Memorial Water Feature Design Aspects

The Memorial features multiple water effects, and it's one of the largest scale fountains in the world.

9/11 Memorial at Night

The Memorial lighting creates a ethereal glow through the water.

September 11 Memorial Weir Designer

Delta Fountains developed the weirs for the September 11 Memorial fountains to be able to withstand wind and weather conditions during the entire 29 foot fall.

September 11 Memorial

New York, NY

  • Date2012
  • ClientNational September 11 Memorial & Museum at the World Trade Center Foundation, Inc., The Port Authority of New York and New Jersey
  • Categories
  • DesignMichael Arad, Handel Architects LLP

Delta Fountains was honored to join the team that created the largest,  man-made waterfalls and reflecting pool in the world. The September 11 Memorial reflecting pools, also known at the 9/11 Memorial, are located in the exact footprints of the Twin Towers. It was built to remember those whose lives were lost at the World Trade Center in 1993 and 2001. The memorial site is home to the two fountains, the 9/11 Memorial Museum and One World Trade Center and Observatory. The 9/11 Memorial’s North and South Fountains have combined recirculating systems that pump as much as 18,000 gallons of water at peak performance, every minute of every season. The water flows over the walls of the memorial’s two deep reflecting pools and then into catch basins for recirculation.

September 11 Memorial Reflecting Pools

9/11 Waterfall Challenges

The September 11 Memorial project required that we design a method to keep water flowing in clear streams from a 29 foot fall and maintain consistent reflective and acoustic properties year-round, no matter what the weather.


Weir & Reflecting Pool Solutions

Delta Fountains designed and constructed stainless steel fabrications and redesigned the entire weir structure. We discovered through testing that the weir structure needed to be easily adjusted to be level within 1/16th inch with an even water flow over the entire 1400 linear feet.

Dry spots on the reflecting pool upper levels were avoided through integral-design adjustability that allowed for continuous expansion and contraction of conductive materials yet maintained a strict level tolerance. We added ribs to prevent buckling and allow for field welding, and created a high-tech chemical feed system to anticipate and react to weather conditions. We also created a state-of-the-art networking control system to monitor more than a thousand points of contact and to be responsive to the operational maintenance of the systems.


To learn more about the 9/11 Memorial, you may view the links below or request one of our AIA and ASLA accredited presentations on the engineering and design process of the fountains.

September 11 Memorial Reflecting Pools Tribute Video


More Articles About This Fountain:

National September 11 Memorial and Museum Waterfall Weirs

Delta Fountains & Siemens Industry Inc. Case Study PDF

9/11 Memorial Fountain Tribute Video

Delta Fountains’ 9/11 Memorial in The Florida Times Union



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