Except for regulated activities proposed within the Critical Area, an activity that qualifies for a letter of authorization is exempt from the permit and mitigation requirements of this subtitle. Activities proposed in the Critical Area are not exempt from the mitigation requirements of COMAR 26.23.04.02—.07. Upon application, the activities listed below may qualify for a letter of authorization provided that the conditions in Regulation .02B of this chapter are satisfied and best management practices, which may be required by the Department, are all met: Activities in isolated nontidal wetlands of less than 1 acre and having no significant plant or wildlife value. An applicant's determination of whether an area is an isolated nontidal wetland shall be based on published hydrologic and hydraulic data or data obtained in the field which shows whether the nontidal wetland is hydrologically connected. Activities whose cumulative loss of nontidal wetlands and buffer, which contains no significant plant or wildlife value, is: Less than 5,000 square feet; or Greater than 5,000 square feet, provided that: The actual loss of nontidal wetlands is less than 5,000 square feet, and Activities in the buffer result in minimal additional adverse impacts to nontidal wetlands, as determined by the Department. Installation of Utility Lines. The installation of utility lines includes the following activities: Trenching, jetting, jackhammering, or plowing of nontidal wetlands; Laying of pipe, cable, or wire; Backfilling of the excavated trench containing the pipe, cable, or wire; Placement of riprap; and Rectification of nontidal wetland areas which have been disturbed. Utility lines do not include: Intake and outfall structures; Pipe or pipeline used to transport any liquid or slurry substance except as associated with water and sewage lines; Natural gas lines greater than 12 inches in diameter; or Storm water conveyance systems. Construction of overhead power transmission lines. Mitigation projects not required under this subtitle. Regulated activities which impact the buffer, and less than 2 acres of farmed nontidal wetlands with 15 or more consecutive days of inundation during the growing season, except in nontidal wetlands of special State concern or their expanded buffer. The repair of the following serviceable structures or fills: Aboveground and underground utilities; Structures in rights-of-way; Railroad beds; Road beds, roadside ditches, culverts, and outlet ditches; Bridges; Dams; Dikes; Levees; Water and wastewater control structures; and Facilities designed for storm water management. Activities which will result in the loss of nontidal wetlands that have been temporarily created by a permitted or authorized construction activity or as a result of a permitted mining activity, including wetlands created: Incidental to mining activities that were conducted under an approved mining plan or permit, or wetlands that have been created incidental to a mining activity, and that will be impacted during implementation of an approved reclamation plan; As a result of the construction of an approved sediment control structure; and For a specific purpose that will remain for a specified period of time, including wash ponds and grassed waterways. The following conditions apply to the activities listed in §B(7) of this regulation: If the structure or fill has been put to uses other than the use originally intended or authorized for the original construction, and the repair activity will alter or impair any additional nontidal wetland area, the repair of the structure may not be exempted. Repair to be made more than 3 years after damage occurs or is first identified does not qualify for an exemption. An applicant seeking a letter of authorization under §B(8) of this regulation shall submit the following: Information regarding the creation of the wetlands; The purpose of the wetland creation, if applicable; The length of time the wetland will exist; A copy of the approved site plan, erosion and sediment control plan, mining plan, or reclamation plan; A description of the function the created wetland will serve; A request for the length of time the letter of authorization is to be valid; and Justification for conducting the regulated activity in the nontidal wetland. Structures that have been placed in nontidal wetlands (for example, sediment traps), or that have impacted nontidal wetlands through their construction or operation do not qualify for a letter of authorization under §B(8) of this regulation. A letter of authorization issued under §B(8) of this regulation is in effect for a period of up to 5 years and may be extended for one additional 5-year period. A letter of authorization granted under §B(8) may not be extended for more than one 5-year period, for a total of 10 years, unless the regulated activity is part of a permitted mining activity or involves implementation of a mining reclamation plan.