St. Louis Gateway Arch Park – Luther Ely Smith Square
Client: Michael Van Valkenburgh Associates and the National Park Service
In the early 1930s, civic leader Luther Ely Smith presented the idea of building a memorial to help revive the St. Louis riverfront and to memorialize the nation’s westward expansion. After a nationwide design competition, Eero Saarinen’s Arch design was selected to memorialize the early pioneers. Construction of the St. Louis Gateway Arch began in 1959, with the final section of the Arch was secured in 1965.
In 2009, the CityArchRiver project envisioned a major upgrade to the St. Louis Gateway Arch park’s grounds to celebrate the upcoming 50th anniversary of the Arch, and an international design contest was held. World-renowned landscape architecture firm Michael Van Valkenburgh Associates’ design was chosen, connecting the Gateway Arch grounds with the East and West riverfronts and with the region. With “10 Design Goals” for the project, one was to develop a sustainable future- this is where Wahaso came in.
For more information about the park, this video from KMOV News St. Louis highlights the opening of the St. Louis Gateway Arch park in October of 2015.
System Type: Stormwater Harvesting
Commissioning Date: September 2015
Challenge: More challenging than designing a rainwater harvesting system that simply harvests rainwater off of a clean roof surface, harvesting and treating stormwater for reuse requires special consideration along the entire treatment process. Contaminants in stormwater run-off can include hydrocarbons, nitrates, organic matter, and animal waste, and in order to be used for irrigation, treated water would need to be clean, clear, and free from these harmful pathogens. The Park Service was also insistent that the harvesting equipment not interfere with the sightlines of the park.
Solution: It was critical that most of the suspended solids in the stormwater runoff would be removed before they entered the storage system, so in order to deliver a complete solution, Wahaso brought in two other partners: SunTree Technologies and Oldcastle Precast. SunTree Technologies recommended their Nutrient Separating Baffle Box system to remove sediment, organic material, and hydrocarbons from large storm flows entering the cistern. The system holds trash above the standing water line, and uses a series of baffles to remove suspended solids to less than 350 microns. Oldcastle Precast supported the design and engineering of the Storm Capture system for this project, and was designed to hold 37,000 gallons of pre-treated stormwater below-grade in nine pre-cast modules. Oldcastle also helped to resolve the sightlines requirement by providing an additional module to contain all the harvesting equipment below-grade. An 8’ X 10’ pre-cast equipment room was delivered with ventilation, sump pump, ladder, and large access doors to avoid confined space restrictions. Once suspended solids are removed, Wahaso’s filtration and sanitation skid was designed to further sanitize the water as well as to minimize maintenance of the system. Special high-intensity UV units are utilized in the system to eliminate any potentially harmful pathogens, even if the water is cloudy. To minimize maintenance requirements, a special 50-micron filter was installed that is capable of self-cleaning while it is operating, eliminating the need to replace bag filters.
Results: Wahaso’s stormwater harvesting system was installed and started up in time to join in the opening celebration of the Luther Ely Smith Square in the Fall of 2015. In the following Spring of 2016, harvested water was available and provided for irrigation of the lawns and landscaping. The system delivers clean, clear, and safe water for spray irrigation at 40 GPM and 70 PSI, and is expected to only require service at the beginning and end of each irrigation season. The use of a below-grade water storage system and equipment room provides that the park will remain clear of obstructions so that attendees can focus on the beautiful Gateway Arch and surrounding park.