author: KAPSNER, Justice. NEUMANN, Justice, MARING, Justice,

text:
    2002 ND 61
    Kathleen A. OLSON and Amy Howard, Plaintiffs and Appellants, v. BISMARCK PARKS AND RECREATION DISTRICT, Defendant and Appellee.
    No. 20010249.
    Supreme Court of North Dakota.
    April 16, 2002.

      Orell D. Schmitz, Schmitz, Moench & Schmidt, Bismarck, for plaintiffs and appellants.
    Ronald F. Fischer, Pearson Christensen, Grand Forks, for defendant and appellee.
    Douglas A. Bahr (on brief), Solicitor General and Reid Alan Brady (on brief), Assistant Attorney General, Attorney General’s Office, Bismarck, for amicus curiae.
   KAPSNER, Justice.

[¶ 1] Kathleen A. Olson and Amy Howard appealed from a summary judgment dismissing their negligence action against the Bismarck Parks and Recreation District (“District”) because the District was immune from suit. We conclude, under the circumstances of this case, the limited liability afforded the District for recreational use of property under N.D.C.C. ch. 53-08 does not violate the equal protection provisions of N.D. Const, art. 1, § 21, and we affirm.

I

[¶ 2] On November 26, 2000, Olson and Howard were seriously injured while sledding on a hill at Bismarck’s Tom O’Leary golf course, which is owned, operated, and maintained by the District. During the winter, about 100 acres of the Tom O’Leary Recreational Complex are open free of charge to the general public for sledding, snowboarding, tobogganing and cross-country skiing. The hill has not been altered from its natural state and is not groomed or maintained for sledding. Signs posted at the top of the hill cautioned people, “SLIDE AT YOUR OWN RISK,” “NOT RESPONSIBLE FOR ACCIDENTS,” “INJURY MAY RESULT FROM HIGH SPEEDS,” and “USE EXTREME CAUTION.”

[¶ 3] Olson and Howard sued the District, claiming it negligently failed to maintain the sledding area in a safe and hazard-free condition for its users. The District contended the lawsuit was barred by the recreational use immunity statutes, N.D.C.C. ch. 53-08. Olson and Howard moved for partial summary judgment declaring the recreational use immunity statutes unconstitutional as violative of their equal protection rights. The District also moved for summary judgment requesting the court to dismiss the lawsuit based on the recreational use immunity statutes. The trial court concluded the recreational use immunity statutes are constitutional, granted the District’s motion for summary judgment, and dismissed the lawsuit. Olson and Howard appealed.

II

[¶ 4] Summary judgment is a procedural device for promptly and expeditiously disposing of an action without a trial if either party is entitled to judgment as a matter of law and no dispute exists as to either the material facts or the reasonable inferences to be drawn from undisputed facts, or resolving the factual disputes will not alter the result. Anderson v. Meyer Broadcasting Co., 2001 ND 125, ¶ 14, 630 N.W.2d 46. Whether a statute is constitutional presents a question of law which is fully reviewable on appeal. State v. Burr, 1999 ND 143, ¶ 9, 598 N.W.2d 147.

A

[¶ 5] The relevant provisions of N.D.C.C. ch. 53-08 state:

Subject to the provisions of section 53-08-05, an owner of land owes no duty of care to keep the premises safe for entry or use by others for recreational purposes or to give any warning of a dangerous condition, use, structure, or activity on such premises to persons entering for such purposes.

N.D.C.C. § 53-08-02.

Subject to the provisions of section 53-08-05, an owner of land who either directly or indirectly invites or permits without charge any person to use such property for recreational purposes does not thereby:
1. Extend any assurance that the premises are safe for any purpose;
2. Confer upon such persons the legal status of an invitee or licensee to whom a duty of care is owed; or
3. Assume responsibility for or incur liability for any injury to person or property caused by an act or omission of such persons.

N.D.C.C. § 53-08-03.

Nothing in this chapter limits in any way any liability which otherwise exists for:
1. Willful and malicious failure to guard or warn against a dangerous condition, use, structure, or activity; or
2. Injury suffered in any case when the owner of land charges the person or persons who enter or go on the land other than the amount, if any, paid to the owner of the land by the state.

N.D.C.C. § 53-08-05.

In this chapter, unless the context or subject matter otherwise requires:
1. “Charge” means the amount of money asked in return for an invitation to enter or go upon the land.
2. “Land” includes all public and private land, roads, water, watercourses, and ways and buildings, structures, and machinery or equipment thereon.
3. “Owner” includes tenant, lessee, occupant, or person in control of the premises.
4. “Recreational purposes” includes any activity engaged in for the purpose of exercise, relaxation, pleasure, or education.

N.D.C.C. § 53-08-01.

[¶ 6] Almost all states have statutes that limit a landowner’s liability for personal injury suffered by a person using the land reereationally. Robin C. Miller, Annotation, Effect of Statute Limiting Landowner’s Liability for Personal Injury to Recreational User, 47 A.L.R.4th 262 (1986). Generally, the statutes are “intended to reduce the growing tendency of landowners to withdraw land from recreational access by removing the risk of gratuitous tort liability that a landowner might run unless he could successfully bar any entry to his property for enumerated recreational uses.” 62 Am.Jur.2d Premises Liability § 119 (1990) (footnote omitted). The recreational use immunity statutes were first enacted in North Dakota in 1965, and were also intended to “encourage landowners to make available to the public, land and water areas and other property for recreational purposes by limiting their liability toward users.” 1965 N.D. Sess. Laws ch. 337.

[¶ 7] This Court has previously construed the recreational use immunity statutes. In Stokka v. Cass County Elec. Coop., Inc., 373 N.W.2d 911, 915-16 (N.D.1985), this Court upheld the constitutionality of the provisions of N.D.C.C. ch. 53-08 in effect at that time as applied to a private landowner, but ruled there was a genuine issue of material fact whether the landowner was “[wjillful or malicious” in failing to guard or warn against a dangerous condition, rendering improper a summary judgment dismissing the plaintiffs personal injury action. In Fastow v. Burleigh County Water Res. Dist., 415 N.W.2d 505, 508-09 (N.D.1987), this Court relied on Umpleby v. United States, 806 F.2d 812 (8th Cir.1986), in concluding the protection of the recreational use immunity statutes applied to political subdivisions, but held the political subdivision in that case had waived immunity by purchasing liability insurance.

[¶ 8] In 1993, the Legislature first amended the statutes by changing the language of N.D.C.C. § 53-08-05(1) from “[wjillful or malicious” to “[wjillful and malicious.” 1993 N.D. Sess. Laws ch. 503, § 1. After this Court abrogated sovereign immunity in Bulman v. Hulstrand Const. Co., Inc., 521 N.W.2d 632 (N.D.1994), the Legislature again amended the statutes. In 1995, the Legislature changed the definition of “[ljand” in N.D.C.C. § 53-08-01 to include “all public and private land,” and amended the definition of “[rjecreational purposes” to its present form. 1995 N.D. Sess. Laws ch. 162, § 7. The amendment to the definition of land was intended to clarify that the statutes provide “a limitation of liability for all landowners, regardless of whether they are private or public.” Hearing on S.B. 2127 Before the Senate Agriculture Comm., 54th N.D. Legis. Sess. (Jan. 5, 1995) (testimony of Robert Olheiser, State Land Commissioner). In Hovland v. City of Grand Forks, 1997 ND 95, ¶¶ 8, 17, 563 N.W.2d 384, a majority of this Court ruled the Fastow court’s discussion of N.D.C.C. ch. 53-08 and political subdivisions was “dictum,” and ruled the pre-1995 version of the recreational use immunity statutes did not apply to political subdivisions. The present case is the first time we have been squarely confronted with a challenge to the constitutionality of the statutes as amended in 1995 and applied to a public landowner.

B

[¶ 9] Olson and Howard argue N.D.C.C. ch. 53-08 violates our state equal protection guarantee, N.D. Const, art. I, § 21, which provides:

No special privileges or immunities shall ever be granted which may not be altered, revoked or repealed by the legislative assembly; nor shall any citizen or class of citizens be granted privileges or immunities which upon the same terms shall not be granted to all citizens.

[¶ 10] A facially neutral statute may violate equal protection in its application or effect. State v. Wilt, 371 N.W.2d 159, 160 (N.D.1985); State v. Mathisen, 356 N.W.2d 129, 133 (N.D.1984). Generally, a party may only challenge the constitutionality of a statute as applied to that party. State v. Dvorak, 2000 ND 6, ¶ 28, 604 N.W.2d 445; Tooz v. State, 76 N.D. 599, 607, 38 N.W.2d 285, 290 (1949). Consequently, when addressing equal protection challenges to legislation, we have often noted a person to whom a statute constitutionally may be applied cannot challenge the statute on the ground that it might conceivably be applied unconstitutionally to others. First Bank of Buffalo v. Conrad, 350 N.W.2d 580, 584 (N.D.1984); State v. Morris, 331 N.W.2d 48, 58 (N.D.1983); State v. Unterseher, 255 N.W.2d 882, 886 (N.D.1977); State v. Amerada Petroleum Corp., 71 N.W.2d 675, 680 (N.D.1955); Benson v. Schneider, 68 N.W.2d 665, 670 (N.D.1955); Asbury Hosp. v. Cass County, 72 N.D. 359, 392, 7 N.W.2d 438, 456 (1943).

[¶ 11] All regularly enacted statutes carry a strong presumption of constitutionality, which is conclusive unless the party challenging the statute clearly demonstrates that it contravenes the state or federal constitution. In re M.D., 1999 ND 160, ¶ 25, 598 N.W.2d 799. When a statute is challenged on equal protection grounds and an important substantive right is involved, we apply an intermediate standard of review which requires a close correspondence between the statutory classification and the legislative goal. Gange v. Clerk of Burleigh County Dist. Court, 429 N.W.2d 429, 433 (N.D.1988). The right to recover for personal injuries is an important substantive right. Dickie v. Farmers Union Oil Co. of LaMoure, 2000 ND 111, ¶ 5, 611 N.W.2d 168; Bouchard v. Johnson, 555 N.W.2d 81, 87 (N.D.1996); Hanson v. Williams County, 389 N.W.2d 319, 325 (N.D.1986). Therefore, the inquiry in this case is whether there is a close correspondence between the statutory classification and the legislative goal. We may consider unarticulated legislative purposes or goals in an equal protection analysis of a statutory classification. Haney v. North Dakota Workers Comp. Bureau, 518 N.W.2d 195, 202 (N.D.1994); State v. Knoefler, 325 N.W.2d 192, 195 (N.D.1982).

C

[¶ 12] Olson and Howard have not cited, nor have we found, any caselaw striking down as unconstitutional similar recreational use immunity statutes. Rather, courts have uniformly rejected a variety of constitutional attacks against such legislation. See, e.g., Mattice v. United States, Dep’t of Interior, 969 F.2d 818, 822 (9th Cir.1992) (holding California statutes did not violate equal protection when applied to public landowner); Simpson v. United States, 652 F.2d 831, 833-34 (9th Cir.1981) (holding same); Harlan v. Frazier, 635 F.Supp. 718, 724 (W.D.La.1986), aff'd 811 F.2d 601 (5th Cir.1987) (holding Louisiana statutes did not violate equal protection when applied to private landowner); Dickey v. City of Flagstaff, 197 Ariz. 422, 4 P.3d 965, 972-73 (1999) (holding Arizona statutes did not violate state constitutional right-of-aetion provision when applied to public landowner); Corey v. State, 108 Idaho 921, 703 P.2d 685, 687 (1985) (holding Idaho statutes did not violate due process when applied to public landowner); Johnson v. Sunshine Mining Co., Inc., 106 Idaho 866, 684 P.2d 268, 271-73 (1984) (holding Idaho statutes did not violate equal protection or due process when applied to private landowner); Sublett v. United States, 688 S.W.2d 328, 329 (Ky.1985) (holding Kentucky statutes did not violate state constitutional open-courts provision when applied to public landowner); Stokka, 373 N.W.2d at 915 (holding North Dakota statutes did not violate equal protection when applied to private landowner); Moss v. Dep’t of Natural Resources, 62 Ohio St.2d 138, 404 N.E.2d 742, 745 (1980) (holding Ohio statutes did not violate equal protection when applied to public landowner); Riksem v. City of Seattle, 47 Wash.App. 506, 736 P.2d 275, 278-79 (1987) (holding Washington statutes did not violate equal protection when applied to public landowner); Johansen v. Reinemann, 120 Wis.2d 100, 352 N.W.2d 677, 679 (Ct.App.1984) (holding Wisconsin statutes did not violate equal protection when applied to public landowner). Although the above cited courts employed a rational basis standard of review in these equal protection challenges, rather than the intermediate, close correspondence standard of review, we believe the entire lack of contrary authority under any standard of review demonstrates the overall judicial acceptance of recreational use immunity statutes.

[¶ 13] Olson and Howard rely on statements made by a majority of this Court in Hovland, 1997 ND 95, 563 N.W.2d 384. In Hovland at ¶¶ 12, 13, 16, the majority declined to interpret the recreational use immunity statutes as applying to political subdivisions because it would raise “a serious equal protection question”:

If public lands were granted immunity for all recreational activities, Caroline could not recover for her injuries because she was using the bike path for a recreational use, but had she been using the bike path for a non-recreational use she would be allowed to recover. This interpretation allows the government to treat two classes of persons injured on public lands differently: it forbids recovery for personal injuries incurred during recreational activities, but permits recovery for personal injuries incurred during non-recreational activities. The recreational use immunity statute was created to encourage private landowners to permit public access to private lands. In the context of public access to private lands, the disparate treatment of recreational users seems to make sense. In the context of public access to public lands, the disparate treatment is much harder to understand.
The legislative history does not disclose any reason why a recreational user of public lands could not recover for personal injuries when a non-recreational user could. Without a close correspondence with legislative goals supporting this classification, the statute might well fail an equal protection challenge under an intermediate standard of review.

(Footnote omitted). These statements are dicta, and we are not compelled by stare decisis to follow them. Id. at ¶ 8. We do not follow the path outlined in the Hov-land dicta here because, under the circumstances of this case, we believe there is a close correspondence between the statutory classification and the legislative goals.

[¶ 14] The recreational use immunity statutes create two classes of persons and treat them differently: nonpaying recreational users of another’s land and all other persons using the land of another. The class distinction is based upon the location and nature of the injured person’s conduct when the injury occurs. See Harlan, 635 F.Supp. at 724. Although not clearly articulated in the legislative history of the 1995 amendments, the primary purpose of the recreational use immunity statutes has not changed since their original enactment in 1965. The statutes are intended to provide limited tort immunity to landowners and to encourage them to provide access to their land without charge for public recreational use. Such encouragement was necessitated by the threat of tort liability which had led some landowners throughout the country to bar people from using their land. See Simpson, 652 F.2d at 833. We agree with the Idaho Supreme Court that the “encouragement of recreation enhances the physical well-being of ... people, has a positive effect on [the] economy,” and is an important legislative goal. Johnson, 684 P.2d at 272. It is logical for the Legislature to conclude that a limitation on a landowner’s liability exposure to nonpaying recreational users has an influence on the landowner’s decision not to exclude recreational users from the land. Id. Limited tort immunity is the quid pro quo for the noncommercial opening of property to the public for recreational use. Hendrickson v. Georgia Power Co., 80 F.Supp.2d 1374, 1378 (M.D.Ga.2000). The recreational use immunity statutes therefore protect landowners when others use the property without charge for their personal enjoyment, see Harlan, at 724, but continue to hold landowners responsible for their willful and malicious conduct.

[¶ 15] Olson and Howard argue the logic for providing a private landowner with limited liability in exchange for opening land for public use without charge for recreational purposes does not have the same justification when applied to public landowners because, “[i]n theory, public land is already open to the public.” This argument is unpersuasive. The distinction urged by Olson and Howard has been rejected by several courts. In Gard v. United States, 594 F.2d 1230, 1233 (9th Cir.1979), the court addressed the appellant’s argument that the Nevada sightseer statute did not apply to the government:

[Gard] argues first that the purpose of [the statute] is to encourage landowners to open up their land to recreational use and that such a rationale does not apply to the Government. We disagree. Gard does not suggest that the Government could not completely close various federal lands to public use if it felt its potential tort liability was too great. Thus the principle of encouraging landowners to open their land by limiting potential tort liability applies with equal force to the Government as to other landowners.

See also Jones v. United States, 693 F.2d 1299, 1302 (9th Cir.1982); Otteson v. United States, 622 F.2d 516, 519 (10th Cir.1980); McCarver v. Manson Park and Recreation Dist., 92 Wash.2d 370, 597 P.2d 1362, 1366 (1979). Olson and Howard do not argue the District lacks the power to close or severely limit the use of its land to the public. The District and other governmental entities have the power to control the use of public lands. See, e.g., N.D.C.C. §§ 11-28-05; 11-28-16; 55-05-22; 55-08-01.3.

[¶ 16] Olson and Howard raise hypothetical examples of situations in which the recreational use immunity statutes, if broadly interpreted, might be unfairly applied. However, as in Stokka, 373 N.W.2d at 915, we do not find helpful “[r]eference to abstract, factually dissimilar hypotheses” because Olson and Howard “may assert only matters relating to [their] constitutional rights.” Olson and Howard concede they were engaged in a voluntary recreational use of the hill free of charge when they were injured. Winter sledding is a recreational use in the clearest sense of the term. See, e.g., Kelly v. Ladywood Apartments, 622 N.E.2d 1044, 1048 (Ind.Ct.App.1993); Boaldin v. University of Kansas, 242 Kan. 288, 747 P.2d 811, 813 (1987); Marrek v. Cleveland Metroparks Bd. of Comm’rs, 9 Ohio St.3d 194, 459 N.E.2d 873, 877 (1984). Like siding, winter sledding has many inherent risks and dangers. See Bouchard, 555 N.W.2d at 85; Jordon by Jordon v. K-Mart Corp., 417 Pa.Super. 186, 611 A.2d 1328, 1331-32 (1992). “Voluntary participants in sporting and recreational activities are presumed to have consented, by their participation, to those injury-causing events which are known, apparent, or reasonably foreseeable consequences of the participation.” Dickey, 4 P.3d at 973 (citations and internal quotation marks omitted). There may be situations in which application of the recreational use immunity statutes would be unconstitutional, but this case does not present such a situation.

[¶ 17] Under the undisputed facts of this case, we conclude the recreational use immunity statutes advance the important legislative goal of opening property to the public for recreational use in a manner that closely corresponds to the achievement of that goal. We hold N.D.C.C. ch. 53-08, as applied here, does not violate N.D. Const, art. I, § 21.

Ill

[¶ 18] Olson and Howard do not argue the District’s actions in this case were “[w]illful and malicious” under N.D.C.C. § 53-08-05(1). Consequently, we affirm the summary judgment.

[¶ 19] GERALD W. VANDE WALLE, C.J., WILLIAM A. NEUMANN, and DALE V. SANDSTROM, JJ„ concur.

NEUMANN, Justice,

concurring.

[¶ 20] I have joined the majority in this case despite the dicta I authored in Hovland v. City of Grand Forks, 1997 ND 95, 563 N.W.2d 384. On the facts of this case, I see a close correspondence between the statutory classification in N.D.C.C. ch. 15-03 and the legislative goal of fostering the availability of free recreational opportunities. As the majority opinion points out, these appellants were recreational users in the clearest sense of the term, utilizing a free recreational facility for a traditional recreational purpose.

[¶ 21] The legislature has declared a general policy of protecting citizens from injury caused by the negligent omissions of others. However, the legislature also realized this policy could limit the availability of free recreational opportunities for those same citizens. The legislature decided our people would best be served by increasing free recreational opportunities, even if the safe use of those free opportunities would have to depend primarily upon the caution and watchfulness of those who use them. To my mind that is a clear close correspondence between classification and legislative goal.

[¶ 22] What is more of a mystery and concern to me is the expansively broad language of the act, encompassing not just recreational facilities but every publicly owned building, road and “ways” in the State of North Dakota. The effect of that broad language is to treat drivers and pedestrians on our public streets and sidewalks differently, depending on their purpose in being there. A citizen who chooses to walk to work because it is a beautiful spring day arguably is owed no duty of care by the city to keep the sidewalk safe, while the person beside him, walking to work because he has no car, is owed such a duty. A close correspondence between that classification and the legislative goal is much harder to see. Further concern is raised by the inclusion of “education” in the definition of “recreational purposes.” The statute appears to relieve all school districts of any duty to keep their buildings and other premises safe for use by students who have not paid a fee for the educational use of those premises. At the same time, the statute holds the school districts to a higher standard of care for the student who pays a fee to use those same premises for an extracurricular activity. Again, the correspondence between classification and legislative goal is elusive.

[¶ 23] Fortunately, as the majority opinion points out, none of those facts are presented in this case. I have therefore joined the majority.

[¶ 24] MARY MUEHLEN MARING, and DALE V. SANDSTROM, JJ, concur.

MARING, Justice,

specially concurring.

[¶ 25] Although I concur in the result, I write separately because I disagree with the majority opinion’s conclusion that the primary purpose of the recreational use immunity statutes has not changed since their original enactment in 1965. The majority does acknowledge that when the recreational use statutes were first enacted the purpose was to encourage private landowners to open their lands for recreational use by the public by removing the potential for liability. 1965 N.D. Sess. Laws ch. 337. However, when the Legislature changed the definition of land in N.D.C.C. § 53-08-01 to include public land as well as private land, I am of the opinion the focus of the statutes changed. The majority of the public lands which the public would be using for recreational purposes are already lands open for recreational use to the public. Some of these public lands are open to the public for a fee and some for free. The focus is no longer on “opening” lands for recreational purposes, but rather on limiting liability of a landowner to a person who enters the owner’s property to engage in a recreational activity. Perhaps it is more accurate to state that the goal of the legislation, as it applies to public lands is to prevent the “closing” of public lands which have been used primarily for recreational purposes in the aftermath of the abolishment of sovereign immunity. Bulman v. Hulstrand Const. Co., Inc., 521 N.W.2d 632 (N.D.1994). In my opinion, there is a close correspondence between the classification and the Legislature’s goal of continuing to make public lands available for free recreational use.

[¶ 26] I also disagree with the majority’s conclusions that “[l]ike skiing, winter sledding has many inherent risks and dangers” and that “[v]oluntary participants in sporting and recreational activities are presumed to have consented, by their participation, to those injury-causing events which are known, apparent, or reasonably foreseeable consequences of the participation.” In this case, there was no issue whether Olson was engaged in a recreational activity, and I consider these statements nothing but dicta.

[¶ 27] MARY MUEHLEN MARING.


source: Caselaw Access Project

author: SANDSTROM, Justice.

license: Public Domain

text:
    2002 ND 55
    BTA OIL PRODUCERS, Cenex Harvest States Cooperatives, Conoco, Inc., Equitable Resources Energy Company, Exxon Mobil Corporation, Midgard Energy Company, (formerly known as Maxus Exploration Company), Sinclair Oil Corporation, Kerr-McGee Oil & Gas Onshore, L.P., TBI Exploration, Inc., (formerly known as Presidio Exploration, Inc.), Tipperary Oil & Gas Corporation, and Tom Brown, Inc., Plaintiffs and Appellants, v. MDU RESOURCES GROUP, INC., (formerly known as Montana-Dakota Utilities Company), Williston Basin Interstate Pipeline Company, Inc., Koch Industries, Inc., and Koch Hydrocarbons Company, Defendants and Appellees.
    No. 20010122.
    Supreme Court of North Dakota.
    April 16, 2002.
    Rehearing Denied May 17, 2002.

      James B. Wilcox, Jr. (argued), Hall, Es-till, Hardwick, Gable, Golden & Nelson, P.C., Washington, DC, and Albert J. Hardy (appeared), Hardy, Maus & Nordsven, P.C., Dickinson, ND, for plaintiffs and appellants.
    Daniel S. Kuntz (argued) and James S. Hill (on brief), Zuger Kirmis & Smith, Bismarck, for defendants and appellees MDU Resources Group, Inc., and Williston Basin Interstate Pipeline Company, Inc.
    James M. Armstrong (argued), Foulston & Siefkin L.L.P., Wichita, KS; John W. Morrison (appeared), Fleck, Mather & Strutz, Bismarck, ND, James D. Oliver (on brief), Foulston & Siefkin L.L.P., Topeka, KS, Michael A. Ceramella (on brief), Koch Industries, Inc., Wichita, KS, for defendants and appellees Koch Industries, Inc. and Koch Hydrocarbons Company.
   SANDSTROM, Justice.

[¶ 1] BTA Oil Producers, Cenex Harvest States Cooperatives, Conoco, Inc., Equitable Resources Energy Company, Exxon Mobil Corporation, Midgard Energy Company, Sinclair Oil Corporation, Kerr McGee Oil & Gas Onshore, L.P., TBI Exploration, Inc., Tipperary Oil & Gas Corporation, and Tom Brown, Inc. (collectively “BTA”) appeal from a judgment that dismissed most of their claims against MDU Resources Group, Inc., and Williston Basin Interstate Pipeline Company, Inc. (collectively “MDU”), and Koch Industries, Inc., and Koch Hydrocarbons Company (collectively “Koch”), and that awarded Exxon $404,122.34 from Koch for breach of contract for miscalculating treating fees. We affirm in part, reverse in part, and remand, concluding: (1) MDU was not barred by judicial estoppel from disputing BTA’s claims; (2) the district court did not err in granting summary judgment dismissing BTA’s unjust enrichment and implied trust claims against MDU; (3) the district court did not err in dismissing BTA’s breach of contract and unjust enrichment claims against Koch; (4) BTA failed to present competent admissible evidence establishing a genuine issue of material fact on its claim against Koch for an accounting for liquid hydrocarbons; (5) the district court applied the appropriate statute of limitations to Exxon’s treating fees claim; and (6) the district court erred in determining Exxon first asserted its treating fees claim when it moved to amend the complaint on September 3, 1997.

I

[¶ 2] During the time relevant to this case, Koch bought and processed natural gas at its processing plant in McKenzie County. BTA and the other appellants produced natural gas and sold it to Koch. The contracts between Koch and BTA were percentage-of-proceeds contracts, which did not establish a set price for the gas purchased. Under these contracts, Koch took title to the raw natural gas, processed it, and paid BTA a percentage of the price Koch received when it resold the gas. Although the contracts between Koch and the various producers differed slightly, on average the producers received seventy-five percent of the resale price of the gas when sold by Koch.

[¶ 3] MDU operates a natural gas distribution system. In 1979, when natural gas was in short supply, MDU and Koch entered into a ten-year contract, with MDU agreeing to purchase certain minimum volumes of gas at the highest price permitted by the Natural Gas Policy Act of 1978. MDU originally bought all of the gas available from Koch. In 1983 a surplus of gas developed, and natural gas prices fell. MDU reduced the volume of its gas purchases, taking less than Koch had available.

[¶ 4] MDU continued paying the maximum price allowed under the Natural Gas Policy Act through 1984. On January 1, 1985, prices for natural gas were deregulated and a dispute arose over the price of gas under the contract. MDU contended the lower, unregulated market price should apply. Koch argued the last regulated price, which was higher than market price, should be applied.

[¶ 5] In 1986, Koch acquired the rights of another seller, Phillips Petroleum Company, which had a similar gas purchase contract with MDU running through 2000. Similar disputes over gas pricing arose under that contract.

[¶ 6] In January 1987, Koch sued MDU in federal district court for breach of contract. On May 6, 1987, MDU advised Koch it would no longer take gas under the contracts. The federal district court held MDU had breached the contract, but Koch was only entitled to recover damages based upon its twenty-five percent share of the proceeds of its sales to MDU. Koch was not allowed to recover damages based upon the seventy-five percent of the sale proceeds that went to BTA and other producers. The United States Court of Appeals for the Eighth Circuit affirmed the percentage-of-proceeds reduction in damages, and remanded to the district court on other issues. See Koch Hydrocarbon Co. v. MDU Resources Group, Inc., 988 F.2d 1529 (8th Cir.1993). Koch and MDU subsequently settled all of their claims.

[¶ 7] Shortly thereafter, two of Koch’s producers sued MDU in state court. These producers claimed they were third-party beneficiaries of the MDU-Koch contracts, MDU had been unjustly enriched by being allowed to retain profits after defaulting on its contracts, and MDU held the remaining seventy-five percent of the alleged “damages” in an implied trust. The district court concluded the producers were not third-party beneficiaries under the MDU-Koch contracts, MDU was not unjustly enriched, and there was no evidence establishing an implied trust. We affirmed the district court judgment. Apache Corp. v. MDU Resources Group, Inc., 1999 ND 247, 603 N.W.2d 891.

[¶ 8] In March 1997, while the Apache case was still pending in district court, BTA brought this action against MDU and Koch. BTA alleged unjust enrichment and implied trust claims against MDU, and alleged breach of contract, unjust enrichment, fraud, and civil conspiracy claims against Koch. In July 1997, Exxon was permitted to intervene in this action as a plaintiff. Exxon pleaded an additional breach of contract claim, alleging Koch had underpaid Exxon for its gas by miscalculating “treating fees” under the contract.

[¶ 9] MDU and Koch moved for partial summary judgment. Relying upon Apache, the district court dismissed all claims except Exxon’s treating fees claim against Koch. After further discovery, Exxon and Koch both moved for summary judgment on the treating fees claim. The district court concluded Koch had breached its contract with Exxon by miscalculating treating fees and found damages of $404,122.34. Judgment was entered dismissing all claims except the treating fees claim and awarding damages to Exxon on its treating fees claim. BTA appealed.

[¶ 10] The district court had jurisdiction under N.D. Const, art. VI, § 8, and N.D.C.C. § 27-05-06. The appeal was timely under N.D.R.App.P. 4(a). This Court has jurisdiction under N.D. Const, art. VI, § 6, and N.D.C.C. § 28-27-01.

II

[¶ 11] Summary judgment is a procedural device for promptly and expeditiously disposing of an action without a trial if either party is entitled to judgment as a matter of law and if no dispute exists as to either the material facts or the reasonable inferences to be drawn from undisputed facts or if resolving the factual disputes will not alter the result. E.g., Anderson v. Meyer Broadcasting Co., 2001 ND 125, ¶ 14, 630 N.W.2d 46; Van Valkenburg v. Paracelsus Healthcare Corp., 2000 ND 38, ¶ 17, 606 N.W.2d 908. On appeal, we review the evidence in the light most favorable to the party opposing the motion for summary judgment, and we give that party the benefit of all favorable inferences that reasonably can be drawn from the evidence. Jaskoviak v. Gruver, 2002 ND 1, ¶ 11, 638 N.W.2d 1.

[¶ 12] We outlined the duty of a party opposing a summary judgment motion in Anderson, 2001 ND 125, ¶ 14, 630 N.W.2d 46 (quoting Peterson v. Zerr, 477 N.W.2d 230, 234 (N.D.1991) (internal citations omitted)):

“Although the party seeking summary judgment has the burden of showing that there is no genuine issue of material fact, the party resisting the motion may not simply rely upon the pleadings. Nor may the opposing party rely upon unsupported, conclusory allegations. The resisting party must present competent admissible evidence by affidavit or other comparable means which raises an issue of material fact and must, if appropriate, draw the court’s attention to relevant evidence in the record by setting out the page and line in depositions or other comparable documents containing testimony or evidence raising an issue of material fact.”
“In summary judgment proceedings, neither the trial court nor the appellate court has any obligation, duty, or responsibility to search the record for evidence opposing the motion for summary judgment. The opposing party must also explain the connection between the factual assertions and the legal theories in the ease, and cannot leave to the court the chore of divining what facts are relevant or why facts are relevant, let alone material, to the claim for relief.”

Ill

[¶ 13] BTA argues the defenses raised by MDU in this case are inconsistent with the position MDU took in Koch Hydrocarbon Co. v. MDU Resources Group, Inc., 988 F.2d 1529 (8th Cir.1993), and MDU is therefore barred from challenging the unjust enrichment and implied trust claims under the doctrine of judicial estoppel.

[¶ 14] We have never adopted the doctrine of judicial estoppel in this state. Judicial estoppel prohibits a party from assuming inconsistent or contradictory positions during the course of litigation. See State v. Profit, 591 N.W.2d 451, 462 (Minn.1999); 28 Am.Jur.2d Estoppel and Waiver § 74 (2000); 31 C.J.S. Estoppel and Waiver § 139(a) (1996). The underlying rationale for the doctrine is summarized in 28 Am.Jur.2d Estoppel and Waiver § 74 (footnotes omitted):

The fundamental concept of judicial es-toppel is that a party in a judicial proceeding is barred from denying or contradicting sworn statements made therein. Judicial estoppel is a judge-made doctrine that seeks to prevent a litigant from asserting a position inconsistent, conflicts with, or is contrary to one that she has previously asserted in the same or in a previous proceeding; it is designed to prevent litigants and their counsel from playing fast and loose with the courts, and to protect the integrity of the judicial process. Judicial estop-pel doctrine is equitable and is intended to protect the courts from being manipulated by chameleonic litigants who seek to prevail, twice, on opposite theories. The purpose of the doctrine of judicial estoppel is to reduce fraud in the legal process by forcing a modicum of consistency on the repeating litigant.

The doctrine applies only where a party’s subsequent position is totally inconsistent with its original position, and does not apply where distinct or different issues or facts are involved. Profit, 591 N.W.2d at 462; 28 Am.Jur.2d Estoppel and Waiver § 74; 31 C.J.S. Estoppel and Waiver § 139(a).

[¶ 15] Assuming, without deciding, that the doctrine of judicial estoppel applies in this state, we conclude the doctrine would not bar MDU’s arguments because the position taken by MDU in this case is not inconsistent with the position it took in Koch. In that case, Koch sued MDU for breach of contract, seeking to recover the difference between the amount Koch would have received if MDU had purchased the gas at the higher contract rate and the amount Koch actually received selling the gas on the open market. Koch sought to recover 100 percent of the difference, including the 75 percent it would have passed on to the producers under the percentage-of-proceeds contracts. MDU argued Koch could recover only its own losses, represented by the 25 percent Koch would retain upon sale of the gas. The United States Court of Appeals for the Eighth Circuit agreed with MDU:

In this appeal, Koch argues that the damage award should not have been reduced, since Koch may yet be obligated to reimburse the producers for their seventy-five percent share. We reject this argument. The court did not enforce the contract by ordering specific performance but merely awarded Koch its actual damages. MDU was not ordered to take the gas and pay for it, in which case Koch would be liable to the producers for a percentage of the proceeds. The other producers did not intervene in Koch’s suit, and Koch should be allowed to collect only the damages it sustained. If the gas was not sold, Koch did not owe the producers their cut; if Koch did sell to other customers the gas that MDU had contracted to buy, Koch presumably paid the producers the appropriate percentage from those proceeds, and the producers would have no further recourse against Koch.
We believe the court correctly found that Koch could not prove that it sustained three-quarters of the damages claimed, and that Koch did not prove
that it would be liable in the future to pay producers for gas not sold merely because Koch collects on a judgment for its damages resulting from MDU’s breach. The percentage-of-proceeds reduction in damages is affirmed.

Koch, 988 F.2d at 1547.

[¶ 16] BTA contends, because MDU argued in Koch that the producers were the real parties in interest as to 75 percent of' the damages and bore the burden of that loss, MDU should now be estopped from arguing it is not liable to the producers for those losses. BTA cited the following quotations from MDU’s pleadings and briefs in Koch as examples of positions inconsistent with MDU’s defenses in this case:

“It is axiomatic that the real party in interest in an action for damages is the party who has, or can at least offer evidence that he has, actually been damaged by the underlying events.... [V]ir-tually all of the effects of reduced gas cost and things like that were passed on to the producers.”
“[M]uch of the burden of decreased gas prices is passed up the line to producers who sell to Koch.”
“As a result of all these various arrangements, when MDU reduced its purchases from Koch, the producers bore the burden.”
“As a result, when MDU reduced its purchases from Koch, the producers sustained a 75% share of the deduction from the price differential, Koch took at most a 25% share of the loss.”

[¶ 17] The issue in Koch was whether Koch could recover 100 percent of the difference between the contract price and the price it actually received when it sold the gas elsewhere. MDU argued Koch was not the real party in interest as to 75 percent of the difference and the producers bore that loss. MDU did not, however, concede or otherwise imply it was liable to the producers for that loss. The statements quoted by BTA are not admissions of liability to the ^producers but merely arguments, within the context of that litigation, that Koch had not suffered those losses. Furthermore, the extent of MDU’s liability to Koch for breach of their contract and MDU’s potential liability to the producers for unjust enrichment or implied trust are entirely different and distinct issues. BTA has not shown any position taken by MDU in Koch was inconsistent with its arguments in this case.

[¶ 18] We conclude the doctrine of judicial estoppel, if recognized in this state, would not bar MDU from challenging the unjust enrichment and implied trust claims in this ease.

IV

[¶ 19] BTA contends the trial court erred in granting summary judgment dismissing its unjust enrichment and implied trust claims against MDU.

[¶ 20] We addressed identical issues raised against MDU by other producers in Apache Corp. v. MDU Resources Group, Inc., 1999 ND 247, 603 N.W.2d 891. In that case, Apache Corporation and Snyder Oil Corporation, producers who were selling gas to Koch under percentage-of-pro-eeeds contracts, sued MDU after it breached its contracts with Koch. The producers argued they were third-party beneficiaries under the MDU-Koch contracts, MDU was unjustly enriched by its repudiation of its contracts with Koch, and MDU held damages in an implied trust. The trial court dismissed the producers’ claims, and they appealed. BTA and the other producers in this case filed an ami-cus curiae brief in support of Apache and Snyder. See Apache, at ¶ 8 n. 1.

[¶ 21] We affirmed the dismissal of the producers’ claims, concluding the producers were not third-party beneficiaries under the MDU-Koch contracts, MDU had not been unjustly enriched, and there was no evidence to establish an implied or constructive trust. In rejecting the unjust enrichment claim, we explained:

Apache benefited when MDU performed MDU’s contract with Koch. Although MDU saved money by breaching its contract with Koch, and Apache received less money from Koch when MDU breached its contract with Koch, MDU contracted with Koch and not with Apache. The money MDU saved by breaching its contract with Koch was not a “benefit at the direct expense of’ Apache. [Midland Diesel Serv. & Engine Co. v.] Sivertson, 307 N.W.2d [555,] 557 [ (N.D.1981) ]. Apache’s reduced income resulted from its use of a percentage of proceeds as a pricing factor in its agreements with Koch, which contemplated increases or decreases in gas prices. Where the impoverishment results from a valid contractual arrangement made by a party, the result is not contrary to equity. Albrecht [v. Walter], 1997 ND 238, ¶ 23, 572 N.W.2d 809. Thus, we are unpersuaded the essential element of recovering under a theory of unjust enrichment — “receipt of a benefit by the defendant from the plaintiff which would be inequitable to retain without paying for its value” — is present here. Zuger [v. North Dakota Ins. Guar. Ass’n], 494 N.W.2d [135], 138 [ (N.D.1992) ].

Apache, 1999 ND 247, ¶ 15, 603 N.W.2d 891.

[¶ 22] BTA does not argue there are factual distinctions between this case and Apache. Nor has BTA drawn our attention to different provisions in the pereent-age-of-proceeds contracts involved here. In essence, the facts of the two cases are identical and arise from the same series of transactions.

[¶ 23] BTA does not attempt to distinguish Apache, but invites us to overrule our decision in that case. We decline to do so. Unjust enrichment requires a showing of an enrichment, an impoverishment, and a connection between the two. Apache, 1999 ND 247, ¶ 13, 603 N.W.2d 891; Albrecht v. Walter, 1997 ND 238, ¶ 23, 572 N.W.2d 809. When the impoverishment results from a valid contractual arrangement made by a party, the result is not contrary to equity and there has been no unjust enrichment. Apache, at ¶ 15; Albrecht, at ¶ 23. BTA has not cited a single decision allowing a third-party supplier to recover for unjust enrichment under facts similar to this case. Any enrichment of MDU and impoverishment of BTA in this case was the result of BTA’s voluntary contractual arrangement with Koch.

[¶ 24] We decline to overrule Apache and conclude the district court did not err in dismissing the claims against MDU.

V

[¶ 25] BTA argues the trial court erred in granting summary judgment dismissing its breach of contract and unjust enrichment claims against Koch.

A

[¶ 26] BTA contends Koch breached its contracts with the producers by failing to apprise them of “major developments” in the Koch v. MDU litigation. Shortly after suing MDU in federal court in January 1987, Koch sent a letter to the producers outlining the history of the dispute over the contract price after deregulation and indicating Koch had filed suit against MDU. The letter indicated Koch would apprise the producers of any “major developments.” BTA argues Koch had thereby contractually agreed to notify the producers of any “major developments” in the federal litigation, and Koch breached the contract when it failed to notify them the court had held Koch could only recover 25 percent of the damages sought.

[¶ 27] Assuming, without deciding, that Koch breached an agreement when it failed to apprise the producers of the alleged “major development,” we conclude the trial court did not err in granting summary judgment, because BTA has not shown it suffered damages caused by the alleged breach. See Hummel v. Mid Dakota Clinic, P.C., 526 N.W.2d 704, 709 (N.D.1995). In support of its assertion that Koch should be liable for “millions of dollars” in damages for failing to apprise the producers of the court’s holding in the federal litigation, BTA argues it could have intervened in that case or taken other affirmative steps to protect its interests against MDU if it had been apprised of this “major development.” BTA’s entire argument is premised upon its belief it could have recovered damages from MDU had it learned earlier of the federal court’s ruling. In Apache and this case, however, we have held the producers had no valid claim for damages against MDU. BTA lost no rights against MDU by Koch’s failure to notify it of the federal court’s ruling, because BTA has been afforded the full opportunity to litigate its claims against MDU and has failed to demonstrate how a different result would have been reached had it acted earlier to protect its interests against MDU.

B

[¶ 28] BTA argues Koch breached its contracts with the producers when it failed to share the settlement proceeds it received from MDU in the Koch v. MDU litigation. BTA claims the producers are entitled to 75 percent of the settlement proceeds.

[¶ 29] In its brief on appeal, BTA argues “the settlement was expressly an agreement to settle the Koch v. MDU case,” and “Koch had sued for the price differential on 100% of contract volumes.” However, at the time Koch and MDU settled, the federal district court and the United States Court of Appeals for the Eighth Circuit had held Koch could recover only its own 25 per cent loss, and “Koch did not prove that it would be liable in the future to pay producers for gas not sold merely because Koch collects on a judgment for its damages resulting from MDU’s breach.” Koch, 988 F.2d at 1547. The case was remanded to the district court for reconsideration of damages and other issues between MDU and Koch. See id. at 1548.

[¶ 30] The settlement agreement was reached after, and must be read in context with, the opinion of the United States Court of Appeals for the Eighth Circuit in Koch. It is clear the 75 percent of “damages” represented by the producers’ percentage of proceeds had been effectively removed from the case. When MDU and Koch settled their claims, they could settle only Koch’s own 25 percent of the losses. See Koch, 988 F.2d at 1547 (“The other producers did not intervene in Koch’s suit, and Koch should be allowed to collect only the damages it sustained.”). Any liability of MDU for the remaining 75 percent was left for subsequent litigation between the producers and MDU. The producers’ alleged damages were not “settled” by MDU and Koch; the producers claims against MDU have been “settled” by our opinions in Apache and this ease.

[¶ 31] We conclude the producers were not entitled to share in the settlement proceeds and Koch’s failure to share the proceeds was not a breach of contract.

C

[¶ 32] BTA argues Koch breached a duty of good faith owed to the producers when it entered into the settlement agreement with MDU. BTA contends there was an implied covenant of good faith and fair dealing included in the gas purchase contracts between the producers and Koch and, in addition, some of the contracts expressly required Koch to make good faith efforts to sell the gas to MDU. BTA has drawn our attention to the following language in a purchase contract between Koch and Sinclair Oil Corporation: “[Koch] shall exert diligent and good faith efforts to sell all of Producer’s Plant Output of Residue Gas to [MDU].” BTA argues Koch violated its duty of good faith when it agreed to a buyout and termination of its contracts with MDU in settling the Koch v. MDU litigation.

[¶ 33] BTA’s argument wholly ignores the realities of the situation leading to the settlement. MDU had repudiated its contracts with Koch and stopped accepting gas in 1987. Koch sued MDU, and through six and one-half years of litigation, sought at its own expense to recover full damages on behalf of the producers. The producers did not seek to intervene or otherwise assist in financing the lengthy litigation against MDU. Koch pursued the claims, including those that would have benefitted the producers, to the United States Court of Appeals. Only after that court unequivocally held Koch could not recover damages that would benefit the producers did Koch settle its claims against MDU.

[¶ 34] Koch could not require MDU to resume accepting gas at the pre-deregulation price, and Koch had engaged in costly litigation seeking to secure payment for the producers. BTA has not presented any evidence establishing Koch’s settlement with MDU breached any duty of good faith owed to the producers.

[¶ 35] Furthermore, the Koch-Sinelair contract provision relied upon by BTA, read in its entirety, clearly demonstrates the parties anticipated the gas might not be sold to MDU and made explicit provisions for that eventuality:

[Koch] shall exert diligent and good faith efforts to sell all of Producer’s Plant Output of Residue Gas to [MDU] (as [Koch] does with respect to all producers on its system); and if not purchased by [MDU], and Producer does not instruct otherwise, [Koch] shall exert diligent and good faith efforts (as [Koch] does in behalf of all producers on its system, unless they instruct otherwise) to sell the portion remaining of Producer’s Plant Output of Residue Gas to other purchasers on the terms and for the Net Sales Proceeds which [Koch], in its sole judgment, considers best....

BTA has not drawn our attention to evidence in this record demonstrating Koch failed to exert “diligent and good faith efforts” to sell the producers’ gas to MDU. When MDU repudiated the contract and refused to accept gas from Koch, Koch sold the gas to other purchasers and paid the producers 75 percent of the proceeds. Under these circumstances, Koch did not breach its contracts with the producers.

D

[¶ 36] BTA contends the district court erred in granting summary judgment dismissing its unjust enrichment claim against Koch.

[¶ 37] The determination of unjust enrichment is a conclusion of law and is fully reviewable on appeal. Schroeder v. Buchholz, 2001 ND 36, ¶ 14, 622 N.W.2d 202; Apache, 1999 ND 247, ¶ 13, 603 N.W.2d 891. Unjust enrichment is an equitable doctrine based upon quasi- or constructive contracts implied by law to prevent a party from being unjustly enriched at another’s expense. Schroeder, at ¶ 14; In re Estate of Hill, 492 N.W.2d 288, 295 (N.D.1992). It is well-settled, unjust enrichment in this context applies only in the absence of a contract between the parties, and there can be no implied-in-law contract when there is an express contract between the parties relative to the same subject matter. See, e.g., Dolan v. Paracelsus Healthcare Corp., 640 N.W.2d 726, 2002 ND 46, ¶ 24; Schroeder, at ¶¶ 14, 18; Apache, at ¶ 13; Estate of Hill, 492 N.W.2d at 294-95 n. 1; First Nat’l Bank of Belfield v. Burich, 367 N.W.2d 148, 154 (N.D.1985); Cavalier County Mem’l Hosp. Ass’n v. Kartes, 343 N.W.2d 781, 785 (N.D.1984).

[¶ 38] We agree with the reasoning of the United States Court of Appeals for the Eighth Circuit in JN Exploration & Prod. v. Western Gas Res., Inc., 153 F.3d 906, 910 (8th Cir.1998) (footnotes omitted), in which the court summarized application of the doctrine under North Dakota law:

Because unjust enrichment is synonymous with quasi contract, and because in North Dakota quasi contractual princi-pies find no application in the face of an express contract, it follows necessarily that in the face of an express contract, an action for unjust enrichment cannot lie. The Supreme Court of North Dakota has repeatedly recognized this, stating, “the doctrine [of unjust enrichment] serves as a basis for requiring restitution of benefits conferred in the absence of an express or implied in fact contract.” Sykeston Township [v. Wells County ], 356 N.W.2d [136,] 139 [ (N.D. 1984) ] (emphasis added); see also D.C. Trautman Co. [v. Fargo Excavating Co.], 380 N.W.2d [644,] 645 [ (N.D. 1986) ] (unjust enrichment applies in the absence of an express or implied in fact contract); [First Nat’l Bank of Belfield v.] Burich, 367 N.W.2d [148,] 154 [ (N.D.1985) ] (same). In Burich, the Supreme Court of North Dakota highlighted the incompatibility of unjust enrichment and an express contract when it concluded, “[i]n this instance, an express contract existed between Burich and the Bank and therefore it was error to rely on the theory of unjust enrichment.” 367 N.W.2d at 154. In short, because unjust enrichment is grounded in quasi contract, where, as here, the parties have voluntarily entered into an express written contract which defines the rights of each, unjust enrichment is a non sequi-tur.

[¶ 39] BTA argues the decision in JN Exploration conflicts with earlier decisions of this Court, citing Trauger v. Helm Bros., Inc., 279 N.W.2d 406 (N.D.1979), Fiebiger v. Fischer, 276 N.W.2d 241 (N.D.1979), and Cargill, Inc. v. Kavanaugh, 228 N.W.2d 133 (N.D.1975). In those eases, this Court stated: “Where an action sounds in contract, invocation of equity powers of court is inappropriate in absence of showing of unjust enrichment, fundamental unfairness, or miscarriage of law requiring intervention of equitable principles.” Trauger, at 414; Fiebiger, at 246; see also Cargill, at 140. None of these cases involved an attempt to impose an implied-in-law, quasi-contract theory of unjust enrichment when there was an express agreement between the parties. Rather, those cases were merely recognizing that when an extraordinary equitable remedy — such as restitution or reformation — is sought in a contract case, extraordinary circumstances must be shown. These cases do not conflict with the holding in later cases of this Court that unjust enrichment based upon quasi-contract is unavailable if there is an express contract between the parties.

[¶ 40] BTA also quotes Dan B. Dobbs, Law of Remedies § 12.7(1) (2d ed.1993), which states: “Restitution — recovery of benefits conferred — is permitted to prevent unjust enrichment. Restitution is an important remedy in connection with contracting.” BTA argues this language indicates an action for unjust enrichment may lie even if the parties had an express contract that was not breached. However, the heading of the above section quoted from Dobbs is “Money Awards as Restitution for Breach of Contract.” Dobbs is addressing restitution as an element of damages for breach of contract, not the separate equitable remedy for unjust enrichment based upon quasi-contract.

[¶ 41] Finally, we reiterate our conclusion in Apache, 1999 ND 247, ¶ 15, 603 N.W.2d 891:

[The producers’] reduced income resulted from [their] use of a percentage of proceeds as a pricing factor in [their] agreements with Koch, which contemplated increases or decreases in gas prices. Where the impoverishment results from a valid contractual arrangement made by a party, the result is not contrary to equity.

[¶ 42] We conclude the district court did not err in dismissing BTA’s unjust enrichment claim against Koch.

E

[¶ 43] In resolving BTA’s breach of contract and unjust enrichment claims against Koch, we are mindful of the unique circumstances presented in this case. BTA seeks to recover damages when it is clear it has suffered no “loss” under its contract with Koch. BTA received the full benefit of its bargain — 75 percent of the proceeds Koch received upon sale of the processed gas. Any “loss” suffered by the producers is a result of their voluntary choice to enter into percentage-of-proceeds contracts, which envisioned the possibility of lower prices. The Koch-Sinclair contract cited by BTA expressly contemplated the gas might be sold to someone other than MDU, and made provisions for the parties’ rights in that event. For example, the Sinclair contract provided, if the producer was dissatisfied with sales of gas to an entity other than MDU, the producer could direct Koch to discontinue such sales.

[¶ 44] Simply put, the producers entered into a contract with Koch and received full performance under the terms of that contract. Any “loss” they suffered directly resulted from their decision to enter into the percentage-of-proceeds contracts, not from any wrongdoing by Koch.

VI

[¶ 45] BTA argues the district court erred in granting summary judgment dismissing its breach of contract claim against Koch based upon sale of liquid hydrocarbons from its gas.

[¶ 46] In addition to receiving a percentage of the proceeds from the processed natural gas, the producers’ contracts with Koch provided the producers would also receive a percentage of the proceeds from the sale of liquid hydrocarbons extracted from the gas they sold to Koch. BTA contends Koch sold these liquid hydrocarbons to its own subsidiaries and affiliates for less than market price, resulting in losses to some of the producers. BTA claimed this was a breach of contract and sought an accounting for the liquid hydrocarbons sold under the producers’ contracts with Koch. On Koch’s motion for summary judgment, the district court determined BTA had failed to raise a genuine issue of material fact on the liquid hydrocarbons claim and granted summary judgment dismissing the claim.

[¶ 47] Once a party seeking summary judgment has met its initial burden of showing no genuine issue of material fact exists, the opposing party may not simply rely upon its pleadings or upon unsupported, conclusory allegations, but must present competent admissible evidence by affidavit or other comparable means that raises an issue of material fact. Anderson v. Meyer Broadcasting Co., 2001 ND 125, ¶ 14, 630 N.W.2d 46. The resisting party must draw the court’s attention to relevant evidence in the record by setting out the page and line in depositions or other comparable documents containing testimony or evidence raising an issue of material fact. Id. Summary judgment is appropriate against a party that fails to establish the existence of a factual dispute on an essential element of its claim and on which it will bear the burden of proof at trial. Id. at ¶ 15.

[¶ 48] BTA argues paragraph 8 of the affidavit of its expert, Carol Freedenthal, raised material issues of fact on its claim Koch had transferred liquid hydrocarbons to its subsidiaries or affiliates for less than market value. Freedenthal prefaces this paragraph by noting “my observations and analysis are only preliminary at this point.” Freedenthal then states:

Koch is accepting less than market prices for the liquid products and thus short changing the Producers from moneys owed to them.... In selling for less than market acceptable prices, Koch may be giving its so-called subsidiary and affiliated companies product at lower than market prices and at the same time, using its affiliates and subsidiaries for Koch’s additional profit and abuse of the Producers.

[¶ 49] Affidavits offered in opposition to a motion for summary judgment must set forth specific facts showing there is a genuine issue for trial. N.D.R.Civ.P. 56(e); Ellingson v. Knudson, 498 N.W.2d 814, 818 (N.D.1993). Affidavits containing conclusory statements unsupported by specific facts are insufficient to raise a material factual dispute. Fetch v. Quam, 2001 ND 48, ¶ 19, 623 N.W.2d 357; Nonuest Mortgage, Inc. v. Nevland, 1999 ND 51, ¶ 4, 591 N.W.2d 109; Resolution Trust Corp. v. Gosbee, 536 N.W.2d 698, 701 (N.D.1995); Federal Land Bank of St. Paul v. Asbridge, 414 N.W.2d 596, 598 (N.D.1987). Mere speculation will not defeat a motion for summary judgment. Ellingson, at 818.

[¶ 50] Freedenthal’s affidavit is conclu-sory and speculative. He expressly indicates his “observations and analysis are only preliminary” and “Koch may be giving its so-called subsidiary and affiliated companies product at lower than market prices.” Freedenthal’s conjecture and speculation is unsupported by specific facts detailing what the market price was and how these sales deviated from that market price. Freedenthal does not provide a single example of a below-market sale relating to a specific contract or specific producer. Freedenthal’s affidavit does not provide competent admissible evidence raising a genuine issue of material fact on the sale of the liquid hydrocarbons.

[¶ 51] BTA also cites other evidence showing Koch used interaffiliate transfers as “sales” of liquid hydrocarbons, paid its own affiliates to transport the liquid hydrocarbons, and charged various fees through its affiliates and subsidiaries, which lowered the price the producers ultimately received for the liquid hydrocarbons. However, without a showing that the ultimate amount received for specific sales was less than would have been received in sales to third parties at market price, this evidence does not create an issue of material fact on the necessary elements of BTA’s breach of contract claim.

[¶ 52] BTA suggests it was unable to provide more specific evidence on the liquid hydrocarbons claim because it had not yet completed discovery and Koch had “stonewalled” some of BTA’s discovery requests. BTA did not move under N.D.R.Civ.P. 56(f) for a continuance to conduct further discovery to develop additional evidence to oppose the motion for summary judgment. The possibility that further discovery will yield evidence favorable to a party opposing summary judgment is not a ground to deny the motion when the party has failed to invoke N.D.R.Civ.P. 56(f). Opp v. Source One Mgmt., Inc., 1999 ND 52, ¶ 11, 591 N.W.2d 101; American State Bank and Trust Co. v. Sorenson, 539 N.W.2d 59, 62 (N.D.1995); Hummel v. Mid Dakota Clinic, P.C., 526 N.W.2d 704, 708 (N.D.1995). Because BTA did not comply with N.D.R.Civ.P. 56(f), the alleged incomplete state of discovery provides no basis to reverse the summary judgment. Hummel, at 708.

[¶ 53] BTA had ample opportunity to conduct discovery. When Koch moved for partial summary judgment in August 1999, the case had been in litigation and discovery had been proceeding for nearly two and a half years. Another year passed before the court finally entered its order for judgment granting partial summary judgment dismissing the liquid hydrocarbons claim against Koch. Under these circumstances, including its failure to invoke N.D.R.Civ.P. 56(f), BTA cannot now be heard to suggest its insufficient response to the motion for summary judgment was due to an inadequate opportunity to conduct discovery.

[¶ 54] We conclude the court did not err in granting summary judgment dismissing the liquid hydrocarbons claim.

VII

[¶ 55] Exxon Corporation argues the district court applied the wrong statute of limitations governing its separate claim against Koch for breach of contract for incorrectly calculating “treating fees.”

[¶ 56] Under Exxon’s contract with Koch, Koch was entitled to deduct certain treating fees from the amount it paid Exxon upon resale of the processed gas; Exxon alleges Koch miscalculated the treating fees, resulting in overcharges against Exxon’s share of the proceeds from the processed gas. The district court concluded Koch had breached the contract by using an improper method to calculate treating fees, resulting in an underpayment to Exxon for its gas.

[¶ 57] In calculating damages for the breach, the court determined the contract was governed by the Uniform Commercial Code (N.D.C.C. Title 41) and applied the four-year statute of limitations of N.D.C.C. § 41-02-104 (U.C.C. § 2-725). The court further determined Exxon filed its claim on September 3, 1997, when the plaintiffs, including Exxon, moved for leave to file an amended complaint. The court accordingly awarded damages incurred after September 8, 1993, in the amount of $404,122.34.

A

[¶ 58] Exxon argues its contract with Koch was not a “contract for sale” under the U.C.C. and the four-year statute of limitations under N.D.C.C. § 41-02-104(1) (U.C.C. § 2-725) should not have applied. Exxon contends the general six-year statute of limitations for non-U.C.C. contracts found in N.D.C.C. § 28-01-16(1) should have applied.

[¶ 59] The U.C.C., as adopted in North Dakota, applies to a contract for sale of natural gas. See N.D.C.C. § 41-02-05(2) (U.C.C. § 2-105); JN Exploration & Prod. v. Western Gas Res., Inc., 153 F.3d 906, 913 (8th Cir.1998); Koch, 988 F.2d at 1534; see also Dawn Enters. v. Luna, 399 N.W.2d 303, 306 n. 3 (N.D.1987). Section 41-02-104(1) (U.C.C. § 2-725) provides “[a]n action for breach of any contract for sale must be commenced within four years after the claim for relief has accrued.”

[¶ 60] “Contract for sale” is defined in N.D.C.C. § 41-02-06(l)(b) (U.C.C. § 2-106): “ ‘Contract for sale’ includes both a present sale of goods and a contract to sell goods at a future time.” Section 41-02-06(l)(d) (U.C.C. § 2-106) provides: “ ‘Sale’ consists in the passing of title from the seller to the buyer for a price.”

[¶ 61] Exxon argues the contract at issue in this case is a gas processing contract for services, and is not a contract for sale under the U.C.C. The contract, however, provides gas will be delivered from Exxon to Koch at metering facilities at or near the wellhead, and “title to said gas and all constituent components therein shall pass from [Exxon] to [Koch] at said point(s).” Article VIII of the contract is entitled “PRICE,” and provides, in part:

The price to be paid by [Koch] to [Exxon] shall be an amount equal to eighty percent (80%) of the net sales proceeds received for the liquefiable hydrocarbons and residue gas saved and sold which is attributable to [Exxon’s] gas as determined in Article V hereof, less the fees attributable thereto.

The contract specifies title to the gas passes from Exxon to Koch at the wellhead, before any processing of the gas takes place, and sets a price for the gas to be paid by Koch to Exxon. See N.D.C.C. § 41-02-06(l)(b) and (d) (U.C.C. § 2-106). This is a contract for sale.

[¶ 62] The substantive provisions of the contract are analogous to those in JN Exploration, which the United State Court of Appeals for the Eighth Circuit concluded was a contract for sale governed by the U.C.C. under North Dakota law. JN Exploration, 153 F.3d at 912-13. The court in JN Exploration specifically noted the “producer/processor relationship” in that case was “nearly identical” to the one presented in Koch, and the two cases presented “nearly identical facts and an analogous contract.” JN Exploration, 153 F.3d at 912-13. The producer/processor contracts at issue in Koch are the same contracts at issue in this case.

[¶ 63] Exxon argues the contract must be for gas processing services, and not a sale, because it is entitled “Gas Processing Agreement” and the parties are identified throughout the contract as “Producer” and “Processor.” In determining whether an agreement is a contract for sale governed by the U.C.C., the labels used by the parties to characterize the transaction are not determinative; rather, it is the substance of the transaction and intent of the parties which control. See American Family Mut. Ins. Co. v. Jepson, 148 F.3d 954, 955-56 (8th Cir.1998); Western Enters., Inc. v. Arctic Office Machs., Inc., 667 P.2d 1232, 1234 (Alaska 1983); Lease Finance, Inc. v. Burger, 40 Colo. App. 107, 575 P.2d 857, 859 (1977). In this case, the substantive provisions of the contract clearly establish a contract for sale.

[¶ 64] Exxon also contends, the fact it had an option to take processed gas rather than cash in payment for its gas indicates this is a service contract, not a contract for sale. Under Article VIII of the contract, entitled “PRICE,” Koch was to pay 80 percent of the net sales proceeds it received from the processed gas and liquid hydrocarbons to Exxon as payment for Exxon’s raw gas. As an alternative, Exxon had the option to receive 80 percent of the processed gas and liquid hydrocarbons attributable to its gas. In order to exercise this option, Exxon was required to give Koch sixty days written notice. We do not believe this provision changes the basic substantive nature of the contract. The title to the gas still passed to Koch at the wellhead before any processing took place. Article VIII of the contract specified the price to be paid for the gas, giving Exxon the option of having that “price” be paid in processed gas and liquid hydrocarbons. The hallmarks of a contract for sale under N.D.C.C. § 41-02-06 (U.C.C. § 2-106) are present.

[¶ 65] We conclude the court did not err in determining the parties’ agreement was a contract for sale governed by the U.C.C., and the four-year statute of limitations under N.D.C.C. § 41-02-104(1) (U.C.C. § 2-725) applied.

B

[¶ 66] Exxon contends the district court erred in concluding Exxon first asserted its treating fees claim, for purposes of the statute of limitations, on September 3,1997.

[¶ 67] Exxon was not a party when this action began on March 14, 1997. On June 30, 1997, Exxon filed a motion to intervene as a plaintiff in the action and attached a proposed complaint that included a claim for breach of contract against Koch based upon the disputed calculation of treating fees. The court granted Exxon’s motion to intervene by a written order filed on July 18,1997.

[¶ 68] On September 3, 1997, Exxon and the other plaintiffs moved to file an amended complaint, which added new allegations and included Exxon’s treating fees claim. The court granted the motion to amend the complaint on February 18, 1998.

[¶ 69] The district court ultimately determined Koch had breached its contract with Exxon by improperly calculating treating fees, resulting in a substantial underpayment to Exxon for its gas. The court concluded Exxon had first asserted its treating fees claim on September 3, 1997, when the plaintiffs moved to amend the complaint, and therefore determined any claim for treating fees arising more than four years prior to that date was barred by the statute of limitations. On appeal, Exxon argues the court erred in determining the date it first asserted the treating fees claim, contending it adequately raised the claim when it filed its complaint with the motion to intervene on June 30, 1997.

[¶ 70] The procedure governing intervention is set out in N.D.R.Civ.P. 24(c), which provides in part:

A person desiring to intervene shall serve a motion to intervene upon the parties as provided in Rule 5. The motion shall state the grounds therefor and shall be accompanied by a pleading setting forth the claim or defense for which intervention is sought.

[¶ 71] The rule explicitly requires a pleading setting forth the intervenor’s claims or defenses be attached to the motion. Courts construing corresponding federal or state rules have consistently held the filing of a motion to intervene, accompanied by a proper pleading, constitutes the commencement of an action for purposes of the statute of limitations. See United States ex rel. Canion v. Randall & Blake, 817 F.2d 1188, 1192 (5th Cir.1987); Braxton v. Virginia Folding Box Co., 72 F.R.D. 124, 126 (E.D.Va.1976); Securities and Exch. Comm’n v. Keller Bros. Sec. Co., 30 F.R.D. 532, 533-34 (D.Mass.1962); Jack v. Travelers Ins. Co., 22 F.R.D. 318, 319 (E.D.Mich.1958), aff'd, 277 F.2d 736 (6th Cir.1960); Ioannou v. Ivy Hill Park Section Four, Inc., 112 N.J.Super. 28, 270 A.2d 295, 301-02 (1970); Callaway v. Ryan, 67 N.M. 283, 354 P.2d 999, 1001-02 (1960); Engert v. Peerless Ins. Co., 53 Tenn.App. 310, 382 S.W.2d 541, 550 (1964); 7C Charles Alan Wright et al., Federal Practice and Procedure § 1914 (2d ed.1986); see also Farris v. Sears, Roebuck & Co., 415 F.Supp. 594, 595-96 (W.D.Ky.1976) (service of motion to intervene with attached pleading is not commencement of an action, but tolls the statute of limitations).

[¶72] These courts have concluded, if the motion to intervene is subsequently granted, the attached pleading will be considered effective from the time the motion was originally filed for purposes of the statute of limitations. In the seminal case Jack v. Travelers Ins. Co., 22 F.R.D. at 319, the court explained:

Applicants were required under Rule 24 to seek leave before they might file their complaint in intervention.... Who can possibly predict what length of time might elapse between the filing of a motion to intervene and a final order granting it? There are time factors to be taken into consideration — a hearing date in open court dependent upon the condition of the docket when the motion is filed, the possibility of counsel requesting time for the filing of briefs, the inability of the Court to study the briefs at the exact moment of their delivery, and a number of other factors which are obvious to those accustomed to processing motions. No matter how diligent counsel for an applicant intervenor may be, we do not perceive what guarantee can be available that there will be an opportunity to file the complaint prior to the running of the statute.

[¶ 73] The United States Court of Appeals for the Fifth Circuit further explained the rationale for the rule in Randall & Blake, 817 F.2d at 1192 (footnote omitted):

We have found, however, almost unanimous agreement among the district courts addressing the question: the filing of the motion for intervention, and not the later approval of the motion and actual filing of the complaint, determines the commencement of the action for purposes of the statute of limitations. We find this rule to be the only sensible one and adopt it as our own. Once the party seeking intervention has filed its motion to intervene with its proposed complaint, it has done all it can do, in a timely sense, to commence its action. The complaint cannot be filed until the court approves the intervention. Here, Geer Construction filed its motion to intervene well before the expiration of the limitation period. The district court did not act on that motion, however, for over fourteen months. We see no justification for a rule that would bar a meritorious action as untimely because of a congested court docket or other circumstances over which the claimant has absolutely no control.

[¶74] We agree with the rationale of these cases. Because the rule requires that a copy of the intervening party’s pleading accompany the motion and be served upon all of the parties, it would be superfluous to require a subsequent motion explicitly requesting amendment of the pleadings after the court grants the motion to intervene. We will not interpret our rules in a manner that would result in unnecessary, duplicative procedures.

[¶ 75] We agree with the courts that hold an intervenor’s action is begun, for purposes of the statute of limitations, upon the making of a proper motion under Rule 24, accompanied by an appropriate pleading, which is subsequently granted by the court. Accordingly, we conclude the trial court erred in determining Exxon first asserted its treating fees claim against Koch on September 3, 1997, when the plaintiffs moved to amend the complaint. Exxon’s treating fees claim was begun, for purposes of the statute of limitations, when it filed and served its motion to intervene under N.D.R.Civ.P. 24. We therefore reverse and remand for recalculation of damages to Exxon on its treating fees claim.

VIII

[¶ 76] We have considered the remaining issues raised by BTA and find them to be either without merit or unnecessary to our decision. We do not answer questions that are not necessary to the determination of an appeal. E.g., Johnson v. Johnson, 2001 ND 109, ¶ 13, 627 N.W.2d 779.

[¶ 77] We reverse and remand that part of the judgment awarding Exxon damages on its treating fees claim for recalculation of damages in accordance with this opinion. In all other respects the judgment is affirmed.

[¶ 78] WILLIAM A. NEUMANN, acting C.J., GERALD G. GLASER, Surrogate Judge, CAROL RONNING KAPSNER and MARY MUEHLEN MARING, JJ., concur.

[¶ 79] The Honorable GERALD G. GLASER, Surrogate Judge, sitting in place of VANDE WALLE, C.J., disqualified.

      . On this appeal, BTA concedes it is not a third-party beneficiary under the MDU-Koch contracts. BTA has not provided any argument or citations to support an implied trust in this case.

      . BTA did not argue it was entitled to nominal damages. See Hummel, 526 N.W.2d at 709.

      . Exxon was the only producer that pleaded a “treating fees” claim.


author: VANDE WALLE, Chief Justice.

text:
    2002 ND 66
    Kevin Gerald DesLAURIERS, Plaintiff, Appellant and Cross-Appellee, v. Sandra Jane DesLAURIERS, n/k/a Sandra Jane Wade, Defendant, Appellee and Cross-Appellant.
    No. 20010145.
    Supreme Court of North Dakota.
    April 16, 2002.

      Richard B. Baer, Richard B. Baer, P.C., Bismarck, for plaintiff, appellant and cross-appellee.
    Karen L. McBride, Bucklin, Klemin & McBride, Bismarck,for defendant, appellee and cross-appellant.
   VANDE WALLE, Chief Justice.

[¶ 1] Kevin DesLauriers appealed from a judgment awarding custody of the couple’s two minor children to his former wife, and dividing the marital property. Kevin contends the trial court failed to adequately consider the custody guidelines as set forth by Section 14-09-06.2(1) of the North Dakota Century Code and, therefore, the trial court’s custody decision was clearly erroneous. Further, Kevin contends the trial court’s division of the marital debt and property was also clearly erroneous. We disagree, and affirm the judgment.

[¶ 2] On April 19, 2001 Kevin DesLau-riers was granted a divorce from Sandra DesLauriers on the grounds of irreconcilable differences. The marriage had lasted nearly eleven years and produced two children. Before the divorce the couple had been separated for nearly a year.

[¶ 3] Among other issues, the trial court resolved the dispute over the custody of the couple’s two minor children. The trial court awarded the primary physical custody of the children to Sandra. In its judgment the trial court explained it reached its decision because Sandra had been the primary caretaker of the children, and because Sandra was “stable and in a positive job setting and relationship with her children.” Additionally, the trial court noted “I am adopting the report of the guardian ad litem, which is herewith incorporated by reference.” Without further discussion of the statutory factors, the trial court concluded “[biased on the foregoing, the Court is awarding the primary physical custody of the children to [Sandra].”

[¶ 4] Further, the trial court ordered a property and debt division. Kevin received net marital property worth approximately $13,560, and Sandra received net marital property of approximately $1,300. The trial court explained this disparity of division by stating “[i]n view of the fact that a substantial amount of Kevin’s equity is from the tools with which he is able to earn a living, the Court finds this to be an equitable distribution.”

I

[¶ 5] When a trial court is asked to determine which parent of a divorcing or divorced couple should be awarded custody of the couple’s minor children, the trial court must strive to serve the children’s best interests. Schmaltz v. Schmaltz, 1998 ND 212, ¶ 6, 586 N.W.2d 852. To assist the trial court in this task, the legislature has set forth several factors which must be considered by the trial court as it forms its custody decision. These factors are set forth in N.D.C.C. § 14-09-06.2(1) and include:

a. The love, affection, and other emotional ties existing between the parents and child.
b. The capacity and disposition of the parents to give the child love, affection, and guidance and to continue the edu-‘ cation of the child.
c. The disposition of the parents to provide the child with food, clothing, medical care, or other remedial care recognized and permitted under the laws of this state in lieu of medical care, and other material needs.
d. The length of time the child has lived in a stable satisfactory environment and the desirability of maintaining continuity.
e. The permanence, as a family unit, of the existing or proposed custodial home.
f. The moral fitness of the parents.
g. The mental and physical health of the parents.
h. The home, school, and community record of the child.
i. The reasonable preference of the child, if the court deems the child to be of sufficient intelligence, understanding, and experience to express a preference.
j. Evidence of domestic violence....
k. The interaction and interrelation'ship, or the potential for interaction and interrelationship, of the child with any person who resides in, is present, or frequents the household of a parent and who may significantly affect the child’s best interests. The court shall consider that person’s history of inflicting, or tendency to inflict, physical harm, bodily injury, assault, or the fear of physical harm, bodily injury, or assault, on other persons.
l. The making of false allegations not made in good faith, by one parent against the other, of harm to a child as defined in section 50-25.1-02.
m. Any other factors considered by the court to be relevant to a particular child custody dispute.

[¶ 6] A trial court is not required to make specific findings of fact for each of the above statutory factors, but the trial court should consider all relevant factors in making its custody decision. Corbett v. Corbett, 2001 ND 113, ¶6, 628 N.W.2d 312. Such a decision is a finding of fact which will not be reversed on appeal unless clearly erroneous. Id. “A finding of fact is clearly erroneous if it is induced by an erroneous view of the law, if no evidence exists to support it, or if the reviewing court, on the entire evidence, is left with a definite and firm conviction a mistake has been made.” Id. As we have explained:

We give due regard to the trial court’s opportunity to assess the credibility and observe the demeanor of witnesses, and we do not retry custody issues or reassess the credibility of witnesses if the court’s decision is supported by evidence in the record. We will not reverse a trial court’s factual findings merely because we may have viewed the evidence differently, and a choice between two permissible views of the weight of the evidence is not clearly erroneous.

Corbett v. Corbett, 628 N.W.2d 312, 2001 ND 113, ¶ 6 (citations omitted).

[¶ 7] The trial court considered the best interests of Kevin’s and Sandra’s children under the statutory provisions of N.D.C.C. § 14-09-06.2(1), and awarded the primary physical custody of the two minor children to Sandra. In its judgment the trial court explained it reached its decision because Sandra had been the primary caretaker of the children, and because Sandra was “stable and in a positive job setting and relationship with her children.”

[¶ 8] “Although the primary caretaker rule has not been given presumptive status in this state, it remains a relevant factor to be considered by the trial court in its review of the statutory factors under N.D.C.C. § 14-09-06.2.” Reeves v. Chepulis, 1999 ND 63, ¶ 17, 591 N.W.2d 791. This is true because even though N.D.C.C. § 14-09-06.2(1) does not enumerate a primary caretaker factor, the rule nonetheless is inherent within the statutory factors. Id. (citing Gravning v. Gravning, 389 N.W.2d 621, 622 (N.D.1986) which explained the primary caretaker rule “inheres in the statutory factors and has not yet been accorded elevated status”). Accordingly, the trial court’s reliance upon Sandra’s role as primary caretaker is clearly erroneous only if there is no evidence of Sandra playing such a role.

[¶ 9] The record contains evidence to support the assertion Sandra was the primary caretaker. Both parties testified at trial, each claiming he or she was the primary care giver. The trial court is in a better position to judge the credibility of witnesses than this Court, so we will not now re-weigh or reconsider the trial testimony of each party.

[¶ 10] In addition to relying upon its conclusion that Sandra was the primary caretaker, the trial court adopted the guardian ad litem’s report. Kevin contends doing so resulted in the trial court’s failure to fulfill its obligation to consider the factors of N.D.C.C. § 14-09-06.2(1). We disagree.

[¶ 11] Though “[t]he trial court, not the guardian ad litem, has the authority to make a child custody award,” Nefzger v. Nefzger, 1999 ND 119, ¶ 20, 595 N.W.2d 583, “[t]he weight assigned to a guardian ad litem’s report or other independent recommendation is within the trial court’s discretion.” Id. A trial court, however, should not “regard a guardian ad litem’s testimony and recommendation as conclusive.” Id. Accordingly, it is not reversible error for a trial court to rely upon a guardian ad litem’s findings, and even to incorporate them wholly by reference into the court’s findings, although this is not the preferred approach, so long as the trial court does not abdicate its obligation to independently weigh the evidence. Indeed, experts are retained to provide just such assistance to the courts.

[¶ 12] The guardian ad litem’s report included detailed findings and a discussion of every one of the thirteen factors set forth in N.D.C.C. § 14-09-06.2(1). The guardian ad litem concluded seven of the statutory factors favored neither of the parents, and the remaining five factors all favored Sandra. Kevin asserts the guardian ad litem’s conclusions and discussion were mistaken and, therefore, cannot support the trial court’s judgment. We decline Kevin’s invitation to re-weigh the evidence of this case. Two of the guardian ad litem’s findings, however, require further discussion.

[¶ 13] First, the guardian ad li-tem found that the “reasonable preference” of the children was to live with Sandra and therefore concluded this factor, N.D.C.C. § 14-09-06.2(1)®, favored Sandra. Kevin protests that the children, born October 3, 1990 and March 26, 1992 respectively, were simply too young at the time of trial, December of 2000, to have a legally significant opinion on the subject. Sandra correctly points out, however, that while a trial court has no obligation to consider the preference of an immature child, see N.D.C.C. § 14-09-06.2(1)®, the trial court may determine whether or not a child is capable of intelligently choosing between parents. McDowell v. McDowell, 2001 ND 176, ¶ 20, 635 N.W.2d 139. Because the trial court adopted the guardian ad litem’s report and thus found the reasonable preference of the children was to live with Sandra, the trial court implicitly determined the children were capable of intelligently choosing between Kevin and Sandra. This was not clearly erroneous.

[¶ 14] Second, the guardian ad li-tem found evidence of domestic violence by Kevin and therefore concluded this factor, N.D.C.C. § 14-09-06.2(l)(j), favored Sandra. Kevin argues the guardian ad litem found domestic violence where there was none. The term “domestic violence,” as defined by N.D.C.C. § 14-07.1-01(2), includes “physical harm, bodily injury, sexual activity compelled by physical force, assault, or the infliction of fear of imminent physical harm, bodily injury, sexual activity compelled by physical force, or assault, not committed in self-defense, on the complaining family or household members.” If there is credible evidence of any of the above a trial court shall consider it and weigh it against the perpetrator of the abuse. Holtz v. Holtz, 1999 ND 105, ¶ 27, 595 N.W.2d 1. If there is credible evidence of domestic violence “and there exists one incident of domestic violence which resulted in serious bodily injury or involved the use of a dangerous weapon or there exists a pattern of domestic violence within a reasonable time proximate to the proceeding,” id. (quoting 1997 N.D. Sess. Laws ch. 147, § 2), a rebuttable presumption against awarding custody to the parent who perpetrated the domestic violence is created.

[¶ 15] Sandra concedes Kevin’s behavior does not create the statutory presumption against awarding him custody; however, Sandra maintains Kevin’s behavior was, nonetheless, abusive and appropriately weighed against him as one factor among others.

[¶ 16] The guardian ad litem noted:

Sandi feels Kevin was verbally abusive to her and the children. She said he became abusive in what he called joking around with her and the children. Sandi said if he were joking around the children wouldn’t have been crying. Sandi feels Kevin used degrading names to the children and that he had a temper. The sexual aspect of their marriage was another source of problems according to Sandi.

The guardian ad litem further reported:

According to the Domestic Abuse Intervention Project, the characteristics of emotional abuse include putting her down, making her feel bad about herself, calling her names, making her think she is crazy, playing mind games, humiliating her and making her feel guilty. If we include the mental anguish portion of the domestic violence definition then I believe domestic violence was present (emphasis ours).

The guardian ad litem concluded this factor favored Sandra, but, there is no evidence that the guardian ad litem considered the mental anguish sufficient to trigger the statutory presumption against Kevin as a domestic abuser.

[¶ 17] Other than the fear specifically defined at N.D.C.C. § 14-07.1-01(2), mental anguish is not within the statutory definition of domestic violence, and it is not part of the calculus of N.D.C.C. § 14-09-06.2(l)(j). The last factor of N.D.C.C. § 14-09-06.2(1), factor (m), however, allows a trial court to consider any relevant information not covered by a specific factor of N.D.C.C. § 14-09-06.2(1). The deliberate infliction of mental anguish upon one parent and the children by the other parent is relevant to the custody determination and may be considered under the last factor, the catch-all factor, of N.D.C.C. § 14-09-06.2(1).

[¶ 18] The custody decision is affirmed.

II

[¶ 19] Kevin further asserts the trial court’s division of property was inequitable and clearly erroneous because, despite the fact it left him with more marital property than Sandra, he was also charged with paying, what he considers to be, Sandra’s credit card debt.

[¶ 20] A trial court’s decision on the division of marital property is a finding of fact, and therefore such decisions will not be set aside unless they are clearly erroneous. Schwartz v. Schwartz, 1997 ND 91, ¶ 4, 563 N.W.2d 391(reminding also “due regard shall be given to the opportunity of the trial court to judge the credibility of the witnesses”). “A finding of fact is clearly erroneous if it is induced by an erroneous view of the law, if there is no evidence to support it, or if, although there is some evidence to support it, on the entire evidence there is a definite and firm conviction a mistake has been made.” Fox v. Fox, 2001 ND 88, ¶ 14, 626 N.W.2d 660.

[¶ 21] In the past we have found where one spouse has amassed credit card debt for his or her own “personal benefit and to pay court-ordered support to a separated spouse, that debt should not be shifted to the supported spouse.” Lohstreter v. Lohstreter, 1998 ND 7, ¶ 21, 574 N.W.2d 790. In contrast, here there is evidence Kevin and Sandra both used credit cards to directly or indirectly benefit the entire family, even though one of the credit cards was solely in Sandra’s name. The debt produced by using credit cards to benefit the entire family is, like property, neither uniquely the husband’s nor the wife’s and can be allocated by the trial court in its equitable division of the marital estate. See Lohstreter v. Lohstreter, 574 N.W.2d 790, 1998 ND 7, ¶ 17 (reversing a trial court’s allocation of credit card debt to both spouses because the record did not support the trial court’s assumption the credit card debt “inured to the benefit of the entire family”). In order to divide the net marital estate between the parties, the trial court must also allocate the debt. See, e.g., Corbett v. Corbett, 628 N.W.2d 312, 2001 ND 113, ¶¶ 14-15(affirming a trial court’s division of property and debt); Schmaltz v. Schmaltz, 586 N.W.2d 852, 1998 ND 212, ¶¶ 16-17(affirming a trial court’s division of marital property and debt); Schwartz v. Schwartz, 563 N.W.2d 391, 1997 ND 91, ¶¶ 6-7(affirming a trial court’s division of property and debt).

[¶ 22] A trial court’s division of marital property must be equitable. N.D.C.C. § 14-05-24(1). “[A] property division need not be equal to be equitable,” however. Schwartz v. Schwartz, 563 N.W.2d 391, 1997 ND 91, ¶ 4. If the property division is not equal and there is a “substantial disparity” in the property division, the trial court must explain the reasons for the disparity. See id.

[¶ 23] Here the trial court calculated the value of the marital assets and debts and awarded Kevin marital property with a net value of approximately $13,560, and Sandra net marital property of approximately $1,300. The trial court explained this disparity of division by stating “[i]n view of the fact that a substantial amount of Kevin’s equity is from the tools with which he is able to earn a living, the Court finds this to be an equitable distribution.” There is evidence in the record to support the trial court’s findings, and therefore, the property division is not clearly erroneous.

[¶ 24] The judgment is affirmed.

[¶ 25] CAROL RONNING KAPSNER, MARY MUEHLEN MARING, WILLIAM A. NEUMANN, JJ., concur.

I concur in the result, DALE V. SANDSTROM.