Down the drain
Many cities in America are waking up to the fact that water supply for buildings is fast becoming an urgent issue.
View the full story , including all images and figures, in our monthly digital edition . Many cities in America are waking up to the fact that water supply for buildings is fast becoming an urgent issue. With rainfalls decreasing and droughts increasing, water conservation techniques need to become a vital part of the discussion of the planning and development of future projects.
Cities such as Las Vegas, Atlanta, and Los Angeles have been the poster children of urban water shortages. Ultimately, urban water shortages have multiple impacts on MEP engineers, municipal planners, and building owners, including costs for hooking up new buildings to water utilities, HVAC and plumbing systems designs, and water metering and control.
In the Mountain and Pacific regions, the dominant water resources are Lakes Mead and Powel. These vast reservoirs, fed by the Colorado River, provide water to major urban areas such as Phoenix, Los Angeles, and Las Vegas. The Scripps Institution of Oceanography conducted a water budget analysis, which showed that under current conditions, there is a 10% chance that live storage of freshwater in Lake Mead and Lake Powell will disappear by 2013, and a 50% chance that it will be gone by 2021. If there are no changes in the water use and water allocation, the decrease in runoff from the Colorado River will drastically affect the major urban communities of the southwestern United States.
The southwestern United States, with its arid climate and scare water supplies, is not the only region of the country whose water shortage continues to be a growing problem. Several states in the East South Central and South Atlantic states continue to engage in Supreme Court legal battles to determine the use of water within their state.
A two-decade-long, tri-state battle between Georgia, Florida, and Alabama involves the appropriation of water from the Lake Lanier reservoir. The reservoir, which is located just north of Atlanta, provides drinking water for more than 3 million people. Due to the statewide drought in Georgia, especially in Atlanta, the 38,000-acre Lake Lanier reservoir is down more than 15 ft from normal levels. At the lake’s southern tip, it feeds into the Chattahoochee River, which runs along the border of Alabama. Eventually, the river flows south into Florida’s Apalachicola River and into the Gulf of Mexico.
Georgia filed a legal motion demanding the U.S. Army Corps of Engineers (USACE) limit the amount of water it releases from the reservoir. Georgia Governor Sonny Perdue publicly pleaded with President Bush to exempt Georgia from the Endangered Species Act out of fear of not being able to provide ample drinking water for its citizens. President Bush dispatched Interior Secretary Dirk Kempthorne to broker negotiations between the three states near the end of 2007. Negotiations failed, and Kempthorne, the USACE, and other federal agencies implemented a water-sharing plan that limited the amount of water that could be siphoned from Lake Lanier. In June 2008, the Florida Dept. of Environmental Protection (FDEP) sued USACE for violation of the Endangered Species Act. In the lawsuit, the FDEP outlined concerns that the Corps’ management of reservoirs endangers the native wildlife.
Proactive state governments, such as California, and major urban areas such as Chicago and New York City already have begun addressing the issue of water conservation before the problem reaches a critical level. For example, in 2007 Chicago enacted the Automatic Meter Reading (AMR) program in accordance with its citywide Water Agenda, formed in 2003. Chicago’s Water Agenda involves the aggressive investment in water-utility infrastructure upgrades to Chicago’s distribution systems. The AMR program and the Dept. of Water Management will install AMR technology on 162,000 existing water meters over the next three years. The AMR technology consists of a water meter with a remote transmitter that will allow greater efficiency in the collection of data. Based on gallons, rather than cubic feet, the customers can now identify exactly where they use the most water and rectify any problem areas.
New York City’s Dept. of Environmental Protection (NYCDEP) and its Water Conservation Program addresses water conservation in several ways. Each year the program surveys more than 4,000 miles of the distribution piping for leaks and replaces 55 to 60 miles of old water mains. The NYCDEP extended fixture replacement financial incentives during the 2008 to 2010 period to include toilets, urinals, and clothes washers. Since 1990, the group of water conservation programs implemented by NYCDEP has resulted in a decrease in city water consumption and wastewater flow by approximately 23%.
California’s government continues to combat the effects of water scarcity in its major urban areas in several ways. The state will develop and put into practice a “water bank” to counteract the recent water scarcity in the San Joaquin-Sacramento River Delta, near San Francisco. California’s 2009 Drought Water Bank will buy water from local water agencies and farmers upstream of the delta. The water will then be available for sale to public and private water systems expecting to run short of water next year. The agencies that purchase the water will need to commit to a 20% reduction in water usage, which will act as a safeguard against agencies that would use water for frivolous reasons.
In May 2008, Los Angeles Mayor Antonio Villaraigosa proposed a 20-year, $1.5 billion water supply strategy called “Securing LA’s Future Water Supply.” Due to the increasing population and the projected 15% increase in water use by 2030, Los Angeles and its Dept. of Water and Power plan to conserve 32.6 billion gal of water, or enough to supply water to 200,000 homes for one year. The project intends, by 2019, to supply half of all new water demand with the six-fold increase in recycled water supplies. The program includes a combination of commercial and residential rebates and incentives; the installation of smart sprinklers, efficient washers, and urinals; and the long-term measures such as the expansion of water recycling and the investment in the Tillman wastewater reclamation plant.
In Orange County, Calif., aggressive measures have been taken to provide a more stable source of water to its inhabitants. In January 2008, a water reclamation and purification plant at the Orange County Water District headquarters in Fountain Valley began operation. The plant injects fresh water resources into the county’s groundwater basin to fight against saltwater intrusion and supplement the area’s decreasing water supplies. The $490 million plant turns consists of pipes, filters, holding tanks, and pumps across 20 acres.
The plant works in conjunction with the Orange County Sanitation District sewage treatment plant. Initially, the reclamation plant pumps the brackish water into its 26 holding basins, which filter the sewage water with 270 million micro-filters. From there, high-pressure forces the water through a series of thin plastic membranes housed in rows of white cylinders. Next, hydrogen peroxide covers the water and then UV light blankets it to neutralize remaining contaminants. Free of all harmful intoxicants, the water pumps into the underground aquifer and continues to be filtered as it sinks to depths of more than 1,000 ft. At its full potential, the plant will be able to add 130 mgd into the fresh water supply.
National programs: LEED
The “LEED for Existing Buildings: Operations and Maintenance Guide” Water Efficiency section attempts to address several of the key issues in commercial building’s water usage, such as reducing indoor fixture and fitting water use, measuring building and subsystem water performance, maximizing indoor plumbing fixture efficiency, limiting and eliminating the use of potable water for landscape irrigation, and reducing potable water consumption designed for cooling tower equipment.
Although the LEED standards do an adequate job of addressing some of the major water conservation concerns, the disproportionate distribution of accreditation points is a cause for concern. According the April 2008 LEED standards, only 10 out of a possible 92 accreditation points are dedicated to water efficiency.
David DeBord, CPD, LEED AP, vice president of technical services of Environmental System Design, Chicago, believes in increase is necessary now, but inevitable for future guidelines. “The standards should be higher and it will surely increase every time the standards are revised or new standards are written,” he said. “For new construction, water credit points are doubling for 2009. A 20% reduction in water use is a prerequisite and will receive no points, but the other points are increased to a total of 10 points. Other changes are included also, which represent a shift toward water and energy use reduction, and away from materials credits.”
In the future, there may be an opportunity for additional credits. Currently, there are only credits for a 10% and 20% water use reduction, but if additional incentives are given for the reduction of water use by 30%, 40%, or 50%, existing buildings are more likely to implement more aggressive water reduction strategies.
National programs: FEMP
The Federal Energy Management Program (FEMP) works to reduce the cost and environmental impact of the federal government by advancing energy efficiency and water conservation, promoting the use of distributed and renewable energy, and improving utility management decisions at federal sites.
A major area of concern for FEMP is water-use efficiency. The federal government uses an estimated 244 to 256 billion gal of water annually. To process and use water, the federal government uses an estimated 138.3 billion Btu of energy annually; 98% of this energy is used to heat water. With moderate efficiency efforts, the federal government could conserve approximately 40% of its water and related energy use, or 102.4 billion gal of water annually. Working with the U.S. Environmental Protection Agency’s WaterSense office, FEMP updated its Best Management Practices (BMP) to reflect the changes in water use technology.
In accordance with Executive Order 13423, “Strengthening Federal Environmental, Energy, and Transportation Management,” the updated BMP provide guidelines for water-use efficiency in federal buildings including how to develop a successful water management plan, water-efficient irrigation techniques, cooling tower management, and the effective use of non-potable water from alternative sources.
Future of water metering
The future of water metering involves improved water use practices in all types of facilities. In the future, commercial buildings, hotels, restaurants, and residential properties need to address water conservation and metering in ways that will force the occupants to change their behavior.
Water conservation programs in hotels across the country continue to expand as hotels try to reduce their water consumption by imparting behavioral changes on their guests. The Hilton Hotels “Green Program—Conserve to Preserve” helps hotels save water and money while practicing more efficient housekeeping and landscaping.
Through the program, the hotels provide guests with cards to indicate how frequently they would like to have their sheets, towels, and linens dry-cleaned during their stay. Hilton installed low-gallons per flush toilets and high-pressure, low-water showerheads to save on water costs. The program uses low-water washers and dryers that use 1 gal of water per pound of linen. The program saves more than 12 million gal of water per month, in addition to the $1.50 per occupied room per day the program saves the Hilton Hotels in water utility bills.
Future conservation programs will to develop to include stricter monitoring practices on individual hotel rooms, where surcharges increase due to excessive water use within the room. Pilot water conservation projects involve hotel rooms in arid climates that will monitor individual hotel rooms.
The restaurant industry is a major consumer of water resources and newly formed conservation programs address the issue. Southwest Florida Water Management District’s Water Program for Restaurant Outreach) helps restaurants lower operating costs and conserve water by making a few adjustments in service and appliances. The program focuses on practical ways that restaurants can reduce their water consumption.
By serving water only at the customer’s request, a restaurant saves the equivalent of two glasses worth of water that it takes to wash the glass in a dishwasher. The program encourages the installation of low-flow spray valves, which use only 1.6 gpm compared to conventional models that use 3 to 6 gpm. The spray valves are responsible for more than 50% of the total water used in all dishwashing procedures and the installation of the new valves will save the restaurant more than $1,300 per year.