RIVER ICE INFLUENCES ON FORT PECK REACH, MISSOURI RIVER
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Table 1. Ice impact processes investigated.
Ice influence
Documenting measurements
Sites of special interest
Elevated freeze-
Border ice collapse process:
Pipal, RM 1716,
up and breakup
Size of border ice pieces
Vournas, RM 1632
Failure process
Tveit-Johnson, RM 1624
Disturbance of bank soil
Mattelin, RM 1646
Flow distribution
Bathymetry:
Culbertson, RM 1620
in reaches with
Open water before winter (early
multiple
November)
subchannels
Ice-covered water in early and
mid-winter (January, February)
Open water in early spring (April)
Ice cover:
Thickness distribution
Flow distribution:
For open water
For ice cover
Tveit-Johnson, RM 1624
Bathymetry:
Local scour of
Vournas, RM 1632
Open water before winter (early
channel bed and
Pipal, RM 1716
November)
bank toe
Ice-covered water in early and
mid-winter (January, February)
Open water in early spring (April)
Flow distribution:
For open water
For ice cover
Date of ice run
Ice gouging and
All sites
Photo series of ice run
abrasion during
Flow record
an ice run
Ice thickness
Date
Ice jam
Vournas, RM 1632
Bathymetry of jam location
Photos of ice movement
Flow record
Flow stages at site
Culbertson sites. A jam occurs on occasional years at the Vournas Farm. Three of
the sites--the Pipal, Mattelin, and Tveit-Johnson sites--appear most prone to the
adverse effects of elevated freeze-up, thalweg shifting, and freezethaw weak-
ening of bank soil. Table 2, taken from Simon et al. (1999), lists the soil types for
the banks at the sites.
Survey schedule
Six site visits were conducted in the course of the survey. Four bathymetric
surveys were conducted over approximately a four-month period: October 1998
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