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Portland’s Drinking Water

Portland’s Drinking Water. Safe Drinking Water Act (SDWA) 1974. EPA standard for public drinking water 1986: Act amended to increase requirements for safety testing 1996: Act amended to increase source protection, capacity to carry water to the public. Bull Run --Source.

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Portland’s Drinking Water

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  1. Portland’s Drinking Water

  2. Safe Drinking Water Act (SDWA) 1974 • EPA standard for public drinking water • 1986: Act amended to increase requirements for safety testing • 1996: Act amended to increase source protection, capacity to carry water to the public

  3. Bull Run--Source • 102 square-mile area • primary drinking water supply for Portland • Located 26 miles from downtown Portland in Sandy River basin, in Mt. Hood National Forest

  4. Portland Drinking Water • Protected in 1892 • Serves 900,000 residents • 2001: protection boundary extended by federal law • Groundwater back-up supply since 1986 • peak water demand during summer months • emergency source of supply when Bull Run is not available

  5. Reservoirs • Uncovered • Receive water by gravity flow or pumping • 17 billion gallons stored • Store 3 days’ worth of water

  6. Mt. Tabor & Washington Park Powell Butte Reservoir • Security surveillance cameras monitor the reservoirs 24 hours per day • Open reservoirs must be cleaned every six months • Will be disconnected in 2015 • Purchased in 1925 for $135,000 for future reservoirs • 1981 the first reservoir operational • Currently being expanded—completion expected 2014 • Replacing volume of Mt Tabor/Washington Park

  7. Testing Portland Water • Performs 54,400 analyses on 11,800 water samples each year • Samplers collect water from the watershed reservoirs, in-town reservoirs, the distribution system , groundwater and consumers' taps

  8. Treating Portland Water • Currently not filtered • Meets the filtration avoidance criteria of the 1989 Surface Water Treatment Rule • Waiver from the requirement to filter since 1991 • Bull Run water is very soft: typically ranges from 1/3 to ½ a grain of hardness per gallon • Portland's groundwater hardness is approximately 5 grains per gallon -- considered moderately hard • No fluoride added

  9. Disinfection • 2012: received variance for cyrptosporidium • Portland's water: chloramination • chlorine to disinfect the water • ammonia to ensure that disinfection remains

  10. pH adjustment for corrosion control • January 1997: Portland Water Bureau began corrosion control treatment • raise pH of the water so less likely to leach metals • target pH range is 7.8 to 8.0 • at least a 50 percent reduction in lead at the tap with pH adjustment • “soft” water

  11. How water gets to the sink • To Portland by gravity • Through water mains to all parts of the city -- run beneath sidewalks and streets to individual homes and businesses • Smaller pipe travels to the water meter at each home or business not on a well • water passes through the meter on its way to your home to measure the amount of water your house uses • mains and the water meter owned by the City of Portland • Enters pipes which are the owned by property owner. Those pipes deliver water to your tap.

  12. 3/7 • Demo: testing drinking water • Earth Resources Discussion Thursday: Joe, Abby, Daniel, Baisley • Earth Resources Discussion Friday: Francesca, Eli, Dreyson, Kyle • Friday 3/8 last day for discussions, assignment list grading, log 1

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