Hurricane Agnes
was the first hurricane of the season. When Agnes
slammed into the Gulf Coast on June 19, 1972, danger to Pittsburgh had seemed remote, but
the following day, while the storm center was still over Florida, its currents forced
moist Atlantic Ocean air inland, dropping widespread rains on Pennsylvania. A cool air
front was approaching the Pittsburgh District from the west.
The cold front stalled on June 21 along the Ohio and Pennsylvania
border and Agnes moved into North Carolina, its counterclockwise circulation sending
increasing amounts of moisture inland. There was intense rain over the upper Allegheny and
Clarion River basins; Pittsburgh
Agnes arrived over New Jersey on June 22, 1972. It had lost its
hurricane winds and become a tropical storm, but its rains hammered New Jersey, Delaware,
Pennsylvania and New York all that day. Storms such as Agnes commonly moved up the coast
and passed out to sea off Cape Hatteras, but Agnes was uncommon. It moved west and inland
on Thursday night, and when Pittsburgh District personnel donned their raingear and
splashed to work on Friday morning, June 23, Agnes was centered directly over the upper
Allegheny basin and its rains were lashing the entire district. In three days as much as
11 inches of rain fell on parts of the district, averaging from 5 to 9 inches in a 50-mile
band along the western slope of the mountains from a point south of Pittsburgh to New York
state. Flood waters moving down swollen tributary streams on the way toward Pittsburgh and
Wheeling would bring the region the greatest flood in its history.
While the wipers slapped monotonously back and forth across the
windshields, the staff dispatched from the Pittsburgh District office to measure
precipitation and stream flow eased by downed power lines and around road washouts into
the flood-stricken towns northeast of Pittsburgh. In Eldred, McKean County,
water was 3 feet deep over roads into town. Water was rising 2 inches an
hour, with no end in sight. The next day water was 7 feet deep in the
main street.
At Punxsutawney, Pa., where the Pittsburgh
District built a local flood protection project, better than 6 inches of
rain had fallen, but the project had held damages there to a minimum.
The same was true at Brookville, Pa., where there was another Corps
local flood protection project; rainfall had exceeded 7 inches in that
town.
In Salamanca, New York, on the Allegheny River,
where the district had built dikes and walls to protect against floods
of record. The river at Salamanca was 7.5 feet higher than ever before
known. It had overtopped the dike by 2 feet and left the town in
shambles. At Olean and Portville, also on the Allegheny, the river
was within a foot of overtopping dikes.
Reports coming into the district office from
the south also looked bad. Uniontown, Connellsville and West Newton had
serious damage. Fayette City, Sutersville, Masontown, Brownsville,
McKeesport and other communities were partially under water.
By the end of the day on June 23, the
Pittsburgh District had 15 engineers and technicians in the flooded
areas helping fight the flood, collecting hydrologic data and estimating
the amount of damages. Runoff into the reservoirs was continuing at
alarming rates. East Branch Lake was soon completely full, with water
discharging through the spillway.
Hannibal Dam on the Ohio River and
Woodcock Creek Dam near Meadville were under construction. Orders went
out to move construction equipment to safety and flood the cofferdams at
Hannibal before the flood waters arrived.
At Woodcock Creek Lake flow into the reservoir
was greater than the outlet conduit pipes could pass and water was
rising fast behind the half-finished dam. It appeared the flood would go
over the top and damage the dam. The engineers at the district office
debated on whether to let the dam be overtopped and repair the damages
later, cut a diversion ditch or bulldoze a temporary dike into place
atop the dam.
After measuring the flow of the streams
entering into the reservoir, it was determined that the reservoir would
rise about 2 feet over the unfinished dam. District engineers decided to
put a 4-foot temporary earth dike atop the dam.
The contractor's bulldozers were put to work at
noon and by 2:45 p.m. they had pushed a temporary dike about 4 feet high
and 250 feet long into place. The reservoir level climbed up the dam,
onto the dike and crested two feet up the side of the dike at about 5:45
p.m. Fast work had prevented damage to the dam, as well as reduced flood
damages at Meadville.
Dams in the district were storing immense water
volumes. East Branch was more than full. Water was within 3 feet of the
top of Kinzua Dam. Tygart Reservoir was 85% full and other dams in the
district had stored water to 90% of their capacity. The deluge falling
over uncontrolled streams still pushed the rivers at Pittsburgh and
Wheeling to flood stage and beyond.
People in the Golden Triangle of downtown
Pittsburgh watched apprehensively as the flood crept up the Point and
into the Fort Pitt Museum. The mayor of Pittsburgh asked all businesses
to get their employees out of the downtown area. Steel flood doors over
entrances to underground garages were bolted shut; low level vents were
closed; sandbags were trucked in and stacked; and elevators were shut
down. Switchboards, computer and other equipment were moved to higher
floors.
The Agnes flood crested on June 24 at 35.85
feet in Pittsburgh -- 11 feet above flood stage. A headline in the June
25 Pittsburgh Press read "The Engineers Were
Right."
The flood wave moved on down the Ohio, heavily
damaging McKees Rocks, Coraopolis, Welllsburg, Wheeling and unprotected
towns all along the upper Ohio river.
Then-President Richard Nixon on June 23
declared Florida, Virginia, Maryland, Pennsylvania and New York major
disaster areas, qualifying them for federal assistance. After reports
came in from the Pittsburgh District parts of West Virginia and Ohio
were added to the President's list of disaster areas.
By Sunday, July 2, the rivers had returned to
their banks, the sun had begun to dry things out, reservoirs were
returning to normal levels ready for the next flood and the Pittsburgh
District was helping people dig out from under the mud and debris.
Agnes was no lady. It killed 122 people and
caused catastrophic damages, especially in eastern and central
Pennsylvania, where even Governor Milton Shapp had to evacuate his
Harrisburg mansion. The Agnes flood would have crested at Pittsburgh two
feet above the 46.0 foot record state set on the day after St. Patrick's
Day in 1936 had it not been for the upstream reservoirs. They clipped
about 12 feet off the top of the flood, holding it 10 feet below the
record set in 1936. More gratifying to the Corps was the fact that not a
single person died in the district as a result of the greatest flood of
record.
District reservoirs during the Agnes Flood
prevented $849,219,800 in damages, nearly four times what it had cost to
build the projects, and adding local protection projects, the flood
damages prevented more than a billion dollars of damages. Kinzua
Dam on the Allegheny, built at a cost of $108 million, saved people
living downstream of the dam a tidy $247 million.
