(A) Where acceptable natural vegetation exists in wetland and wetland buffer strip areas, the retention of such vegetation in an undisturbed state is required unless an applicant receives approval to replace such vegetation. A wetland and/or wetland buffer strip has acceptable natural vegetation if it:
(1) Has a continuous, dense layer of perennial grasses that have been uncultivated or unbroken for at least five consecutive years;
(2) Has an overstory of trees and/or shrubs with at least 80% canopy closure that have been uncultivated or unbroken for at least five consecutive years; or
(3) Contains a mixture of the plant communities described in (1) and (2) above that have been uncultivated or unbroken for at least five consecutive years.
(B) Notwithstanding the vegetation standards set forth above in § 155.346(A), the Zoning Administrator may determine existing wetland and/or wetland buffer strip vegetation to be unacceptable if:
(C) Where wetlands and/or wetland buffer strips, or a portion thereof, are not vegetated or have been cultivated or otherwise disturbed within five years of the permit application, such areas shall be re-planted and maintained. The wetland and wetland buffer strip plantings must be identified on the development application. The wetland and wetland buffer strip landscaping shall be according to each of the following standards:
(1) Prior to planting and seeding, wetland mitigation and buffer areas must be treated to control weed growth with a herbicide that breaks down sufficiently within 14 days prior to seeding;
(2) Planted with a seed mix containing 100% perennial native vegetation, except for a one-time planting of an annual nurse or cover crop such as oats or rye;
(3) Seed mix used shall be broadcast at a minimum rate of 30 pounds per acre. The annual nurse or cover crop to be used shall be applied at a minimum rate of 20 pounds per acre. The seed mix shall consist of at least 12 pounds pure live seed (PLS) per acre of native prairie grass seed and three pounds PLS per acre of native forbs. Native prairie grass and native forb mixes shall contain no fewer than five native prairie grasses and 15 native forb species. The Minnesota Department of Transportation Mix for prairie sedge and prairie meadow areas, Mixture 25A Modified (25B or 26B) or other alternative pre-approved by the Zoning Administrator can be used to meet these requirements. Applicants may obtain from the city a set of Native Wetland & Buffer Area Seeding Guidelines for wetland buffer strips that meet city requirements.
(4) All new wetland mitigation sites must be seeded appropriately with a native seed mix and planted with a variety of wetland species at a minimum of 1,000 plugs per acre;
(5) Native shrubs may be substituted for native forbs. All substitutions must be pre-approved by the Zoning Administrator. Such shrubs may be bare root seedlings and shall be planted at a minimum rate of 60 plants per acre. Shrubs shall be distributed so as to provide a natural appearance and shall not be planted in rows.
(6) Any groundcover or shrub plantings installed within the wetland buffer strip are independent of landscaping required elsewhere by city code.
(7) Native prairie grasses and forbs shall be seeded or planted by a qualified contractor. The method of application and determination of the contractor qualifications shall be made by the Zoning Administrator. It is the responsibility of the applicant to have the contractor and method used approved by the Zoning Administrator prior to planting or seeding.
(8) No fertilizer shall be used in establishing new wetland buffer strips, except on highly disturbed sites when deemed necessary to establish acceptable wetland and/or wetland buffer strip vegetation and then limited to amounts indicated by an accredited soil testing laboratory; determination of proper accreditation shall be made by the Zoning Administrator.
(9) All seeded areas shall be mulched immediately with clean straw at a rate of 1.5 tons per acre. Mulch shall be anchored with a disk or tackifier.
(10) Wetland and wetland buffer strips (both natural and created), shall be protected by erosion control during construction in accordance with § 154.087 of this code.
(11) The erosion control shall remain in place until the area vegetation is established.
(Ord. 0408, passed 12-14-04; Am. Ord. 0802, passed 3-11-08)