ICETHK's summary output file: FIN.DAT
Outputs
ICETHK includes a number of output options.
The ice data from the final ICETHK run are
The most important product is the updated HEC-
listed in ICETHK's summary output file, FIN.DAT
2 input file containing ice thicknesses and rough-
(App. G). The user can assess the stability of the
nesses calculated by the previous ICETHK run.
solution by comparing final ice thickness to the
The ICETHK summary output file FIN.DAT also
thickness found in the previous iteration. Over-
lists important ice parameters, as well as caution-
bank ice thickness, channel ice roughness, veloc-
ary notes on the stability of the ice accumulation.
ity of water flow, and cumulative ice volume are
Ice and hydraulic data from the first and last iter-
listed. The TMODE column lists the mode of
ations are written to the files FIRST.SMP and
thickening for each reach. The THIN message
LAST.SMP. The comma-delimited files QP.DAT
indicates that current velocity is high enough to
and PROFILE.DAT are designed to export data to
erode the underside of the ice accumulation. The
spreadsheets for plotting. QP.DAT contains data
SHOVE and JUXT messages tell that the calculat-
from successive iterations and is used to check
ed ice thickness is the result of shoving or juxta-
solution stability. An ice jam profile can be easily
position, respectively. The notes included in
plotted by importing the file PROFILE.DAT into
FIN.DAT are important because they point out
a spreadsheet. Additional external files used to
some of ICETHK's limitations. They are listed and
store data from one iteration to the next include
explained below:
TEMP.STO, RUF.DAT, and OBI.DAT. The follow-
ing section describes ICETHK's output options in
1. Ice thickness = 0 due to VCH > VEROS (= 5
detail.
ft/s) with no ice. This comment tells that the
average channel velocity (VCH) is greater
Updated HEC-2 input file created by ICETHK
than the maximum non-eroding velocity
The original HEC-2 deck (App. E) contains
(VEROS) and that the ice cover has entirely
only one IC card following the first QT line. The
eroded away.
IC card is the record in the HEC-2 input file that
2. Ice thickening mode is SHOVING and VCH
provides ice thickness and roughness data (U.S.
> VEROS: Ice pack unstable. Thickness
Army 1990). This single IC record signifies a single-
required for stability is greater than that
layer sheet ice cover of constant thickness and
listed. This condition may occur in high dis-
roughness over the entire river. Appendix F shows
charge and/or high channel slope situa-
the first page of a HEC-2 input file, created after
tions. In the actual river, this condition may
five HEC-2/ICETHK iteration cycles. Note that
correspond to an ice-free reach.
two IC lines appear before each X1 card, provid-
3. Water entering floodplain, channel ice thick-
ing ice data for each cross section. On the updated
ness nearing maximum. Channel ice not sta-
deck an NC card has been inserted above each
ble. As the water level increases above the
pair of IC lines for any cross sections where an NC
floodplain elevation, the area of ice in con-
record did not exist in the original HEC-2 deck.
tact with the channel banks decreases or dis-
NC records provide HEC-2 with information on
appears. With the resisting force decreased
channel bed roughness. This channel bed rough-
or eliminated, the ice accumulation is
ness information is used by ICETHK to calculate
increasingly likely to move downstream.
4. Floodplain depth > XTo (1.5) initial ice
overbank ice thickness. Each HEC-2/ICETHK
iteration creates a new HEC-2 input file that
thickness or floe thickness. Ice in floodplain?
serves to transfer the updated ice data to the next
This alerts the user that overbank flow is
HEC-2 run (see Fig. 3). For example, if the origi-
occurring and that ice in the floodplain is
nal file is WINDN.DAT (App. E) and there are five
possible. FIN.DAT includes the summary of
iterations, the files WINDN1, WINDN2, WINDN3,
run conditions and initial values found at
WINDN4, and WINDN5 will be created. To con-
the end of Appendix G.
serve space in memory, it's a good idea to periodi-
cally delete intermediate files that are not being
Summary output files:
used. ICETHK is capable of up to nine iterations
FIRST.SMP, LAST.SMP
at a time. If a stable solution is not reached after
The ICETHK subprogram DATCHK produces
nine iterations, it is unlikely that additional itera-
t h e summary output files FIRST.SMP and
tions will improve convergence.
LAST.SMP during the first and last iterations
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