Challenges Met at the Monterey Bay Aquarium
By Matthew Schneider
Recently, I had the privilege of performing a plumbing systems assessment of the Monterey Bay Aquarium, located in Monterey, California. The third such facility assessment performed by our company — Ballinger Architects and Engineers, Philadelphia — it was an overall assessment, including electrical, HVAC, architectural and structural, in addition to the plumbing systems. These assessments have enabled the aquarium’s facilities department to successfully focus capital expenditures on areas of the aquarium in most need of repairs and improvements. They also have stimulated improvements in system design, updating the systems allowing the facility to capitalize on new technologies and industry advancements.
These assessments have enabled us to conclude that the two primary causes of system degradation are the harsh shore line location and the use of actual seawater for the sea life habitats. The use of plastics and stainless steel, whether original or upgraded in the systems piping, fittings, valves, supports or equipment has greatly increased the life and reduced the required maintenance of those systems.
The Monterey Bay Aquarium is housed in a total of 322,000-square-feet floor area and was built on the site of the Hovden Cannery, a former sardine cannery, located on the shores of Monterey Bay. Being an aquarium, its plumbing systems are critical. Portions of these systems are unlike any other in the country, if not the world. In fact, it is one of only a couple of aquariums in the country to actually draw seawater for its exhibits, in this case from the Monterey Bay.
The aquarium is one of the largest in the world. It has two levels and consists of two wings, the Near Shore Wing and the Outer Bay Wing. The Oceans Edge Wing is the original aquarium building built in 1984, and the Outer Bay Wing was added in 1996. The facility also has 25,500 square feet of multilevel ocean view deck area overlooking a large natural tide pool, as well as the Monterey Bay itself.
The Oceans Edge Wing consists of three large tanks. The 335,000-gallon forest kelp tank, which is the first aquarium tank to grow live California Giant Kelp. The tank has a large wave machine at the top, which keeps the water circulating, supplying the kelp with nutrients obtained from natural seawater. Another large tank in this wing is the 326,000-gallon Monterey Bay Tank that houses gill sharks, stingrays, and a variety of other fish, which inhabit the nearby bay. The third large tank is the 55,000-gallon Sea Otter Tank, which is open at the top to the exterior and is equipped with large artificial rocks, as well as a fenced in area to allow the otters to exit and enter the tank in a somewhat familiar natural environment. There are two viewing areas of this exhibit: one is on the first level which allows an underwater perspective; the second level gives observers a view of the playful otters when they are at the tank surface and on the exterior rocks.
The Outer Bay Wing has a 1,000,000-gallon tank housing (at the time it opened), the world’s largest single pane viewing window. This tank is home to large tuna, sharks, giant sea turtles, mahi mahi, ocean sunfish and other species from the outer Monterey Bay. This Wing also contains an anchovies tank exhibit containing approximately 3,000 anchovies swimming against a simulated steady current movement. There is also a jellyfish exhibit featuring multiple kreisel tanks (tanks without corners) providing a slow, circular water flow without physical interference.
Overall, the main seawater system draws directly from Monterey Bay via two 16-inch fiberglass intake pipes. The water is pumped into the facility at a maximum rate of 2,000 gallons per minute. The system consists of two seawater intakes extending 1,000 feet into Monterey Bay. There are grates at the ends of these pipes to keep from drawing fish and other large marine life into the pipes.
The intakes feed a large main reservoir pit below a main pump house at the exterior of the aquarium. The pump house contains two 40-horsepower vertical pedestal main seawater pumps that supply the building’s main seawater system. An 18" main runs from the pumps into the Near Shore wing basement mechanical room. As the main enters the basement, it splits into two systems: filtered seawater and raw seawater.
The filtered seawater is supplied to the displays during the day to provide clear water for viewing purposes. The filtered water system consists of end suction corrosion resistant fiberglass reinforced, plastic composite pumps, pumping raw seawater through large sand filters at various locations, out to the exhibits.
The larger display tanks, the Monterey Bay, the Kelp Tank, the Sea Otter Tank, the Outer Bay Tank, and the Jellies System are all equipped with their own pumps and filters. The smaller systems are fed from the larger tank overflows.
Raw seawater is supplied to the exhibits at night to provide the necessary nutrients such as plankton to the aquarium sea life. This system bypasses filters or strainers associated with each individual display system.
The systems are switched by a series of automatic valves and bypasses located in the Oceans Edge Wing’s main mechanical room. The main seawater systems, raw and filtered, were originally installed when the Oceans Edge Wing was built in 1984. The piping and fittings are fiberglass and the valves were cast iron. The fiberglass piping has held up well but the valves have been replaced over the years because of failures due to the corrosive environment. The valves have been replaced with PVC butterfly valves, which were not available above 6" when the original aquarium was built.
The main seawater intake system pulls direct raw seawater from the Monterey Bay with the intake grates as the only method of screening the water before it reaches the sand filters. Some systems, such as the Sea Otter system, have basket strainers at the filters. The interior of the raw seawater piping can get encrusted with plankton and other tiny sea life, like clams and mussels over time.
The aquarium has developed an innovative way of dealing with this problem. The raw seawater piping is cleaned by using a “pigging” procedure. This process is used in the oil industry to clean sludged piping. The pipes are cleaned by inserting a hard foam “pig,” shaped like a large bullet, which is a slightly larger diameter than the pipe, into the raw seawater pipe, and forcing it through the pipe with pumped water pressure. The swirling water wound the pig scours the pipe as it travels through the pipe. The pig is then discharged out a cleanout at the end of the pipe at various locations in the system.
When the two 18" intake pipes, which extend out into the bay are pigged, the pig is forced from inside the aquarium mechanical room out into the bay. The intake screens are removed and the foam pig discharges from the intake at the bottom of the bay then comes bobbing to the surface where the facilities crew is waiting in a boat to retrieve it. Because the pig is made of foam and uses the swirling water to scour the pipe, it does not damage the pipe, although it does make quite a loud squealing noise (hence its name).
The Outer Bay Wing is supplied by the raw seawater system in the Oceans Edge Wing and has two larger systems and a number of smaller systems. The larger systems are the Outer Bay Tank System and the Jellies System. The Jellies System’s water is also sterilized with ultraviolet light and chilled with a small chiller. This ensures the correct water temperature and quality for the jellies since the water can be altered by the buildings ambient temperature and equipment, such as pumps, as it travels through the aquarium's piping to the exhibit. The smaller systems are the anchovies tank and a temporary sea horse exhibit. The Outer Bay Wing's systems are schedule 80 PVC piping with PVC valves and has had minimal problems since it was built.
Because the aquarium uses direct raw seawater for its exhibits, maintaining these systems is challenging and requires the use of some unconventional materials.
The systems in the aquarium which have the larger filtration systems, the Kelp Tank, the Monterey Bay Tank, the Sea Otter Tank, the Outer Bay Tank, and the Jellies exhibit are equipped with back wash systems. Through a series of valves and bypass pipes the main pumps can be used to reverse the flow of water through the large sand filters backwashing the filters and collecting it in large storage reservoirs. The water is then discharged back into the bay. There is a desalination system fed from the discharged water from the filters, supplying the aquariums toilets and urinals.
The building, being built out over the beach and shore, exposes the PVC drainage piping, which serves the first floor, to the weather, pounding waves, and high winds. These elements can damage the piping and conventional pipe hangers. The aquarium's facilities crew have installed rather clever nonconventional vinyl V hangers at close spacing, approximately 12 to 18 inches to support, secure, and protect the piping. The vinyl will not corrode from the seawater or airborne salts, providing a longer service life than metal hangers.
The Monterey Bay Aquarium does an excellent job of keeping up with regular maintenance, as the seawater, airborne salts, and the marine environment continue to take an ongoing toll on the plumbing systems and general facilities infrastructure. Ballinger's assessment provided an organized method for identifying and categorizing such maintenance, repairs, and industry advancements needed for the upkeep of the facility and to simply maintain the outstanding marine environment and visitor experience for which the Aquarium is famous.
Matthew Schneider is an associate, senior technical plumbing/fire protection lead at Ballinger Architects and Engineers. For six years he has served as the Plumbing/Fire Protection Department manager. Matt has 25 years of experience in the plumbing design engineering field.