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Location: Cincinnati, OH
Construction Schedule: March 2015 – July 2016
Customer: Cincinnati Zoo & Botanical Garden
Architect and/or Engineer: Cornette-Violetta Architects
HGC Role: Construction Manager

For the first time in 20 years, Nile Hippos have made their return to the Cincinnati Zoo & Botanical Garden. The Hippo Cove exhibit is considered the most complex project ever accomplished in the Cincinnati Zoo’s history. Hippos are not the cleanest of the creatures who inhabit the zoo, combined, they defecate nearly 600 pounds a day, making an underwater viewing exhibit very challenging.

Keeping the water clean for visitors was the most complex task for the team. The Zoo’s system uses a complex system of screens, carbon and sand make it possible. The hippo life support system (LSS) is the most advanced and in depth LSS in the Cincinnati Zoo.

The viewing exhibit consists of a 16,000 gallon outdoor pool with an underwater viewing area through a 65 ft. glass viewing window. The 4,000 Sf holding building has an additional pool area. The 6,000 SF water filtration building is home to the complex LSS that works to keep the exhibit clean and the ozone levels stable.

Rain water is collected under the Africa yard to help aid in collecting the nearly 100,000 gallons necessary to make this exhibit work. Solar panels installed on the roofs of the two buildings provide electricity to power the equipment. Synthetic thatch roofing was used for the viewing area’s canopy. LEED was used for the platforms. The rocks surrounding the Hippo yard are made of shock concrete, which had to be modified and minimized during build. The steel and glass also had to minimized throughout the project.


  • Each large blue sand filter holds 3000 gal & weighs 75,000 lbs when full and is 12’ high and 8’ wide (larger than a Fiat 500).
  • Main viewing glass is designed as 7 plies of ½” laminated glass to withstand the 4500psi of pressure from the water and the impact from a Hippo going 10 mph.
  • There is approximately 293,800 pounds (147 tons) of just LSS equipment and piping in the filtration building (the weight of 90 hippos).
  • Hippo holding pool is approx. holds approx. 11,000 gal. (about 140 bathtubs) and the exhibit pool is approx. 67,000 gal (about 840 bathtubs).
  • There is approx. 3500 LF of piping for the LSS system alone (over ½ mile).
  • Exhibit pool system pushes water through the system at 1800 gallons per minutes (7.5 times more than a fire hose).
Aerial of Cincinnati Zoo Hippo Cove
Cincinnati Zoo Hippo Cove
Cincinnati Zoo Hippo Cove viewing area
Cincinnati Zoo Hippo Cove with one hippo swimming
Cincinnati Zoo Hippo Cove with two hippos swimming
Cincinnati Zoo Hippo Cove view of water systems
Cincinnati Zoo Hippo Cove view of background water systems

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