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Definition

Water Access is an umbrella term for several issues surrounding a building's water supply, especially water pressure for upper floors during a power outage sufficient to provide potable water and to keep toilets flushing. For the purposes of this Wiki, the related issue of greywater/stormwater re-use and water treatment shall be discussed in a separate article.


Issues Addressed

Due to the ingenious way in which NYC designed its water supply, nearly every building can receive potable water up to several stories without the aid of pumps or filtration. Our system is designed on the same principles of the Roman Aqueduct[1] . This means that gravity alone is enough to filter and build up the pressure necessary to bring water to all fire hydrants and up to the 5th floor of most buildings. During an outage like the Blackout of 2003, or a severe weather event like Hurricane Sandy, those residents of the City had no interruption of their water supply.

The way high-rises get water above the fifth floor is by pumping it up to a rooftop water tank that generally holds enough water for one day's usage. The water can then be gravity-fed to the upper levels of the building[2] . This system feeds both the domestic water use and the fire suppression system.


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Source: NYC DDC



Power Failure

In the event of a power failure, anyone above the 6th floor in one of the City's 5,854[3] high-rise buildings will have enough water (via the rooftop water tank) to only last for perhaps one day. Given the critical nature of potable water and having an active sprinkler system, most experts are now advising micro-grids and/or Solar PV as a way to bridge the gap during a power outage.

Special Initiative for Rebuilding and Resiliency (SIRR)
The SIRR makes the following recommendations regarding Solar PV:

  • Amend the building codes to allow building-mounted Solar PV
  • Solar PV installations reduce demand on the traditional power grid
  • Work with public and private partners to scale up distributed generation (DG) and micro-grids [with a special emphasis on Solar PV]
  • Increase the generation and use of renewable energy supplies such as... solar energy

Building Resiliency Task Force (BRFT)

Additionally, the BRFT makes the following recommendations:
  • Require residential buildings to provide drinking water to a common area, supplied directly through pressure in the public water main.
  • Require that toilets and faucets be capable of operating without grid power.
  • Encourage building owners to maintain existing water towers and consider using water towers in new construction.



Considerations

Whether the recommended upgrades are put into practice are tied closely to the issue of micro-grids and solar panels. If these and other alternative energy sources are implemented, they can be hooked up to power the water pumps. Despite this, a couple of the recommendations can be put into practice relatively easily.

A common area faucet on a lower floor can be installed in most instances in one day. While it may be inconvenient for a 12th floor resident to walk down 7 flights to get drinking water, it could be the difference between life and death in a severe calamity. This water can also be used to help flush toilets on the upper floors. Recent changes to the building code, don't require water towers, but these developers can easily incorporate one into the design so electric pumps are not their only source of water.


Applications


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Vairous types of NYC water towers. Source: Roy Googin
Water towers have been used for over 150 years, but only recently have we seen the advent of solar-powered pumping stations. A notable example, is the San Diego Water District. The 1.2 MW project will supply a large portion of the city with water. It was completed in 2008[4] .

A similar (but unrelated) technology that has started experimenting with solar power is pumped-storage hydroelectricity. The city of Brea, CA has recently installed such a system[5] . This type of system uses solar power to power water pumps that fill an elevated reservoir.









References


  1. ^ McIntire, Mike. "THE BLACKOUT: WATER; Up on the Top Floors, Powerless and Parched." Editorial. The New York Times 16 Aug. 2003: n. pag. The New York Times Company, 16 Aug. 2003. Web.
  2. ^ Brain, Marshall. "How Water Towers Work." How Stuff Works. HowStuffWorks, Inc, n.d. Web. 12 Nov. 2013.
  3. ^ "New York City." Buildings. Emporis GMBH, n.d. Web.
  4. ^



    "WorldWater To Build Solar Powered Pumping System For San Diego Municipal Water District." Water Online. VertMarkets, Inc., 30 Aug. 2007. Web.
  5. ^


    Soos, Andy. "Brea Solar Power." Environmental News Network. Environmental News Network, 11 July 2011. Web.