Updated 3/1/12

In Podcast #55 the Trekkers take you to Great Falls on the Potomac River near Washington DC.  But first we paid a visit to the fourth grade students at Guilford Elementary.  Then we headed to the amazing Great Falls Park.  Find out why it’s called Great Falls, watch the River Rescue crew practice their life saving techniques, see how high the water was here during some recent floods, discover why the Powhatan Indians used to meet here, take a look at the beautiful fall foliage, and learn how ships traveled up the river using locks. Come on, let’s go trekkin’!

The Potomac River floods are both good and bad.  The damage they cause is bad of course.  But the floods spread sediment and seeds along the tops of the cliffs to create unique ecosystems.  Without the floods, the plants that grow in the cliff tops would die.  How does the water get so high here?  The Potomac watershed upstream from the falls covers 15,000 square miles (source), so all that water has to flow down the narrow passageway at Great Falls.  At its narrowest part, Mather Gorge, the river has gone from almost 1000 feet wide to just 60 feet wide! (Source)  Also, Great Falls has the steepest fall line of all the rivers along the east coast.  The falls drop a total of 76 feet in less than one mile!  So there’s a lot of water moving very fast through a really narrow passageway... perfect conditions to make a flood!  No wonder the visitor’s center is built on stilts!  (Source)

SOL Correlation:

2.3 The student will identify and compare changes in community life over time in terms of buildings, jobs, transportation, and population.

VS.2c The student will demonstrate knowledge of the physical geography and native peoples, past and present, of Virginia by locating and identifying water features important to the early history of Virginia (Atlantic Ocean, Chesapeake Bay, James River, York River, Potomac River, Rappahannock River, Lake Drummond, and the Dismal Swamp).

VS.6c The student will demonstrate knowledge of the role of Virginia in the establishment of the new American nation by explaining the influence of geography on the migration of Virginians into western territories.

VS.10c The student will demonstrate knowledge of government, geography, and economics by explaining how advances in transportation, communications, and technology have contributed to Virginia’s prosperity and role in the global economy.

2.6a The student will investigate and understand basic types, changes, and patterns of weather. Key concepts include identification of common storms and other weather phenomena;

2.7b The student will investigate and understand that weather and seasonal changes affect plants, animals, and their surroundings. Key concepts include weathering and erosion of land surfaces.

3.10c  The student will investigate and understand that natural events and human influences can affect the survival of species. Key concepts include the effects of fire, flood, disease, and erosion on organisms; and

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Coastal Plain

Same view during a flood Source - Flickr

View of the Falls Source - Wikipedia

The high water mark post during a flood (left) & at normal times Source

The overlook sign during regular times (top) & during a flood Source - NPS

These photos compare different parts of the park at normal times and flood times.  You can see the post with the high water marks that Frank was standing near.  We found it hard to believe that water could get that high until we saw these photos!