Importing HEC-MetVue Projects

It is best practice to create an HEC-MetVue project outside the CWMS watershed before importing the HEC-MetVue project using the CAVI.  The HEC-MetVue project directory should also include a “maps” directory with polygon shapefiles meant for basin average computations.  The polygon shapefiles should also have a “Name” filed in their attribute tables with informative location names for each polygon.

HEC-MetVue Project Setup in the CAVI

The minimum requirement to create a CAVI-MetVue alternative is to ensure that an HEC-MetVue Session and corresponding Map Windows are created in the HEC-MetVue project.  For the base copy of the HEC-MetVue Project, as the required definition of the necessary input data for forecast simulations are defined in the CAVI-MetVue Alternative Editor, it is optional to link data directly in the input Map Window(s) of the HEC-MetVue Project.  However, adding a small amount of sample data in the base copy of the HEC-MetVue project is highly encouraged to help with customizing any desired gridset spatial extents clipping, contour layer display settings (especially scales and corresponding color palettes), and any desired temporal transformation sets.

Memory Management and Settings

Gridded datasets with large spatial extents and/or long temporal coverage can consume a large amount of memory.  When possible, using clipping extents (e.g. clipping RFC input data sets to watershed extents) in the HEC-MetVue data reader can alleviate memory usage and computational processing time.  Otherwise, if a minimum of 16GB of installed PC memory is available, the HEC-MetVue maximum allowable memory usage setting should be increased (from Xmx3200m to Xmx8000m) by editing the “CWMS-v#.#.#\HEC-MetVue\etc\metvue.conf” file then restarting the CAVI.

HEC-MetVue Project and CAVI Model Alternative Updates

When there is a need to make updates or modifications to the watershed’s HEC-MetVue project and/or CAVI-MetVue Alternative, it is best to make the changes in the base copy (i.e. from the Setup Module), update the CAVI Model Linking if necessary, and then rely on Replace-from-Base to update Forecast copies of the HEC-MetVue project and/or CAVI-MetVue Alternative.

Data Types and Durations

When setting up the CAVI-MetVue alternative, it important to ensure that appropriate durations and parameter types are specified for Input and Output datasets.  In particular, SWE and Temperature datasets are typically instantaneous data and their CAVI-MetVue Alternative’s input duration should be set to “0” and their output parameter type should be set to “INST-VAL”.   Precipitation dataset are typically period cumulative with input duration of x-hours and output parameter type of “PER-CUM”.

HEC-MetVue Temporal Transformation Tool

The CAVI-MetVue Model Alternative will apply uniformly weighted gridded data transformation by default.  But, using the HEC-MetVue Temporal Transformation Tool to set a peaked weighting pattern can be especially useful to maximize precipitation volume within a desired portion of the input interval.

CAVI-MetVue Input Data Time Window Controls (Hamon ET Support)

When planning to link HEC-MetVue to an HMS model that uses the Hamon Evapotranspiration (ET) method, supplying HMS with the required extra one days’ worth of temperature data prior to the Start of Lookback and after the End of the Simulation can be achieved by:

    • Ensuring that the Extract list has a minimum of “-1 Day” offset from the Lookback Time for the observed Temperature extract group.
      • Applying a corresponding SoS (Start of Simulation) “-1 Day” Offset to the Lookback Temperature Map Window in the CAVI-MetVue alternative’s Input Settings.
    • Ensuring the Extract list has a minimum of “+1 Day” offset from the Forecast Simulation End Time for the Forecast Temperature extract group.
      • Applying a corresponding EoF (End of Forecast) “+1 Days” Offset to the Forecast Temperature Map Window in the CAVI-MetVue alternative’s Input Settings.

CAVI-MetVue Input Data Time Window Controls (SWE and QPF Handling)

When the CAVI forecast simulation time window times do not coincide with the time stamps of input datasets (e.g. forecast start and end times are at 0700 while input SWE registers at 0600 every day and QPF registers at 0000/0600/1200/1800), input data beyond the forecast simulation time window will be required.  Setting reasonably buffered time offsets in the relevant Extract List Groups and the CAVI-MetVue Alterative’s input datasets can ensure that sufficient data is available before and after the Forecast Simulation’s start and end times, respectively so that the HEC-MetVue input data preprocessing and model alternative computation can proceed successfully.

Multiple CAVI Forecast Runs and CAVI Map Window Displays

When working with multiple CAVI forecast runs, only one forecast run can be displayed in a CAVI Forecast Simulation Map Window.  To view the results of an HEC-MetVue alternative that belongs to a CAVI Forecast Run that is not the current display of the CAVI Simulation’s Map Window, right-clicking on the desired CAVI Forecast Run and selecting “Display in Map” will provide two options:

    • Replace the “existing” Map Window’s display, or
    • Display the selected CAVI Forecast Run’s models and results in a “new” Map Window.