Chicago and North Western Transportation Company (CNW) appeals from an order affirming an order of the Commissioner of Railroads requiring CNW to install and maintain drainage improvements in an earthen railroad grade ,as designed by the Milwaukee Metropolitan Sewerage District. CNW argues that: (1) the District does not have standing to initiate an action under § 88.87(4), Stats., because the District did not first comply with all of the procedural requirements set forth in § 88.87(2); (2) the Commissioner cannot order CNW to modify its grade if the grade has not already caused an unnecessary or unreasonable accumulation of waters; and (3) CNW cannot be required to modify its grade if there is no evidence that an unnecessary or unreasonable accumulation of waters will arise from changes in natural conditions or the enlargement of the water flow. We conclude that these claims are without merit and, therefore, affirm.
BACKGROUND
CNW maintains an earthen railroad grade containing five forty-eight-inch culverts through which the Edgerton Channel flows. In 1978 and 1990, the District authorized the Southeastern Wisconsin Regional Planning Commission to study and report on land uses and the flooding consequences in the channel area pursu*6ant to its duties under § 66.89(1), Stats.1 The study found that upon the completion of the planned use development within the channel drainage area, annual flooding costs within this drainage area would exceed $140,000.
The District decided to improve the channel by increasing its drainage capacity. It also concluded that CNW would have to modify its grade to accommodate the additional flow of water. The District's plan called for CNW to replace the existing forty-eight-inch culverts with three ninety-six-inch culverts. The District petitioned the Office of the Commissioner of Railroads under §§ 88.87(4) and 190.08, Stats., for an order requiring CNW to make these improvements.
After a public hearing on the matter, the Commissioner found that past flooding along the channel was caused by inadequate drainage upstream from CNW's grade rather than by the railroad grade and culverts. The Commissioner also found that the District did not have to wait until CNW's grade caused flooding before the District could petition the Commissioner under § 88.87(4). The Commissioner found that the District's plan for increasing the channel's drainage capacity called for CNW to modify the culverts in the grade to handle the additional water flowing through the channel because "[ljeaving the railroad culverts at their existing elevation and capacity would create a 'dam-like' effect." Accordingly, the Commissioner ordered CNW to install and maintain the drainage improvements as designed by the District.
*7CNW sought certiorari review of the Commissioner's decision under ch. 227, STATS., and the trial court affirmed. CNW appeals.
STANDARD OF REVIEW
In a ch. 227, STATS., appeal, we review the agency's decision and, therefore, give no deference to the decision of the trial court. Soo Line R.R. Co. v. Office of Comm'r of Transp., 170 Wis. 2d 543, 549, 489 N.W.2d 672, 674 (Ct. App. 1992). CNW challenges the Commissioner's interpretation and application of § 88.87, Stats. Interpretation of a statute and its application to the undisputed facts of a case are questions of law which we review de novo. Local No. 695 v. LIRC, 154 Wis. 2d 75, 82, 452 N.W.2d 368, 371 (1990). Our primary purpose when interpreting a statute is to give effect to the legislature's intent. Riverwood Park, Inc. v. Central Ready-Mixed Concrete, Inc., 195 Wis. 2d 821, 827, 536 N.W.2d 722, 724 (Ct. App. 1995). We first look at the language of the statute and if that language is clear and unambiguous, we construe the statute in accordance with its ordinary meaning. Id. at 828, 536 N.W.2d at 724. A statute is ambiguous if it is capable of being understood by reasonably well-informed persons as having two or more different meanings. Id. If the statute is ambiguous, then we may examine its content, subject matter, scope, history and purpose. Id. Upon reviewing the Commissioner's factual findings, we shall not substitute our judgment for that of the agency as to the weight of the evidence on any disputed finding of fact if that fact is supported by substantial evidence in the record. Section 227.57(6), STATS.
*8We do, however, defer to an agency's legal conclusions in certain instances:
First, if the administrative agency's experience, technical competence, and specialized knowledge aid the agency in its interpretation and application of the statute, the agency determination is entitled to "great weight." The second level of review provides that if the agency decision is "very nearly" one of first impression it is entitled to "due weight" or "great bearing." The lowest level of review, the de novo standard, is applied where it is clear from the lack of agency precedent that the case is one of first impression for the agency and the agency lacks special expertise or experience in determining the question presented.
Jicha v. DILHR, 169 Wis. 2d 284, 290-91, 485 N.W.2d 256, 258-59 (1992) (citations omitted).
CNW argues that because this is a case of first impression, we owe no deference to the Commissioner's order. This appeal involves two major issues: (1) whether compliance with all of the paragraphs contained in § 88.87(2), Stats., is a prerequisite to the Commissioner having the authority to act under § 88.87(4); and (2) whether the Commissioner may order CNW to make improvements when CNW's grade has not been shown to have caused flooding. These are issues of statutory interpretation and the District has not shown that the Commissioner has decided these issues or similar ones. When, as here, we have issues of first impression and the agency has no special expertise or experience in deciding them, we will review the Commissioner's legal decisions de novo. Jicha, 169 Wis. 2d at 291, 485 N.W.2d at 259.
*9I.
CNW argues that the District did not have standing to initiate this administrative proceeding under § 88.87(4), Stats., because the requirements of § 88.87(2), including para. (2)(c), were not satisfied before the District filed its petition. According to CNW, before a petition may be filed pursuant to § 88.87(4), CNW's grade must have already caused past flooding, the railroad must be given an opportunity to correct the cause of the water damage or to acquire rights to use the flooded land, or it must have denied an injured landowner's claim. Section 88.87(2)(c). We disagree.
Section 88.87(4), STATS., provides:
If a railway company fails to comply with sub.(2), any person aggrieved thereby may file a complaint with the office of the commissioner of railroads setting forth the facts. The office shall investigate and determine the matter in controversy in accordance with ch. 195, and any order it makes in such proceeding has the same effect as an order in any other proceeding properly brought under ch. 195.
Contrary to CNW's assertions, sub. (4) does not state that the railroad company must comply with "all of sub. (2)" before the Commissioner may investigate and determine the matter in controversy. It states that a railroad company must first "comply with sub. (2)." We read that language as requiring compliance with those parts of sub. (2) which are germane to the matter in controversy.
Section 88.87(2)(a), Stats., provides in relevant part:
*10Whenever any . . . railroad company . . . has heretofore constructed and now maintains or hereafter constructs and maintains any . . . railroad grade in or across any . . . channel or drainage course, it shall not impede the general flow of surface water or stream water in any unreasonable manner so as to cause either an unnecessary accumulation of waters flooding or water-soaking uplands or an unreasonable accumulation and discharge of surface waters flooding or water-soaking lowlands. All such highways and railroad grades shall be constructed with adequate ditches, culverts, and other facilities as may be feasible, consonant with sound engineering practices, to the end of maintaining as far as practicable the original flow lines of drainage.
This paragraph imposes an affirmative duty on a railroad to refrain from impeding the general flow of water in an unreasonable manner when constructing or maintaining a railroad bed. See Van v. Town of Manito-woc Rapids, 150 Wis. 2d 929, 930, 442 N.W.2d 557, 558 (Ct. App. 1989).
Section 88.87(2)(c), Stats., provides in relevant part:
If a . . . railroad company . . . constructs and maintains a . . . railroad grade not in accordance with par. (a), any property owner damaged by the . . . railroad grade may, within 3 years after the alleged damage occurred, file a claim within the appropriate governmental agency or railroad company. ... Within 90 days after the filing of the claim, the governmental agency or railroad company shall either correct the cause of the water damage, acquire rights to use the land for drainage or overflow purposes, or deny the claim. If the agency or company denies the claim or fails to take any action *11within 90 days after the filing of the claim, the property owner may bring an action in inverse condemnation under ch. 32 or sue for such other relief, other than damages, as may be just and equitable.
This paragraph imposes procedural prerequisites upon a landowner who is claiming that a railroad caused damage by past flooding before a petition may be filed under § 88.87(4).
It is undisputed that CNW's grade has not caused past flooding. But according to engineers' reports, once the capacity of the Edgerton Channel is increased, the grade will cause flooding and damage. Section 88.87(2)(c), Stats., is triggered only when flooding and damage has already occurred and provides remedial steps which may be taken by the railroad. If we read sub. (4) as requiring compliance with para. (2)(c) before a petition could be filed under sub. (4), then the Commissioner could not act to prevent certain harm and damage. This is unreasonable. We conclude that para. (2)(c) is only applicable when a party is filing a claim against a railroad for damage and not when a party is trying to prevent it.2
In Lemonweir River Drainage Dist. v. Chicago, M., St. P. & P. R.R., 199 Wis. 46, 49, 225 N.W. 132, 133 (1929), the supreme court relied upon § 89.65, STATS., *121929, which is similar to § 88.87, STATS., to conclude that the legislature intended to give the Commissioner the authority to avoid harm.3 This same intent is now expressed in § 88.87(1), Stats., in which the legislature provides: "The legislature finds that it is necessary to control and regulate the construction and drainage of all highways and railroad grades so as to protect property owners from damage to lands caused by unreasonable diversion or retention of surface waters due to . . . railroad grade construction . . . ." Thus, in order for the Commissioner to implement this intent, compliance with para. (2)(c) is not necessary when a railroad's grade has not, but will, cause damage.
But CNW argues that this reading of § 88.87(4), Stats., renders § 88.87(2)(c) superfluous. We are not to read statutes in a manner that leaves parts of a statute meaningless. Kelley Co. v. Marquardt, 172 Wis. 2d 234, 250, 493 N.W.2d 68, 76 (1992). But our interpretation of sub. (4) does not excise the procedural requirements of para. (2)(c) from § 88.87(2). Indeed, property owners who have incurred actual damáge and who seek court action still must comply with para. (2)(c) before filing a petition under sub. (4). Van, 150 Wis. 2d at 934, 442 N.W.2d at 559. But here, damage has not yet, but will, occur. Thus, we believe that a better reading of sub. (4) is one that allows the District to petition the Commissioner when damage is certain to occur but before that damage has occurred.
*13II.
CNW further asserts that § 88.87(4), STATS., does not apply prospectively to permit the Commissioner to act when there is no finding that a railroad has caused any actual harm. Specifically, CNW argues that in order for the Commissioner to require CNW to protect against future damage, the District must first demonstrate that CNW's grade actually impeded the general flow of water and that any impediment to the flow has already caused an unnecessary or unreasonable accumulation of waters. CNW asserts that while the Commissioner found that CNW's grade will impede the channel's flow in the future, the prospect of future flooding is insufficient to trigger the remedy provided in § 88.87(4). We disagree.
Section 88.87(2), Stats., imposes a duty on a railroad to refrain from impeding the general flow of water in an unreasonable manner when constructing or maintaining railroad grades. See Van, 150 Wis. 2d at 930, 442 N.W.2d at 558. The legislature's intent to give the Commissioner the authority to protect landowners before damage has occurred is expressed in § 88.87(1) which provides:
It is recognized that the construction of highways and railroad grades must inevitably result in some interruption of and changes in the preexisting natural flow of surface waters and that changes in the direction or volume of flow of surface waters are frequently caused by the erection of buildings, dikes and other facilities on privately owned lands adjacent to highways and railroad grades. The legislature finds that it is necessary to control and regulate the construction and drainage of all highways and railroad grades so as to protect property owners from damage to lands caused by *14unreasonable diversion or retention of surface waters due to a highway or railroad grade construction and to impose correlative duties upon owners and users of land for the purpose of protecting highways and railroad grades from flooding or water damage.
(Emphasis added.) We conclude that the legislature used this "protection" language to indicate that it not only intended to assist property owners already damaged, but that it also intended to shield them from circumstances that would cause future damage. This conclusion is further supported by language in § 88.87(2)(b), Stats., which provides:
Drainage rights and easements may be purchased or condemned by the public authority or railroad company having control of the highway or railroad grade to aid in the prevention of damage to property owners which might otherwise occur as a result of failure to comply with par. (a).
Permitting the District to file a petition under § 88.87(4) to prevent future flooding is consistent with this policy.
Indeed, the supreme court has concluded that a statute similar to § 88.87, STATS., imposes on a railroad an ongoing duty to accommodate increased floodwaters impeded by a grade or embankment. Lemonweir, 199 Wis. at 49-50, 225 N.W. at 133. In that case, the court wrote:
[The statute] is but a declaration of the common-law rule that a railroad company crossing with its roadbed a natural watercourse is bound to construct its roadbed so as not to materially interfere with the natural flow of such watercourse; and further, that such duty is not a once-and-for-all duty and forever *15discharged by a proper original construction over such stream, but is a continuing one, and such railroad must adjust such construction thereafter and, in the absence of statute to the contrary, at its own expense, to meet changes in the condition of such watercourse arising, either from natural causes, or by reason of any lawful enlargement of the flow in the same because of construction such as are here in question.
Id. (emphasis added).
Following this reasoning, we concluded in Soo Line, 170 Wis. 2d at 555,489 N.W.2d at 677, that:
the precedent supports our reading of the statute: the railroad "shall not impede the general flow" of water, sec. 88.87(2)(a), Stats., and the duty not to impede is "ongoing," Lemonweir, where the railroad now "maintains" any grade across any drainage course, sec. 88.87(2)(a), even if the increased flow arises from "changes in ... volume ... caused by the erection of buildings, dikes and other facilities on privately owned lands." Section 88.87(1), Stats.
We conclude that the statutes and case law demonstrate that the legislature intended to give the Commissioner the power to act before damage has occurred. The Commissioner's finding was based upon engineers' conclusions that when the channel's capacity was increased, CNW's grade would cause flooding if it was not modified. Despite the absence of evidence that CNW's grade did not cause past flooding, we nonetheless conclude that the Commissioner had the authority to act in this case to prevent certain future flooding.
*16HH I — I H-1
CNW's final assertion is similar to the previous one albeit cast in other language. CNW argues that it cannot be ordered to modify its grade if there is no evidence that an unnecessary or unreasonable accumulation of waters will arise from changes in natural conditions or the enlargement of the water flow. To this end, it contends that under Lemonweir and Soo Line, it has an ongoing duty to make improvements to its grade after it completes the grade and after flooding occurs. Again, we disagree.
As we concluded in the previous discussion, where evidence is presented that a channel's water flow will increase from a planned change, § 88.87, Stats., does not require that those changes be implemented before the Commissioner can act if doing so would cause certain flooding. Furthermore, while Lemonweir and Soo Line concerned factual scenarios in which flooding had already occurred, the Commissioner's duty to protect against certain future flooding is not grounded in those cases, but upon § 88.87 and its predecessor.
Indeed, CNW's suggestion that the Commissioner cannot act unless flooding has taken place is troublesome. We conclude that it is entirely reasonable for the District to attempt to coordinate the modifications to the channel by first requiring CNW to improve its grade to accommodate the increased water flow. Otherwise, at the very moment those changes in the channel are made, flooding would result. As we said above, it is within the Commissioner's authority to order CNW to make modifications to its grade when the evidence demonstrates that an unreasonable and unnecessary increase in water flow is certain to result. Accordingly, we affirm.
By the Court. — Order affirmed.
Section 66.89(1), STATS., provides that the commission shall "[p]roject, plan, design, construct, maintain and operate a sewerage system...."
CNW also asserts that pursuant to § 88.87(2)(c), STATS., a claim may only be filed by a damaged property owner and the District has not shown that it is a damaged property owner. Because we conclude that the procedural requirements of para. (2)(c) are not triggered in this case, we need not address this issue. See Sweet v. Berge, 113 Wis. 2d 61, 67, 334 N.W.2d 559, 562 (Ct. App. 1983) (this court need not address all issues when one is dispositive of the appeal).
In Soo Line R.R. Co. v. Office of Comm'r of Transp., 170 Wis. 2d 543, 551 n.3, 489 N.W.2d 672, 675 (Ct. App. 1992), we noted that "[blecause former ch. 89 was subsumed into ch. 88 [in 1963], pre-1963 precedents under ch. 89 are relevant to interpreting ch. 88 also."