MAJOR FLOODS ON THE POTOMAC BASIN
I have relied heavily upon the work of Harlan Unrau in gathering the data for the operating
period of the canal. I am also indebted to the Advanced Hydrologic Prediction Service of the
National Weather Service for data which can be found at their website.
If there is a waterway, there will be floods. Great engineers have, with mixed results, mitigated
some of the consequences of flood waters. Nevertheless, the largest of floods cannot be
controlled and inevitably leave devastation in their wake. For communities in the path of such a
flood, it becomes a pivotal moment. For a generation or two, “The Flood” is the fulcrum around
which time is measured.
The C&O Canal, situated as it was in the flood plain of the Potomac River, was destined to be
inundated on numerous occasions. Often this resulted in the Canal Company making large
outlays of cash to make repairs for damages to the structures of the canal, its dams, and company
buildings along the waterway. Eventually a flood drove the canal into receivership in 1889.
Another flood in 1924 closed the canal for good.
The chart below lists the major floods on the Potomac River since 1810. The selection of which
floods are considered to be “major” until 1889 is admittedly subjective. The loose criteria are
that the flood disrupted the operation of the canal for an extended period of weeks. After 1889
river crests began to be recorded more frequently.
It must be remembered that a particular flood will strike a river basin much harder at some places
than others. For example, the great Shenandoah flood of 1870 did not harm the canal a great deal
at points west of Harpers Ferry. Only a few of the floods affected the entire line of the canal. In
the end, though, that didn’t matter much. One significant break upon any portion brought the
navigation to a halt until repairs could be made. Thus, all floods, local or regional, had the
potential to create problems for the Canal Company.
Month
June
April
September
Year
1810
1836
1843
1843
October
April
1847
1852
February,
April, May
September
August
1857
1870
1873
Comments
Highest known flood prior to the building of the canal
Highest freshet since 1810.
Highest freshet since commencement of canal.
Higher than the April freshet. Forced canal company to initiate measures to
protect the canal from flooding.
Surpassed all previous high water marks.
Worst flood to date in Potomac valley. Public began to lose confidence in the
canal as a reliable means of transportation.
Three freshets -- each succeeding freshet took away many of the repairs from
the previous one.
Shenandoah Flood of 1870.
Most destruction on canal since 1852. Tributaries were so full that many culverts
were washed out.
September
April-May
1877
1886
May-June
1889
March
March
1924
1936
April
1937
October
1942
August
June
November
January
1955
1972
1985
1996
September
1996
Worst flood to date, cresting two feet about the 1852 flood.
Three freshets in a matter of six weeks -- became clear that canal company was
teetering on edge of bankruptcy.
Another "worst flood to date." Over 50 lives lost. Crests anywhere from 3 to 7.5
above 1877 levels. Canal killer. B&O takes over the waterway.
First major flood in 35 years. Put the B&O out of the canal business.
Highest flood waters on record. The now-deserted canal was left in dilapidated
condition.
At Williamsport, the second highest crest on record. Most of the remainder of
basin hard hit as well.
Came close to exceeding 1936 flood from Point of Rocks east. Actually did
exceed it in Georgetown.
Widespread rainfall from Hurricanes Connie and Diane within a two week period.
Hurricane Agnes inundates Potomac basin.
Second worst flood on record in Hancock and Paw Paw.
Blizzard, rain and rapid snowmelt caused a flood which damaged three-quarters
of the canal.
Tropical Storm Fran was the second of 1996's one-two punch.
A quick glance at the chart reveals that over the past two centuries a major flood has occurred
about once every nine years. These are the largest and most significant events. Countless smaller
inundations have occurred, many which have left their marks upon the C&O Canal. The Potomac
basin appears to be due for another large flood.
In November 1847, W.S. Elgin, maintenance superintendent, wrote to James M. Coale, president
of the C&O Canal Company:
“We are again in the midst of Trouble, Everything we have been doing the Last 6 weeks have
been swept a way; and we may as well & Better have burn [sic], the money we have expended
on this portions of the Canal; The whole canal is now under water; This is discouraging; I am
discouraged after night & day for the Last 6 weeks to restore the navigation; and Just as it was
Ready for the Trade, to entirely be swept away.”
The floods had a dispiriting effect upon all associated with the canal. The 1852 flood, as noted in
the chart, began to create the perception that the canal would never be a reliable source of
transportation.
Today, flooding remains the greatest threat to the canal. One major flood can necessitate millions
in dollars in repairs. Those dollars are hard to come by. The 1996 floods closed Big Slackwater
until funds were available. Big Slackwater did not open until September 2012 – a full 16 years
after closure!