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WATER

CASE STUDY

TD AMERITRADE Omaha, Neb. ADVANCED WATER CONSERVATION

Online brokerage TD Ameritrade Holding Corp. consolidated five offices in Omaha, Neb., into a single 12-story tower expected to receive USGBC’s LEED Platinum certification (see the image below). Along with an abundance of natural lighting, solar-heated hot water, and wind-powered parking lot lights, the building boasts a rainwater harvesting system that waters the landscaping and flushes the toilets. All together, the sustainability measures cut building maintenance costs in half, claims spokesperson Kim Hillyer.

Rainwater Storage Below the parking area of AdvancED's facility is a 30,000-gallon irrigation tank.

M O R E T H A N 70% O F WAT ER CO N SU M ED BY CO M M ERCI A L B U I LD I N GS I S FO R N O N P OTA B L E US E S . T H I S B EGS T H E Q U E S T I O N : W H Y N OT R A I N WAT ER FO R T H E S E PU R P OS E S?

 TD Ameritrade, Omaha

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If your annual precipitation averages 42 in. per year, you could collect:  39,000 gallons annually from a 1,500-sq.-ft. residential roof, or  2.6 million gallons annually from a 100,000-sq.-ft. commercial building.

Stormwater Runoff Impervious surface coverage (paved or roof surfaces where rainwater does not soak into the ground) in the U.S. is 83,337 sq.-km. This is an area as big as 75% of the state of Ohio.

24 | 06.14 | NET ZERO BUILDINGS

According ARCSA, savings are likely to pay off quickly as utilities raise their rates across the country in response to rising demand due to everything from rising populations in some areas, new EPA stormwater regulations, and the replacement of aging infrastructure. Nationally, the EPA expects maintaining existing water services to require $384.2 billion— mostly for repairing and replacing transmission and distribution lines, now estimated to be leaking 16% of the water that passes through them. Water prices have been increasing at an average of 7.7% per year.

The three-story, 60,000-sq.-ft. AdvancED headquarters in Alpharetta, Ga.—the largest school accrediting agency in the world—recently achieved LEED Gold for its eco-friendly designs and energy conservation techniques. For example, the BRAE rainwater cistern (left) harvests water for irrigation and cools the coils of the air conditioning system for greater efficiency. The rainwater harvesting system collects rainwater and condensate from the rooftop packaged A/C system, draining runoff to the subterranean tank. Water moves through underground inlet filters that keep debris from entering the tank. If the tank’s capacity is reached, overflow from the tank is directed to the stormwater drainage system.

The age-old argument inevitably surfaces relating to the overall cost of water. It has been suggested that water prices need to climb before it starts getting the attention of building owners. “Water is too cheap. The problem with rainwater catchment might be not enough immediate payback,” says Bob Boulware, president, Design-Aire Engineering, Inc. Boulware would eventually like to see rainwater catchment for energy saving standards. “I’d also like to see an alternative plan: According to the size of the building there should be environmental impact fees—size of the tap/water main. For instance, a connection fee, which would increase algorithmically after 2 in.,” says Boulware.

System Design One of the first and most importance things to consider when talking design, “Make a significant and meaningful impact on reducing the amount of municipal water use,” says Bauer. Keep the system as simple as possible, and match a system to meet the unique characteristics of the building. Also, ensure that the water is safe for storage and application. To reduce potential of introducing water-borne pathogens, filtration and disinfection treatment methods, which can include ultraviolet treatment, ozonation or chlorination, need to be evaluated. 26 

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Net Zero Buildings - June 2014  

Highlighting the Path Toward Net Zero Building Design.

Net Zero Buildings - June 2014  

Highlighting the Path Toward Net Zero Building Design.