Army could determine whether reconsideration of any of its previous decisions regarding the Lake Oahe crossing under NEPA or other federal laws was necessary. See ECF No. 42-1 at 1. More specifically, the Corps at that time refused to grant the necessary MLA easement. 2. Further Consideration In response to the opportunity for additional consideration, Standing Rock sent several letters to Assistant ■ Secretary of the Army for Civil Works, Jo-Ellen Darcy, expressing its concerns regarding DAPL, the EA’s spill-risk analysis, and the impact of a potential:spill on.hunting, fishing, and other Treaty rights. See ECF Nos. 117-11 (Sept. 22, 2016), 117-12 (Oct. 28, 2016), 117-13 (Oct. 3⅛ 2016), 117-14 (Oct. 21, 2016). It also submitted an expert review of the EA,- which concluded that it was “seriously deficient and [could not] support the finding of no significant impact, even with the proposed mitigations.” ECF No. 117-15 (Accufacts, Inc. Review of EA, Oct. 28, 2016). As part of thé Corps’ internal-review process, its Chief Counsel prepared a memorandum concluding that the agency had “adequately considered and disclosed the environmental, cultural and other potential impacts of its actipns and that its decisions were not arbitrary or capricious,” and that “supplementation of the EA to address any new information [was] not legally required.” ECF No. 117-24 (Memorandum from .David Cooper, Chief Counsel, Corps, Oct. 20, 2016) (Cooper Memo) at 36. He also issued a memorandum that listed 36 possible conditions to be included in an easement that .would “provide further protection from any perceived risks posed by the pipeline ■ crossing at Lake Oahe.” ECF No. 209-3 at 55 (Memorandum from David Cooper, Oct. 31, 2016). On November 14, 2016, Assistant Secretary Darcy wrote to Standing Rock and Dakota Access to inform them that the Army had 'conipleted the review called for on September 9, “accounting for information it .. received from the Tribes' and the pipeline company since September,” and had “concluded that its previous decisions comported with legal requirements.” ECF No. 56-1 (Letter from Jo-Ellen Darcy, Nov. 14, 2016). Nonetheless, in light of the United States’ history with the Great Sioux' Nation, the importance of Lake Oahe to Standing Rock, the government-to-government relationship with Standing Rock, and the mandates of the Mineral Leasing Act regarding public safety and the interests of those who rely on fish, wildlife,- and biotic resources in the general area of a requested right-of-way, see. 33 U.S.C. §§ .185(g), (h)(2)(D), (k), “the Army determined that additional discussion with the Standing -Rock Sioux Tribe and analysis [were] warranted.” Darcy Nov. 2016 Letter at 2. The Army thus invited Standing Rock to engage in discussions concerning “[potential conditions in an easement for the pipeline crossing” that would reduce spill' risk “or otherwise enhance the protection of Lake Oahe, the Tribe’s water supplies, and its treaty rights”; 'the impact of those conditions on'spill risk; “whether to grant an easement for the pipeline to cross Lake 'Oahe at the location currently proposed” given those conditions; and anything élse “the Tribe believes is relevant to the proposed pipeline crossing or easement.” Id. Darcy also wrote to Frazier to inform him of the Corps’ decision and to express the Corps’ interest in “confer[ring] with [him] to better understand” his concerns. See ECF No. 131-4, Attach. A (Letter from Jo-Ellen Darcy to Harold Frazier, Nov. 14, 2016); see also ECF No. 131-4 (Declaration of Harold Frazier, Feb. 22, 2017), ¶ 15. Two days later, Darcy and other Cbrps officials met with representatives of the Great Plains Tribal Chairpersons’ Association, including Frazier, to confirm that the November 14 letters “constituted an invitation to the [T]ribes to provide any new information ... relevant to the Corps’ consideration of the easement.” Id, ¶ 16. During this next review phase, Standing Rock offered further comments urging the Corps to deny the easement because of the pipeline’s potential harm to its water, hunting, fishing, and- gathering rights. See ECF No. 117-17 (Dec. 2,2016). The Oglala Sioux Tribe, which had brought a related case against the Corps that has been consolidated with Standing Rock’s action, see Minute Order of Mar. 16, 2017, submitted an expert report critiquing the EA’s spill-volume analysis. See ECF No. 117-18 (EarthFax Review of EA, Dec. 2, 2016). The Corps’ Omaha District Commander met with representatives of Standing Rock and Dakota Access to review the Tribe’s concerns -and discuss conditions that could be imposed on an easement to reduce the risk of spill or rupture. See ECF No.- 209-5 at 1-2 (Email from Scott Spellmon, Commanding General, NW Division, Corps, to Jo-Ellen Darcy, Dec. 2, 2016). The day after the meeting, the District Commander issued a memorandum recommending that the Corps grant an easement to Dakota Access to cross Lake Oahe. See Henderson Memo. ■ The Corps also used this review phase to.solicit the opinion of the Department of the Interior “on the extent to which tribal treaty rights ... weigh in favor of or against authorizations needed for the Lake Oahe crossing.” ECF No. 117-6 (Memorandum from Hilary C. Tompkins, Solicitor, Dep’t of Interior, Dec. 4, 2016) at 1. Interior’s Solicitor accordingly supplied a memorandum concluding that the Corps had “ample legal justification to decline to issue the proposed Lake Oahe easement on the current record,” and that it “would be equally justified in suspending or revoking the existing Section 408 permit as it relates to the Lake Oahe crossing.” Jd. at 4. Alternatively, the Solicitor recommended that the Corps not make a decision to issue the easement prior to engaging in government-to-government consultation with' the Tribe; preparing an EIS to “adequately evaluated the existence of and potential impacts to tribal rights and interests,” “consider a broader range of alternative pipeline routes,” and undertake “a catastrophic spill analysis prepared by an independent expert”; and more comprehensively assessing “DAPL’s impact on tribal rights, lands, and resources, including the socioeconomic impacts, ... in light of the fact that the reservation is a permanent homeland for the Tribes, as well as other federal obligations towards the Tribes.” Id. On December 4, the same day the Interior Solicitor issued her Opinion, Assistant Secretary Darcy issued a memorandum to the Corps’ Commander. She explained that, to date, the Army had “not made a final decision on whether to grant the easement pursuant to [the Mineral Leasing Act].” ECF No. 172-7 (Memorandum from Jo-Ellen Darcy, Dec. 4, 2016), ¶ 6. Despite the Omaha District Commander’s recommendation that the Corps do so, Darcy stated that she had “concluded that a decision on whether to authorize the Dakota Access Pipeline to cross Lake Oahe at the proposed location merits additional analysis, more rigorous exploration and evaluation of reasonable siting alternatives, and greater public and tribal participation and comments.” Id,, ¶ 12. “Accordingly,” she continued, the Army would “not grant an easement to cross Lake Oahe at the proposed location based on the current record.” Id. She directed a “robust consideration of reasonable alternatives ..., together with analysis of potential spill risk and impacts, and treaty rights,” which she thought would be “best accomplished ... by preparing an Environmental Impact Statement.” Id. Darcy emphasized, though, that her “policy decision” did “not alter the Army’s position that the Corps’ prior reviews and actions have comported with legal requirements.” Id., ¶ 15. On January 18, 2017, Darcy followed up by publishing in the Federal Register a notice of intent to prepare an EIS. See 82 Fed. Reg. 5,543 (Jan. 18, 2017). Cheyenne River sent a letter to her that same day requesting that the Corps include it as a Cooperating Agency in the preparation and drafting of the EIS given the potential for the pipeline to affect the Tribe and its Reservation. See ECF No. 131-4, Attach. B (Letter from Harold Frazier to Jo-Ellen Darcy, Jan. 18,2017). 3. A New Administration As we all know, .elections have consequences, and the government’s position on the easement shifted significantly once President Trump assumed office on January 20, 2017. A Presidential Memorandum issued on January 24 directed the Secretary of the Army to instruct the Assistant Secretary of the Army for Civil Works and the Corps “to take all actions necessary and appropriate to ,.. review and approve in an expedited manner, to the extent permitted by law and as warranted, and with such conditions as are necessary or appropriate, requests for approvals to construct and operate the DAPL, including easements or rights-of-way” and to “consider, to the extent permitted by law and as warranted, whether to rescind or modify” the December 4 memorandum and the Notice of Intent to Prepare an EIS. See ECF No. 172-8, § 2. The Army completed a technical and legal review on February 3 and determined that the Final EA and FONSI “satisfied] the NEPA requirements for evaluating the easement required for the DAPL to cross Corps-managed federal lands at Lake Oahe” and “supported] a decision to grant an .easement.” ECF No. 172-9 (Memorandum from Todd Semonite, Lieutenant General, Corps, Feb, 3, 2017) at 10. Based on a review of the entire record, including the input received since September 2016, the Corps also concluded that the Final-EA did not require further supplementation, as there were no “substantial changes in the proposed action” or “new significant circumstances or information relevant 'to environmental concerns.” Id.. at 11 (citing 40 C.F.R. §§ 1502.9(c)(l)(i)-(ii)). The Corps thus published in the Federal Register a notice of termination of its intent to prepare an FIS, see ECF No. 95-3, provided notice to Congress of its intent to issue the easement, see ECF No. 172-10 (Congressional Notifications, Feb. 7, 2017), and did so on February 8. See ECF No. 172-11 (Easement). The final easement contains 36 conditions intended to mitigate the risk of rupture at Lake Oahe and otherwise address the Tribe’s concerns. Id. at 37-43. To facilitate the Corps’ granting of the easement, the Acting Secretary of the Interior withdrew the Interior Solicitor’s December 4 Opinion. See ECF No. 127-15 (Memorandum from K. Jack Haugrud, Acting Secretary, Dep’t of Interior, Feb. 6, 2017). Having finally been given the green light, Dakota Access, by late March, completed construction of'this last segment beneath Lake Oahe and began placing oil in the pipeline. See ECF No. 191 (DA Status Report, Mar. 27, 2017). DAPL became fully operational on June 1, 2017. See Energy Transfer, Energy Transfer Announces the Bakken Pipeline Is in Service Transporting Domestic Crude Oil from the Bakken/Three Forks Production Areas, June 1, 2017, http://ir.energytransfer.com/phoenix.zhtml?c=106094 & =irol-newsArticle. The day after the Corps granted Dakota Access the easement, Cheyenne River moved for leave to file a Second Amended Complaint, see ECF No. 97, andalso filed a motion for preliminary injunction and application for a temporary restraining or-dér, both based solely on the Religious Freedom Restoration Act. See ECF Nos. 98, 99; Standing Rock II, 239 F.Supp.3d at 82-83, 2017 WL 908538, at *3. Standing Rock joined the TRO application, but not the preliminary-injunction motion. See ECF No. 107. In both filings, Cheyenne River argued that its members “believe that the mere existence of a crude oil pipeline under the waters of Lake Oahe will desecrate those waters and render them unsuitable for use in their religious sacraments,” and that DAPL “correlates with a terrible Black Snake prophesied to come into the Lakota homeland and cause destruction.” Standing Rock II, 239 F.Supp.3d at 82, 2017 WL 908538, at *3 (quoting ECF No. 98 at 2-3). After orally denying the TRO, see Minute Order of Feb. 13, 2017; ECF No. 119 (TRO Oral Arg. Tr., Feb. 13, 2017) at 29:20-30:19, the Court issued an Opinion similarly denying the preliminary-injunction motion, as it concluded that the extraordinary relief requested was not appropriate in light of the equitable doctrine of laches and Cheyenne River’s unlikelihood of success on the merits. Standing Rock II, 239 F.Supp.3d at 80-81, 2017 WL 908538, at *1. In the midst of these proceedings, Standing Rock — after moving for leave to amend its Complaint to address new developments since it first filed this case in July 2016, see ECF No. 106 — filed the instant Motion for Partial Summary Judgment on claims concerning the Corps’ decision not to prepare an EIS for the Lake Oahe crossing; its granting of the easement; and its permitting of the Lake Oahe crossing under NWP 12. The Corps responded with its own Cross-Motion for Partial Summary Judgment on' these causes of action, see ECF No. 172 (Corps SRST MSJ), and Dakota Access fíléd briefs opposing Standing-Rock’s Motion and joining the Corps’ Cross-Motion. -See ECF Nos. 159 (DA SRST Opp.), 184 (Notice of Join-der), 202-1 (DA SRST Reply). Cheyenne River joined Standing Rock’s Motion, see ECF No. 131 (CRST MSJ) at 8, and filed its own Motion for Partial Summary Judgment on claims concerning the Corps’ decisions to grant' Dakota Access a permit under Section 408 of the RHA and an easement under the MLA. The Corps and Dakota Access then cross-moved for partial summary judgment on those claims as weh. See EOF No. 183 (Corps CRST MSJ); ECF No. 185 (DA CRST MSJ). These Motions are now ripe. Although the Tribes do not raise exactly the same causes of action, because their Motions are closely related and sometimes overlap, the Court addresses both in this Opinion, turning first to Standing Rock’s claims and then to Cheyenne River’s. For purposes of their resolution, the Court has also today issued a Minute Order granting the Tribes’ motions for leave to amend, such that the claims relating to post-July 2016 events are properly before it. After setting out the governing legal standard, the Court first addresses the relevant claims raised by Standing Rock, see Section III, infra, and then turns to those asserted by Cheyenne River. See Section IV, infra. II. Legal Standard The parties have cross-moved for partial summary judgment on the administrative record. The summary-judgment standard set forth in Federal Rule of Civil Procedure 56(c), therefore, “does not apply because of the limited role of a court in reviewing the administrative record.” Sierra Club v. Mainella, 459 F.Supp.2d 76, 89 (D.D.C. 2006); see also Bloch v. Powell, 227 F.Supp.2d 25, 30 (D.D.C. 2002), aff'd, 348 F.3d 1060 (D.C. Cir. 2003). “[T]he function of the district court is to determine whether or not as a matter of law the evidence in the administrative record permitted the agency to make the decision it did.” Sierra Club, 459 F.Supp.2d at 90 (quotation marks and citation omitted). “Summary judgment is the proper mechanism for deciding, as a matter of law, whether an agency action is supported by the administrative record and consistent with the [Administrative Procedure Act] standard of review.” Loma Linda Univ. Med. Ctr. v. Sebelius, 684 F.Supp.2d 42, 52 (D.D.C. 2010) (citation omitted), aff'd, 408 Fed.Appx. 383 (D.C. Cir. 2010). The Administrative Procedure Act “sets forth the full extent of judicial authority to review executive agency action for procedural correctness.” FCC v. Fox Television Stations, Inc., 556 U.S. 502, 513, 129 S.Ct. 1800, 173 L.Ed.2d 738 (2009). It requires courts to “hold unlawful and set aside agency action, findings, and conclusions” that are “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A). Agency action is arbitrary and capricious if,, for example, the agency “entirely failed to consider an important aspect of the problem, offered an explanation for its decision that runs counter to the evidence before the agency, or is so implausible that it could not be ascribed to a difference in view or the product of agency expertise.” Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State Farm Mut. Auto. Ins., 463 U.S. 29, 43, 103 S.Ct. 2856, 77 L.Ed.2d 443 (1983). This is a “narrow” standard of review, under which “a court is . not to substitute its judgment for that of the agency.” Id. Rather, the Court “will defer to the [agency’s] interpretation of what [a statute] requires so long as it is ‘rational and supported by the record.’ ” Oceana, Inc, v. Locke, 670 F.3d 1238, 1240 (D.C. Cir. 2011) (quoting C & W Fish Co. v. Fox, 931 F.2d 1556, 1562 (D.C. Cir. 1991)). In other words, an agency is required to “examine-the relevant data and articulate a satisfactory explanation for its action including a rational connection between the facts found and the choice made.” State Farm, 463 U.S. at 43, 103 S.Ct. 2856 (quoting Burlington Truck Lines v. United States, 371 U.S. 156, 168, 83 S.Ct. 239, 9 L.Ed.2d 207 (1962)). Courts, accordingly, “do not defer to the agency’s conclusory-or unsupported suppositions,” United Techs. Corp. v. Dep’t of Def., 601 F.3d 557, 562 (D.C. Cir. 2010) (quoting McDonnell Douglas Corp. v. Dep’t of the Air Force, 375 F.3d 1182, 1187 (D.C. Cir. 2004)), and “agency ‘litigating positions’ are not entitled to deference when they are merely [agency] counsel’s ‘post hoc rationalizations’ for agency action, advanced for the first time in the reviewing court.” Martin v. Occupational Safety & Health Review Comm’n, 499 U.S. 144, 156, 111 S.Ct. 1171, 113 L.Ed.2d 117 (1991). Although a reviewing court “may not supply a reasoned basis for the agency’s action that the agency itself has not given,” a decision that is not fully explained may, nevertheless, be upheld “if the agency’s path may reasonably be discerned.” Bowman Transp., Inc. v. Arkansas-Best Freight System, Inc., 419 U.S. 281, 285-86, 95 S.Ct. 438, 42 L.Ed.2d 447 (1974) (citation omitted)^ III.' Analysis of Standing Rock’s Claims As earlier noted, Standing Rock seeks summary judgment on three claims: (1) The Corps’ July 25, 2016, and February 8, 2017j' conclusions that the Oahe crossing did not warrant an EIS violated NEPA because the- agency did not make a convincing case that no significant impacts would result and failed to take a hard look at the project’s effects on Treaty rights and environmental-justice considerations; (2) The Corps’ February 8, 2017, decision to grant the easement was arbitrary, capricious, and contrary to law because the Corps reversed a prior policy without reasoned justification and because the decision constituted a breach of trust responsibilities; and (3) The Corps wrongfully concluded on July 25, 2016, that the. pipeline activities satisfied the terms and conditions of NWP 12. The Court addresses each in turn. ■ ' ■ A. Decision Not to Prepare EIS In reviewing an agency’s decision not to issue an EIS, the Court’s role is a “ ‘limited’ one, designed primarily to ensure ‘that no arguably significant consequences have been ignored.’ ” TOMAC, Taxpayers of Michigan Against Casinos v. Norton, 433 F.3d 852, 860 (D.C. Cir. 2006) (quoting Pub. Citizen v. Nat’l Highway Traffic Safety Admin,, 848 F.2d 256, 267 (D.C. Cir. 1988)). An agency’s decision to issue a FONSI and thus not to prepare an EIS will fie overturned only “if the decision was arbitrary, capricious, dr an abuse of discretion.” Sierra Club v. Peterson, 717 F.2d 1409, 1413 (D.C. Cir. 1983). When examining the adequacy of the FONSI and the EA upon' which it was based, courts must determine whether the agency: (1) has accurately identified the relevant environmental concern, (2) has taken a hard look at the problem in preparing its [FONSI or Environmental Assessment],' (3) is able to make a convincing case for its finding of no significant impact, and (4) has shown that even if there is an impact of true significance, an EIS is unnecessary because changes or safeguards in the project . sufficiently reduce the impact to a minimum. Sierra Club v. Van Antwerp, 661 F.3d 1147, 1154 (D.C. Cir. 2011) (quoting. TOMAC, 433 F.3d at 861) (internal quotation marks omitted). In so doing, courts in this circuit apply, “a rule of reason .to an agency’s NEPA analysis” and decline to “ ‘flyspeck’ -ihe agency’s findings in search of ‘any deficiency -no matter how- minor.’ ” Myersville Citizens for a Rural Cmty., Inc. v. FERC, 783 F.3d 1301, 1322-23 (D.C. Cir. 2015) (quoting Nevada v. Dep’t of Energy, 457 F.3d 78, 93 (D.C. Cir. 2006)). Standing Rock contends that the EA for DAPL “runs afoul of these standards.” SRST MSJ at 19. In particular, the Tribe argues that the Corps did not take a hard look at or make a convincing case that the Lake Oahe crossing will have no significant environmental impact, and that it did not sufficiently consider route alternatives or environmental-justice implications. Id. at 19-31. For these reasons, it asserts that “[t]he Corps’ conclusion that the Oahe crossing was not significant enough to warrant an EIS is arbitrary, capricious, and contrary to law.” SRST MSJ at 17; see Nevada, 457 F.3d at 87 (“[Courts] apply the APA’s arbitrary and capricious standard to a NEPA challenge.”). The Court begins its analysis with environmental impact and then turns to alternatives and environmental justice. 1, Hard Look/Convincing Case Pursuant to NEPA’s “hard look” requirement, the agency must ensure that “the adverse environmental effects of the proposed action are adequately identified and evaluated.” Robertson, 490 U.S. at 350, 109 S.Ct. 1835. In evaluating the significance of a proposed action’s impact, an agency is to consider, inter alia, the effect on “public health or safety”; “[ujnique characteristics of the geographic area such as proximity to historic or cultural resources”; the extent to which the environmental effects “are likely to be highly controversial” or “are highly uncertain or involve unique. or unknown risks”; “[w]hether the action is related to other actions , with individually insignificant but cumulatively significant impacts”; and the degree to which the action “may cause loss or destruction of significant ... cultural ] qr historical resources.” 40 C.F.R. § 1508.27. The Tribe identifies several ways in which the Corps allegedly failed to take a hard . look at the environmental consequences of permitting DAPL’s construction and operation and to make a convincing case of no significant, impact. It principally argues that the agency did not properly assess the risk of a spill under Lake Oahe or sufficiently consider the environmental impacts on Treaty rights of the construction of. the pipeline or .of a spill. Before proceeding to address each of the Tribe’s points, however, .the Court must dispense with a threshold issue, a. ■ Extent of Record To substantiate many of its critiques of the EA’s analysis, the Tribe relies on expert reports and other records dated after July 25, 2016, when the Final EA and Mitigated FONSI were published. Dakota Access argues that the Court should not consider these reports or any. evidence from the Tribe that post-dates July 25. “It is a widely accepted principle of administrative law that the courts base their review of an agency’s actions on the materials that were before the agency at the time its decision was made.” IMS, P.C. v. Alvarez, 129 F.3d 618, 623 (D.C. Cir. 1997) (listing cases). Here,' in challenging the Corps’ decision not to prepare an EIS, the Tribe in effect challenges authorizations made at two different times: the RHA Section 408 authorization and NWP 12 verification on July 25, 2016, and the easement approval on February 8, 2017. See ECF No. 196-1 (SRST Reply) at 3. The Section 408 and NWP 12 decisions were based on the conclusion set out in the EA and. FONSI that the permissions would not have a significant impact on the environment, and the easement decision was also based on “additional, review, analysis of terms and conditions for the easement, and. on the Corps’ decision that supplementation of the. EA/FONSI was not required.” Corps SRST MSJ at 10. The Corps thus decided at two junctures that an EIS was not required, and it prepared an administrative record encompassing the materials that were before it at each decision date. Although Dakota Access is technically correct that the expert reports and other evidence submitted after July 25, 2016, are outside the record for the RHA Section 408 and NWP 12 decisions, that offers them little aid. This is because the Court can review the materials before the Corps as of February 8, 2017, for purposes of evaluating the decision to grant the easement absent an BIS. The Court, consequently, will consider all materials dated up to February 8. To complicate matters further, however, the Tribe wishes the Court to also review “some uncontroversial background materials (e.g., maps) and declarations from its expert” that post-date February 8. See SRST Reply at 3. It argues that such extra-record evidence comes within the “accepted exceptions to the principle that the court cannot consider information that falls outside the agency record” — namely, where “the agency failed to examine all relevant factors or to ade-. quately explain its grounds for decision, or ... acted in bad faith or engaged in improper behavior in reaching its decision.” IMS, 129 F.3d at 624; SRST Reply at 3. On this point, the Tribe first contends that the Corps engaged in improper behavior by withholding confidential spill-model discussions and geographic-response plans to which its post-easement éxpert declarations respond. See SRST Reply at 3-4. But the showing required “to justify supplementing the record” is a “‘strong’” one, IMS, 129 F.3d at 624 (quoting Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 420, 91 S.Ct. 814, 28 L.Ed.2d 136 (1971)), and the Court does not find that the Tribe has made it here. The Corps has explained that it withheld from the Tribe and the public a small number of documents supporting the EA “[b]ecause of security concerns and sensitivities.” Dec. 4 Memo, ¶5. Indeed, the Court recently concluded that there was good cause to protect from public disclosure certain information in some spill-model reports that, if released, could endanger life or physical safety. Standing Rock Sioux Tribe v. U.S. Army Corps of Eng’rs (Standing Rock III), No. 16-1534, 249 F.Supp.3d 516, 522-24, 2017 WL 1316918, at *5-6 (D.D.C. Apr. 7, 2017). Absent a showing to the contrary, the Court thus c'annot permit supplementation of the record on the ground of some withholding impropriety. The Tribe next argues that its extra-record evidence describes how the Corps failed to examine all relevant factors and provide adequate grounds for its decision. But “[t]his is not a case where the agency failed ‘to explain administrative action [so] as to frustrate effective judicial review.’ ” IMS, 129 F.3d at 624 (quoting Camp v. Pitts, 411 U.S. 138, 142-43, 93 S.Ct. 1241, 36 L.Ed.2d 106 (1973)). The EA addressed each factor for which the Tribe marshals extra-record evidence, even if not with the depth or ultimate conclusion ' the Tribe would prefer. Compare SRST MSJ at 21 (criticizing Corps’ failure to address “slow leaks in the HDD bore,” which, based on Tribe-commissioned expert review, would be “ ‘complicated if not impossible to clean up and likely would have significant impacts on soils’ and underlying aquifers”) (quoting ECF No. 117-23 (Envy Report, Jan. 5, 2017) at 14); SRST Reply at 11 (“Landslides are a major source of pipeline failures and a critical factor in route selection.”) (citing ECF No. 195-4 (Corrective Action Order, Belle Fourche Pipeline Company, Dec. 20, 2016); Accufacts, Inc. Review at 3; ECF No. 120 (Sealed Declaration of Richard Kuprewicz, Feb. 12, 2017), ¶ 21); id. at 12 (describing EA’s failure to acknowledge “undisputed evidence” regarding failure rates of spill-detection systems) (citing ECF No. 209-5 at 110 (Letter from Sierra Club Indigenous Environmental Network, Oct. 10, 2016); Accufacts, Inc. Review at 5); id at 12-13 (“[T]he EA fails to acknowledge that with a pipeline 90 feet underground, there is no way to discover a slow leak until the oil sheen appears on the surface of the water, at which point a massive release will have occurred that would be nearly impossible to clean up.”) (citing Envy Report at 13-14; Oct. 28, 2016, SRST Letter at 5); id. at 13 (stating the EA’s “startlingly optimistic times for responding to a spill after it has been detected ... have been the subject of withering criticism”) (citing Ac-cufacts, Inc. Review at 5-6; EarthFax Report at 9; Sealed Kuprewicz Deck, ¶¶ 15-17; Envy Report at 27); id. at 13-14 (“One expert review found numerous flaws in the Corps’ analysis of water quality impacts of a spill, including a failure to identify key pollutants; overstatement of flows that dilute likely pollutant impacts; use of an inappropriate standard to determine toxicity; and reliance on the wrong drinking water standard.”) (citing Earth-Fax Report at 5-7); id at 14 (arguing EA’s treatment of impact of winter conditions on spill risk was inadequate) (citing EarthFax Report at 7-8; Oct. 28, 2016, SRST Letter at 5; ECF No. 196-2 (Declaration of Elliott Ward, Mar. 25, 2017), ¶ 12) with EA at 19, 36 (borehole leaks); 26-28 (landslides); 42, 46, 90-91 (description of leak-detection system as “capable of detecting leaks down to 1 percent or better of the pipeline flow rate within a time span of approximately 1 hour or less and capable of providing rupture detection within 1 to 3 minutes”); 36-49 (discussing impacts of spill to water quality); 39, 43, 123 (discussing impact of “[s]ub-freezing temperatures during the winter months” and means of responding to spill in winter, including identifying “all-weather access and collection point” downstream of Oahe crossing and undertaking “full scale winter/ice” emergency response drills/exercises). Disagreement with an agency’s analysis is not enough to warrant the consideration of extra-record evidence, which, after all, is “the exception, not the rule.” Oceana, Inc. v. Pritzker, 126 F.Supp.3d 110, 113 (D.D.C. 2015) (quoting Theodore Roosevelt Conservation Partnership v. Salazar, 616 F.3d 497, 514 (D.C. Cir. 2010)). As it proceeds through Standing Rock’s arguments regarding the deficiencies in the EA’s analysis, therefore, the Court will not engage with those contentions, - that turn on evidence that post-dates February 8, 2017. This procedural brush now cleared away, the Court tackles the substance of the Tribe’s no-convincing-case position, beginning with spill risks and continuing to Treaty rights. , ■. b. .Spill-Risk Analysis Although grouped under the “spill-risk” heading, Standing Rock’s challenges here encompass the'risk of spills, the degree of scientific controversy, and the cumulative risk of the project, each of which is analyzed separately. i. Risk of Spill Standing Rock first maintains that the 'EA understates and does not properly assess the risk of an oil spill under Lake Oahe. See SRST MSJ at 21 (“[T]he Corps falls back on a rote mantra that the risk of oil spills is low.”); id. at 22 (citing Solicitor Op. at 28-29 & n.171 (noting PHMSA data shows average of' over 283 significant incidents involving gas, oil, or other pipelines per year since 1996)).> It argues that, although the" EA repeats that the spill risk is “very low,” “unlikely,” or “negligible,” see, e.g., EA at 48, 63, 87, it does not explain what “low” means. See SRST Reply at 9. And “to conduct a. credible assessment of spill risks,” the- Corps, should have addressed -concerns relating to landslide risks, inadequate spill-detection systems, underground leaks, response times, spill volumes, water-quality analysis, and winter conditions, id, at 11-14, and looked at portions of the pipeline entering and exiting the boreholes. Id. at 15-16. The EA, in fact, devotes several pages to discussing DAPL’s “reliability and safety.” EA at 88-94. The relevant section first explains that, “[t]o prevent pipeline failures resulting in inadvertent releases,” DAPL will be constructed and maintained in accordance with “industry and governmental requirements and standards,” including those from PHMSA, the American Society of Mechanical Engineefs, the National Association for Corrosion Engineers, and the American Petroleum Industry. Id. at 88. After its installation, the pipeline will undergo “hydrostatic pressure testing at the crossings, checking coating integrity, and X-ray inspection of the welds.” Id. The pipeline right-of-ways will also “be patrolled and inspected by air ... at least every three weeks and not less than 26 times per year[] to check for abnormal conditions or. dangerous activities,, such as unauthorized excavation along the. pipeline route.” Id In addition, Dakota Access plans to use “a supervisory control and data acquisition ... system to provide constant remote oversight of the pipeline facilities,” including the detection of “rapid drops in:, pressure,” and pipeline-monitoring software to identify any leaks by tracking “pipeline, pressure, flow, and temperature data”- pulled every six seconds. Id at 89-90. The EA reports that such a system “is capable of detecting leaks down to 1 percent or better of the pipeline flow rate within a time span of approximately 1 hour or less and capable of providing rupture detection within 1 to 3 minutes.” Id. at 90. If a leak is detected, remotely operated valves are to be triggered and closed within three minutes. Id. Other courts, including this Circuit, have favorably viewed similar agency reliance on applicable regulatory standards -when assessing impacts as part of a NEPA-required analysis. See, e.g., EarthReports, Inc. v. FERC, 828 F.3d 949, 957 (D.C. Cir. 2016) (holding agency fulfilled its NEPA obligations to evaluate baliast-water impacts by, inter alia, noting requirements of applicable regulatory agencies); Sierra Club v. Clinton, 746 F.Supp.2d 1025, 1047 (D. Minn. 2010) (holding agency properly considered impacts of pipeline abandonment by referencing PHMSA regulations). The EA then proceeds tb review the basis for its conclusion that the risk of an oil spill is “low.” EA at 92. Specifically, that conclusion comes from a risk analysis conducted by Dakota Access that was derived from criteria set out in “the W. Kent Muhlbauer Relative Index Methodology (2004), in accordance with 49 CFR 195.452 ‘Hazardous Liquid Pipelines in High Consequence Area’, API RP 1160 ‘Managing System Integrity for Hazardous Liquid Pipelines’, and ASME B31.8S ‘Managing System Integrity of Gas Pipelines.’” Id. That analysis' “addressed nine industry-recognized pipeline integrity threat categories”: (1) third-party damage; (2) external corrosion; (3) internal corrosion; (4) pipe-manufacturing defects; (5) construction-related defects; (6) incorrect operations; (7) equipment failure; (8) stress-corrosion cracking; and (9) natural forces. Id. at 92-94. The underlying analysis is not itself in the record, see SRST Reply at 8, but the EA summarizes its conclusions as to each of the nine factors. Although no explanation is provided, three of the nine factors— external corrosion, internal corrosion, and construction-related defects — are assessed only as to the crossing at Lake Sakakaw-ea;- the other six are applied to both Saka-kawea and Oahe. See EA at 92-94. The EA’s explanation of its choice of methodology and subsequent treatment of the different factors' is nonetheless enough to give substance to the Corps’ conclusion that the risk of a spill is low. See Sierra Club v. Watkins, 808 F.Supp. 852, 868 (D.D.C. 1991) (explaining courts should “defer to an agency’s decision to use a particular risk assessment methodology that is consistent with general principles of science”) (citing Sierra Club v. Dep’t of Transp., 753 F.2d 120, 128-29 (D.C. Cir. 1985)). For example, the EA explains that, at the Oahe crossing, spill risk due to third-party damage is low because the pipeline is positioned 92 feet below the lakebed; spill risk from manufacturing defects is also slim because the pipeline will be “hydrostatically strength-tested”; and spill risk from “incorrect operations (e.g., overpressure event caused by human error)” is low because the pipeline is designed to withstand twice the maximum-allowable operating pressure. See EA at 92-94. The EA thus does not simply use “[a]n unbounded term” that “provides no objective standard for determining what kind of differential makes one impact more or less significant than another.” Mainella, 459 F.Supp.2d at 101. Admittedly, the EA does not quantify the risk of,a spill,with exact numerical precision. But in setting out the specific factors that undergirded its risk analysis and explaining their application to DAPL, the EA reasonably gives the necessary content to its top-line conclusion that the risk of a spill is low. As noted above in the discussion of extra-record evidence, moreover, the EA did not omit discussion of borehole leaks (EA at 19, 36); landslides (EA at 26-28); leak-detection systems (EA at 42, 46, 90 — 91); water quality (EA at 36-49); or winter temperatures (EA at 39, 43, 123). To the extent the.Tribes’ experts disagree with the Corps’ technical assessments or overall conclusion, such disagreements are “a classic example , of a factual dispute the resolution of which implicates, substantial agency expertise.” Wisc. Valley Improvement Co. v. FERC, 236 F.3d 738, 746 (D.C. Cir. 2001) (quoting Marsh, 490 U.S. at 376, 109 S.Ct. 1851). In such .situations, courts “must defer to ‘the informed discretion of the responsible federal agencies.’” Id. at 747 (quoting Marsh, 490 U.S. at 377, 109 S.Ct. 1851); see also Nat’l Comm. for the New River v. FERC, 373 F.3d 1323, 1327 (D.C. Cir. 2004) (“When an agency ‘is evaluating scientific data within its technical expertise,’ an ‘extreme degree of deference to the agency’1 is warranted.”) (quoting B & J Oil & Gas v. FERC, 353 F.3d 71, 76 (D.C. Cir. 2004)). ii. Highly Controversial Although the Court cannot agree with Standing Rock that the Corps did not adequately consider or explain its conclusion that the risk of an oh spill is low, a related position gains more traction. As explained above, CEQ regulations provide that one factor that “should be considered” in evaluating the significance of a proposed action’s impact is ‘‘[t]he degree to which the effects on the quality, of, the human environment are likely to be highly controversial.” 40 C.F.R. § 1508.27(b)(4). Standing Rock argues that evidence in the .record indicated that the pipeline’s effects were highly controversial, and that ■ the Corps therefore should have concluded that the project would have significant impacts on the environment. See SRST MSJ at 20-421. Such controversy is not measured by newsworthiness; instead, according to the Court of Appeals, “The term ‘controversial’ refers, to cases where a .substantial dispute exists as to the size, nature, or effect of the major federal action rather than to the existence of opposition to a use.” Town of Cave Creek, Arizona v. FAA, 325 F.3d 320, 331 (D.C. Cir. 2003) (quoting Found. for N. Am. Wild Sheep v. Dep’t of Agric., 681 F.2d 1172, 1182 (9th Cir. 1982)). Despite that explanation, how-éver, as other courts in this district have observed, “Just what constitutes the type of ‘controversy’ -that requires a full EIS is not entirely clear.” Nat’l Parks Conservation Ass’n v. United States, 177 F.Supp.3d 1, 33 (D.D.C. 2016) (quoting Nat’l Wildlife Fed’n v