§ 9.5. Stormwater provisions.

9.5.1.

Stormwater management.

A.

Engineering and construction on any land within the county shall be carried out in a manner as to maintain water quality and rate of run-off to protect neighboring persons and property from damage or loss resulting from excessive stormwater runoff, pollution, soil erosion, or deposition upon private property or public streets of water-transported silt and debris.

1.

Plans shall be submitted for review by the department. These plans shall be prepared by a professional engineer or landscape architect, currently registered to practice in the State of Georgia, with stamp affixed.

2.

The plans shall be accompanied by profiles of natural and proposed drainage ways, including storm pipes, cross-sections, drainage swales and downstream analysis.

9.5.2.

Design for stormwater management. (Amended 9-2-15)

A.

Grading and design plans for the land disturbance permit must include erosion, sedimentation, and pollution control plans and hydrology study as required by the Georgia Soil and Water Conservation Commission Checklist, effective January 1 of the year submitted. The design criteria must follow:

1.

The current authorization to discharge under the National Pollutant Discharge Elimination System (NPDES) Permit GAR 100001, 100002 or 100003.

2.

The current authorization to discharge under the National Pollutant Discharge Elimination System (NPDES) Permit No. GAS 00117, Municipal Separate Storm Sewer System (MS4).

3.

The current Manual of Erosion and Sediment Control in Georgia (Green Book).

4.

The current Georgia Stormwater Management Manual (Blue Book).

5.

The current Fulton County Stormwater Management Design Manual.

B.

In order to ensure full compliance with the approved construction plans, final plat approval will be withheld until as-built drawings, prepared by a professional engineer or landscape architect currently registered in Georgia, have been submitted and approved by the department in accordance with section 4.2.3. No occupancy permit shall be issued until released by the department.

C.

The owner shall be responsible for the maintenance of the storm drainage facilities during grading, construction, and for a 36-month period following final plat approval. Maintenance will be construed to include preserving the enclosing walls or impounding embankment of the detention basin and permanent sedimentation ponds and security fences, in good conditions; ensuring structural soundness, functional adequacy, and freedom from sediment of all drainage structures; and rectifying any unforeseen erosion problems.

9.5.3.

Detention/retention design.

A.

General provisions.

1.

Installation of properly functioning detention facilities, including outflow control devices, shall be the responsibility of the owner. If any control devices are damaged or destroyed during grading or construction, all processes shall cease until such devices are restored to their functioning capability. The owner, through application for grading or construction permits, accepts the responsibility of maintenance of the control devices.

2.

When serving more than three lots, detention ponds, retention ponds, and water quality features (including all required access easements, landscape strips, and fences) shall be located on a separate parcel where no home can be constructed. This parcel shall be owned and maintained by the homeowners' association or the owners of the lots being served by this pond. The parcel shall have a minimum of 20 feet wide continuous access to a public or private road in a manner that allows access and maintenance of this parcel. In addition, this parcel will not be required to meet the normal lot standard.

B.

Layout design standards. The ponds layout shall provide for the following minimums: (Amended 9-2-15)

1.

A 20-foot graded access easement from the right-of-way to the pond;

2.

A 20-foot landscape strip for screening purposes or as may be approved by the director;

3.

A ten-foot access easement for maintenance or as may be approved by the director; and

4.

A 6-foot high security fence with gate and lock.

C.

Alternative design standards. Applicants are encouraged to carry out innovative detention/retention layout that is intended to make such facilities an attractive amenity or focal point to the subdivision.

The director may approve the following alternative design standards in lieu of those in sections 9.5.3.A. and 9.5.3.B.

1.

Such alternative design should provide for attractive layout and means for detaining/ retaining/moving water.

2.

The design should follow the natural land forms around the perimeter of the basin. The basin should be shaped to emulate a naturally formed depression.

3.

Redistributing soils from basin construction to create natural landforms around the perimeter of the basin is encouraged. These forms should be located strategically to filter views or redirect and soften the views from residential areas.

4.

Side slopes of basins must not exceed one-foot vertical for every four-foot horizontal. Where possible, side slopes should be varied to imitate natural conditions. Associated natural landforms should have side slopes no greater than one-foot vertical for every three-foot horizontal to accommodate lawn maintenance equipment. Varied slopes will be encouraged.

5.

The applicant should consider the use of plant materials that naturally grow in the area. Trees and shrubs should be grouped in informal patterns to emulate the natural environment. The intent is to soften the views of these basins.

9.5.4.

Storm drain system stenciling/identification.

A.

All residential subdivision and commercial entity storm drainage structures or facilities (catch basins, storm sewer inlets, culverts, impoundment facilities, man holes, and other facilities that convey stormwater run-offs) shall be properly identified. Each drainage structure shall be identified with the use of durable and reusable Mylar stencils (stencils will not be provided by the county) that measure 20 inches × 30 inches with two-inch lettering and an environmentally formulated, water base, but soluble striping paint (color: blue). The message on the stencil shall read:

"DUMP NO WASTE"
(picture of a trout)
"DRAINS TO STREAM"

9.5.5.

Sanitary and storm sewer easement.

A.

All permanent easements shall be 20 feet in width. When access for maintenance purposes is required, the maximum longitudinal slope along the easement shall be 30 percent at grade in steepest direction.

B.

No fill shall be placed on a sanitary or storm sewer easement without approval by the director of public works. All sanitary manholes must extend to the ground surface. All easements terminating on a parcel shall extend to the property line.

C.

No retaining wall, building, pole, sign or other vertical structure shall be constructed in sanitary and storm sewer easements, including vehicular access easements around structures, without approval from the director. No fence shall be placed across sanitary or storm sewer easements without gates to which the department of public works has full access. No planting shall take place in a sanitary or storm sewer easement that will impede vehicular access along the easement or endanger the pipeline. No surface water shall be impounded on a sanitary sewer easement. No other pipeline or utility shall be placed in a sanitary or storm sewer easement without approval by the director of public works.

D.

Each lot or parcel of land in a subdivision shall have a separate sewer connection terminating at the easement limit or right-of-way limit with a vertical clean-out pipe. No connection of the public sewer system shall be made except at a sewer connection approved by the director of public works.

E.

No surface water, ground water, storm drain, gutter, downspout, or other conveyance of surface water or ground water shall be discharged into the sanitary sewer.