charges could not be thrown far enough out onto
about 6:30 p.m. on 18 March 1969, and within two
the ice. Eleven rockets were fired on the 26th be-
hours, it sent water spilling over the banks to the
fore a determination was made that a bar forma-
north and south. A decision to blast the ice jam
tion precluded movement in the desired direc-
was made by city officials on 21 March, according
tion. A twelfth rocket was fired in a different
to the 21 March Columbus Telegram, but the 22
location, but it failed to detonate and had to be
March Columbus Telegram stated that the Platte
destroyed by means of a hand-placed charge. On
County Board of Supervisors decided late 20
the 27th, nine more rockets were fired, and a small
March to blast. The ice jam extended 0.5 mile up-
area was cleared of ice. However, two of the rock-
stream and downstream from the Highway 81
ets failed to explode, and the testing was sus-
bridge. Blasting operations began at 1:00 p.m. and
pended. It was also noted that the explosion of
lasted until about 6:45 p.m. on 21 March. A total
each rocket threw steel fragments from the casing
of 1100 lb of explosives were used, but the length
and motor as much as 600 yd, which posed a
of channel blasted was not reported. The Colum-
safety hazard for anyone in the area.
bus Telegram reported that 1230 sticks of dyna-
An attempt was made to remove an ice jam at
mite were placed in 1- to 5-gallon cans weighted
Black Bird Bend on 1 and 2 March using hand-
with sand or bricks, which were then dropped in
placed charges of Composition C-3. The jam was
holes in the ice jam from a helicopter. The heli-
8001000 ft wide and 1 mile long and was com-
copter pilot and explosives expert reported
posed of ice 1034 in. thick and piled 56 ft above
progress in the blasting effort after each drop.
the water surface. The jam was caused by a bar
Fifteen minutes after the blasting operation was
formation over which the ice could not pass. Most
suspended, the water level began to drop. Water
of the water was bypassing the toe of the jam, so
levels had dropped 34 ft by the next morning.
an effort was made to loosen the ice along one
Platte and Elkhorn River west of Gretna and Platte
shore so that a rise in stage would carry the ice
River near Yutan and near Ames, February 1971. Ice-
downstream. Eight-hundred and fifty pounds of
jam flooding in late February caused breaks in
explosives were used over 1500 ft to loosen the
several private levees between Ashland and Fre-
ice. Overnight a rise of approximately 2 ft cleared
mont. A situation report describing the flooding
the lower 300 ft of the ice that had been blasted,
mentions local officials and private interests plac-
but additional ice from upstream increased the
ing dynamite by helicopter west of Gretna and
length of the jam to 1.5 miles. Approximately 1400
near Yutan in efforts to break up ice jams on the
lb of explosives were used to clear a channel ap-
Platte and Elkhorn Rivers, but little else is known
proximately 0.5 mile long, but the ice again
of the blasting efforts or success. A long-time
jammed at the lower end of the jam. The experi-
resident near Fremont also recalled blasting from
ment was then stopped as there was insufficient
a helicopter near Ames for the same flood event.
flow to carry the ice downstream.
Platte River, 15 March 1979. Blasting operations
Platte River near Ashland, 911 February 1966.
were conducted by the State of Nebraska down-
Runoff from a rainfall event in early February
stream of the Highway 92 bridge for two days.
caused a breakup of the ice cover on the lower
The blasting was reported to be relatively unsuc-
Platte and its tributaries. An ice jam formed be-
cessful as little ice movement was observed in the
low the confluence of the Elkhorn and Platte Riv-
blast areas.
ers, and private agricultural levees on both banks
Confluence of Elkhorn and Platte Rivers, 818
were overtopped. Local interests spent about 00
March 1993. An ice jam formed near Thomas Lakes
to remove the ice jam by blasting. The effort was
in early February when the Elkhorn River ice broke
deemed unsuccessful in a Corps post-flood re-
up and was stopped by an intact ice cover on the
port. The floodwaters in the overbank froze in
Platte. Discharges soon dropped and temperatures
place after temperatures dropped. Floodwaters
dropped, and the jam stayed in place until break-
caused damage to the Interstate 80 bridge abut-
up in early March. A large increase in discharge
ments, in excess of ,000. The levees were re-
and a large volume of ice from upstream com-
paired at a cost of 2,250 after it was deter-
bined to overtop private levees and create numer-
mined that the river would not return to its
ous breaches on both sides of the river near and
channel even after removal of the ice jam. Little
just below the mouth of the Elkhorn on 8 March
else is known of the blasting effort.
1993. The breaches on the left bank allowed flow
Columbus, Loup River, 1821 March 1969. An ice
to destroy two bridges on Highway 6 and close
jam formed at Columbus on the Loup River at
Interstate 80 for parts of three days. The Sarpy
48
Previous Page
