Atlanta City Council Adopts Post Development Stormwater Management Ordinance (20-O-1498)

On November 16, 2020 the Atlanta City Council held its regular full council meeting with the Post Development Stormwater Management ordinance (20-O-1498) on the consent agenda for a second reading. By an unanimous vote, the Atlanta City Council adopted the Post Development Stormwater Management ordinance by Substitute as Amended from the City Utilities Committee. The ordinance will now become law on November 25, 2020 and go into effect on December 1, 2020. The City had to adopt necessary revisions to adhere to the Metropolitan North Georgia Water Planning District’s Stormwater Management Model Ordinance and to meet the City’s Municipal Separate Storm Sewer System (MS4) permit with Georgia Environmental Protection Division (EPD) by the end of the year. The City also adopted additional requirements which exceed the mandatory requirements.

The Council for Quality Growth successfully advocated to remove an extended detention penalty requirement (48-hr extended detention of 25 year, 24-hour return frequency storm event) if a site could not meet the 80% runoff volume reduction requirement by using vegetated green infrastructure or rainwater harvesting treatment systems. Additionally, the Council was able to advocate for a grandfather clause to be included in the ordinance. When the updated ordinance goes into effect on December 1, residential and commercial developers who have already invested in the City but had not accounted for the financial burden of new regulatory changes underwriting for a new or redevelopment project prior to December 1 would be vested under the City’s current post-development stormwater management ordinance.

The Council for Quality Growth will continue to work with our members to ensure the City’s post-development stormwater management ordinance balances the City’s economic needs. The details below illustrates the regulations required and additional regulations in the ordinance.

  1. Metropolitan North District Georgia Water Planning District’s Stormwater Management Model Ordinance,
  2. the City’s Municipal Separate Storm Sewer System (MS4) permit, and
  3. additional regulations that exceed the mandatory requirements

Updates required by the Metropolitan North Georgia Water Planning District Model Ordinance

  • Minor typographical changes to improve consistency
    • Adopt and define new terms ~ Section 74-503 Best management practices (BMP)
    • Construction Sequencing Plan
    • Stormwater Planting Plan
    • Predevelopment Hydrology Memo
  • Updated Runoff Reduction Feasibility Policy ~Section 74-523, ~Section 74-524
    • The runoff reduction feasibility policy details the criteria and documentation needed to determine whether compliance with the Runoff Standard is feasible for non-transportation-related development.
  • Alternative Compliance Process. ~Section 74-524 
    • The City adopted a tiered alternative compliance process replacing existing provisions allowing development to use alternative methods if the site development cannot meet the entire runoff requirement volume that captures the first 1.0” of rainfall retained on-sight by using vegetated green infrastructure or rainwater harvesting systems.

Updates required for the City to maintain its MS4 Permit

  • The City applied post-development stormwater standards to linear transportation projects except for city-funded projects. This applies to new or reconstructed: roads, sidewalks, and multi-use paths and trails. ~Section 74-504(d)
  • The City adopted linear transportation feasibility policy-allows transportation-related projects with certain on-site conditions to avoid full compliance with the water quantity and water quality standards. Transportation projects that are fully exempt from stormwater standards: (1) roadway projects less than 5,000 sq. ft. of impervious surface, (2) isolated maintenance and repair projects, (3) city-sponsored projects with approved budgets and emergency work.

Additional Regulations Exceed the Water District and MS4 Permit

  • The City extended the term of the stormwater performance ad maintenance bond from one year to three years ~Section 74-518(4)
  • Development projects that will be carried out in two or more phases extending over multiple years, under more than one Permit, must complete a stormwater master plan approved by the DWM Commissioner. ~Section 74-525
    • For example, suppose a site development cannot meet all the stormwater management standards during the first phase of the development. In that case, construction can be permitted as long as the site is not increasing runoff from the site and if the stormwater masterplan demonstrates that the site development will meet all of the stormwater management standards during the last phase of the project.
    • The Commissioner may impose conditions on the master plan requiring identified stormwater management systems to be installed at a particular phase of the development.
    • The construction of that phase or part of a phase cannot increase runoff above the existing rate prior to the Permit.
    • Trees and canopy coverage must be explicitly identified on plans (i.e., stormwater management plans. ~ Section 74-510(3)(b)
  • The Utilities Committee decided to eliminate a proposed provision prohibiting the removal of trees solely for installing stormwater management systems. The committee wants to consider this provision when city leadership reviews the revised new tree protection ordinance rewrite legislation.
  • Sewer Capacity Clarification-Codified an Existing Policy into the Updated Ordinance
    • If a site development needs to tie into the City’s combined sewer system, an applicant must obtain a sewer capacity certification.

Grandfather Provision-Vesting Schedule ~Secs. 74-526-74-600.

  • Before December 1, 2020, development projects had received a stormwater consultation meeting; or projects for which a complete rezoning application, building permit application, land disturbance application, special use permit application, special administrative permit application, subdivision permit application, or platting application has already received by the Office of Buildings or by the Office of Zoning and Development do not have to adhere to all of the new amendments to the City’s post-development stormwater management ordinance.