FLOOD03407

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Stormwater Management in the United States - A Study of Intsitutionl Problems, Solutions and Impacts
• Date: 9/1/1980
• Prepared By: Office of Water Research and Technology
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Mountains, between Estes Park and Loveland. The runoff from the 10-inch rains in
the area that night produced 40,000 cubic feet per second flows in the Big Thompson
canyon, whereas the River's normal flow is only 82 cfs. The death toll is thought
to have been 100 or more. Hundreds more were injured and scores were hospitalized.
Many others were reported missing and it was difficult to tell whether they had
escaped or had been buried by debris. The major reason for the heavy loss of life
was that thousands of people were in the Canyon that Saturday in August, either at
~ampsites, motels or cabins located in the floodplain--many on the very edge of the
channel. Besides the total destruction of several sections of U.S. Highway No. 34,
numerous man-made objects in the path of the floodwall were demolished and washed
downstream. This included automobiles, mobile homes, camping vehicles and equip-
ment, motorcycles, cabins, motels, stores and recreation facilities. These objects,
intermingled with hundreds of tons of forest debris and mud, quickly accumulated as
huge debris piles and barriers downstream, hampering rescue efforts. Army heli-
coptors were used to rescue thousands following the rainstorm.

Hurri~ane Agnes. The Eastern States suffered serious damages in June 1972
from Hurricane Agnes. It caused about $165.7 million damages in Virginia alone.
Damages from flooding, erosion and sedimentation were large in Fairfax County. The
dam of the 115-acre Lake Barcroft was breached by flood waters. Repairs were made
during a two-year, $2 million construction program financed by property owners sur-
rounding the dam, without any governmental funding. Agnes also gouged a path of
destruction through urban areas of Pennsylvania, particularly in Harrisburg, Wilkes-
Barre and Scranton. Urban places in Maryland and New York were hit hard too. Lives
were lost, and property damages and other economic losses were massive and difficult
to quantify.

Lorado, West Virginia. On February 26, 1972, following 20 inches of snow
and three inches of rain, 118 residents of small towns in Buffalo Creek Hollow were
killed when a dam collapsed. A 20-foot wall of water smashed through this Appala-
cian valley when coal slag, serving as the dam, could not sustain the pressure of
the floodwaters. Apparently, there was no warning of impending danger. Some of
the victims were drowned, while other were buried by landslides. The town of
Lorado was completely destroyed and others were hard hit. Except for helicopter
contact, communications with the survivors were wiped out. Water had reached the
tops of the utility poles. The road alongside Buffalo Creek was severely damaged
and many bridges were completely washed away. Efforts to reach the hardest-hit
area with bulldozers and other heavy equipment got rescue crews no closer than six
miles. Rain and fog also interfered with rescue operation. Houses, stores, auto-
mobiles and other property located along the Creek were washed away along with the
victims. The disaster was sudden and devestating. There was no opportunity for
escape or precautionary measures.

Kansas City, Missouri(5). Twenty-five people were killed on Monday night,
September 12, 1977 when 14 inches of rain fell in a concentrated area in Kansas City,
Missouri. The ground surfaces shed the rain freely because it had been saturated
the previous day by a 4-inch rainfall. The large amount of impervious surfaces in
the area combined to produce a peak flow estimated at 35,000 cubic feet per second
in Brush Creek which drains the impacted area. The stream's previous recorded peak
flood flow had been only 4,300 cfs, about 12 percent of this latest event. Because
the flooding took place in an area including the Country Club Plaza-~an exclusive
shopping center considered the oldest in the United States--property damages were
large. Estimates of damage were placed at $6 million. Flood waters filled base-
ments and portions of first floors of most commercial buildings in the Plaza border-
ing the creek. Hundreds of homes along tributary streams were flooded. Overland
flows in some areas reached depths of six feet.

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