A. Generally: This section applies to all wetlands and watercourses on public or private land located within the city, whether or not the wetland or watercourse is located on the same property as the development.
B. Wetland Management Plan: Utilization and development impacts to wetlands shall be consistent with the city's wetland management plan. No grading permit to allow wetland disturbing activities shall be issued until approval of the wetland replacement plan application or a certificate of exemption has been obtained in strict conformance with the provisions of this title and the Minnesota wetland conservation act.
C. Buffer Widths; Setbacks:
1. Protective Buffer: A protective buffer of natural vegetation shall surround all wetlands and watercourses in accordance with the following provisions:
a. Wetlands: The buffer shall have a minimum width from the delineated edge of the wetland at the time of development based upon the wetland classification defined by the wetland management plan as follows:
Wetland Classification | Buffer Requirement |
Wetland Classification | Buffer Requirement |
Preserve | 50 feet |
Manage I | 25 feet for wetlands <2 acres; or |
35 feet for wetlands >2 acres | |
Manage II | 17 feet for wetlands <2 acres; or |
25 feet for wetlands >2 acres | |
Utilize | 17 feet |
Restore | 25 feet |
Wetland mitigation sites | 25 feet |
(1) Average Width: The width of the buffer may be averaged, provided that a minimum buffer width is maintained equal to one-half (1/2) the required buffer or seventeen feet (17'), whichever is greater.
(2) Public Trails And Sidewalks: Public trails and sidewalks that are a maximum of ten feet (10') in width can be included within the buffer, provided the designated width is maintained.
(3) Building Setbacks: For properties developed or redeveloped after March 17, 2003, a building setback of ten feet (10') for a side yard and twenty feet (20') for a rear yard shall be provided from the delineated edge of all required wetland buffers at the time of development. A building setback of thirty three feet (33') shall exist from the delineated edge of all wetlands at the time of development within areas developed or redeveloped between July 17, 2000 and March 17, 2003.
b. Watercourses: Buffers shall be established adjacent to watercourses within the Vermillion River watershed as shown and classified on the Vermillion River watershed stream classification and buffer standards map, prepared by the Vermillion River watershed joint powers organization, adopted October 26, 2006, as part of the Vermillion River watershed plan as amended February 2008, and kept on file in the office of the city engineer, adopted and incorporated herein by reference, as described as follows:
Stream Buffer Standards (Source: Vermillion River Watershed Joint Powers Organization Standards, February 2008, as amended) | |
Classification
|
Buffer Width Standard
|
Stream Buffer Standards (Source: Vermillion River Watershed Joint Powers Organization Standards, February 2008, as amended) | |
Classification
|
Buffer Width Standard
|
Conservation corridor | Lower reach (Vermillion River downstream of Biscayne Avenue) - 150 foot average, 100 foot minimum measured from the edge of the meander belt |
Upper reach (Vermillion River upstream of Biscayne Avenue and South Branch Vermillion River) - 150 foot average, 100 foot minimum measured from the edge of the meander belt | |
Aquatic corridor-principal connector | 100 foot average, 65 foot minimum measured from the edge of the meander belt of the river |
Aquatic corridor-principal connector with trout stream designation | 100 foot, no averaging |
Aquatic corridor-tributary connector | 50 foot average, 35 foot minimum plus 2 feet for every 1 percent of slope measured from the edge of the meander belt of the tributary |
Water quality corridor | 30 foot average, 20 foot minimum where there is a flow path for concentrated surface runoff measured from the centerline of the flow path |
These buffer standards may be altered by the city's approval of a variance and the Vermillion River joint powers organization's approval of a variance.
D. Buffer Standards: The following standards apply to all required buffers adjacent to wetlands and watercourses:
1. Acceptable Vegetation: Buffers shall be staked and protected in the field prior to construction. Where acceptable natural vegetation exists in buffer areas, the retention of such vegetation in an undisturbed state is required unless approval to replace such vegetation is received. A buffer has acceptable vegetation if it:
a. Has a continuous, dense layer of perennial grasses that has been uncultivated or unbroken for at least five (5) consecutive years; or
b. Has an overstory of trees and/or shrubs that has been uncultivated or unbroken for at least five (5) consecutive years; or
c. Contains a mixture of the plant communities in subsections D1a and D1b of this section that has been uncultivated or unbroken for at least five (5) years.
2. Unacceptable Vegetation: Topography or sparse vegetation that tends to channelize the flow of surface water or vegetation that is unlikely to retain nutrients and sediment are not considered acceptable vegetation for buffer purposes.
3. Replanting Vegetation: Where buffer vegetation and conditions are unacceptable, or where approval has been obtained to replant, buffers shall be replanted and maintained according to the following standards:
a. Buffers shall be planted with a native seed mix approved by MnDOT, BWSR, NRCS or the Dakota SWCD, with the exception of a onetime planting with an annual nurse or cover crop. Plantings of native forbs and grasses may be substituted for seeding. All substitutions must be approved by the city. Groupings or clusters of native trees and shrubs, of species and at densities appropriate to site conditions, shall also be planted throughout the buffer area.
b. The seed mix and planting shall be broadcast/installed according to MnDOT, BWSR, NRCS or Dakota SWCD specifications. The selected seed mixes and plantings for permanent cover shall be appropriate for the soil site conditions and free of invasive species.
c. Buffer vegetation (both natural and created) shall be protected by erosion and sediment control measures during construction.
d. During the first five (5) full growing seasons, except where the city has determined vegetation establishment is acceptable, the owner or applicant must replant buffer vegetation where the vegetative cover is less than ninety percent (90%). The owner or applicant must assure reseeding or replanting if the buffer changes at any time through human intervention or activities.
4. Alterations Prohibited: Alterations, including building, storage, paving, routine mowing, burning, plowing, introduction of noxious vegetation, cutting, dredging, filling, mining, dumping, grazing livestock, agricultural production, yard waste disposal, or fertilizer application are prohibited within any buffer. Periodic mowing or burning, or the use of fertilizers and pesticides for the purpose of managing and maintaining native vegetation is allowed. Noxious weeds may be removed and mechanical or spot herbicide treatments may be used to control noxious weeds. Aerial or broadcast spraying is prohibited. Prohibited alterations do not include plantings that enhance the natural vegetation or selective clearing or pruning of trees or vegetation that are dead, diseased or pose similar hazards, or as otherwise clarified in subsection D5 of this section.
5. Alterations Permitted: The following activities may be permitted within any required buffer:
a. The following activities are allowed within both the minimum and average buffer width areas:
(1) Use and maintenance of an unimproved access strip through the buffer, not more than ten feet (10') in width, for recreational access to the major waterway or wetland and the exercise of riparian rights.
(2) Structures that exist when the buffer is created.
(3) Placement, maintenance, repair, or replacement of public roads and utility and drainage systems that exist on creation of the buffer or are required to comply with any subdivision approval or building permit obtained from the city, so long as any adverse impacts of public road, utility, or drainage systems on the function of the buffer have been avoided or minimized to the extent practical.
(4) Clearing, grading, and seeding is allowed if part of an approved wetland replacement plan, or approved stream restoration plan.
(5) Construction of a multipurpose trail, including boardwalks and pedestrian bridges, provided it is constructed to minimize erosion and new impervious surface, and has an undisturbed area of vegetative buffer at least ten feet (10') in width between the trail and the wetland or public waters wetland edge, or the bank of the major waterway; or where needed to cross the major waterway, the minimum impact alignment is used.
(6) The construction of underground utilities such as water, stormwater, and sanitary sewers and pipelines, provided the minimum impact alignment is used and the area is stabilized.
b. The following activities are allowed within those portions of the average buffer width that exceed the minimum buffer width:
(1) Stormwater management facilities, provided the land areas are stabilized. (Ord. 847, sec. 5, 11-17-2008)
(2) The area of shallow vegetated infiltration and biofiltration facilities, and stormwater basins not to exceed fifty percent (50%) of the basin area, adjacent to wetlands and major waterways may be included in buffer averaging, provided the facilities do not encroach into the minimum buffer width, and the land areas are stabilized. (Ord. 847, sec. 5, 11-17-2008; amd. Ord. 866, sec. 10, 5-17-2010)
E. Conservation Easement/Outlot: A conservation easement or a dedicated outlot is required for all buffer areas as part of platting and subdivision approval, except where the buffer is located in a public transportation right of way. Buffers shall be marked to clearly designate the boundaries of all new buffers within new residential subdivisions. A monument shall consist of a post and a buffer strip sign approved by the city. Property owned by the city of Lakeville shall be exempted from establishing an outlot or conservation easement for required buffer areas. (Ord. 847, sec. 5, 11-17-2008)