Time-Varying Weir Input File

The time varying weir input file contains one line for each weir node (or node pair, for internal barrier boundaries) that will change its elevation during the course of the simulation.

The first line of the file contains the number of time varying weir nodes (or node pairs) that will appear in the file. Each subsequent line contains a comma separated list of variables that describes how the elevation of that weir node (or node pair) should change during the simulation. The exact content of each line depends on the type of elevation change specified for that node (or node pair). The variables on a particular line can appear in any order.

The following variables are required for each line:

X1 – This is the x-coordinate location of the first node as part of this weir
Y1 – This is the y-coordinate location of the first node as part of this weir

If the weir is an internal boundary, a type 24, there are two more required parameters:

X2 – This is the x-coordinate location of the second node as part of this weir
Y2 – This is the y-coordinate location of the second node as part of this weir

ADCIRC searches the mesh to associate the X1, Y1 coordinates (and X2, Y2 if specified) with the locations of weir nodes. If a weir node is not found at those coordinates, the code will terminate.

VARYTYPE – Specifies the trigger or timing of the elevation change for that node:

1. One time elevation change based upon time
2. One time elevation change based upon water surface elevation (WSE)
3. Schedule based elevation change

The value of the VARYTYPE variable dictates the additional variables that are required on that line as described in the following sections.

One Time Elevation Change Based Upon Time (VARYTYPE=1)

The following parameters are all optional except that some combination of them must define both a start time and an end time.

The “Hot” parameter should be set to 1 if the start and end time for the weir elevation change are relative to the simulation hot start time, or set to 0 if they are relative to the simulation cold start time. The Hot parameter is optional and the default value is 0 (times all relative to cold start).

Hot – 1 if time trigger is relative to hot start time, 0 if relative to cold start time
TimeStartDay – number of days before start of weir node elevation change
TimeStartHour – number of hours before start of weir node elevation change
TimeStartMin – number of minutes before start of weir node elevation change
TimeStartSec – number of seconds before start of weir node elevation change
TimeEndDay – number of days before end of weir node elevation change
TimeEndHour – number of hours before end of weir node elevation change
TimeEndMin – number of minutes before end of weir node elevation change
TimeEndSec – number of seconds before end of weir node elevation change

The “start” and “end” parameters are additive; for example, specifying TimeStartDay=3.0 and TimeStartHour=12.0 represents a start time of 3.5 days.

The following additional parameter is required for this type of elevation change:

ZF – This is the final weir elevation in meters relative to the mesh datum (positive up). During elevation change, the weir height elevations will be linearly interpolated in time from the elevation found in the fort.14 file to this elevation.

The weir will not decrease below the topographic elevation specified at the node. In the case of an internal weir with two nodes, the weir height will not decrease below the topographic elevation of either node.

One Time Elevation Change Based Upon Water Surface Elevation (VARYTYPE=2)

The sudden failure of a levee due to high stage or surge could be simulated using this type of weir height variation. The ZF parameter is required for VARYTYPE=2, and the following additional parameters are also required:

ETA_MAX – Water surface elevation at this weir node which triggers the simulated weir failure at this weir node.

Some combination of the following parameters must be used specify the duration of weir failure:

FailureDurationDay – Time in days for duration of failure
FailureDurationHour – Time in hours for duration of failure
FailureDurationMin – Time in minute for duration of failure
FailureDurationSec – Time in seconds for duration of failure

The failure duration parameters are all additive; for example, setting FailureDurationHour to 2.0 and FailureDurationMin to 30.0 results in a failure duration of 2.5 hours.

Schedule Based Elevation Change (VARYTYPE=3)

The schedule based elevation change requires an additional ScheduleFile parameter that provides the name of the Schedule File that describes when and how much the weir nodes should change their height. There is no default file name; if this parameter is not specified, ADCIRC will stop with an error message.

The following parameters are optional for each weir node (or node pair) for VARYTYPE=3 in the Time Varying Weirs Input File:

Loop – Set to 1 if the schedule should repeat from the beginning after it has completed. The default value is 0. Setting Loop to -1 specifies that the schedule should repeat indefinitely.

NLoops – The number of times the schedule should repeat.

TimeStartDay – number of days since hotstart when weir node elevation starts to change
TimeStartHour – number of days since hotstart when weir node elevation starts to change
TimeStartMin – number of days since hotstart when weir node elevation starts to change
TimeStartSec – number of days since hotstart when weir node elevation starts to change

Notes for VARYTYPE=3: The “TimeStartDay/Hour/etc parameters are relative to either hotstart or coldstart depending on if the line includes the “HOT” parameter and provide a buffer from the start of the current simulation. Using the HOT parameter would offset the schedule.

Important Consideration for use of this file:

A hot start simulation will not have any knowledge of the change in weir elevations that occurred in the previous simulation and will always use the fort.14 elevation unless specified otherwise in a new time varying weir input file tailored to the current simulation. The time varying weir input file should not assume anything happens prior to the first ADCIRC time step and weir elevation changes prescribed before the start of the current simulation, even during hot start, will not be considered