City Council Adopts Ordinance to Improve Stormwater Runoff Processes

The City is moving forward with its efforts to revise its Post-Development Stormwater Management Ordinance – the purpose of which is to control the quality and quantity of stormwater runoff discharged from development.

Now before I lose you! – I understand this may not be a topic that jumps out as particularly interesting and you might wonder why you should pay any attention, but the fact is we are all affected by how well our City’s stormwater is managed. Have you been affected by flooding? Does that stream in your backyard get littered with trash and debris every time it rains? Is your local watershed healthy, or is it full of pesticides, oil, and other harmful substances? Look no further than stormwater runoff.

Effective stormwater management plays a critical role in keeping our watersheds healthy and reducing flooding. That’s because every time it rains, that water must go somewhere. It can either soak into the ground (think soil or other natural vegetation) or it can flow across our streets, sidewalks, rooftops, parking lots, etc., collect whatever substances it encounters along the way, and wind up untreated in the nearest waterway. Doesn’t sound appealing, does it?

That’s where stormwater management comes in. That’s what the Department of Watershed Management (“DWM”) is working to accomplish with its Post-Development Stormwater Management Ordinance.

On Monday, November 16, the Atlanta City Council adopted the version of this ordinance that was approved by the City Utilities Committee last week. This version will be effective on December 1, 2020.

There are two categories of updates to the ordinance:

1. Regulatory updates. These address requirements in the City’s new MS4 Permit – this is what authorizes the City to release stormwater collected by its storm sewer system into certain waterways – as well as requirements in the Metro Water District’s new Model Ordinance. These updates change what types of projects and developments fall within the ordinance’s purview. For example, linear transportation projects must now comply with the ordinance and apply post-development stormwater management controls. Linear transportation projects include those that construct or redevelop roads, sidewalks, and multi-use paths and trails. Single-family residential developments that install more than 5,000 ft² of impervious surface must also comply with stormwater management standards.
2. Housekeeping updates. These include defining new terms, clarifying how to handle conflicts with other rules and regulations, and the like.

What didn’t make it in?

A big ticket item that was included in DWM’s April 2020 version of the draft ordinance – but which was dropped by the City Utilities Committee last week and did not make its way into the version approved by City Council on Monday – is the Extended Detention provision. This provision required developers to build infrastructure that could detain large volumes of stormwater onsite for a longer period of time following a major storm event.

Why does this matter? The goal with this provision was to reduce localized flooding and the pressure that places on the City’s stormwater infrastructure during major storm events.

There is the potential for future efforts to continue improving the ordinance, though, including one aimed at extended detention.