At a Glance

The exhibit recovers and recycles backwash from the robust life-support filtration systems that would otherwise be lost to the sewer using a natural-systems based treatment wetland.

Project Description

Fresno Zoo's Sea Lion Cove exhibit, which opened in August 2012, is modeled on the ecology of California's Central coast and features sea lions, seals and pelicans in a 200,000 gallon pool. Visitors are afforded an up close and personal view 35 ft underwater through a massive glass window into the depths of the exhibit. Underwater viewing requires pristine water quality, however, and that's where Biohabitats' expertise comes in.

Working with lead designer The Portico Group, and T.A. Maranda & Associates who designed the primary water filtration and life support systems, Biohabitats created a constructed wetlands system to recycle the backwash water generated by the filtration system, saving the Zoo up to 200,000 gallons of fresh, potable water per year. Instead of dumping the backwashed water to the sewer, the natural treatment system first settles the water to reduce solids, then provides biofiltration of organic matter and nutrients in the subsurface flow constructed wetlands. Water recovered from the wetlands is then returned to the filtration system for polishing and disinfection before being returned to the exhibit's pools.



Southwest Basin & Range

Physiographic Province

Pacific Border


San Joaquin River

Expertise Areas

Design & Build


Fresno Chaffee Zoo


Fresno, California, United States