Full opinion text
RANDALL, Circuit Judge: This is an appeal from a district court judgment that enjoined the private defendants from any additional clearing, except by permit under 33 U.S.C. § 1344 (Supp. V 1981), of certain lands determined by the district court to be wetlands. The federal defendants contend that the district court' should have reviewed the Environmental Protection Agency’s (“EPA”) final wetlands determination (attached as an appendix to this opinion) on the basis of the administrative record, and that the court erred in adopting its own wetlands determination instead of reviewing the agency’s determination under the arbitrary and capricious standard. The federal defendants also dispute the district court’s conclusion that the mere removal of vegetation from wetlands constitutes a discharge of a pollutant under section 301(a) of the Clean Water Act (“CWA”), 33 U.S.C. § 1311(a) (1976). The private defendants contest the validity of the district court’s determination that approximately ninety percent of their land is a wetland, as well as the court’s conclusion that their landclearing activities fall under the CWA’s prohibition on the discharge of pollutants into waters of the United States. For the reasons set forth below, to the extent that the district court’s decision that ninety percent of the Lake Long Tract is a wetland is inconsistent with the EPA’s determination, the decision of the district court is reversed. The court’s determination that the private defendants’ actual landclearing activities require permits is affirmed. I. FACTUAL AND PROCEDURAL BACKGROUND. This case concerns an approximately 20,-000 acre tract of land (the “Lake Long Tract”) in Avoyelles Parish, Louisiana. The tract lies within the Bayou Natchitoches basin, an area of approximately 140,000 acres, which, along with the Ouachita, Black and Tensas river basins, makes up the Red River backwater area. The Bayou Natchitoches basin is subject to flooding during the spring months, and it experiences an average rainfall of sixty inches per year. Much of the basin had been cleared of forest before the private defendants began their landclearing activities, but 80,000 acres were still forested. The Lake Long Tract made up a quarter of this forested area. The topography of the tract itself is uneven, resulting in some areas with permanent water impoundments and other drier areas that support a variety of plant species. The private defendants own the Lake Long Tract. They decided that the land could be put to agricultural use, specifically soybean production. Consequently, they began a program of large-scale deforestation in June of 1978. Using bulldozers with shearing blades that “floated” along the ground, the defendants cut the timber and vegetation at or just above ground level. The trees were then raked into windrows, burned, and the stumps and ashes were disced into the ground by other machinery. The shearing and raking caused some leveling of the tract, and the defendants dug one drainage ditch. On August 25, 1978, the Vicksburg District of the Army Corps of Engineers ordered defendant Prevot to halt his activities pending a wetlands determination by the Corps. Thereafter, Dr. Donald G. Rhodes, an expert consultant employed by the Corps, undertook a comprehensive vegetative mapping of the Lake Long Tract and determined that thirty-five percent of it was a wetland. In October, 1978, the Fish and Wildlife Service wrote a letter to the Corps stating that the Service believed that the entire tract was a wetland. After Dr. Rhodes had made his determination, the landowners resumed their activities on the portion of the tract that the Corps had not designated as a wetland. On November 8, 1978, the plaintiffs brought this citizens’ suit against a number of Corps and EPA officials, as well as against the private landowners. The plaintiffs claimed, inter alia, that the landclearing activities would result in the discharge of dredged and fill material into the waters of the United States in violation of sections 301(a) and 404 of the CWA, 33 U.S.C. §§ 1311, 1344 (1976 & Supp. V 1981), and also result in the discharge of pollutants into the waters of the United States in violation of section 402 of the CWA, 33 U.S.C. § 1342 (1976 & Supp. V 1981). The plaintiffs requested a declaration that the tract was a wetland within the scope of the CWA, that the private defendants could not engage in their landclearing activities without obtaining a permit from the EPA or the Corps, and that the federal defendants had failed to exercise their “mandatory duty” to designate the tract a wetland and to order the private defendants to cease and desist from discharging pollutants and dredged materials. The plaintiffs also sought injunctive relief against the federal defendants to require them to exercise their jurisdiction over the property and to issue cease-and-desist orders until the private defendants obtained the requisite permits. The district court immediately issued a temporary restraining order, preventing the private defendants from engaging in land-clearing activities pending the court’s action on the plaintiffs’ motion for a preliminary injunction. On January 17, 1979, the district court granted the plaintiffs' motion for a preliminary injunction and ordered the federal defendants to prepare a final wetlands determination within sixty days. All of the private parties were to have the opportunity to participate in the administrative proceedings, and the federal defendants were to file a preliminary report within forty-five days. The court allowed the private defendants to engage in normal cultivation on the more than 10,000 acres that had been cleared, but ordered them to apply for a permit with respect to the area already designated by the government as a wetland and enjoined them for sixty days from engaging in landclearing activities on the remainder of the tract. The parties complied with the court’s preliminary order, and the EPA submitted its final wetlands determination on March 26, 1979. After examining the vegetation, soil conditions, and hydrology of the tract, the EPA concluded that approximately eighty percent of the land was a wetland. In a brief final paragraph, the EPA also offered its views of the types of activities that would require a section 404 permit. At the private defendants’ request, the district court agreed to bifurcate the consideration of the two major issues in the case: (1) how much of the Lake Long Tract was a wetland, and (2) which activities required a section 404 permit. After extensive trials on both issues, the court decided that a section 404 permit was required for the landclearing activities and that over ninety percent of' the Lake Long Tract was a wetland. The court then enjoined the private defendants from engaging in any additional landclearing activities, without a section 404 permit, on the land that the court had determined to be a wetland, other than the land already cleared. The defendants timely appealed. 11. THE WETLANDS DETERMINATION. The procedural posture of this case is, to say the least, unusual. Issues were raised by the parties at one stage of the litigation only to be forgotten or ignored by both the parties and the court at a later stage in the proceedings. Indeed, as in Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U.S. 519, 540, 98 S.Ct. 1197, 1210, 55 L.Ed.2d 460 (1978), the parties in this litigation have “changed positions as nimbly as if dancing a quadrille.” In deciding to give the federal defendants an opportunity to make a final wetlands determination, the district court recognized that the federal defendants bore the “primary responsibility” for the determination of which lands were wetlands: But these matters often come up to a court in the nature of a review of a ruling made by a Governmental agency. In this instance one of the primary requests for relief made by the plaintiffs was that the agencies be directed to take up this matter of delineation of wetlands, the definition of what are wetlands, and then the enforcing of their order after it is so defined. Also, coupled with that was a prayer more directly to the merits; that is, that the Court itself makes such definitions and defines them. This is something which does not come up every day, and Congress has burdened and designated certain Government agencies with the responsibility for doing just what the prayer in this petition requests .... Whatever the reason, the matter of wetlands in this area, the definition of what is wetlands in that area is not now definite.... [B]asically speaking, since this is a responsibility which Congress has designated the Corps and two other Government agencies to accomplish, it is their primary responsibility and they have the expertise to handle the question. And since in just about all cases that the Court has come into contact with, these cases have been cases in which the Court has the benefit of the consideration given by the agencies and is not called upon to be the agency of first impression, or to use its own initiative in making a definition or enforcing it. It has been asked to review a definition made by persons who are experts in that field and have accumulated expert testimony. ... [T]he Court ordinarily has the benefit of this consideration. And I feel that the Court in this instance should also have the benefit of this consideration, if it is possible to do so. Preliminary Injunction Hearing Transcript at 34r-36. After asking the federal agencies to use their expertise in making a final wetlands determination, however, the court proceeded to conduct a de novo trial on the wetlands issue and to substitute its judgment for the EPA’s, without any explanation in its opinion of why it had found it necessary to go outside of the administrative record or of the standard that it was using to review the EPA’s determination. Thus, while it may not be a sea that we have all been cast adrift upon, we have nevertheless been cast adrift. The federal defendants maintain that the court’s de novo review of the EPA’s final wetlands determination was inappropriate. They contend that the district court should have reviewed the agency’s determination on the basis of the administrative record, and that the agency’s determination should have been upheld as long as it was not “arbitrary and capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(B) (1976). We agree with the federal defendants that the district court’s wetlands determination must be set aside because the court applied the wrong standard in reviewing the agency’s determination. A. Standard of Review. Since the Clean Water Act does not set forth the standards for reviewing the EPA’s or the Corps’ decisions, we look to the Administrative Procedure Act (APA), 5 U.S.C. §§ 701 et seq. (1976), for guidance. See Save the Bay, Inc. v. Administrator of the EPA, 556 F.2d 1282 (5th Cir.1977); Natural Resources Defense Council, Inc. v. Train, 510 F.2d 692 (D.C.Cir.1975). In general, the APA provides that a court shall set aside agency findings, conclusions, and actions that are “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law,” or that fail to meet statutory, procedural or constitutional requirements. 5 U.S.C. §§ 706(2)(A), (B), (C), (D). This standard of review is highly deferential. A final agency decision is “entitled to a presumption of regularity.” Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 415, 91 S.Ct. 814, 823, 28 L.Ed.2d 136 (1971). While the court “must consider whether the decision was based on a consideration of the relevant factors and whether there has been a clear error of judgment,” and while “this inquiry into the facts is to be searching and careful, the ultimate standard of review is a narrow one.” Id. at 416, 91 S.Ct. at 824. In Overton Park, the Supreme Court stated unequivocally that the “court is not empowered to substitute its judgment for that of the agency.” Id.; accord Bowman Transportation, Inc. v. Arkansas-Best Freight System, Inc., 419 U.S. 281, 285, 290, 95 S.Ct. 438, 442, 444, 42 L.Ed.2d 447 (1974); Louisiana Environmental Society, Inc. v. Dole, 707 F.2d 116, 118-19 (5th Cir.1983); City of Houston v. FAA, 679 F.2d 1184, 1190 (5th Cir.1982). In Ethyl Corp. v. EPA, 541 F.2d 1 (D.C. Cir.) (en banc), cert, denied, 426 U.S. 941, 96 S.Ct. 2663, 49 L.Ed.2d 394 (1976), the Court of Appeals for the District of Columbia explained the boundaries of a court’s role in reviewing an agency decision under the arbitrary and capricious standard. The Ethyl court directed reviewing courts to “immerse” themselves in the evidence in the administrative record in order to determine whether the “agency decision was rational and based on consideration of the relevant factors.” 541 F.2d at 36 (citing Overton Park). The court warned, however, that this effort to understand the evidence must be performed with a “conscientious awareness of the limited nature” of the court’s function and the need to defer to the agency’s expertise: The enforced education into the intricacies of the problem before the agency is not designed to enable the court to become a superagency that can supplant the agency’s expert decision-maker. To the contrary, the court must give due deference to the agency’s ability to rely on its own developed expertise. . .. Thus, after our careful study of the record, we must take a step back from the agency decision. We must look at the decision not as the chemist, biologist or statistician that we are qualified neither by training nor experience to be, but as a reviewing court exercising our narrowly defined duty of holding agencies to certain minimal standards of rationality. Id. (citations and footnotes omitted). The basis for a court’s review of an agency decision is subject to narrow limitations. Where an agency’s decision is based on an administrative record, the decision should be reviewed in light of that record. Camp v. Pitts, 411 U.S. 138, 142-43, 93 S.Ct. 1241, 1244, 36 L.Ed.2d 106 (1973); accord Louisiana Environmental Society, supra. If the agency decision is not sustainable on the basis of the administrative record, then “the matter should be remanded to [the agency] for further consideration.” Camp, 411 U.S. at 143, 93 S.Ct. at 1244 (emphasis added); accord Vermont Yankee Nuclear Power Corp. v. National Resources Defense Council, Inc., 435 U.S. 519, 549, 98 S.Ct. 1197, 1214, 55 L.Ed.2d 460 (1978). In “certain narrow, specifically limited situations,” agency action may also be set aside if it is not supported by “substantial evidence,” 5 U.S.C. § 706(2)(E), or, in “other equally narrow circumstances,” a court may engage in de novo review of the action and set it aside if it is “unwarranted by the facts”, 5 U.S.C. § 706(2)(F). Overton Park, 401 U.S. at 414, 91 S.Ct. at 822. De novo review under section 706(2)(F) is authorized only “when the action is adjudicatory in nature and the agency factfinding procedures are inadequate,” or “when issues that were not raised before the agency are raised in a proceeding to enforce nonadjudicatory agency action.” Overton Park, 401 U.S. at 415, 91 S.Ct. at 823. No one contends that the substantial evidence test applies to this case, nor is there any indication that de novo review was authorized by the presence of either of the circumstances mentioned in Overton Park. Had this case commenced as a challenge to the Corps’ decision to grant or deny a section 404 dredge-and-fill permit, the district court would clearly have been expected to review the agency’s decision under the arbitrary and capricious standard on the basis of the administrative record. See Buttrey v. United States, 690 F.2d 1170, 1183-85 (5th Cir.1982), cert, denied, - U.S. -, 103 S.Ct. 2087, 77 L.Ed.2d 298 (1983) (Corps’ denial of permit reviewed on administrative record under arbitrary and capricious standard); Joseph G. Moretti, Inc. v. Hoffman, 526 F.2d 1311, 1312 (5th Cir.1976) (discovery not improperly curtailed because challenge to Corps’ denial of permit must be reviewed on basis of administrative record; Corps’ decision was not arbitrary and capricious); Di Vosta Rentals, Inc. v. Lee, 488 F.2d 674, 678-79 (5th Cir. 1973), cert, denied, 416 U.S. 984, 94 S.Ct. 2387, 40 L.Ed.2d 761 (1974) (court’s review of Corps’ permit decision is limited to whether that decision is arbitrary and capricious in light of administrative record). The plaintiffs argue that the court’s de novo review of the final wetlands determination was appropriate in this case because the EPA’s determination was a jurisdictional decision. We disagree. This is not a case where the parties have challenged the federal agency’s jurisdiction to assert any authority over the tract. The landowners have conceded that thirty-five percent of the tract is a wetland subject to the federal defendants’ regulatory jurisdiction under the CWA. We are not confronted with a situation where the court must determine whether the property falls under the agency’s jurisdiction at all before it may determine whether the exercise of the agency’s jurisdiction is appropriate. See, e.g., United States v. Lee Wood Contracting, Inc., 529 F.Supp. 119 (E.D.Mich.1981) (enforcement action holding that land is “neighboring wetland” within Corps’ jurisdiction); Parkview Corp. v. Department of the Army Corps of Engineers, 469 F.Supp. 217 (E.D.Wis.1979) (granting Corps’ summary judgment motion that the land is a wetland under 1974 definition within Corps’ jurisdiction); P.F.Z. Properties, Inc. v. Train, 393 F.Supp. 1370 (D.D.C.1975) (holding that Corps had jurisdiction over proposed building site). The question in this case is the extent, not the existence, of agency jurisdiction. Since there is no assertion that the EPA’s jurisdiction is conspicuously lacking, its findings with respect to' the extent of its jurisdiction must be reviewed under the same standard as any other administrative findings. See Federal Power Commission v. Transcontinental Gas Pipe Line Corp., 423 U.S. 326, 331, 96 S.Ct. 579, 582, 46 L.Ed.2d 533 (1976) (commissioner’s findings reviewed under “substantial evidence” standard where existence of gas shortage formed “the factual predicate necessary to the Commission’s assertion of authority”); Buttrey, supra, 690 F.2d at 1185-86 (Corps’ determination of the extent of wetlands reviewed under arbitrary and capricious standard); cf. Deltona Corp. v. Alexander, 682 F.2d 888, 893-94 (11th Cir.1982) (upholding district court’s grant of summary judgment in Corps’ favor on jurisdictional issue because plaintiff had not exhausted administrative remedies and extent of wetlands is type of decision necessitating agency expertise). The wetlands determination is precisely the type of agency decision that is normally subject to limited judicial review. The EPA developed an extensive administrative record in making its decision; it collected reports from its own expert consultants, as well as from the parties. The determination itself, which requires an analysis of the types of vegetation, soil and water conditions that would indicate the existence of wetlands, is the kind of scientific decision normally accorded significant deference by the courts. See Deltona Corp., supra; Hercules, Inc. v. EPA, 598 F.2d 91, 106 (D.C.Cir. 1978); Ethyl, supra. De novo review would permit the courts to intrude into an area in which they have no particular competence, and the presentation of the scientific evidence at both the administrative and judicial levels of the proceeding would result in inefficiencies and delays where they are most harmful. See Sierra Club v. Sigler, 695 F.2d 957, 981 (5th Cir.1983) (noting that “protracted litigation in environmental eases can kill projects by delay”). The arbitrary and capricious standard affords the proper deference to the agency’s scientific expertise, while the requirement that a court engage in a thorough in-depth review of the administrative record to ascertain whether the agency has considered all of the relevant factors and whether the agency’s decision is rational, Overton Park, 401 U.S. at 416, 91 S.Ct. at 823-24, assures that deference to the agency does not.result in abdication of judicial responsibility. See Ethyl, supra, 541 F.2d at 36-37. At trial, the landowners objected to the EPA’s reliance on the administrative record, claiming that it was not a true administrative record because it had been “prepared by order of the court, which was not in the ordinary course of administrative proceedings.” 23 Record at 444 — 45. The administrative determination in this case is something of a hybrid since it was prepared in a sixty day period under a court order. In the absence of any indication that it was actually tainted by the nature of the proceedings, however, see Overton Park, 401 U.S. at 420, 91 S.Ct. at 825 (court may go outside of administrative record only upon showing of bad faith or improper behavior), the administrative record compiled by the agency should have served as the “focal point” for judicial review of the EPA’s final wetlands determination. See Camp, supra, 411 U.S. at 142, 93 S.Ct. at 1244; Louisiana Environmental Society, supra, 707 F.2d at 119. We hold that the district court erred in substituting its own wetlands determination for the EPA’s instead of reviewing the agency’s decision, as supported by the administrative record, under the arbitrary and capricious standard. Under different circumstances, we might end our review of the wetlands determination here and remand to the district court for review of the agency decision under the appropriate standard. This litigation has, however, already gone on long enough, particularly because it involves the type of project that may be killed by the delay. See Sierra Club, supra. Because the nature of the dispute over the EPA’s wetlands determination is primarily a legal one, subject to our own independent review, and because the reasonableness of the EPA’s decision turns on an analysis of documentary evidence, rather than on the credibility of witnesses appearing before a trial judge, we do not believe that anything could happen in the district court on remand that would change our view of whether the EPA’s determination was arbitrary and capricious. Accordingly, we have decided to review the agency’s determination ourselves. See Sierra Club, supra, 695 F.2d at 981; Di Vosta, supra, 488 F.2d at 679. B. Methodology. The private defendants claim that the EPA’s decision to examine additional species of vegetation, as well as the soil and hydrology of the tract, in making its wetlands determination constituted rule-making. Emphasizing the substantial difference between the Vicksburg District consultant’s methodology and determination and the EPA’s, and the probable impact of this change in methodology throughout the State of Louisiana, the landowners contend that the agencies could not make such a drastic change in their methodology without complying with the notice and comment procedures required by 5 U.S.C. § 553. The plaintiffs and federal defendants argue that the change in methodology was merely an interpretation of the Corps’ existing wetlands definition, 33 C.F.R. § 323.2(c) (1982), and that therefore notice and comment proceedings were not required. 5 U.S.C. § 553(b)(A) (notice and comment requirements do not apply to “interpretative rules, general statements of policy, or rules of agency organization, procedure or practice.”). All of the parties recognize that we must look beyond the label to the substance of an administrative action in order to determine whether rulemaking procedures were required. CBS, Inc. v. United States, 316 U.S. 407, 419, 62 S.Ct. 1194, 1201, 86 L.Ed. 1563 (1942). 1. Legislative Or Interpretative Rule. The APA defines the term “rule” broadly enough to include virtually every statement an agency may make, 5 U.S.C. § 551(4), but not every ruling requires the procedures set forth in section 553. While “legislative” or “substantive” rules may only be promulgated in compliance with section 553, “interpretative” rules are expressly excluded from the section. In Batterton v. Marshall, 648 F.2d 694 (D.C.Cir.1980), the District of Columbia Circuit reviewed some of the differences between the two types of rulings: Legislative rules ... grant rights, impose obligations, or produce other significant effects on private interests. They also narrowly constrict the discretion of agency officials by largely determining the issue addressed. Finally, legislative rules have substantive legal effect. 648 F.2d at 701-02 (footnotes omitted). In contrast, interpretative rules are not determinative of issues or rights addressed. They express the agency’s intended course of action, its tentative view of the meaning of a particular statutory term, or internal house-keeping measures organizing agency activities. They do not ... foreclose alternate courses of action or conclusively affect rights of private parties. Id. at 702 (footnotes omitted). Perhaps most importantly, interpretative rules are subject to more extensive judicial review than are legislative rules. Id The Batterton court admitted, however, that it would be “less than candid if [it] pretended that the labels ... neatly place particular agency actions within any particular category. Instead, the categories have ‘fuzzy perimeters’ and establish ‘no general formula.’ ” 648 F.2d at 702 (quoting Pacific Gas & Electric Co. v. FPC, 506 F.2d 33, 38 (D.C.Cir.1974); F. Cooper, Administrative Agencies and the Courts 87 (1951)); see also NLRB v. Wyman-Gordon Co., 394 U.S. 759, 770, 89 S.Ct. 1426, 1432, 22 L.Ed.2d 709 (1969) (Black, J., concurring in the result) (the line between an agency’s quasi-legislative function and its quasi-judicial function is not always clear); see generally 2 K. Davis, Administrative Law Treatise § 7 (2d ed. 1983). Further, an agency has the discretion to proceed through case-by-case adjudications and interpretative orders, rather than through the rulemaking process, for the agency will often confront special problems necessitating a flexible approach to their resolution. In SEC v. Chenery Corp., 332 U.S. 194, 67 S.Ct. 1575, 91 L.Ed. 1995 (1947), the Supreme Court explained: The function of filling in the interstices of the Act should be performed, as much as possible, through this quasi-legislative promulgation of rules to be applied in the future. But any rigid requirement to that effect would make the administrative process inflexible and incapable of dealing with many of the specialized problems which arise.... Not every principle essential to the effective administration of a statute can or should be cast immediately into the mold of a general rule. Some principles must await their own development, while others must be adjusted to meet particular, unforeseeable situations. In performing its important functions in these respects, therefore, an administrative agency must be equipped to act either by general rule or by individual order. To insist upon one form of action to the exclusion of the other is to exalt form over necessity. 332 U.S. at 202, 67 S.Ct. at 1580; accord Viacom International, Inc. v. FCC, 672 F.2d 1034, 1042 (2d Cir.1982); Giles Lowery Stockyards, Inc. v. Department of Agriculture, 565 F.2d 321, 325 (5th Cir.1977), cert, denied, 436 U.S. 957, 98 S.Ct. 3070, 57 L.Ed.2d 1122 (1978); West v. Chafee, 560 F.2d 942, 947 (8th Cir.1977); Port Terminal Railroad Association v. United States, 551 F.2d 1336, 1345 (5th Cir.1977). In Chenery, the Supreme Court recognized: In other words, problems may arise in a case which the administrative agency could not reasonably foresee, problems which must be solved despite the absence of a relevant general rule. Or the agency may not have had sufficient experience with a particular problem to warrant rigidifying its tentative judgment into a hard and fast rule. Or the problem may be so specialized and varying in nature as to be impossible of capture within the boundaries of a general rule. In those situations, the agency must retain power to deal with the problems on a case-to-case basis if the administrative process is to be effective. There is thus a very definite place for the case-by-case evolution of statutory standards. And the choice made between proceeding by general rule or by individual, ad hoc litigation is one that lies primarily in the informed discretion of the administrative agency. 332 U.S. at 202-03, 67 S.Ct. at 1580. The critical question in any challenge to the propriety of the method used by the agency in reaching its decision is whether the decision-making procedure satisfied the underlying purpose of the APA: affording a procedure that is fair to the affected parties. Batterton, supra, 648 F.2d at 703; National Helium Corp. v. Federal Energy Administration, 569 F.2d 1137, 1146 (Temp.Emer.Ct.App.1978). We hold that under the circumstances of this case, the EPA’s wetlands methodology was not void for failure to comply with the section 553 notice and comment requirements because the methodology was an interpretative application, not an amendment of, the 1977 definition. The federal defendants’ development of the methodology appears to have been a response to the agencies’ perception that the Corps’ 1977 amendments of its regulations expanded the scope of its wetlands definition. Unlike the rules establishing fixed criteria to control the agencies’ decisions in the cases cited by the landowners, see, e.g., Batterton, supra (regulation established critical statistical variable in formula for computing unemployment rate); Pickus v. United States Board of Parole, 507 F.2d 1107 (D.C.Cir.1974) (Parole Board’s use of guidelines established specific factors for determining parole eligibility); Lewis-Mota v. Secretary of Labor, 469 F.2d 478 (2d Cir.1972) (regulation effectively repealed prior method for obtaining immigration visa); Texaco, Inc. v. Federal Power Commission, 412 F.2d 740, 741 (3d Cir.1969) (regulation required payment of interest “compounded monthly”), the federal defendants’ methodology was designed as a flexible approach to implementation of the Corps’ definition. In fact, some of the factors that the landowners object to appear to have been included to insure that the agencies did not unduly expand the definition. The methodology requires an analysis of soil and hydrology because the types of vegetation added to the agencies’ calculus may or may not be wetland indicators; thus, the analysis of soil and hydrology may narrow, as well as expand, the agencies’ jurisdiction. Final Wetlands Determination at 3, 2 Record at 375. While the landowners’ challenge to the methodology is cast in procedural terms, their underlying contention is really nothing more than a challenge to the EPA’s interpretation of the regulation. The EPA maintains that the 1977 amendments, not the methodology, expanded the Corps’ wetlands definition. The landowners contend that the amendment was purely technical and was not intended to add facultative hydrophytes to the types of vegetation that would indicate the existence of wetlands. Because the landowners view the methodology as a significant expansion — or amendment — of the 1977 definition, they contend that rulemaking was required. We proceed, therefore, to consider whether the federal defendants’ interpretation alters the regulation. 2. Vegetation Typically Adapted for Life in Saturated Soil Conditions. In reviewing the federal defendants’ interpretation, we must keep in mind that “the interpretation given [a] statute by the officers or agency charged with its administration” is entitled to substantial deference. Ford Motor Credit Co. v. Milhollin, 444 U.S. 555, 566, 100 S.Ct. 790, 797, 63 L.Ed.2d 22 (1980) (quoting Zenith Radio Corp. v. United States, 437 U.S. 443, 450, 98 S.Ct. 2441, 2445, 57 L.Ed.2d 337 (1978)); see also Udall v. Tallman, 380 U.S. 1, 16, 85 S.Ct. 792, 801, 13 L.Ed.2d 616 (1965); Quarles v. St. Clair, 711 F.2d 691 at 706 (5th Cir.1983). An agency’s construction of its own regulations is entitled to even greater deference. Ford Motor, supra, 444 U.S. at 566, 100 S.Ct. at 797; Udall, supra, 380 U.S. at 16, 85 S.Ct. at 801. Regardless of whether the court would have arrived at the same interpretation, if the agency’s interpretation is reasonable the court must respect it. Udall, supra; Kinnett Dairies, Inc. v. Farrow, 580 F.2d 1260, 1270 (5th Cir.1978). A number of factors will influence the amount of deference due in a given case. These include: the degree of scientific or technical agency expertise necessarily drawn on in reaching the interpretation, Ford Motor, supra; Kinnett, supra; “the consistency of the interpretation and the length of adherence to it, undisturbed by Congress; [and] the explicitness of the congressional grant of authority to the agency.” Quarles, supra. Evaluation of these factors requires a high degree of deference in this case. Congress has delegated substantial authority to the EPA administrator, and with respect to the dredge-and-fill permits, to the Corps, for the implementation of the CWA. See, e.g., 33 U.S.C. §§ 1311, 1314, 1342, 1362 (EPA responsible for setting effluent limitations, and water quality standards, issuing National Pollution Discharge Elimination System permits, and prescribing necessary regulations); 33 U.S.C. §§ 1344, 419 (Corps responsible for issuing dredge-and-fill permits and is authorized to prescribe regulations under Rivers and Harbors Act). See also E.I. Dupont de Nemours & Co. v. Train, 430 U.S. 112, 134, 97 S.Ct. 965, 978, 51 L.Ed.2d 204 (1977) (Supreme Court defers to EPA’s interpretation of CWA because agency is charged with administering the Act, interpretation is reasonable and supported by scholarly opinion) (quoting Train v. Natural Resources Defense Council, Inc., 421 U.S. 60, 87, 95 S.Ct. 1470, 1485-86, 43 L.Ed.2d 731 (1976) (deferring to EPA’s interpretation of Clean Air Act)). While the methodology used in this case had been recently established, the interpretation of the wetlands definition necessarily drew on the agencies’ scientific expertise. The definition concerns the scope of the CWA, and with it the scope of the federal government’s ability to control the discharge of pollutants into the waters of the United States. The EPA and the Corps were in the best position to determine precisely what property must come under federal control in order to protect the nation’s waters. The Corps’ 1975 regulations defined “fresh water wetlands” as “those areas that normally are characterized by the prevalence of vegetation that requires saturated soil conditions for growth and reproduction.” 42 Fed.Reg. 37128 (July 19, 1977) (emphasis added). In 1977, the Corps revised its regulations to define “wetlands” as The term “wetlands” means those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas. 33 C.F.R. § 323.2(e) (1982) (emphasis added). The Corps explained that this revision was intended to eliminate several problems and to'achieve certain results: The reference to “periodic inundation” has been eliminated. Many interpreted that term as requiring inundation over a record period of years. Our intent under Section 404 is to regulate discharges of dredged or fill material into the aquatic system as it exists, and not as it may have existed over a record period of time. The new definition is designed to achieve this intent. It pertains to an existing wetland and requires that the area be inundated or saturated by water at a frequency and duration sufficient to support aquatic vegetation. This inundation or saturation may be caused by either surface water, ground water, or a combination of both. The use of the word “normally” in the old definition generated a great deal of confusion. The term was included in the definitions to respond to those situations in which an individual would attempt to eliminate the permit review requirements of Section 404 by destroying the aquatic vegetation, and to those areas that are not aquatic but experience an abnormal presence of aquatic vegetation. Several such instances of destruction of aquatic vegetation in order to eliminate Section 404 jurisdiction actually have occurred. However, even if this destruction occurs, the area still remains as part of the overall aquatic system intended to be protected by the Section 404 program. Conversely, the abnormal presence of aquatic vegetation in a non-aquatic area would not be sufficient to include that area within the Section 404 program. We have responded to the concern for the vagueness of the term “normally” by replacing it with the phrase “... and that under normal circumstances to [sic] support.... ” We do not intend, by this clarification, to assert jurisdiction over those areas that once were wetlands and part of an aquatic system, but which, in the past, have been transformed into dry land for various purposes. Concerns were also expressed over the types and amount of vegetation that would be required to establish a “wetland” under this definition. We have again used the term “prevalence” to distinguish from those areas that have only occasional aquatic vegetation interspersed with upland or dry land vegetation. At the same time, we have changed our description of the vegetation involved by focusing on vegetation “typically adapted for life in saturated soil conditions.” The old definition of “freshwater wetlands” provided a technical “loophole” by describing the vegetation as that which requires saturated soil conditions for growth and reproduction, thereby excluding many forms of truly aquatic vegetation that are prevalent in an inundated or saturated area, but that do not require saturated soil from a biological standpoint for their growth and reproduction. We intend to publish shortly vegetation guides to indicate the types of vegetation intended to be included in this definition, and to rely on the assistance of biologists, scientists and other technical experts from other Federal and State agencies to assist in delineating those wetland areas intended to be included in this definition. 42 Fed.Reg. 37128 (July 19, 1977). Focusing on the Corps’ statement in the preamble in the Federal Register to the effect that the section 404 program was “being revised to clarify many terms,” 42 Fed.Reg. 37122 (July 19, 1977) (emphasis added), the private defendants maintain that the definitional change was intended to be minor. They emphasize that the Corps expressed an intent to include only “truly aquatic areas,” listing “swamps, bogs, and marshes at the end of [the] definition to further clarify [its] intent,” 42 Fed. Reg. 37129. They maintain that the facultative hydrophytes were never meant to be considered as wetland indicators. The private defendants’ analysis merely begs the question of what is a “truly aquatic area” within the Corps’ definition, since “truly aquatic” is not defined in the regulations. While the list of “aquatic areas” at the end of the definition may give us some idea of its scope, that list is inclusive, not exclusive, and the terms “swamps, bogs and marshes” are also undefined. The obligate hydrophytes might be the only species able to survive in a “deep water swamp,” but the definition clearly does not limit its scope to such permanently inundated areas. The comments accompanying the promulgation of the 1977 regulations may be read to support the federal defendants’ interpretation as easily as they may be read to support the landowners’. The comments explained that the Corps had “changed [its] description of the vegetation involved by focusing on vegetation typically adapted for life in saturated soil conditions.” 42 Fed. Reg. 37128 (emphasis added). This “change” was designed to close a “technical loophole” that had “excluded many forms of truly aquatic vegetation that are prevalent in an inundated or saturated area, but that do not require saturated soil from a biological standpoint for their growth and reproduction.” Id. These statements suggest that the Corps fully intended to add certain previously excluded species to its list of wetland indicators. We are equally unpersuaded that the federal defendants’ position is in error by the landowners’ parsing of the definition itself. The landowners would read the words “vegetation typically adapted for life in saturated soil conditions” as limiting the wetlands indicators to species able to survive their entire life cycle in saturated soils. The federal defendants argue that “typically adapted for life in” these soil conditions means the ability to live in such conditions, although some of the species may require relief at certain points in their life cycles. A reading of the entire definition indicates that the agencies’ interpretation is the more reasonable, since wetlands are not limited to areas that are permanently inundated. Finally, we agree with the federal defendants that the decision to analyze the soil and hydrology flows from the language of the definition. The definition speaks of areas that are inundated or saturated “at a frequency and duration sufficient to support” the wetland indicators. We fail to understand how the agency may determine whether a tract is such an area without examining its hydrology. Similarly, the definition provides that a ' wetland is an area that “under normal circumstances [does] support” vegetation typically adapted for life in “saturated soil conditions.” It would seem that the logical method for determining whether this requirement is met is to examine whether the soil is or is likely to be frequently saturated. Regardless of whether the agencies had engaged in an analysis of soil and hydrology in the past, no new burden not already contained in the definition was imposed on the landowners by this change in practice. See Yale Broadcasting Co. v. FCC, 478 F.2d 594, 595-96 (D.C.Cir.), cert, denied, 414 U.S. 914, 94 S.Ct. 211, 38 L.Ed.2d 152 (1973). Since we conclude that the agencies’ interpretation of the wetlands definition is reasonable, we are required to respect it. Udall, supra. A fortiori, we agree with the federal defendants that the methodology was not a significant alteration of the 1977 regulations, and therefore notice-and-comment procedures were not required. 3. Fairness. There is an additional reason why we have concluded that the failure to engage in notice-and-comment procedures should not invalidate the EPA’s final wetlands determination. As discussed above, in deciding whether such procedures are required, a court must keep in mind the underlying purpose of the APA: fairness to the affected parties. The landowners had, and took advantage of, the opportunity to argue about which species were wetlands indicators both at the administrative proceeding and at the trial. Further, while disclaiming the usefulness of the approach, Dr. Rhodes, on whose report the landowners rely heavily, conducted his own analysis of the Lake Long Tract’s soil and hydrology conditions. Admin.Record, Tab 3.17. Therefore, the EPA’s adoption of the methodology did not make the administrative proceedings less than fundamentally fair. Compare Giles Lowery Stockyards, supra (rulemaking not required for agency’s adoption of method for computing livestock exchange rates where plaintiff was aware of agency’s plan to use the methodology and had had an opportunity to build case around it; plaintiff’s decision to use different method not relevant), with Port Terminal, supra (agency’s rejection of plaintiff’s cost studies on ground that studies failed to use specific formula unfair where agency had previously refused to standardize formula); Hill v. Federal Power Commission, 335 F.2d 355 (5th Cir.1964) (hearing unfair where standards applied had not evolved or been announced until agency decision held them unsatisfied). We note further that even if we were to accept the landowners’ contention that the methodology should have been adopted pursuant to notice-and-comment procedures, the same methodology would be required under the EPA’s present regulations. In 1980, the EPA, in conjunction with the Corps, revised its regulations implementing the section 404 permit program. See 45 Ref. 85336 (Dec. 24, 1980). These revisions were made after notice in the Federal Register and a comment period. Id. The regulations require the permitting authority to examine the soil, the hydrology and the aquatic ecosystem to determine the effects of the proposed activity on the aquatic environment. 40 C.F.R. §§ 230.11(a), (b), (c), .20, .21, .22. Section 230.41(a)(3) provides: Wetland vegetation consists of plants that require saturated soils to survive (obligate wetland plants) as well as plants, including certain trees, that gain a competitive advantage over others because they can tolerate prolonged wet soil conditions and their competitors cannot. In addition to plant populations and communities, wetlands are delimited by hydrological and physical characteristics of the environment. These characteristics should be considered when information about them is needed to supplement information available about vegetation, or where wetland vegetation has been removed or is dormant. 40 C.F.R. § 230.41(a)(3) (1982). Since an appellate court must apply the agency’s current regulations, Thorpe v. Housing Authority, 393 U.S. 268, 282, 89 S.Ct. 518, 526, 21 L.Ed.2d 474 (1969); Florida Power & Light Co. v. Costle, 650 F.2d 579, 590 (5th Cir.1981), the most that we could do would be to remand for reconsideration under the new regulations. See Florida Power & Light, supra; Port Terminal, supra (permit-, ting agency to apply new standards on remand as long as plaintiff is given opportunity to present additional evidence). Here, there is no reason for a remand because the landowners have already had an adequate opportunity to present their evidence under the “new” regulations. 4. The Regulations and the Clean Water Act. Having determined that the federal defendants’ interpretation is consistent with the Corps’ wetlands definition, we must consider whether the definition is consistent with the statute and the Constitution. Again in reviewing the statutory question, we must keep in mind the principle that an agency’s interpretation of the statute that it administers is to be accorded significant deference. Ford Motor, supra; Quarles, supra. We conclude that the federal defendants’ interpretation of this “complex” statute is sufficiently reasonable to preclude us from substituting our judgment for the agencies’. See DuPont, supra, 430 U.S. at 134, 97 S.Ct. at 978; Natural Resources Defense Council, supra, 421 U.S. at 87, 95 S.Ct. at 1485. As the district court recognized, Congress had lofty goals in enacting the CWA: “The objective of this chapter is to restore and maintain the chemical and biological integrity of the Nation’s waters.” 33 U.S.C. § 1251(a) (1976). Congress expressly stated its intent “that the term ‘navigable waters’ be given the broadest possible constitutional interpretation.... ” 1 Legislative History, at 178 (Senate consideration of the Conference Report on S. 2770, Oct. 4, 1972); see also 1 Legislative History, at 250-51 (House Consideration of same, Oct. 4, 1972). The report of the Senate Committee on Public Works submitted with S. 2770 explained the need for a broad definition of “navigable waters” in order to control the discharge of pollution at its source: The control strategy of the Act extends to navigable waters. The definition of this term means the navigable waters of the United States, portions thereof, and includes the territorial seas and the Great Lakes. Through narrow interpretation of the definition of interstate waters the implementation [of the] 1965 Act was severely limited. Water moves in hydrological cycles and it is essential that .discharge of pollutants be controlled at the source. Therefore, reference to the control requirements must be made to the navigable waters, portions thereof, and their tributaries. 2 Legislative History, at 1495 (emphasis added); see also Leslie Salt Co. v. Froehlke, 578 F.2d 742 (9th Cir.1978). Attempts by the House to limit the statute’s reach to waters that were in fact navigable were rejected in 1977. See 3 Legislative History, at 281 (H.Conf .Rep. No. 830). When Congress rejected the attempts to limit the Corps’ jurisdiction in 1977, it was well aware of the extension of that jurisdiction beyond the traditional definition of “navigable waters,” as well as the Corps’ proposed revision of its wetlands definition. See 4 Legislative History, at 920-22 (statement of Sen. Baker during Senate debate over Bentsen amendment, August 4, 1977); 3 Legislative History, at 347-A8 (statement of Rep. Roberts, member of Conference Committee, during House debate, December 15, 1977). In fact, Congress repeatedly recognized the importance of protecting wetlands if the nation was to realize the statutory goal of restoring the chemical and biological integrity of the nation’s waters. Senator Muskie, one of the primary sponsors of the CWA, explained: There has been considerable discussion of the provisions of section 404 of the act, much of which has been related to the suspicions and fears with respect to that section, and little of which has been related to substantive solutions to real problems while providing an adequate regulatory effort to assure some degree of wetlands protection. There is no question that the systematic destruction of the Nation’s wetlands is causing serious, permanent ecological damage. The wetlands and bays, estuaries and deltas are the Nation’s most biologically active areas. They represent a principal source of food supply. They are the spawning grounds for much of the fish and shellfish which populate the oceans, and they are passages for numerous upland game fish. They also provide nesting areas for a myriad of species of birds and wildlife. The unregulated destruction of these areas is a matter which needs to be corrected and which implementation of section 404 has attempted to achieve. 4 Legislative History, at 869 (remarks of Sen. Muskie during Senate debate on S. 1952, Aug. 4, 1977). While there were statements during the 1972 deliberations to the effect that the CWA was not intended to extend beyond currently navigable waters, 1 Legislative History, at 178, 250 (statements of Sen. Muskie and Rep. Dingell), those statements were rendered virtually meaningless by Congress’ refusal to restrict the definition in 1977. The EPA and the Corps expanded the wetlands definition in order to control “the discharge of pollutants at the source.” We cannot say that the EPA’s application of the definition to areas, like the Lake Long Tract, which experience significant flooding during a substantial portion of the year and serve as major overflow or backwater areas for the nation’s rivers, or its conclusion that the discharge of pollution into such areas would have a significant effect on the nation’s waters, was an unreasonable application of the statute. The EPA’s decision is therefore entitled to our respect. 5. Constitutional Challenges to the Corps’ Definition. The landowners also contend that if the CWA authorizes regulation to the extent proposed by the federal defendants, then the Act is unconstitutionally vague and an unlawful delegation of legislative power. We find no merit in either claim. The federal Constitution provides that “[A]ll legislative powers herein granted shall be vested in Congress.” U.S.Const. art. 1, § 1. While Congress is not permitted to “abdicate or transfer to others the essential legislative functions with which it is vested,” it may authorize other bodies to determine specific facts and may also establish general standards and delegate to others the responsibility for effectuating the legislative policy. Schechter Corp. v. United States, 295 U.S. 495, 529-30, 55 S.Ct. 837, 842-43, 79 L.Ed. 1570 (1935); accord Panama Refining Co. v. Ryan, 293 U.S. 388, 421, 55 S.Ct. 241, 248-49, 79 L.Ed. 446 (1935); United States v. Gordon, 580 F.2d 827, 839 (5th Cir.), cert, denied, 439 U.S. 1051, 99 S.Ct. 731, 58 L.Ed.2d 711 (1978). In considering an attack on a congressional delegation, our task is to determine whether the standards set forth by Congress are “sufficiently definite in light of the complexity of the area at which the legislation is directed.” Gordon, supra (citing Carlson v. Landon, 342 U.S. 524, 542, 544, 72 S.Ct. 525, 535, 536, 96 L.Ed. 547 (1952)). The CWA’s delegation of authority to the EPA and the Corps clearly meets this test. Congress’ goal — the restoration of the integrity of the nation’s waters and the elimination of discharges of pollutants into those waters — is succinctly set forth in 33 U.S.C. § 1251(a). The agencies’ jurisdiction under the CWA extends to all “waters of the United States,” and the 1977 regulation provides specific criteria further defining the statutory term. In reviewing an application for a dredge-and-fill permit, the agencies are to consider any “unacceptable adverse effect on municipal water supplies, shellfish beds and fishery areas (including spawning and breeding wells), wildlife, or recreational areas,” 33 U.S.C. § 1344(c), and the effect of the “disposal of pollutants on human health or welfare, ... marine life, ... esthetic, recreation and economic values . .. [and] the persistence and permanence of [these] effects.. .. ” 33 U.S.C. § 1343(c)(1)(A)-(D). This is not the kind of standardless discretion condemned in Schecter, supra. The .landowners’ vagueness challenge is really just the other side of their delegation challenge. We cannot agree that the application of the Corps’ wetlands definition in this case is so vague as to deprive the landowners of notice that they may be subject to civil and criminal penalties. Indeed, at this point the vagueness claim is based on pure speculation, since the landowners have not been subjected to either civil or criminal penalties. At the commencement of these proceedings, the landowners were well aware that at least a significant portion of their land was a wetland; if they wished to protect themselves from liability they could have applied for a permit and thus obtained a precise delineation of the extent of the wetland, as well as the activities permissible on the land. See United States v. Byrd, 609 F.2d 1204, 1209 (7th Cir.1979) (upholding grant of summary judgment and permanent injunction to the government and noting that landowner could protect himself from civil and criminal liability by seeking a permit that would set forth the extent of the wetlands on his property). In United States v. Phelps Dodge Corp., 391 F.Supp. 1181 (D.Ariz. 1975), the district court rejected a vagueness challenge to the application of the CWA to “normally dry arroyos” in a criminal proceeding, a circumstance counseling far greater concern for vagueness than this. We are unpersuaded that the Corps’ wetlands definition failed to give the landowners notice of their potential liability in this case. 6. The Merits of the EPA’s Wetlands Determination. The essence of the landowners’ challenge to the EPA’s final wetlands determination concerned the legal issues described above, in particular the use of the new methodology. To a limited extent, the landowners have also disputed some of the agency’s factual findings. Our review of the administrative record in this case does not indicate that the EPA’s findings were arbitrary or capricious. While the EPA found that approximately eighty percent of the Lake Long Tract was a wetland, the district court found that over ninety percent of the tract was a wetland. The court and the agency reached different conclusions because they held differing beliefs about whether Tensas and Dundee soils were wetlands soils. The EPA’s conclusion that areas made up of these two soils should be excluded from the wetlands area was based on the report of the agency’s soil expert, Dr. William H. Patrick, Jr. Dr. Patrick examined the site’s soils for wetness, texture, color and extent of mottling and concluded that the Dundee and Tensas soils were less likely to remain saturated than the other wetlands soils. See Admin.Record, Tab 3.19. The district court found that all of these soils were wetlands soils because they drain poorly. While there may have been room for a difference in opinion about the nature of these soils, such a difference does not mean that the agency’s decision was arbitrary or capricious. The agency and its expert explained their reasons for concluding that the Dundee and Tensas soils were not wetlands, and their decision is not irrational. Since the courts may not require any more than that, Overton Park, supra, the district court erred in substituting its judgment about the character of the soils for the agency’s. The landowners emphasize that the EPA’s determination that approximately eighty percent of the tract was a wetland does not correspond to the findings of any of its experts. In discussing percentages, it is all too easy to lose sight of the fact that we are discussing the characteristics of land, not the amount of octane required in gasoline or the amount of lead permitted in drainage pipes. We must not forget that these percentages are a mere shorthand for the map of wetlands that our pens and tongues cannot adequately describe. The eighty-percent figure is based on Dr. Patrick’s report about the area’s soils. He opined that sixty percent of the tract was a wetland because he would have excluded from his calculations the Tensas-Sharkey soils, which he viewed as mixed and non-mixed wetlands soils, as well as the Dundee and Tensas soils. Admin.Record, Tab 3.19. The EPA decided not to exclude the Tensas-Sharkey soils because it was too difficult to separate these soils from the wetlands soils. Final Wetlands Determination at 6-7, 2 Record at 377-78; Admin.Record, Tab 3.38 (EPA Regional Administrator’s Report). Since the Tensas-Sharkey soils accounted for approximately twenty percent of the tract, their inclusion explains the difference between the EPA’s determination and its expert’s. Finally, the landowners dispute the EPA’s findings with respect to which types of vegetation were wetlands indicators and the extent of the inundation of the tract. The vegetation dispute concerns whether the facultative hydrophytes should be considered wetlands indicators, not which types of vegetation were actually on the tract. We have already determined that the EPA’s view of the matter was not irrational. While there were conflicting reports about the extent of flooding on the tract, both in the administrative record and at trial, this conflict was properly resolved by the agency. In summary, we hold that the EPA’s final wetlands determination was not arbitrary or capricious. Therefore, the district court’s determination must be set aside to the extent that it is in conflict with the agency’s, and the agency’s determination should be reinstated. III. ACTIVITIES REQUIRING A PERMIT. We note at the outset of our discussion of the landclearing activities in this case that the litigation over this issue has not proceeded in the most desirable fashion. At oral argument, we asked the federal defendants why they were not claiming that their determination of which activities would require a permit should be subject to the same standard of review as the wetlands determination. Their counsel responded that the same standard probably should have applied, but he