F I L E D

United States Court of Appeals

Tenth Circuit

February 21, 2006

Elisabeth A. Shumaker

Clerk of Court

PUBLISH

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff-Appellee, 

v.

JOHN HUBENKA,

Defendant-Appellant. 

---------------------------------- 

NORTHERN ARAPAHOE TRIBE,

EASTERN SHOSHONE TRIBE, and

NATIONAL WILDLIFE

FEDERATION,

 Amici Curiae. 

No. 05-8006

Appeal from the United States District Court

for the District of Wyoming

(D.C. No. 04-CR-04-B)

Robert R. Rogers, Assistant Federal Public Defender (Raymond P. Moore, Federal

Public Defender, with him on the briefs), Cheyenne, Wyoming, for DefendantAppellant.

Linda S. Kato, Special Assistant United States Attorney (Matthew H. Mead,

United States Attorney, John R. Green, Assistant United States Attorney, David
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A. Kubichek, Assistant United States Attorney, with her on the brief), for

Plaintiff-Appellee.

Thomas D. Lustig, Jim Murphy and Michael A. Saul, National Wildlife

Federation, Boulder, Colorado, filed an amici curiae brief on behalf of Northern

Arapahoe Tribe, Eastern Shoshone Tribe and National Wildlife Federation.

Before EBEL, McWILLIAMS and MURPHY, Circuit Judges.

MURPHY, Circuit Judge.

I. INTRODUCTION

A second superceding indictment charged John Edward Hubenka with three

counts of discharging pollutants into the Wind River in violation of the Clean

Water Act, 33 U.S.C. §§ 1311(a) and 1319(c)(2)(A). A jury found Hubenka

guilty on all three counts. Hubenka appeals his convictions. He argues his

activities on the Wind River lie beyond the reach of the Clean Water Act. 

Hubenka also contends the district court violated Rule 404(b) of the Federal Rules

of Evidence when it admitted into evidence certain testimony about Hubenka’s

past activities on the Wind River. This court exercises jurisdiction pursuant to 28

U.S.C. § 1291 and affirms.

II. BACKGROUND
1

In an average year, the Wind River’s peak runoff is in the range of 7000 to

8000 cubic feet per second. The highest volume recorded during a flood event on

the river was 13,900 cubic feet per second.

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The Wind River originates in Wyoming’s Wind River Range, on the east

slope of the continental divide near Togwotee Pass. From there, it flows

southeast through the Wind River Indian Reservation. Near Riverton, Wyoming,

the Wind River is joined by the Little Wind River and the Popo Agie River. 

Downstream from this confluence, the river is called the Big Horn River. Water

in the Big Horn River flows north, joins the Yellowstone River in Montana, and

eventually flows east into the Missouri River. The Wind River flows year-round,

with higher volume in the late spring and early summer, and lower volume in the

fall and winter.1

Appellant John Hubenka works as a manager for the LeClair Irrigation

District (“LID”) and lives on a ranch near the Wind River approximately eighteen

miles west of Riverton. Although the river is not a property boundary, it roughly

separates Hubenka’s land on the north from the Wind River Indian Reservation to

the south. LID maintains a diversion gate on the river to the northwest of

Hubenka’s property. The diversion gate allows water from the river to flow into

an irrigation canal which parallels the north side of the river for some distance. 

In the vicinity of Hubenka’s property, the Wind River is a braided stream

which flows through multiple channels within a broad flood plain. Historically,
2The Corps regulates the discharge of dredged and fill material under the

Clean Water Act. 33 U.S.C. § 1344(a), (d). 

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the river’s main flow was contained in a “north channel” which was closer to the

LID irrigation canal and further from the Indian Reservation. 

Over the years, Hubenka and LID have attempted to divert the flow of the

river away from the north channel so that the bank of the river does not erode and

threaten the irrigation canal. In 1979, LID obtained a permit from the United

States Army Corps of Engineers (“Corps”)2

 to stabilize the north bank of the river

at and downstream from the diversion gate. At the same time, LID dredged the

river bottom, effectively moving the main channel of the river away from the

north bank. LID’s original permit did not authorize this recontouring of the river

bottom, but in 1983 the Corps granted LID a permit which retroactively allowed

the dredging. Hubenka signed as the permitee on behalf of LID. 

In 1994, under Hubenka’s supervision, LID constructed a dike in the north

channel of the Wind River, slightly downstream of its diversion gate. The 1994

dike was constructed using river cobbles as well as scrap metal, cottonwood trees,

car bodies, and a washing machine. Similarly, downstream from the dike on

Hubenka’s property, the north bank of the river was reinforced with scrap metal

and construction debris. The Corps sent LID, via Hubenka, a notice of violation. 

The notice advised LID that its actions constituted unauthorized discharges and
3The Corps’ permit approved the use of a “stone-toe revetment” to stabilize

the north bank of the river. The revetment consisted of concrete rubble along the

bottom slope of the river bank held in place with wire mesh.

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instructed LID to refrain from adding material to the dike and to remove the

debris. The Corps sent a similar notice of violation directly to Hubenka.

In October of 1994, Tom Johnson, a representative of the Corps, conducted

a site visit to assess whether the prohibited materials had been removed. During

the site visit, Johnson observed a truck dumping more material on the dike. After

discussions with Hubenka and other representatives of LID, the Corps took action

to require LID to remove the dike in its entirety and to require Hubenka to remove

all debris except for clean concrete from the river bank on his property. After

LID and Hubenka complied with the Corps’ directive, the agency worked with

them to develop and issue a permit to stabilize the north bank of the river

downstream from the diversion gate using more acceptable techniques and

materials.3

 The stabilization project was constructed in 1995 and successfully

protected the north bank from erosion even during periods of high water.

At some point in the late 1990s or early in 2000, the river’s primary course

shifted from the north channel to a new “south channel.” Relative to the north

channel, the south channel is closer to the Indian Reservation and further from the

LID irrigation canal. The cause of the river’s change in course is unclear. 

Several witnesses living nearby testified that the Wind River shifted to the south
4Hubenka also had Neal construct a fourth dike further downstream. The

government did not charge Hubenka in conjunction with the construction of the

fourth dike. 

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channel naturally. The Corps’ Johnson, however, felt the change was not natural. 

Johnson, an expert in hydrology, testified that “something else happened to cause

that sudden and dramatic change.”

In March of 2000, Hubenka hired heavy equipment operator Curtis Neal to

construct a series of dikes or berms in the north channel of the Wind River. 

Using a bulldozer, Neal pushed river cobble from the north channel to form an

initial dike at the point where the north and south channels diverge, just

downstream of the LID diversion gate. “Dike one” blocked the north channel by

directing high flows along the face of the dike and into the south channel. 

Downstream from dike one, Hubenka had Neal construct a second dike parallel to

the south channel. “Dike two” prevented water from the south channel from

returning to the north channel. Further downstream, Neal constructed a third

dike—“dike three”—which again blocked water from reentering the north

channel.4

 All of the dikes were below the ordinary high water mark of the Wind

River. None of the dikes was authorized by a permit from the Corps. 

Early in 2004, Hubenka was charged with three violations of the Clean

Water Act. Specifically, the government alleged that each of the three dikes

constructed in 2000 constituted a knowing discharge of pollutants into the Wind
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River, a “‘water of the United States’ within the jurisdiction of the Clean Water

Act.” Hubenka was convicted on all three counts.

III. ANALYSIS

A. Application of the Clean Water Act to the Wind River

Hubenka argues the Corps’ authority to regulate dredge and fill activities

under the Clean Water Act does not extend to his activities on the Wind River. 

He contends the Corps is without jurisdiction because the dikes were built in a

river that is neither navigable-in-fact nor adjacent to other navigable-in-fact

waters, and because the dikes have no effect on navigable waters downstream. 

We must decide whether the district court erred in concluding that the Clean

Water Act gives the Corps authority to regulate Hubenka’s construction activities

in the north channel of the Wind River. The construction and applicability of the

Clean Water Act is an issue of law which this court reviews de novo. See United

States v. Telluride Co., 146 F.3d 1241, 1244 (10th Cir. 1998). 

Under the Clean Water Act, the Corps has jurisdiction over dredge and fill

activities in “navigable waters.” 33 U.S.C. § 1344(a). The statute itself defines

“navigable waters” as “waters of the United States.” Id. § 1362(7). As the

Supreme Court has recognized, “Congress chose to define the waters covered by

the Act broadly.” United States v. Riverside Bayview Homes, Inc., 474 U.S. 121,

133 (1985). 
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At first, Corps regulations interpreted the Clean Water Act so as to apply

only to navigable-in-fact waters. See id. at 123. In 1975, however, the Corps

issued new regulations which redefined “waters of the United States.” Id. Under

the revised regulations, the Clean Water Act applied not just to navigable-in-fact

waters, but inter alia, to tributaries of navigable waters and interstate waters. Id. 

Substantially identical regulations remain in place today. See 33 C.F.R. §

328.3(a)(5) (“tributary rule”). Hubenka argues the Corps’ “tributary rule”

inappropriately expands the agency’s jurisdiction under the Clean Water Act and

exceeds the agency’s statutory authority to regulate discharges of dredged and fill

material.

(1) Analysis of the Tributary Rule under the Chevron Framework

When a case involves an agency’s interpretation of a statute it administers,

this court uses the two-step approach announced in Chevron U.S.A., Inc. v.

Natural Res. Defense Council, Inc., 467 U.S. 837, 842–43 (1984). See S. Utah

Wilderness Alliance v. Dabney, 222 F.3d 819, 824 (10th Cir. 2000). Under this

approach, when Congress has addressed the precise question at issue, we give

effect to the express intent of Congress. Id. (citing Chevron, 467 U.S. at 842–43). 

“If the statute is silent or ambiguous, however, we defer to the agency’s

interpretation,” so long as it is permissible. Id. (citing Chevron, 467 U.S. at

843–44). 
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Under the first step of the Chevron framework, this court must determine

whether the Clean Water Act precisely addresses the question of whether

Congress intended to include within the Act’s purview tributaries of navigable or

interstate waters. As noted above, the Clean Water Act applies to “navigable

waters,” which it defines as “waters of the United States.” 33 U.S.C. § 1362(7). 

The Supreme Court has observed that Congress’ broad definition evidenced an

intent “to exercise its powers under the Commerce Clause to regulate at least

some waters that would not be deemed ‘navigable’ under the classical

understanding of that term.” Riverside, 474 U.S. at 133. Nevertheless, the statute

does not reveal the extent to which nonnavigable tributaries may be regulated. 

Accordingly, “[t]he statutory term ‘waters of the United States’ is sufficiently

ambiguous to constitute an implied delegation of authority to the Corps.” United

States v. Deaton, 332 F.3d 698, 709 (4th Cir. 2003). Because the Clean Water

Act’s definition of “navigable waters” is ambiguous, we move to the second step

of the Chevron analysis.

Normally, under Chevron’s second step, this court will defer to an agency’s 

interpretation of a statute that it administers, so long as the agency’s

interpretation is permissible. See Chevron, 467 U.S. at 843–44. Hubenka argues,

however, that the Corps’ tributary rule reaches the outer limits of constitutional

authority and raises serious constitutional questions. In such circumstances,
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Hubenka contends, this court should not extend Chevron deference to the Corps’

regulations. See Solid Waste Agency of N. Cook County v. Army Corps of

Engineers (“SWANCC”), 531 U.S. 159, 172–73 (2001). 

In SWANCC, the Supreme Court reviewed the Corps’ “migratory bird rule.” 

Id. at 164. The migratory bird rule purported to extend the Corps’ jurisdiction

under the Clean Water Act to isolated intrastate waters, so long as those waters

were used as habitat by certain migratory birds. Id. at 164–65. The Court struck

down the migratory bird rule, concluding the text of the Clean Water Act clearly

did not contemplate such expansive federal jurisdiction. Id. at 172. It went on to

note, however, that even if the statute itself had not clearly addressed the issue,

the Court would not have extended Chevron deference to the migratory bird rule. 

Id. The Court determined the Corps’ rule “invoke[d] the outer limits of Congress’

power,” and could find no indication that Congress intended that result. Id. at

172–73. It further observed that the migratory bird rule “raise[d] significant

constitutional questions.” Id. at 173. The Court read the statute “to avoid the

significant constitutional and federalism questions,” and therefore declined to

give Chevron deference to the Corps’ migratory bird rule. Id. at 174. 

 In contrast to the migratory bird rule at issue in SWANCC, the Corps’

tributary rule neither invokes the outer limits of Congress’ power nor raises

significant constitutional questions. “It has long been settled that Congress has
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extensive authority over this Nation’s waters under the Commerce Clause.” 

Kaiser Aetna v. United States, 444 U.S. 164, 173 (1979). It has the power to

regulate waters to limit pollution, prevent obstructions to navigation, reduce

flooding, and control watershed development. See, e.g., Riverside, 474 U.S. at

132–33; United States v. Republic Steel Corp., 362 U.S. 482, 489–90 (1960);

United States v. Appalachian Elec. Power Co., 311 U.S. 377, 404–05 (1940). 

Moreover, congressional authority is not limited to navigable-in-fact waters; it

exists throughout watersheds and can encompass actions on nonnavigable,

intrastate tributaries. See, e.g., Riverside, 474 U.S. at 133; Oklahoma ex rel.

Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 523, 525–26 (1941).

Given this background, it is not surprising that courts have consistently

acknowledged Congress’ authority to regulate the discharge of pollutants into

nonnavigable tributaries. See, e.g., United States v. Texas Pipe Line Co., 611

F.2d 345, 347 (10th Cir. 1979); United States v. Ashland Oil & Transp. Co., 504

F.2d 1317, 1329 (6th Cir. 1974). Indeed, the Supreme Court has recognized that 

Congress’ power to regulate water pollution extends beyond tributaries and

reaches even wetlands adjacent to navigable waters. Riverside, 474 U.S. at 134. 

Accordingly, we cannot say that the Corps’ tributary rule invokes the outer limits

of Congress’ power under the Commerce Clause or raises serious constitutional
5We recognize that the Fifth Circuit Court of Appeals, reading SWANCC

broadly, has come to the opposite conclusion. United States v. In re Needham,

354 F.3d 340, 345 n.8 (5th Cir. 2003). As explained below, unlike the Fifth

Circuit, this court sees no conflict between the Court’s holding in SWANCC and

Corps’ tributary rule. We thus conclude the tributary rule is entitled to Chevron

deference.

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questions.5 We join with the Sixth and Fourth Circuits in holding that the Corps’

tributary rule is owed deference under the second step of the Chevron framework. 

See United States v. Rapanos, 376 F.3d 629, 641 (6th Cir. 2004), cert. granted,

126 S. Ct. 414 (2005); Denton, 332 F.3d at 708, 712.

Proceeding under Chevron’s second step, this court will defer to the Corps’

tributary rule as a valid interpretation of the Clean Water Act so long as the rule

is a permissible construction of the statute. See S. Utah Wilderness Alliance, 222

F.3d at 824 (citing Chevron, 467 U.S. at 843–44). “[W]e will give effect to the

agency’s interpretation unless it is arbitrary, capricious, or manifestly contrary to

the statute. We accord the agency such deference given its special institutional

competence . . . .” Pharmanex v. Shalala, 221 F.3d 1151, 1154 (10th Cir. 2000)

(citation omitted).

This court has long acknowledged the Corps’ authority to regulate the

introduction of pollutants into the tributaries of navigable waters. See, e.g., 

Quivira Min. Co. v. E.P.A., 765 F.2d 126, 129–30 (10th Cir. 1985); United States

v. Earth Sciences, Inc., 599 F.2d 368, 375 (10th Cir. 1979). Indeed, we have
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concluded that “[i]t is the intent of the Clean Water Act to cover, as much as

possible, all waters of the United States instead of just some.” Quivira Min. Co.,

765 F.2d at 129. In short, this court’s precedent indicates the Corps’ tributary

rule is a permissible construction of the Clean Water Act. Hubenka, however,

argues that the aforementioned cases “are no longer good law” in light of the

Supreme Court’s decision in SWANCC. 

In SWANCC, the Court was confronted with the question of whether

nonnavigable, isolated, intrastate ponds were subject to the Clean Water Act

under the Corps’ migratory bird rule. 531 U.S. at 162. The Court reviewed its

prior decision in Riverside, where it had recognized the Corps’ authority to

regulate wetlands adjacent to navigable waters. Id. at 167–68. It noted that the

Corps could regulate adjacent wetlands because of the “significant nexus between

the wetlands and the ‘navigable waters.’” Id. at 167–68. The Court further

observed “that Congress’ concern for the protection of water quality and aquatic

ecosystems indicated its intent to regulate wetlands ‘inseparably bound up with

the “waters” of the United States.’” Id. at 167 (quoting Riverside, 474 U.S. at

134). Although the ponds at issue in SWANCC served as habitat for migratory

birds, they were otherwise isolated from navigable waters. Id. at 168. The

Supreme Court determined the Corps’ regulatory authority under the Clean Water

Act is rooted in Congress’ “traditional jurisdiction” over navigable waters. Id. at
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172. The Court held that the Corps exceeded its authority when it attempted to

regulate isolated intrastate waters based solely on their status as habitat for

migratory birds. Id. at 174.

SWANCC, Hubenka contends, must be interpreted to mean that the Corps’

jurisdiction under the Clean Water Act extends only to waters that are navigable

in fact or waters that are actually adjacent to navigable waters. He urges this

court to adopt the reasoning of the Fifth Circuit Court of Appeals, which

determined, under SWANCC, that the Clean Water Act is “not so broad as to

permit the federal government to impose regulations over ‘tributaries’ that are

neither themselves navigable nor truly adjacent to navigable waters.” In re

Needham, 354 F.3d at 345; see also Rice v. Harken Exploration Co., 250 F.3d

264, 270 (5th Cir. 2001) (“[A] body of water is protected under the Act only if it

is actually navigable or is adjacent to an open body of navigable water.”).

 The SWANCC court observed that a “significant nexus” between the

subject water and a navigable water is sufficient to establish jurisdiction under the

Clean Water Act. See 531 U.S. at 167 (discussing rationale for the Court’s prior

decision in Riverside). The Fifth Circuit concluded that a “significant nexus”

occurs only when a nonnavigable water is actually adjacent to a navigable water. 

See Rice, 250 F.3d at 268–70. Under its view, the term ‘adjacent’ does not
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encompass all tributaries that eventually flow into navigable waters. In re

Needham, 354 F.3d at 345. 

The Supreme Court’s opinion in SWANCC does not compel such a narrow

interpretation of the phrase “significant nexus.” The Court has noted “the evident

breadth of congressional concern for protection of water quality and aquatic

ecosystems.” Riverside, 474 U.S. at 133. Indeed, Congress enacted the Clean

Water Act with the comprehensive objective of “restor[ing] and maintain[ing] the

chemical, physical, and biological integrity of the Nation’s waters.” 33 U.S.C. §

1251(a). The legislative history is clear: 

The [pollution] control strategy of the Act extends to navigable

waters. The definition of this term means the navigable waters of the

United States, portions thereof, tributaries thereof, and includes the

territorial seas and the Great Lakes. . . . Water moves in hydrologic

cycles and it is essential that discharge of pollutants be controlled at

the source. Therefore, reference to the [Clean Water Act’s pollution]

control requirements must be made to the navigable waters, portions

thereof, and their tributaries.

 S. Rep. No. 92-414, at 77 (1972), as reprinted in 1972 U.S.C.C.A.N. at 3742–43

(emphasis added). 

It is evident that “[a]ny pollutant or fill material that degrades water quality

in a tributary of navigable waters has the potential to move downstream and

degrade the quality of the navigable waters themselves.” Deaton, 332 F.3d at

707. Given the “breadth of congressional concern for protection of water quality”

evidenced in the text of the Clean Water Act and in its legislative history,
6The United States also argues that the Wind River is a “water of the

United States” because it is navigable in fact. Because we conclude the Wind

River is a water of the United States by virtue of its status as a tributary to a

navigable water, we need not decide whether the river is navigable in fact, and we

express no opinion on the issue.

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Riverside, 474 U.S. at 133, this court concludes the potential for pollutants to

migrate from a tributary to navigable waters downstream constitutes a “significant

nexus” between those waters. Accordingly, we cannot say the Corps’ tributary

rule is arbitrary, capricious, or manifestly contrary to the Clean Water Act. 

Several post-SWANCC courts have determined the connection between

tributaries and downstream navigable waters establishes sufficiently the

“significant nexus” required for jurisdiction under the Clean Water Act. Deaton,

332 F.3d at 712; United States v. Rapanos, 339 F.3d 447, 452 (6th Cir. 2003);

Headwaters Inc. v. Talent Irrigation Dist., 243 F.3d 526, 533 (9th Cir. 2001).

This court holds the Corps’ tributary rule is a permissible interpretation of the

Clean Water Act. Accordingly, under Chevron, we must defer to the Corps’

interpretation of the statute.

(2) Application of the Tributary Rule to Hubenka’s Actions

 It is undisputed that the Wind River is a tributary of navigable waters. 

Thus, under the Corps’ tributary rule, the Wind River is a “water of the United

States” for purposes of the Clean Water Act.6

 See 33 C.F.R. § 328.3(a)(5). 

Accordingly, the Corps may regulate dredge and fill activities below the ordinary
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high water mark of the Wind River. See 33 U.S.C. § 1344(a); 33 C.F.R. §

328.4(c)(1).

On appeal, Hubenka does not dispute that he caused three dikes to be

constructed below the ordinary high water mark of the Wind River. He does

argue, however, that he did not violate the Act because his construction

techniques did not add pollutants to the Wind River. In a similar vein, Hubenka

alleges his dikes do not violate the Clean Water Act because they have no

measurable or theoretical effect on a water of the United States.

Hubenka argues, without citation to authority, that his use of a bulldozer to

construct dikes did not amount to the addition of a pollutant into the Wind River

because the construction did not add materials from outside the river’s banks. 

The Clean Water Act prohibits, absent a permit, the discharge of any pollutant

into a water of the United States. 33 U.S.C. § 1311(a). The Act’s definition of

“pollutant” includes “dredged spoil,” “rock,” and “sand.” Id. § 1362(6). 

“‘[D]redged’ material is by definition material that comes from the water itself.” 

Avoyelles Sportsmen’s League Inc. v. Marsh, 715 F.2d 897, 924 n.43 (5th Cir.

1983); see also United States v. Deaton, 209 F.3d 331, 335–36 (4th Cir. 2000)

(explaining that digging up and redepositing material constitutes the addition of a

pollutant under the Clean Water Act). Under the plain language of the Clean

Water Act, it is clear that Hubenka’s use of river cobbles and sand to construct
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dikes in a water of the United States constitutes a discharge of a pollutant. See

Minnehaha Creek Watershed Dist. v. Hoffman, 597 F.2d 617, 625–26 (8th Cir.

1979) (concluding that the use of rock and sand to construct dams in waters of the

United States “appear[s] to come within the plain meaning of the [Clean Water]

Act”). Moreover, Corps regulations state that 

[t]he Corps and EPA regard the use of mechanized earth-moving

equipment to conduct landclearing, ditching, channelization, instream mining or other earth-moving activity in waters of the United

States as resulting in a discharge of dredged material unless projectspecific evidence shows that the activity results in only incidental

fallback.

33 C.F.R. § 323.2(d)(2)(i) (emphasis added). Hubenka’s use of a bulldozer to

move river bottom materials in order to construct his dikes unquestionably falls

within the scope of § 323.2(d)(2)(i). Hubenka’s claim that he did not add a

pollutant to the Wind River is without merit.

Hubenka’s claim also fails to the extent that he argues there is no violation

of the Clean Water Act unless some deleterious effect upon downstream waters

can be shown. To state a violation of the Clean Water Act, a plaintiff need only

show that the defendant discharged a pollutant into a water of the United States

from a point source without a permit. Sierra Club v. El Paso Gold Mines, Inc.,

421 F.3d 1133, 1141–42 (10th Cir. 2005), petition for cert. filed Jan. 19, 2006

(No. 05-933). There is no need to prove a defendant’s discharge of pollutants

into a tributary caused any deleterious effect on the navigable waters downstream. 
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Ashland Oil, 504 F.2d at 1329; United States v. Eidson, 108 F.3d 1336, 1342 n.7

(11th Cir. 1997). In sum, the Clean Water Act was properly applied to Hubenka’s

three dikes on the Wind River; his arguments to the contrary are unavailing.

B. Admission of Evidence under Rule 404(b)

At trial, the district court allowed testimony about LID’s and Hubenka’s

illegal attempts to divert the Wind River to the south in the years before the

construction of the dikes in 2000. Hubenka argues the court violated Rule 404(b)

of the Federal Rules of Evidence by allowing the government to use this

testimony to show that Hubenka acted in conformity with prior wrongful

activities. “We review a district court’s ruling on the admissibility of evidence

for an abuse of discretion.” Christiansen v. City of Tulsa, 332 F.3d 1270, 1283

(10th Cir. 2003). “We must afford great deference to the district court; review of

a cold record is a poor substitute for a trial judge’s intimate familiarity with the

evidence and its role in the context of the trial as a whole.” Id. (quotation

omitted).

Evidence of other crimes, wrongs, or acts is not admissible to prove

the character of a person in order to show action in conformity

therewith. It may, however, be admissible for other purposes, such

as proof of motive, opportunity, intent, preparation, plan, knowledge,

identity, or absence of mistake or accident.

Fed R. Evid. 404(b). Evidence of other crimes, wrongs, or acts is admissible

under Rule 404(b) if (1) it is offered for a proper purpose; (2) it is relevant; (3)
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the probative value of the evidence is not substantially outweighed by its potential

for unfair prejudice; and (4) the court, upon request, instructs jurors to consider

the evidence only for the purpose for which it was admitted. United States v.

Tan, 254 F.3d 1204, 1207 (10th Cir. 2001). Rule 404(b) is “an inclusive rule,

admitting all evidence of other crimes or acts except that which tends to prove

only criminal disposition.” Tan, 254 F.3d at 1208 (quotation omitted). 

Here, the government was required to prove Hubenka violated the Clean

Water Act knowingly, “not as the result of ignorance, mistake, or accident.” R.

vol. I at 62 (Jury Instruction No. 24). The trial court concluded that evidence

concerning Hubenka’s past encounters with the Corps and the Corps’ Clean Water

Act regulations was “probative in determining [Hubenka’s] knowledge, intent,

and absence of mistake or accident when discharging material into the river.” 

United States v. Hubenka, No. 04-CR-04, at 2 (D. Wyo. Oct. 25, 2004) (order

denying defendant’s motion for new trial). It further determined “that the

probative value of such evidence was not outweighed by the possible prejudicial

effects.” Id. at 3. Lastly, it instructed the jury that it was to consider evidence

concerning Hubenka’s alleged prior violations of the Clean Water Act only for the

purpose of determining whether Hubenka acted knowingly when he constructed

the dikes in 2000. R. vol. I at 62 (Jury Instruction 25). The court specifically

instructed jurors not to consider allegations “as evidence that Mr. Hubenka has a
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tendency to commit” violations of the Clean Water Act. Id. In sum, admission of

the 404(b) evidence satisfied all four prongs of the test set out in Tan. We

therefore conclude the district court did not abuse its discretion when it allowed

testimony about Hubenka’s alleged prior violations.

IV. CONCLUSION

For the reasons stated above, the judgment of the United States District

Court for the District of Wyoming is affirmed.