[1] Petitioner contends the trial court erred in upholding DEHNR’s final agency decision. Specifically, petitioner argues the record contains insufficient evidence to support a violation of the SPCA and the agency erred as a matter of law in assessing the civil penalty. The proper standard for the superior court’s judicial review of a final agency decision “depends upon the particular issues presented on appeal.” Act-Up Triangle v. Commission for Health Services, 345 N.C. 699, 706, 483 S.E.2d 388, 392 (1997); Amanini v. N.C. Dept. of Human Resources, 114 N.C. App. 668, 674, 443 S.E.2d 114, 118 (1994). N.C. Gen. Stat. § 150B-51(b) provides:
[T]he court reviewing a final decision may affirm the decision of the agency or remand the case for further proceedings. It may also reverse or modify the agency’s decision if the substantial rights of the petitioners may have been prejudiced because the agency’s findings, inferences, conclusions, or decisions are:
(1) In violation of constitutional provisions;
(2) In excess of the statutory authority or jurisdiction of the agency;
(3) Made upon unlawful procedure;
(4) Affected by other error of law;
(5) Unsupported by substantial evidence admissible under G.S. 150B-29(a), 150B-30, or 150B-31 in view of the entire record as submitted; or
(6) Arbitrary or capricious.
G.S. § 150B-51(b) (1995).
Judicial review of whether an agency decision was based on an error of law requires a de novo review. Walker v. N.C. Dept. of Human Resources, 100 N.C. App. 498, 502, 397 S.E.2d 350, 354 (1990), disc. review denied, 328 N.C. 98, 402 S.E.2d 430 (1991). When the petitioner argues the agency’s decision was not supported by the evidence or the decision was arbitrary or capricious, then the reviewing court must apply the ‘whole record’ test. In re Appeal By McCrary, 112 N.C. App. 161, 165, 435 S.E.2d 359, 363, (1993). The ‘whole record’ test “requires the reviewing court to examine all competent evidence (the ‘whole record’) in order to determine whether the agency decision is supported by ‘substantial evidence.’ ” Amanini, 114 N.C. App. *474at 674, 443 S.E.2d at 118. Substantial evidence is “more than a scintilla” and is “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” Lackey v. Dept. of Human Resources, 306 N.C. 231, 238, 293 S.E.2d 171, 176 (1982).
The standard of review for an appellate court when reviewing a trial court’s order affirming or reversing a final decision of an administrative agency requires this Court to examine the trial court’s order for error of law, just as in any other civil case. “The process has been described as a twofold task: (1) determining whether the trial court exercised the appropriate scope of review and, if appropriate, (2) deciding whether the court did so properly.” Amanini, 114 N.C. at 675, 443 S.E.2d at 118-19.
The trial court in this case properly employed the correct standard of review of the agency’s order and the judgment of the trial court stated it “reviewed the record and matters on file, . . . considered the oral and written arguments of the attorneys for each of the parties, and . . . considered the relevant statutory provisions. The Court has applied the standard of review set forth in N.C.G.S. § 150B-51.” Upon review of the issues raised by petitioner, we find the trial court did not err in affirming the agency’s conclusion that petitioner failed to comply with applicable BMPs and violated the SPCA.
Petitioner contends that because David Brown inspected the site in June 1991 and found the site to be in compliance, and no further logging activity occurred at the site after that time, and also because there was no evidence that downstream landowners complained about sedimentation damage, the evidence fails to rise to the level of substantial evidence showing a violation occurred. We disagree.
The record shows petitioner’s property was inspected three times between August and October 1991. Each time, the site was found not to be in compliance because sediment from eroded areas on skid trails was entering the stream in at least three different locations, eventually causing a delta to form at a downstream pond. Water bars and natural vegetation at the site were inadequate to prevent sediment from entering the stream. Further, debris from the logging operation was found in the stream, obstructing or impeding the stream’s flow. After each inspection, petitioner was notified of the violations and asked to take corrective measures. Also, forester John Lively testified that Brown’s June 1991 report stated petitioner’s property “was in compliance at that time.” (emphasis added). Lively also testified there had been no additional growth of annual grasses and weeds as *475Brown had perhaps anticipated. He further testified that Brown’s report stated that petitioner needed to check the water bars periodically’ and keep them clear with a shovel, and that petitioner could also sow grass seed to help maintain the property in compliance. Taking all the evidence together, including the evidence that petitioner’s property was found to be in compliance in June 1991, the record contains more than a scintilla of evidence adequate to support a conclusion that the property failed to comply with BMPs. Therefore, substantial evidence existed in the record to find petitioner violated BMPs while conducting logging operations on his property.
[2] Petitioner next argues the agency erred as a matter of law in assessing the amount of the civil penalties. We find no merit to this argument. Under N.C. Gen. Stat. § 113A-64(a) and N.C. Admin. Code tit. 15A, r. 4C .0006 (September 1995), DEHNR has discretion to assess civil penalties in varying amounts, commensurate with the seriousness of the violation, as long as the assessments are within the established guiding standards. See In the Matter of Appeal from Civil Penalty, 324 N.C. 373, 383, 379 S.E.2d 30, 36 (1989). Here, the record shows the amounts assessed were within the guideline ranges and based upon consideration of the factors enumerated within the applicable statute and code regulations. Petitioner seems to argue that because the administrative law judge recommended reduction of the original penalty because some of the violations were acreage dependent, the agency erred in its final decision by not reducing the penalty by a greater amount. However, the $30 a day penalty imposed was based upon the degree of sedimentation that had occurred, a factor not influenced by the amount of land involved. The $50 a day penalty was based on petitioner’s failure to take action to correct the violations and again, was not affected by acreage requirements. Therefore, we find no error of law in the amount assessed as a civil penalty.
[3] Lastly, petitioner argues the SPCA does not authorize a civil penalty to be assessed for land-disturbing activities which uncover less than one acre of property. Petitioner contends that because N.C. Gen. Stat. § 113A-57 (3) and (4) contain a requirement that more than one acre of land must be uncovered before a violation will be found, this constitutes a “clear inference” that G.S. 113A-57(1) and (2) also require more than one acre of land to be involved. We disagree.
G.S. 113A-57(1) deals with land-disturbing activity near a lake or natural watercourse. N.C. Gen. Stat. § 113A-52(6) defines land-*476disturbing activity as: “[A]ny use of the land . . . that results in a change in the natural cover or topography and that may cause or contribute to sedimentation.” (emphasis added). G.S. 113A-57(2) deals with graded slopes. Had our General Assembly also wished these sections to contain a one acre requirement, they could have added it to these sections. See Preston v. Thompson, 53 N.C. App. 290, 292, 280 S.E.2d 780, 783 (1981) (when giving a statute its plain meaning, the courts may not interpolate or superimpose provisions not contained within the statute), disc. review denied and appeal dismissed, 304 N.C. 392, 285 S.E.2d 833 (1981). Further, this view better serves the stated legislative intent behind the enactment of the SPCA, which is to protect against the sedimentation of our waterways. See N.C. Gen. Stat. § 113A-51.
For the reasons stated, the judgment of the trial court is affirmed.
Affirmed.
Judges WYNN and JOHN concur.