06-12-2002 Council Agenda - Laserfiche WebLink

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Buffer design and protection during construction should do any or all of the following: slow water runoff, trap sediment, enhance water infiltration, trap fertilizers, pesticides, pathogens, heavy metals, trap blowing snow and soil, and act as corridors for wildlife. How much stress is put on these functions will determine the buffer zone's final configuration. (Commentary: Native Minnesota plant species have root systems and growth characteristics that are well suited to buffer functions. By way of comparison, deep rooted native grasses have a root system that is about ten times greater than either soy beans or corn. Useful guides for species selection includes the Minnesota Department of Transportation's seeding manual, and their "Plant Selection Matrix" CD ROM. Good plant species selection stresses diversity and allows plant succession and zoning of species from wet soil preference to drier upland species. The Minnesota Department of Natural Resources requires permits when vegetation is introduced downgrade of a water's "ordinary high water mark." The Minnesota Department of Natural Resources' area hydrologist defines the ordinary high water mark Planting permits are obtained from the Minnesota Department of Natural Resources regional fisheries offices) 3.) The applicant or a designated representative shall maintain the buffer strip for the first year. After that the city, or a party designated by the city, shall maintain the buffer strip. (Commentary: Even after a buffer strip is established it will require periodic inspection and possibly maintenance to ensure that it is functioning properly. Otherwise siltation and channeling may short - circuit the strip's function.) 4.) Drain tiles will short- circuit the benefits of vegetated buffer strips. Therefore drain tiles on the development site shall be identified and rendered inoperable. 5.) Buffer strips can be made into perpetual conservation easements. 6.) Buffer strips shall be marked as such with permanent markers. (Commentary: These markers can be in a form that compliments the natural landscape. An example is permanent sighs that face toward the water body that are attached to large artificial or natural bounders.) 7.) The city engineer may allow buffer area averaging in cases where averaging will provide additional protection to either the resource or environmentally valuable adjacent upland habitat, provided that the resource's total buffer area remains the same. Care should be taken in averaging so that the buffer's usefulness is not short- circuited. B.) Water courses used solely for drainage, such as road side ditches, are exempt from this provision. Minnesota Pollution Control Agency Class 7 limited resource (Waters not protected for aquatic habitat or recreational use) value waters are also exempt from this provision, unless the Class 7 water is directly tributary to either a Minnesota Department of Natural Resources designated trout stream or a state designated Outstanding Resource Value Water.