Agenda - Planning Commission - 10/06/2016

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r i i WIDTH OF THE BUFFER ZONE water;limited clearing of trees is allowed along the shoreline,the presence of naturally Many state regulations and local ordinances re- according to a grid and point system,and vegetated cover within the shore impact zone, quire establishment of a shoreland zone within no primary structures are allowed. and the structure setback to determine the which the buffer zone forms the inner protec- A Natural Woodland Buffer extending 50 width of a required"no-mow buffer." tive ring.In Maine,the shoreland zone extends feet to 150 feet from the reference line,in Maine's shoreland zoning law prohibits 250 feet from the normal high-water line of which structures are allowed but at least 25 removing vegetation within a 75-foot buffer water basins,known as great ponds,and tidal percent of the area must be maintained in area around a great pond that is zoned for areas and 75 feet from streams. an unaltered wooded state. resource protection,except to remove safety In Minnesota and Wisconsin,the shore- The Protected Shoreland zone encom- hazards.In all other shoreland areas,no more land zone is 1,000 feet around water basins passes the entire area extending 250 feet than qo percent of the total volume of trees and 300 feet or the width of the floodplain, from the reference line.Some land uses are over four inches in diameter in the buffer if greater,along streams.In Minnesota,the restricted,setback requirements for all new area may b'e harvested in any 10-year period. actual buffer,known as the Shore Impact Zone, septic systems are determined by soil char- Vegetation less than three feet tall,including is limited to one-half the building setback acteristics,and impervious cover is limited groundcover,cannot be removed from shore- from the ordinary high water mark,a distance to maximum of 30 percent of the lot area. land buffers,although pruning the lower third ranging from 25 to loo feet,depending on the of the branches of a tree is allowed.Beyond the shoreland classification of the water body and VEGETATION MANAGEMENT immediate buffer area,a point system is used whether the property is sewered.In agricultural WITHIN THE BUFFER to establish the number of trees that may be areas,a riparian buffer of 50 feet is required. Protection of natural vegetation management removed.Timber harvesting is regulated sepa- Wisconsin's riparian buffer zone extends 35 is a primary reason for the riparian buffer and rately,and agricultural activities are exempt feet inland from the ordinary high water mark, a primary activity within it.In most state and from regulation. but structure setbacks and impervious cover- local regulations the level of managementvar- Wisconsin's shoreland regulations limit age limitations apply within 300 feet. ies with the sensitivity of the water resource. clearing within a 35-foot buffer measured from Many Georgia communities have adopted Most ordinances allow routine maintenance the shoreline,although a 35-foot-wide viewing higher standards than the statewide 25-foot such as pruning,limited clearing for purposes corridor is allowed for each loo feet of shore- or 5o-foot minimums.For example,the city such as removal of invasive plants,diseased or line.Accessory structures such as boathouses of Alpharetta requires a loo-foot buffer on all downed trees,and other safety hazards,and and staircases are also allowed. perennial streams,with an additional 50400t some level of access to the shoreline. Georgia's Environmental Protection setback beyond the buffer in which all impervi- In Minnesota,intensive vegetative clear- Division provides explicit guidance on the ous coverage is prohibited.For non-perennial ing(sometimes known as clear-cutting)is pro- appropriate type of vegetation for shoreland streams,a 5o-foot buffer and a 25-foot setback hibited within the Shore Impact Zone(one-half stabilization.To be ecologically functional and are required.For erosion and sedimentation of the width of the structure setback).However, effective,vegetation must consist of native control during construction,the city requires limited exceptions are allowed fortypical lake- species adapted to Georgia's riparian forests that buffers remain undisturbed on all peren- front activities such as beaches,docks,boat- and stream edges.Vegetation should be"mul- nial streams equal to the width of the loo-year houses,stairways,and paths.Land within the titrophic"—made up of multiple layers such floodplain,where that has been mapped,or 50-foot agricultural buffer must be maintained as low-growing grasses,forbs(non-woody in other locations,five times the width of the in permanent vegetation or under an approved flowering plants other than grass),and other stream at top of bank. Natural Resources Conservation Service(NRCS) plants;an intermediate small trees and shrub All these examples specify a fixed width conservation plan. layer;and tree canopy cover.While buffers for the buffer and,where applicable,the shore- Crow Wing County,a lake-rich region in may be trimmed to create lines of sight to the land zone.In contrast,many model ordinances north-central Minnesota,applies higher stan- shoreline,an entire trophic layer should not recommend a variable width based upon a dards to vegetation management(Land Use be removed.The guidance also includes stan- more detailed evaluation of site characteris- Ordinance Article 11).It allows limited clearing dards for nonstructural and bioengineering tics,clearly a more complex approach.Another in the shore impact zone only on the more techniques for streambank stabilization,such common method,developed originally for the developed classes of lakes(General Develop- as the use of live stakes,brush layering,and Chesapeake Bay,is to establish up to three ment and Recreational Development)in order toe protection(Georgia Department of Natural concentric buffer zones with progressively to provide views of the lake from the principal Resources 2007). more flexible requirements farther away from dwelling and for recreational improvements. Similar regionally specific guidance can the water(Hawes and Smith 2005). A permit is required to remove woody vegeta- be found in many publications by the NRCS, New Hampshire's shoreland protection tion within the shore impact zone of a Natural state cooperative extension service programs, program establishes the following zones: Environment lake,a distance Of 75 feet.The and local conservation districts. county has also developed a"rapid assess- ® A Waterfront Buffer extending 50 feet land- ment model"—a process for analyzing existing MANAGEMENT OF LAND DISTURBANCE AND ward from a defined reference line,within shoreland vegetation and developing a vegeta- RUNOFF WITHIN THE BUFFER which existing natural ground cover must tion restoration plan if needed.The model uses Other land-disturbing or potentially harmful remain intact except for a foot path to the a point system based on the degree of erosion activities such as placement of fill,storage ZONINGPRACTICE 9.16 AMERICAN PLANNING ASSOCIATION ipage4