Honoring Heroes: the 9-11 Memorial Pools

This episode of the Talking Pools podcast reflects on the significance of September 11th, honoring the lives lost and the heroes who emerged on that day. It transitions into a detailed exploration of the engineering behind the 9-11 Memorial Pools, highlighting their design, operation, and the advanced technologies that maintain them as a symbol of remembrance.

takeaways

• September 11th tested the soul of our nation.
• The spirit of America revealed itself in courage and defiance.
• First responders became the definition of heroism.
• Out of the ashes, America rose united.
• We honor the fallen with action and resilience.
• The 9-11 Memorial Pools are dynamic water features.
• Each pool integrates advanced hydraulics and disinfection systems.
• Bromine is used for its stability and efficacy.
• The pools operate year-round, preventing ice accumulation.
• The memorial pools represent a blend of memory and engineering.

Sound Bites

• "This isn't about pools or business."
• "We honor them with action, by living lives worthy."
• "The largest man-made waterfall in North America."

Chapters

00:00
A Day of Remembrance

04:29
The Engineering of Memorial Pools

Transcript

Rudy Stankowitz (00:00.203)
Hey everybody, welcome to the Talking Pools podcast. Today's episode, it's not like the others, not your normal broadcast, definitely not your normal Thursday. Today is Patriots Day, September 11th, a day of remembrance, a day of reflection, and a day of honor. This isn't about pools or business. It's about people. It's about sacrifice, resilience, and the spirit of America. So as we begin,

I want to share some words to honor those we lost and the heroes that stood tall on that fateful day.

Rudy Stankowitz (00:44.6)
September 11th, was a day that tested the very soul of our nation. It was a day of fire and smoke, of heartbreak and loss. But it was also a day when the spirit of America revealed itself in ways that still inspire us nearly a generation later.

Rudy Stankowitz (01:07.298)
That morning, nearly 3,000 innocent men, women, and children had their lives stolen. They were office workers, teachers, service members, mothers and fathers, sons and daughters. They were ordinary Americans living ordinary lives. And that is exactly why their loss cuts so deep. They were us. They were the heartbeat of this nation. And yet, amid the darkness, we saw light.

Amid the chaos, we saw courage. Amid the destruction, we saw defiance. We saw firefighters climbing stairwells, carrying hope on their backs as the weight of danger bore down on them. We saw police officers racing toward danger, determined to save lives no matter what the cost. We saw first responders, paramedics, doctors, nurses, who would not rest.

until the injured were cared for. We saw passengers on Flight 93 who in their final moments chose bravery and sacrifice so countless others could live.

These men and women became the very definition of heroism. They embodied the words we hold dear. Greater love has no one than this, that someone laid down his life for his friends. And so many of them did. All gave, and some gave all. And when the dust began to settle, something extraordinary happened. Out of the ashes, America rose.

Neighbors became brothers and sisters. Flags flew proudly from porches, schools, firehouses and highways. Strangers embraced one another in grief and then in resolve. The world saw not a nation broken, but a nation united. That is the America we remember today. That is the America we must always strive to be.

Rudy Stankowitz (03:19.223)
We do not honor the fallen with silence alone. We honor them with action, by living lives worthy of their sacrifice, by standing tall when tested, by refusing to be divided by fear or hatred, by teaching our children what resilience looks like, what unity feels like, what courage means. The legacy of 9-11 is not just in the lives we lost, but in the spirit we found.

A spirit that says, we may be attacked, but we will not fall. We may mourn, but we will not surrender. We may bend, but we will never, ever break. So today as we bow our heads in remembrance, let us also raise our voices in pride. Pride in the heroes who ran toward the flames. Pride in the men and women in uniform who continue to protect us. Pride.

in the enduring promise of freedom that no enemy can take away. We are Americans. And because of that, we will always rise from the ashes. We will always stand together. And we will always honor those who gave their last breath so that others might see another sunrise.

May God bless the fallen. May God bless the heroes. And may God forever bless the United States of America.

President George W. Bush (05:28.00)                                                                                  Good evening. Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts. The victims were in airplanes or in their offices, secretaries, businessmen and women, military and federal workers, moms and dads, friends and neighbors.

Rudy Stankowitz (05:29.312)
The 9-11 Memorial Pools in New York City represent not only a commemorative landscape, but also a complex engineering and water treatment system. Each pool, occupying nearly one acre of surface area, integrates advanced hydraulics, chemical disinfection, ultraviolet oxidation, and rigorous maintenance protocols. Today I want to examine the construction, hydraulic systems, disinfection methodologies, seasonal adaptations, and operational care of the pools.

situating them within the broader field of applied aquatic engineering and large-scale water feature management.

Rudy Stankowitz (06:06.719)
Urban memorials are typically considered static works of architecture and art. The 9-11 Memorial Pools, however, are dynamic water features that function simultaneously as cultural monuments and complex aquatic systems. Located at the footprints of the former Twin Towers, each pool is designed as a square void with water continuously cascading down its vertical walls. From an engineering perspective, the pools represent a unique integration of civil engineering

fluid mechanics, and water chemistry under extreme operating conditions.

Rudy Stankowitz (06:43.807)
The pools measure approximately 176 feet on each visible side, with an additional eight feet water table extending the total edge length to nearly 196 feet. The vertical drop is approximately 30 feet, followed by a secondary drop into a central void. These parameters make the feature the largest man-made waterfall in North America. The structural engineering required significant adaptation to withstand environmental stressors,

including freeze-thaw cycles, wind shear within the urban canyon, and long-term exposure to chemically treated water. Stainless steel waterfall weirs were fabricated with sub-millimeter tolerances to ensure uniform laminar flow across the perimeter. The supporting plumbing system, consisting of hundreds of feet of pipe, is joined using grooved mechanical couplings, allowing for sectional disassembly, inspection, and biofilm control.

Each pool is powered by eight industrial-scale pumps, achieving a combined flow rate of 30,000 gallons per minute per pool. System reports suggest higher combined flows across both pools ranging from 26,000 to over 50,000 gallons per minute, depending on operational demand. The design achieves complete water turnover approximately every 20 minutes. Automation and control are achieved through Siemens TYA programmable logic controllers

which monitor flow rates, adjust valves, and maintain stable water levels. This level of automation is critical for preventing disruptions to the waterfall uniformity and for integrating chemical dosing and ultraviolet disinfection systems in real time. Unlike most outdoor fountains that rely primarily on chlorine, the 9-11 Memorial Pools employ bromine as the principal chemical disinfectant. Bromine was selected for its stability across a broad pH range

and for its reduced production of volatile byproducts compared to chlorine. In an open-air high-volume water feature subject to variable pH and organic loading, bromine provides greater persistence and efficacy. The pools also employ UV disinfection systems as secondary oxidizers. UV reactors operate continuously, exposing circulating water to germicidal wavelengths. This process induces DNA,

Rudy Stankowitz (09:05.297)
and RNA disruption in microorganisms, rendering them non-viable. The integration of bromine and UV represents a dual-barrier approach, consistent with best practices in advanced aquatic engineering. Filtration banks remove suspended solids and organic debris, preventing turbidity and reducing the chemical oxidant demand. The turnover rate, 20 minutes per pool, ensures rapid dilution of contaminants and uniform disinfectant distribution.

I know what you're asking yourself. What about the EPA's ban on bromine in swimming pools because of harmful disinfectant byproducts? You're absolutely right. Bromate is the concern. But here's the distinction you need to keep in mind. Chlorine systems can generate chloramines, and those pose a real inhalation risk to swimmers and bystanders. Bromate, on the other hand, is only a threat when ingested. Since no one is drinking from the 9-11 Memorial Fountains,

Bromine actually presents a far lower risk in this unique application than chlorine ever would.

The pools operate year-round, including during winter conditions where ambient temperatures fall below freezing. To prevent ice accumulation along the weirs, the water is heated through integrated exchangers, maintaining a temperature sufficient to inhibit freezing without inducing thermal stress or unnecessary evaporative losses. This adaptation ensures uninterrupted operation, a critical requirement given the pool's symbolic role.

Unlike ornamental fountains that are typically decommissioned during cold seasons, the memorial's design necessitates continuous hydraulic and chemical operation. Maintenance represents a significant operational component. Each weeknight, waterfalls are shut down and crews enter the pools for direct cleaning. Activities include vacuuming of the basins, brushing of vertical surfaces, polishing of granite, and cleaning of bronze parapets containing nearly 3,000 engraved names.

Rudy Stankowitz (11:06.173)
The cycle requires approximately eight hours to complete. From an operational perspective, this routine exemplifies the importance of human intervention in supplementing automated disinfection and filtration systems. Mechanical and chemical systems ensure microbial safety, while manual cleaning preserves aesthetic clarity and material integrity. The 9-11 Memorial Pools occupy a unique position in the taxonomy of aquatic systems.

They are neither recreational pools nor ornamental fountains in the traditional sense, but hybrid systems combining aspects of both. The design emphasizes symbolic reflection, yet requires continuous operation at scales typical of municipal water infrastructure.

The choice of bromine over chlorine indicates a preference for chemical stability and reduced volatilization, especially relevant in high-flow outdoor settings. The integration of UV disinfection provides redundancy and reduces reliance on halogenated compounds, aligning with contemporary approaches in sustainable water treatment. From a hydraulic standpoint, the pools represent one of the largest continuous waterfall systems in existence.

with flow demands exceeding many public aquatics facilities. The 20-minute turnover rate reflects not recreational necessity, but an engineering commitment to clarity and consistency of flow. The 9-11 Memorial Pools illustrate how Memorial architecture can intersect with advanced aquatic engineering. Beneath their surface lies an infrastructure of pumps, filtration banks, bromine dosing systems, ultraviolet reactors, and heating loops. Above,

The visible result is water falling, circulating, reflecting. These pools demonstrate that memorialization is not static. It requires continuous movement, chemical balance, hydraulic precision, and human care. Their operation represents an ongoing act of remembrance, maintained through engineering rigor and nightly labor. In this way,

Rudy Stankowitz (13:14.301)
The 9-11 Memorial Pools stand as both a technological achievement and a cultural symbol. They embody the intersection of memory and mechanics, where the language of hydraulics and disinfection sustains a monument dedicated to endurance, reflection, and the continuity of remembrance. If you have not yet visited the Memorial Fountains, make the trip to Manhattan. Go not only as a pool professional who can appreciate the engineering,

But as an American who understands the weight of history, the sound of the water, the sight of the names, the immensity of the voids, it is profoundly moving. Be prepared. It is not just a visit. It is an experience of remembrance, reflection, and reverence that will stay with you long after you leave.

O say can you see, by the dawn's early light, What so proudly we

Rudy Stankowitz (14:38.529)
And the rockets' red glare, the bombs bursting in air, gave