A River Runs Through It

Moxie and Misto inspect the system.

The Washington, D.C. area gets about 39 inches of rain a year, and though the Potomac River's water flow varies with the season, it average seven billion gallons a day.

About 400 million gallons a day are removed to provide water for over 5 million people in the D.C. metro area, and about 370 million gallons a day are returned to the river, after treatment, at Blue Plains water treatment center down river, across from Alexandria.

Most of the water used in D.C. is trapped at the Washington Aqueduct Dam, just above Great Falls, which was built by the Army Corps of Engineers' Montgomery Meigs between 1852 and 1860, and designed so that gravity would take the water downhill 10 miles under MacArthur Boulevard and over the Cabin John Bridge (also designed by Meigs) to the Dalecarlia Reservoir. Meigs built both the Dalecarlia and the Georgetown Reservoir, which is, more or less, across the river from my house, as settlement ponds to remove sediment from the water.

Meigs was also the hand that designed Arlington National Cemetery on Robert E. Lee's family estate at Arlington House, about a mile below my house.  The location was chosen to humiliate Lee for siding with the South, and to make sure the land itself never reverted back to the Lee family.

While building the Washington Aqueduct Dam, Meigs also supervised the building of the wings and dome of the United States Capitol and later he built the Pension Building, which is now the National Building Museum.

Ducks bob on the surface at the edge of the dam.