Defendant Tull, a real estate developer, placed fill on “wetlands” without a permit at several locations on the island of Chincoteague, Virginia. The government sued, alleging that this filling violated both the Clean Water Act,1 33 U.S.C. § 1251 et seq., and the Rivers and Harbors Appropriation Act, 33 U.S.C. § 401 et seq. The district court 615 F.Supp. 610, found Tull had violated both Acts, fined him, and ordered various other remedies. Tull appeals, and we affirm.
I.
We begin our discussion by summarizing the statutory and factual background of this dispute. We then treat those of appellant’s arguments that merit discussion.
Statutory Background
The Clean Water Act aims “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” 33 U.S.C. § 1251(a). To accomplish this purpose, the Act prohibits the discharge without a permit of dredged or fill material into “navigable waters” of the United States. 33 U.S.C. §§ 1311, 1344. The Act authorizes the Secretary of the Army to issue the permits required for such discharges. The Secretary has in turn delegated this authority to the Corps of Engineers. 33 C.F.R. § 325.8 (1984). The Corps evaluates permit applications under guidelines developed by the Environmental Protection Agency in conjunction with the Secretary of the Army. 33 U.S.C. § 1344(b).
*184The reach of the Clean Water Act extends beyond discharges into waters actually supporting navigation. “Navigable waters” are defined as “the waters of the United States, including the territorial seas.” 33 U.S.C. § 1362(7). During the legislative proceedings culminating in the enactment of that section, the Conference Committee explained the legislative intent in defining this term:
The Conferees fully intend that the term “navigable waters” be given the broadest possible constitutional interpretation unencumbered by agency determinations which have been made or may be made for administrative purposes.
S.Conf.Rep. No. 1236, 92d Cong., 2d Sess., reprinted in 1972 U.S.Code Cong. & Ad. News 3668, 3776, 3822.
Included in the areas subject to Corps regulation under the Clean Water Act are “wetlands” adjacent to other “waters” of the United States. 33 C.F.R. § 323.2(a)(1)-(7) (1984). “Wetlands” are defined as “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 to life in saturated soil conditions.” The administrative definition further provides that wetlands “generally include swamps, marshes, bogs and similar areas.” 33 C.F.R. § 323.2(c) (1984).
The Rivers and Harbors Act, which defendant Tull was also found to have violated, prohibits placing fill in navigable waters without the authorization of the Secretary of the Army. 33 U.S.C. § 403. This Act defined “navigable waters” at the time of Tull’s alleged violation as waters that “have been used in the past, are now used, or are susceptible to use” for interstate commerce, and waters subject to the ebb and flow of the tide. 33 C.F.R. § 209.-260(k)(2) (1975), superseded by 33 C.F.R. § 329.4 (1984) (similar definition).
Factual Background
The government sued Tull in July of 1981 for dumping fill at three locations in violation of the Clean Water Act:
(1) Ocean Breeze Mobile Homes Sites;
(2) Mire Pond Properties
(3) Eel Creek.
The government later amended its complaint to allege that by placing fill in Fowling Gut Extended, a manmade waterway on the Ocean Breeze property, Tull also violated the Rivers and Harbors Act.
The evidence at a 15-day bench trial showed that Tull began placing fill on the Ocean Breeze property in 1975, on the Mire Pond properties in 1978, and on the Eel Creek property sometime after December of 1980. Tull filled in Fowling Gut Extended, a body of water described as a canal or ditch, beginning in 1976. Tull never applied for a permit to place fill at any of these locations.
Tull did not deny that he had placed fill at the locations alleged, nor did he claim that he had ever applied for a permit. Rather, he argued that the properties filled did not contain wetlands within the meaning of the Clean Water Act, and that Fowling Gut Extended was not navigable within the meaning of the Rivers and Harbors Act. He further argued that the government was estopped from seeking equitable relief, and that the Clean Water Act as applied to him was unconstitutional.
On the issue of whether the filled properties contained wetlands, the government produced at trial extensive evidence, including 12 expert witnesses, to establish that the areas filled by Tull included “wetlands” within the jurisdiction of the Corps of Engineers. Buried soil analysis showed the presence of peat, which develops only in a wetlands system. Vegetation analysis showed the presence of “obligate” wetlands species, which require saturated soil conditions. Expert testimony established tidal influence and some degree of inundation.
Dr. Donna Ware, a court-appointed expert, agreed with the conclusions of the government witnesses, finding wetlands existed on the properties in question. Mr. Ronald Beebe, a civil engineer testifying *185for Tull, disagreed. His opinion that certain filled areas were not within Corps jurisdiction, however, was based not on the regulatory definition of wetlands, but on the fact that the developed sections lay above the high-water mark. The district court supplemented the extensive expert testimony by conducting a viewing of the filled areas.
The evidence on Fowling Gut Extended showed that the federal government had spent $30,000 in 1963 for construction of a drainage ditch to control mosquito breeding. One witness testified that boats could travel up this ditch or canal, at least for a short time, and that it was subject to the ebb and flow of the tide.
The district court concluded there was “substantial, credible evidence” that Tull had filled areas “typically tidal, marsh or bog in character” on all the properties in question. It found that Fowling Gut Extended “was navigable in fact and was utilized by boat traffic subsequent to 1963 and prior to the time when [Tull] filled in this waterway without applying for or obtaining any permit from the Army Corps of Engineers.” Concluding that Tull had violated both Acts, the district court assessed fines of $75,000 for the filling at Ocean Breeze, Mire Pond, and Eel Creek, and ordered Tull to restore areas on all three properties to wetlands. For filling Fowling Gut Extended, Tull was ordered either to pay a $250,000 fine or to restore the canal “to its former navigable condition.”
II.
Whether the Clean Water Act or its Application Here is Unconstitutional2 A. The Commerce Clause
Tull argues that the regulation of his property under the Clean Water Act goes beyond the proper reach of the commerce clause. The Seventh Circuit rejected this argument in United States v. Byrd, 609 F.2d 1204, 1210 (7 Cir.1979). It found that regulating wetlands was justified by the negative effect that destruction of wetlands could have on the “biological, chemical, and physical integrity of the [navigable] lakes they adjoin.” Id. at 1210. The Supreme Court has cited this discussion in Byrd with approval, noting “we agree with the lower federal courts that have uniformly found the power conferred by the Commerce Clause broad enough to permit congressional regulation of activities causing air or water pollution____” Hodel v. Virginia Surface Mining & Reclamation Assn., 452 U.S. 264, 282, 101 S.Ct. 2352, 2363, 69 L.Ed.2d 1 (1981). We follow these authorities and reject defendant’s argument.
Tull concedes that there is precedent rejecting his commerce clause argument. He urges, however, that the government already litigated this issue against him and lost, in United States v. Tull, No. 75-319-N slip op. (E.D.Va. November 12, 1975). We disagree. Collateral estoppel precludes the government from relitigating “the same issue already litigated against the same party in another case involving virtually identical facts.” United States v. Stauffer Chemical Co., 464 U.S. 165,-, 104 S.Ct. 575, 578, 78 L.Ed.2d 388, 392 (1984). The earlier case against Tull, however, did not present a virtually identical situation, nor was the commerce clause issue squarely presented.
In the earlier case, Tull introduced fill without a permit into an area behind a bulkhead. The district court found that the area was “high and dry most of the time,” and “would probably see a little flooding for only two or three hours per *186month.” It lay above the mean high water line, and the district court found it “could not even be said to be ‘periodically’ flooded” within the meaning of the regulation then defining Corps jurisdiction. See 40 Fed.Reg. 31,320 (1975).3 The district court then suggested in dictum that including land which is “high and dry, above the average high tide” line within federal regulation because it might be periodically inundated “is further than we choose to go.” That decision left open the question whether areas that receive sufficient flooding or saturation to support plants adapted to “saturated soil conditions,” and that therefore meet the current definition of “wetlands,” 33 C.F.R. § 323.2(c) (1984), are constitutionally subject to federal jurisdiction.
B. Vagueness
Tull argues that the Clean Water Act regulations are unconstitutionally vague because the imprecise definition of “wetlands” makes it too difficult for landowners to determine their potential liability. We reject this argument, as have other courts. See Avoyelles Sportsmen’s League, Inc. v. Marsh, 715 F.2d 897, 917 (5 Cir.1983); United States v. Phelps Dodge Corp., 391 F.Supp. 1181, 1187 (D.Ariz. 1975). As applied to this case, the regulatory definition of wetlands is sufficiently definite to give a person of ordinary intelligence fair notice of what conduct the Clean Water Act prohibits or requires. Cf. United States v. Harriss, 347 U.S. 612, 617-18, 74 S.Ct. 808, 811-12, 98 L.Ed. 989 (1954).
III.
Whether Tull Had a Right to a Jury Trial
We find no merit in Tull’s claim that he had a right to a jury trial in this case. The seventh amendment right to a jury trial is limited to suits in the nature of an action existing at common law when the amendment was adopted. Atlas Roofing Co. v. Occupational Safety and Health Review Commission, 430 U.S. 442, 458, 97 S.Ct. 1261, 1270, 51 L.Ed.2d 464 (1977); NLRB v. Jones & Laughlin Steel Corp., 301 U.S. 1, 48, 57 S.Ct. 615, 629, 81 L.Ed. 893 (1937). “... Congress may constitutionally enact a statutory remedy unknown at common law, vesting factfinding in an administrative agency or others without the need for a jury trial.” Republic Industries v. Teamsters Joint Council No. 83 of Virginia Pension Fund, 718 F.2d 628, 642 (4 Cir.1983), cert. denied, — U.S.-, 104 S.Ct. 3553, 82 L.Ed.2d 855 (1984).
Tull urges that he had a right to a jury trial because the government was seeking civil penalties under the Clean Water Act. To support this argument, he points to the Second Circuit’s decision in United States v. J.B. Williams Co., Inc., 498 F.2d 414 (2 Cir.1974). The court there found a seventh amendment “right of jury trial when the United States sues ... to collect a [statutory] penalty, even though the statute is silent on the right of jury trial.” Id. at 422-23 (quoting 5 Moore, Federal Practice 1138.-31[l] at 232-33 (1971 ed.)). In so holding, the Second Circuit found guidance in several older Supreme Court cases. Thus in Hepner v. United States, 213 U.S. 103, 115, 29 S.Ct. 474, 479, 53 L.Ed. 720 (1909), the Supreme Court suggested in dictum that “[t]he defendant was, of course, entitled to have a jury summoned” where the government sued to collect a $1,000 civil penalty for violation of the Alien Immigration Act. See also United States v. Regan, 232 U.S. 37, 34 S.Ct. 213, 58 L.Ed. 494 (1914) (dictum regarding penalty under Alien Immigration Act).
We reject defendant’s argument. First, we note that the Supreme Court has left open the question whether the dictum of *187Hepner and Regan “correctly divines the intent of the Seventh Amendment,” or whether the seventh amendment has no application to government litigation at all. Atlas Roofing, 430 U.S. at 449 n. 6, 97 S.Ct. at 1266 n. 6.
Second, even assuming that the seventh amendment applies to government litigation, the fact that the government is suing to collect statutory penalties does not require a jury trial. The Supreme Court has not gone “so far as to say that any award of monetary relief must necessarily be legal [as opposed to equitable] relief” for purposes of determining the right to a jury trial. Curtis v. Loether, 415 U.S. 189, 196, 94 S.Ct. 1005, 1009, 39 L.Ed.2d 260 (1974). In Regan (as in Hepner), the monetary relief sought was a penalty of a set amount, and the Supreme Court analogized the suit to “a civil action of debt.” Regan, 232 U.S. at 47, 34 S.Ct. at 216. Here the penalties are within the district court’s discretion; the government is not suing to collect a penalty analogous to a remedy at law, but is asking the district court to exercise statutorily conferred equitable power in determining the amount of the fine.
Nor are the penalties simply equivalent to punitive damages in actions at law. Here the assessment of penalties intertwines with the imposition of traditional equitable relief. The district court fashions a “package” of remedies, one part of the package affecting assessment of the others.4 This combined relief serves several goals, including environmental preservation and fairness to third party property buyers as well as deterrence. In such circumstances, the seventh amendment is inapplicable. See Jones & Laughlin, 301 U.S. at 48-49, 57 S.Ct. at 629-630, quoted in Atlas Roofing, 430 U.S. at 453, 97 S.Ct. at 1268 (seventh amendment inapplicable where “recovery of money damages is an incident to [nonlegal] relief even though damages might have been recovered in an action at law,” since equity courts historically granted such monetary relief).
IV.
Whether the Government is Equitably Estopped from Suing Tull
Tull argues that the government is equitably estopped from obtaining relief because Corps personnel misled him into believing that his filling activities were lawful and did not require a permit. The district court emphatically rejected this argument, finding that nothing the government did or failed to do misled the defendant. We cannot say this finding was clearly erroneous, and with no showing that the government misled Tull the equitable estoppel argument certainly must fail. See Heckler v. Community Health Services of Crawford County, Inc., 467 U.S. 51,-, 104 S.Ct. 2218, 2223-24, 81 L.Ed.2d 42, 51-52 (1984) (invoking equitable estoppel against government requires at least a showing that party reasonably relied on government’s misleading conduct). We therefore need not reach the issue whether misleading by silence or inaction, the most Tull alleges here, could ever justify invoking the equitable estoppel doctrine against the government. Cf. id., 467 U.S. at ——, 104 S.Ct. at 2224, 81 L.Ed.2d at 52 (whether doctrine applicable to government at all an open question); United States v. Harvey, 661 F.2d 767, 773-74 (9 Cir.1981), cert. denied, 459 U.S. 833, 103 S.Ct. 74, 74 L.Ed.2d 72 (1982) (invocation of doctrine against government requires affirmative misconduct).
Tull complains in particular about a Corps of Engineers’ visit to the Ocean Breeze property in July of 1976. An engineer told him not to place fill in one part of his property; Tull claims this instruction led him to believe that filling without a permit anywhere else on his property would be proper. Yet several witnesses testified that the purpose of the Corps’ visit was to determine whether ongoing work required filling permits. At the time *188of the visit, Tull did not discuss the future development of the property at issue here with the Corps engineers; indeed, he did not yet even have a development plan. Thus, there did not even exist plans that the engineers could have tacitly endorsed. Further, Tull’s earlier disputes with the Corps over the filling of property meant he could not have been ignorant of the general requirement of obtaining a permit to fill wetlands.
Tull further complains that the government misled him by waiting several years before bringing this suit. The district court found that any such delay did not mislead Tull. The government sued Tull unsuccessfully in 1975, issued a cease and desist order against his filling Eel Creek in 1976, and also obtained an injunction against his filling at Mire Pond. Given such circumstances, we cannot overturn the district court’s finding that Tull was in no way misled by the government’s failure to bring even more lawsuits against him.5
V.
Navigability of Fowling Gut Extended
Tull argues that he did not violate the Rivers and Harbors Act by placing fill in Fowling Gut Extended, since no credible evidence supported the district court’s finding that the waterway was navigable. We disagree. The district court had before it the testimony of an oyster inspector who testified that Fowling Gut Extended was subject to the ebb and flow of the tide. The Corps’ regulations in effect at the time Tull filled the waterway defined navigable waters to include those “subject to tidal action.” 33 C.F.R. § 209.260(k)(2) (1975), superseded by 33 C.F.R. § 329.4 (1984) (includes waters “subject to the ebb and flow of the tide”). See also 33 C.F.R. § 329.8(a) (1984) (“canal or other artificial waterbody that is subject to the ebb and flow of the tide is also a navigable water of the United States”). The district court therefore did not err in finding Fowling Gut Extended navigable.
We do not think that Tull’s other contentions merit discussion.
AFFIRMED.
. Also known as the Federal Water Pollution Control Act.
. Tull made a fifth amendment taking argument in the district court. It, however, rejected the argument on ripeness grounds, and Tull has not reasserted this argument on appeal. A Sixth Circuit panel, we recognize, has narrowly construed the Clean Water Act’s regulatory definition of wetlands to avoid what it sees as "a very real taking problem.” United States v. Riverside Bayview Homes, Inc., 729 F.2d 391, 398 (6 Cir. 1984), cert. granted, - U.S. ——, 105 S.Ct. 1166, 84 L.Ed.2d 318 (1985). Even Riverside's narrow construction, however, encompasses the swamp, marsh or bog adjacent to navigable waters at issue here. 729 F.2d at 398. Riverside would exclude only "inland low-lying areas” from Corps jurisdiction. Id. at 398, 401.
. This regulation, now superseded, provided: Corps jurisdiction would extend to all coastal waters subject to the ebb and flow of the tide shoreward to their mean high water mark ... and also to all wetlands, mudflats, swamps and similar areas which are contiguous or adjacent to coastal waters. This would include wetlands periodically inundated by saline or brackish waters that are characterized by the presence of salt water vegetation capable of growth and reproduction____
. Thus the fine for filling Fowling Gut Extended was offered as an alternative to the injunctive remedy of restoring that waterbody to its previous condition.
. The dissent, in asserting that the government should be estopped, adopts Tull's argument that he followed the Corps’ 1976 directions in placing fill on his property, while the Corps stood by and watched in silence until the government brought suit in 1981. The record establishes, however, that aerial photographs of new filling on Tull’s property in the summer of 1978 revealed possible statutory violations. Corps personnel then asked for an on-site meeting "to determine if the shoreline work being done on Mr. Tull’s property just south of Beebe Road could be in our regulatory jurisdiction.” Tull's lawyer responded by letter that “no work is being done on the property owned by [Tull] adjoining Fowling Gut at Chincoteague Island," and that the Corps’ request for an on-site meeting was therefore denied. A Corps scientist testified that at that time the Corps had information indicating that Tull had violated the law with respect to Ocean Breeze, but that it took no action because it lacked sufficient specific data on which to base a cease and desist order. Its effort to get further information by examining the property was thwarted. Given this evidence, Tull cannot argue meritoriously that he was the victim of innocent reliance, or that following the 1976 visit he had no further word from the Corps that they had any question about the propriety of his activities.