Will We Need Taller Boots? Stormwater Runoff Is a Problem

A new challenge is arising in areas of Georgia with dense urban growth. As compact growth becomes the norm, so do problems with urban stormwater runoff. Studies have found that flooding could become 7.9% more “flashy” by the end of the century—but this is in large part if we continue with high carbon emissions.

The average ocean temperature has risen, causing hurricanes to develop stronger and faster. Preliminary reports say Hurricane Helene cost 232 lives and $14 billion in private-insured damages. Researchers at Imperial College London, Princeton University and others found that Helene was directly correlated with climate change. Stronger hurricanes exacerbate the common issue of stormwater runoff, having a more noticeable effect on Americans living within the Southeast.

Due to this increasing presence, studies on urban flood resilience have become increasingly common. A problem with applying urban durability is that there are no formal policies or requirements. As a result, the definition of urban resilience has become unclear, and the lines for adoption are blurred. This leads to some areas having either top-down or bottom-up approaches. 

A bottom-up approach starts with the smaller parts and builds up from there. A top-down approach begins with the larger components and breaks them down into smaller components. However, a broad and open approach is needed, which may incorporate both plans in different areas. This combination of plans includes all variables that may increase urban flooding.

Thanks to extensive research, there is now an official term for these practices: stormwater control measures (SCMs). These measures include green roofs, permeable pavement, wetlands, retention ponds and many other components. While these are necessary for creating more effective city planning, porous surfaces and retention systems are key to ensuring successful water management programs in cities.

A common misconception is that proper drainage and dense growth are impossible in Georgia. However, this is not the case. Minor tweaks in requirements can make Georgia’s systems and development resilient, which would, in turn, provide affordable housing for residents. 

For example, Historic Fourth Ward Park features a two-acre lake serving as a stormwater retention pond. The park also provides an outdoor area for the neighborhood to enjoy, which adds to its aesthetic value. Fourth Ward was a large project, costing the City of Atlanta $23 million. However, similar projects can be done on smaller scales. 

The University of Michigan has adopted many successful small-scale projects. For example, the university modified a green area with a retention basin that captures and treats 45,000 gallons of runoff. Similarly to many requirements, this project is designed to withstand a 100-year, 24-hour storm and then some. While this is important and the standard, it simply is not enough. These 100-year storms are more frequently becoming 10-year storms.

A major cause of flash flooding is the fact that drainage systems in America either do not exist or do not keep up with the increased flow in urban centers. These drainage systems are unable to keep up because of our materials. We frequently use equipment that does not allow the earth to absorb water in areas that used to have absorbent soil. 

These materials are mostly cement and asphalt, used after clearing and leveling the area. Instead of absorbing water and becoming groundwater, it runs along the surfaces of these roads, sidewalks and other construction projects. For example, in a major city with only 35-50% impervious surfaces –a conservative estimate– there would still be a result of 30% runoff, 20% shallow infiltration and 15% deep infiltration.

Committing to using permeable resources within new developments and modifying former developments is crucial to creating efficient and effective stormwater management. Georgia only limits the number of impervious structures on small water supply watersheds to 25%. While this provides a good starting point, it does not provide ample coverage to protect Georgia’s vulnerable urban areas. 

Overall, Georgia must expand its legislation and policies regarding stormwater control measures. To begin, it should implement tax abatement programs to encourage the adoption of green roofs among state members for large buildings like New York City’s. Additionally, the state already has recommendations for stormwater management practices involving detention ponds. However, without formal requirements, these are unlikely to be adopted. Setting more stringent requirements for retention ponds within the state is also advisable.

As images emerge of people and cars dredging through feet of water in Atlanta streets due to Hurricane Helene, the absolute need for infrastructure for proper drainage and water management programs becomes clearer. This is important considering that Atlanta is far from the coast, which shows that hurricanes affect newer areas.

Matthew Fern is a second-year student at the University of Georgia studying environmental economics and management and political science. He is a member of the environment group.