Great Falls of the Potomac oil by George J Beck 1797

Great Falls is a series of rapids and waterfalls on the

Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augu ...

, upstream from

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

, on the border of Montgomery County,

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

and

Fairfax County Fairfax County, officially the County of Fairfax, is a County (United States), county in the Commonwealth (U.S. state), Commonwealth of Virginia. It is part of Northern Virginia and borders both the city of Alexandria, Virginia, Alexandria and ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

Great Falls Park Great Falls Park is a small National Park Service (NPS) site in Virginia, United States. Situated on along the banks of the Potomac River in northern Fairfax County, the park is a disconnected but integral part of the George Washington Memorial ...

, managed as part of

George Washington Memorial Parkway The George Washington Memorial Parkway, colloquially the G.W. Parkway, is a parkway that runs along the south bank of the Potomac River from Mount Vernon, Virginia, northwest to McLean, Virginia, and is maintained by the National Park Service ( ...

, is on the southern banks in

, and Chesapeake and Ohio Canal National Historical Park parkland is along the northern banks of the river in

. Both are operated by the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propert ...

. The Potomac and the falls themselves are legally entirely within Maryland, with the state and county boundaries following the south bank of the river. Scenic views are offered on both the Maryland side and the Virginia side. The Billy Goat Trail on Bear Island, accessible from Maryland, offers scenic views of the Great Falls, as do vantage points on Olmsted Island (also accessible from Maryland). There are overlook points on the Virginia side. The Great Falls area is popular for outdoor activities such as kayaking,

whitewater rafting Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...

, rock climbing, and

hiking Hiking is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century.AMATO, JOSEPH A. "Mind over Foot: Romantic Walking and Rambling." In ''On Foot: A Histor ...

. Great Falls and Little Falls (about 5 miles downstream) are named in contradistinction to one another.

History

The rocks of the falls date to the late Precambrian and are about 750 million years old. The rocks are a resistant metamorphized

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...

gneisses Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

, metagraywackes, and metaconglomerates. The Falls formed the last time sea level dropped, during the Last Glacial Period about 35,000 years ago, causing the Potomac to downcut its valley. The river cascades over a series of falls, dropping a total of in elevation over a distance of less than . As

sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...

s again, the power of the falls will be reduced due to a shorter vertical drop and likewise downcutting will slow down. Should the ocean level ever exceed the height of the falls again, downcutting would reverse entirely with silt filling in the now-underwater falls. The Potomac narrows significantly as it passes over the falls and through Mather Gorge. Heavy rain or snow in the watershed upstream causes white-water floods which entirely submerge the rocks and even threaten the adjacent park visitor center (built on stilts for this reason). A pillar at the Virginia overlook, well above the river, marks the level reached during the

1936 Northeastern United States Flood The 1936 Northeastern United States flood was a historic flood that occurred across the Northeastern United States, as well as the Mid-Atlantic region and Ohio, in March 1936. Record-setting flooding after a combination of a particularly precipit ...

Gallery

File:ViewfromOlmstedIslandSouthFootBridge.jpg, Southward view of the

from a footbridge on Olmsted Island. July 2021. File:GreatFallsPotomacPanorama.jpg, Great Falls panorama from Virginia File:Potomac Great Falls panorama (from Maryland).jpg, Great Falls panorama from Maryland File:Great falls potomac 20200703 083332 VID.webm, View of Great Falls from the Olmsted Island overlook File:Great Falls of the Potomac River January 2014.webm, Great Falls of the Potomac River, between Virginia and Maryland in the United States. January 1, 2014

Canals

Various attempts to build canals around Great Falls were undertaken. The remains of the

Patowmack Canal The Patowmack Canal, sometimes called the Potomac Canal, is a series of five inoperative canals located in Maryland and Virginia, United States, that was designed to bypass rapids in the Potomac River upstream of the present Washington, D.C., ...

on the Virginia side, were an early attempt to skirt the falls, using 5 locks. That canal was started by

George Washington George Washington (February 22, 1732, 1799) was an American military officer, statesman, and Founding Father who served as the first president of the United States from 1789 to 1797. Appointed by the Continental Congress as commander of ...

. Later the

Chesapeake and Ohio Canal The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the "Grand Old Ditch," operated from 1831 until 1924 along the Potomac River between Washington, D.C. and Cumberland, Maryland. It replaced the Potomac Canal, ...

was built on the Maryland side of the falls and ultimately connected the Potomac tidewater with

Cumberland, Maryland Cumberland is a U.S. city in and the county seat of Allegany County, Maryland. It is the primary city of the Cumberland, MD-WV Metropolitan Statistical Area. At the 2020 census, the city had a population of 19,076. Located on the Potomac River, ...

. The Chesapeake and Ohio also used the Great Falls as a feeder (now abandoned) to supply water for its own use.

Notes

References

External links