Gwinnett County › Unified Development Ordinance
Title 3 — Development and Permitting, Chapter 610 — Buffers
§ 610-10
Applicability
600-10.1 Buffers shall be required between dissimilar districts or uses in accordance with the provisions of
Title 2 of this UDO or as a condition of zoning, special use, or variance approval as provided in Chapter 270.
600-10.2 Buffers shall be established and maintained along required property lot lines in accordance with
the landscaping policies and standards of this Chapter and any additional specifications that may be established by the Department of Planning and Development and approved by the Board of Commissioner
§ 610-20
Standards for Permanent Buffers
610-20.1 Requirements.
A.In the event the buffer includes a utility or pipeline easement, a minimum buffer of no less than 20 feet in width will be required outside the easement. In no case will the buffer be less than 20 feet.
610-20.1 Easement in Buffer I Easement I !
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B.In cases in which both a buffer and landscape strip are required along the same lot line, the width of the required landscape strip shall be counted as part of the required buffer width. When a landscape strip tree is within the buffer it may be counted toward Tree Density Units.
610-20.2 Buffer Screening.
A.Buffers shall meet minimum screening requirements. Screening and/or buffers shall be required for purposes of obscuring features such as but not limited to, dumpsters, rear entrances, utility, and maintenance structures, and loading facilities.
B.Buffers shall be natural, undisturbed, and free of encroachments except as authorized by a condition of zoning, special use or variance approval, or as authorized herein, and shall contain the existing tree cover and vegetation as well as any supplemental plantings or replanting’s as may be required.
C.Buffers shall be of such nature and density so as to screen activities, structures and uses on the property from view from the normal level of a first story window on an abutting lot and shall further provide a year-round effective visual screen.
D.Screening shall be established within any buffer along the entire length of the property lines. However, this screening requirement may be adjusted in order to observe the sight distance required in this UDO or as a condition of zoning, special use, or variance approval or as approved by the Director.
E.Buffers required adjacent to side property lines shall extend to a street right-of-way line unless otherwise required by the Director in order to observe the sight distance requirements contained in this UDO, or as authorized by a condition of zoning, special use, or variance approval.
F.In situations where the required buffer width is partially or completely contained within an existing easement (e.g., power, or natural gas transmission, etc.), the screening requirements of this UDO shall be met outside of the easement area per Section 610-20.1.A.
G.Additional screening shall be required where a nonresidential use abuts a public street across from a residential district. For specifics on additional screening, see Section 610-20.5. However, this screening requirement may be adjusted in order to observe the sight distance required in this UDO or as a condition of zoning, special use, or variance approval or as approved by the Director.
610-20.3 Buffer Plan Standards.
A.All buffers shall be designated on the appropriate permit application(s) and indicated on the required site plan or final subdivision plat.
610-20.4 Reserved.
610-20.5 Non-Vegetative Screening.
A.Non-vegetative materials used to satisfy the screening requirements of this UDO, in addition to the use of existing vegetation and/or supplemental plantings, may consist of walls, fences, earthen berms or any combination thereof.
B.If walls or fences are to be used, their placement and installation shall be such so as to cause minimal disturbance of existing vegetation and located so as to provide an effective visual screen.
610-20.6 Supplemental Plantings.
A.Buffers in which vegetation is non-existent or is inadequate to meet the screening requirements of this UDO shall be supplemented with trees and shrubs to provide an effective year-round visual screen and shall be planted per the ratios as specified in paragraph G. below.
B.Buffers required as a condition of zoning, variance, or waiver, whether they are natural, undisturbed or enhanced shall be planted per the ratios as specified in paragraph G. below.
Landscaped buffers shall be planted as specified in 610-20.7.
C.Buffer plantings shall consist of a combination of evergreen and deciduous trees and evergreen shrubs adaptable to the region. Deciduous trees shall be a minimum of 2 inches in caliper and evergreen trees shall be a minimum of 6 feet in height at time of planting. All shrubs shall be of a large growing species and chosen from the approved Gwinnett County Shrub Species List, listed in the Appendix, shall be a minimum of 3 feet in height at time of planting, and shall be a species which will achieve a height of at least 10 feet at maturity.
D.Trees, shrubs, grasses, and ground covers identified in the Gwinnett County Prohibited Plant Species List in the Appendix are invasive plant species and shall not be planted in buffers.
E.No genus of tree shall comprise more than 33 1/3 percent of plantings in any buffer. Calculations are required to be shown on Tree Preservation and/or Tree Replacement Plan.
F.Leyland Cypress, Cuppressus leylandii may be used in supplemental replanting in buffers but shall not exceed 33 1/3 percent of total buffer trees. Leyland Cypress trees are not allowed to fulfill regulatory density requirements but may be used for screening purposes.
G.Trees planted in buffers shall be small, medium, or large trees chosen from the Gwinnett County Tree Species List in the Appendix. Shrubs planted in buffers shall meet the specifications as outlined in paragraph C. above. Both trees and shrubs shall, at a minimum, meet the following ratios. Large, medium, and small refer to the tree and shrub size at maturity. Calculation results shall be rounded up.
1.Qty. one (1) large hardwood tree per 2,000 sq. ft.
2.Qty. one (1) large evergreen tree per 1,000 sq. ft.
3.Qty. one (1) small or medium ornamental tree per 700 sq. ft.
4.Qty. one (1) large evergreen shrub per 200 sq. ft.
H.Example: The requirement is for an enhanced buffer that is 450 lineal feet and 50 ft. in width in which 70% of the buffer is heavily wooded and 30% is sparse and devoid of vegetation. Therefore 6,750 sq. ft.
of buffer area must be planted with the following quantity of plants:
1.6,750/2,000 = 3.375 = 4 large hardwood trees
2.6,750/1,000 = 6.75 = 7 large evergreen trees
3.6,750/700 = 9.64 = 10 small or medium ornamental trees
4.6,750/200 = 33.75 = 34 large evergreen shrubs
I.Supplemental plantings shall be spaced and installed to allow for proper plant growth and maintenance.
610-20.7 Landscaped Buffer.
Purpose, Intent, Width and Planting Standards.
A.The intent of a landscaped buffer is not only to obtain a diverse selection and varying sizes of plant material, but also to screen the backs and sides of buildings from adjacent property or external streets and serves as an effective long-term replacement of existing trees of poor structure that may be located on the fringe of the buffer after clearing has taken place adjacent to them.
B.The width of the landscaped buffer is as specified in the zoning condition(s) or as required in this UDO.
C.The landscaped buffer shall be planted with a mixture of deciduous and evergreen trees that reach large, medium, and small sizes at maturity; a mixture of evergreen and deciduous shrubs; and ornamental grasses and ground covers. The majority of the evergreen trees and shrubs shall be located to the rear of the buffer that is closest to the sides and rear of buildings as practical with the intent to screen.
D.Landscape plans shall be subject to the review and approval of the Director of Planning and Development prior to permit issuance.
E.Both trees and shrubs for a landscaped buffer shall, at a minimum, meet the following ratios. Large, medium, and small refer to the tree and shrub size at maturity. Calculation results shall be rounded up:
1.Qty. two (2) large hardwood trees per 2,000 sq. ft.
2.Qty. three (3) large evergreen trees per 1,000 sq. ft.
3.Qty. two (2) small or medium ornamental trees per 700 sq. ft.
4.Qty. four (4) large evergreen shrubs per 200 sq. ft.
5.Qty. two (2) medium deciduous shrubs per 100 sq. ft.
610-20.8 Disturbance or Encroachments.
A.Ditches, swales, storm water conveyance facilities, storm water detention ponds, sanitary sewer conveyance facilities, similar facilities, and any associated easements, shall not encroach into a buffer except that necessary access and utility crossings (e.g., storm water or sanitary sewer pipes) may encroach into the buffer as near to perpendicular as practical.
B.Driveways and sidewalks shall not encroach into a buffer except that necessary access crossings may encroach into the buffer as near to perpendicular as practical.
C.Supplemental plantings or replanting’s of vegetation, or authorized non-vegetative screening devices may encroach into a buffer provided there is minimal disturbance of any significant existing vegetation.
D.Fences are authorized in a buffer provided minimal disturbance occurs. Live trees shall not be removed for the placement of the fence.
E.Land disturbance is authorized per Director approval in areas of a buffer that are devoid of significant vegetation provided that the final grade and replanting of vegetation meet the screening requirements contained herein.
F.Dying, diseased or dead vegetation may be removed from a buffer provided minimal disturbance occurs. Vegetation thus removed shall be replaced where necessary to meet the screening requirements contained herein.
G.Greenway paths or trails as identified in the official Gwinnett Trails Countywide Trails Plan are authorized in the buffer. The greenway path or trail shall be located so as to minimize encroachment in the buffer. In cases where there is not adequate existing vegetation to provide an effective year-round visual screen, supplemental plantings shall be planted between the greenway and the property line.
When the greenway does not allow adequate space to supplemental plant inside the buffer, vegetation may be planted outside of the buffer.
610-20.9 Protection during Land-Disturbing Activities.
A.During authorized land-disturbing activities, undisturbed buffers shall be clearly demarcated and protected prior to commencement of, and during, construction.
B.The method of demarcation and protection used shall be in accordance with best management practices.
§ 610-30
Standards for Construction Buffers
610-30.1 Where Required.
Construction buffers shall only be required where specifically provided as a condition of zoning, special use or variance approval.
610-30.2 Time Constraints.
Construction buffers shall only be in effect during the construction period of a project and shall terminate upon project completion. In the case of a residential subdivision, a construction buffer shall terminate upon each individual lot with the issuance of a Certificate of Occupancy for the principal dwelling.
610-30.3 Disturbance or Encroachments.
A.Construction buffers shall be natural, undisturbed, and free of encroachments except as authorized by a condition of zoning, special use or variance approval, or as authorized herein.
B.The encroachment of ditches, swales, storm water conveyance facilities, stormwater management facilities, sediment basins, sanitary sewer conveyance facilities, similar facilities, and any associated easements, into a construction buffer shall not be authorized except that necessary access and utility crossings (e.g., stormwater or sanitary sewer pipes), and natural bottom detention ponds (sediment basins must be located outside of the construction buffer) and their appurtenant structures which require no grading and removal of trees, may encroach upon the construction buffer.
C.If the construction buffer on a residential lot is devoid of existing trees and vegetation, and a tree survey is submitted to document this situation prior to conducting land-disturbing activities (including clearing) on the lot, then the Department may authorize the encroachment of a building or structure into the construction buffer for a distance not to exceed 10 feet.
610-30.4 Protection during Land-Disturbing Activities.
A.During authorized land-disturbing activities, construction buffers shall be clearly demarcated and protected prior to commencement of, and during, construction.
B.The method of demarcation and protection used shall be in accordance with best management practices.