(a) The commissioner shall classify each wetland shown on the freshwater wetlands map according to the classification system set forth in section 664.5 of this Part. That system establishes four separate classes that rank wetlands according to their ability to perform wetland functions and provide wetland benefits. Class I wetlands have the highest rank, and the ranking descends through classes II, III and IV.

(b) When a wetland contains characteristics of more than one class, the wetland shall be classified in the highest of the classes.

(c) If irreversible degradation has removed the benefits associated with the particular characteristic(s) justifying a classification, the wetland shall be classified on the basis of the remaining characteristics. For example, a wetland could be irreversibly contaminated by toxic substances that remove its benefits as habitat for fish and wildlife, or could be irreversibly visually degraded, thus removing some or all of its aesthetic, recreational and open-space benefits.

(d) Notwithstanding subdivision (c) of this section, where land originally designated as a wetland on the map was altered for agricultural purposes following the promulgation of that map, the land shall continue to be classified in light of its wetland conditions, and the wetland benefits set forth in section 24-0105 of the act and in this Part that it provided, at the time of its original designation on the map.

(e) The classification of each wetland shall be set forth in a written order by the commissioner. An explanation of the reasons for the classification shall be on file in the appropriate regional office(s) of the department. A copy of the classification order shall be filed in the office of the clerk of each local government in which the wetland is located and in the appropriate regional office(s) of the department. Notice of each order shall also be given to the chief administrative officer of each affected local government and to each owner of record, as shown on the latest completed tax assessment rolls, of classified wetlands affected by the order, and also shall be published in the department's environmental notice bulletin.

(f) The commissioner may raise or lower a classification on the basis of material new information or materially changed wetland conditions. Notice of the order setting forth the revised classification shall be given and published, and a copy of such order shall be filed, as provided in subdivision (e) of this section.

(g) Any person may request of the department a change in a wetland's classification by setting forth reasons for believing the present classification to be incorrect. Such request shall be submitted in writing in a form and manner prescribed by the department and shall set forth material new information relevant to the wetland or materially changed conditions of the wetland justifying the request. The request must include evidence addressed to the classification system set forth in section 664.5 of this Part, consisting of, for example, photographs identifying cover types justifying a different classification; water samples; or the affidavit of an expert. The department shall notify the person making the request within 15 working days as to whether the request is adequate to warrant consideration. If the department deems the request adequate, the decision to reclassify the wetland as requested, to retain the existing classification, or to change the classification to another classification not so requested shall continue to be at the discretion of the commissioner. Notice of any order setting forth a revised classification shall be given and published, and a copy of such order shall be filed, as provided in subdivision (e) of this section.

(h) Any person intending to submit an application for a permit or a letter of permission may, in the course of a preapplication conference held pursuant to subdivision (b) of section 663.4 of this Title, or in the course of analogous discussions with a local government that is administering the act, request in writing, in a form and manner prescribed by the department, that the commissioner confirm the classification of the wetland that would be affected by the proposed activity. Within 15 working days of the department's receipt of the request, the commissioner shall decide either to confirm the existing classification or to revise (either to raise or lower) the classification on the basis of material new information or materially changed wetland conditions. Within that same 15-day period, the department shall send notice of the decision confirming or revising the classification to the person who submitted the request; and that person shall not file a permit application until such notice has been provided. Where the classification is revised, notice of the order setting forth the revised classification shall also be given and published, and a copy of such order shall be filed, as provided in subdivision (e) of this section. Once the wetland's classification has been confirmed or revised pursuant to this subdivision and the permit application that was the subject of the preapplication conference has been filed, no further department-initiated change in the wetland's classification shall change the standard for permit issuance applied to that application.

(i) If there is a public hearing on a permit application, then once that hearing has commenced, no department-initiated change in the wetland's classification shall change the standard for permit issuance applied to that application. However, any other party to such a hearing may request a change in the existing classification of that wetland in the same manner and under the same conditions as set forth in subdivision (g) of this section. Within five working days of its receipt of the request, the department must determine whether the request is adequate to warrant consideration. If the department deems the request adequate, the commissioner must act upon the request; either to reclassify the wetland as requested, to retain the existing classification, or to change the classification to another classification not so requested; within 15 working days from the date of the request, and before the permit hearing may continue.