Unlocking the Mysteries of Pittsburgh's 4th River

Pittsburgh’s underground aquifer may not resemble its above-ground siblings, but it still does plenty for the city.


photo by dave dicello

 

Our mythical “Fourth River” isn’t a fast-flowing body of water but something much cooler: It’s an aquifer, 50 feet of rock and sand on top of bedrock through which water flows. Formed many thousands of years ago by the coming and going of glaciers, the aquifer continues to fuel life as we know it. It's so important, we wanted to break it down:

Ice, water, rock, sand

  • Formative forces for the aquifer: Glaciers melted, water carved into the earth and deposited rock and sand that formed the rivers and riverbanks of our landscape.
     

80 trillion

  • The number of gallons of groundwater in Pennsylvania
     

6 million

  • Pennsylvanians who get part of their drinking water directly from groundwater
     

798,000 YEARS AGO

  • The time when glacial changes began to carve Pennsylvania’s landscape
     

50 to 54 degrees

  • The temperature of Pittsburgh’s groundwater
     

600

  • The number of gallons per minute a well could draw from Pittsburgh’s aquifer
     

North Side, South Side, Point

  • The areas built on top of the aquifer
     

Crop irrigation

  • The biggest use of groundwater, such as the water found in the aquifer, in the U.S.
     

9 million

  • The number of gallons of water downtown wells drew from the aquifer in 1950, when use was at its peak

 

 

Categories: The 412