February 3, 2016 Eric Kronberg

Thoughts on our current stormwater management policy

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On this rainy February morning we were disappointed to not find the display of dramatic raging stormwater overflow, flooded pathways, and comically overwhelmed drains that Atlanta residents have come to expect due to shortsighted stormwater management practices. Intelligent planning enables the Historic Fourth Ward Park to handle additional stormwater with ease.

I enjoyed a very wet drive dropping my daughters off at school this morning.  The ground was already fully saturated before the current rainstorm, so there was significant runoff in the streets and creeks on the East side of Atlanta and South Decatur.  One road was impassible from an overflowing creek, others just very, very wet. All of this lead me to mull on our current stormwater policies in for Atlanta and Decatur. 

 

Both cities take an approach of requiring each individual site to retain a significant amount of water when a redevelopment is undertaken.  Water needs to be held back for a time period to give the city sewers a chance to absorb other runoff, and water also needs to be percolated back into the ground to recharge the soil.

Both of these water requirements are very positive in the abstract, but both ineffective as a one off solution, and very expensive to implement on a site-by-site basis.  The average cost of an underground storm catchment system typically runs from $70,000-$250,000, depending on the scale of your project.  The thing is, there is a fixed cost to providing just a tie-in to the sewer in the street and the manhole connection, regardless of how much pipe or vault you are providing.  This initial cost is around $40,000 just to start.  The financial burden of this is significantly crushing for a small to medium sized project, and more manageable if spread across 300 units for a larger apartment development.

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Stormwater management infrastructure being installed at a KWA project in the Sweetwater Design District in 2015. The costs of these systems can quickly sink a small scale development project, but improved stormwater management practices could help eliminate some of the financial obstacles.

One of the most frustrating components of storm water requirements is that the cost of stormwater mitigation is directly related to how much impervious (not-drainable) surface you provide on your site for your project.  The biggest driver of impervious surface is parking requirements.  Parking requirements and storm water requirements quickly become a significant tax on infill development.

Both of these requirements, adequately providing space for cars and water, are much more effectively addressed at a community or neighborhood level.  The Historic Fourth Ward Park is a shining example of how a public nuisance- rampant flooding, was addressed in a community beneficial manner.  The only way it could have been improved would have been to allow all the multi-family development to pay into a fund to further improve the park instead of having to provide their own individual and redundant storm water vaults on-site.  This is an approach and funding mechanism that should be considered to facilitate redevelopment opportunities on the West side of town.

Stormwater is an issue and challenge for Atlanta and many other cities.  Looking at the possibility of a neighborhood stormwater solution could and should be considered an economic development driver and opportunity.  Many of our existing parks tend to be in lower lying, difficult to develop pieces of land.  They are natural collectors of runoff, and sensible places to capture stormwater.   Providing these neighborhood solutions provides a development incentive and a funding source for improving our public spaces

Quality infill redevelopment is hard, and our current ordinances make it even harder.  It is important to consider a variety of priorities when considering what kind of city we want Atlanta to become.  If one would consider connectivity and walkability to be important attributes to promote, along with promoting the reuse of our existing and historic building stock, then it is important to consider reductions of both parking and stormwater requirements for older buildings in walkable neighborhoods near transit – let’s say all of Downtown, and buildings older than a certain age, maybe 50 years, within a certain distance of MARTA stations.  Existing buildings on the Beltline could also possibly be included.  Redevelopment is always a game of trade offs.  Let’s continue to think about what tradeoffs we want and need to make in order to make Atlanta an amazing, inclusive, walkable, connected, and affordable city.

UPDATE: For those of you interested in learning more about stormwater management, check out this very thorough article from the Ped Shed blog – a detailed review of the topic that also illustrates stormwater management’s role in creating enjoyable, walkable urban spaces.

About the Author

Eric Kronberg

Eric Kronberg, AIA, LEED AP is co-founder and principal of Kronberg Wall Architects in Atlanta Georgia. A graduate of Tulane University, Eric has worked on a wide range of projects across the US. Eric and co-founder Adam Wall formed Kronberg Wall Architects in 2003 in order to focus on creating happier, healthier urban environments in Atlanta and elsewhere.

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