Scenario

You have been given a copy of a CWMS watershed which contains a ResSim watershed you want to use as the basis for a study model. You want to extract that ResSim watershed from the larger CWMS watershed but there does not exist an "export model" option in CWMS.

Background

A CWMS watershed and a ResSim watershed share the same basic structure. There are also few files and folders that are used in common. But, a CWMS watershed includes folders which contain the model files for other models in the watershed. For example, there are likely to be hms and ras folders that contain HMS and RAS model files. These folders and several others can contain a large quantity of files that require significant storage, especially if they include GIS or terrain files.

The common files and folders

  • stream.align - The most common file in the watershed is the stream.align file. It is located in the root folder of the watershed.
  • /maps – the maps folder and the maps contained therein are common to both ResSim and the CWMS CAVI.
  • /shared – the shared folder was intended to be the location where dss files were stored that contained common data for all the models in the watershed to use. Although ResSim defaults to this folder when looking for DSS files to use as input for an alternative, CWMS takes more advantage of this folder than ResSim does. The CAVI stores the files that define the times series icon, data status summary lists, program orders, and extract groups in the shared folder.
  • /study – this folder contains the files that reflect the information that describe the watershed configurations. These files are used primarily by ResSim and the HEC-WAT, but are still known and read by the CAVI.

The Process

To extract a ResSim watershed from a CWMS watershed simply involves deleting folders and files from the watershed that are unneeded by ResSim. You can do as much or as little of the following steps as you like since ResSim will recognize the ResSim watershed within the CWMS watershed whether or not you delete the CWMS specific stuff or not.

1. Make a Backup

As usual, we recommend that you make a backup of the whole watershed. That way, if you happen to delete something you shouldn't have, you'll be able to get it back, or at worst, start over. For instructions on backing up your watershed, please see: https://www.hec.usace.army.mil/confluence/display/CTG/How+To...+BackUp+Your+Watershed.

2. Delete the other model folders

The typical model folders that you can expect to find in a CWMS watershed include (in alphabetic order):
/fia
/hms
/metvue
/mfp
/ras
These folders and their contents are ignored by ResSim and can usually be deleted without worry. BUT, before you do, check your ResSim alternatives to see if they reference files that are stored in any of these model folders. The most likely folder that ResSim might be reaching into is the /hms folder. If so, we recommend that you move the needed files into the /shared folder and update the references to the new location.
NOTE – the /rss folder is the folder that contains most of the ResSim model files so DO NOT delete that folder.

3. Delete the CAVI specific folders

There are folders in the watershed that are created by the CWMS CAVI for one reason or another and are ignored by ResSim. These folders are:
/cavi
/dashboard
/layouts
These folders can be deleted without concern.
There are a two more folders that may be deleted but you should know what's in them before you delete them:
/scripting
/scripts
These folders contain scripts for the CWMS watershed.
The /scripting folder is a model folder (like ras and hms) for the Scripting plugin in CWMS. The Scripting plugin allows you to insert a script into the program sequence and the /scripting folder holds the model files that define a scripting alternative.
The /scripts folder is intended to hold utility scripts written by users to perform a variety of functions including data retrieval and custom plotting and reporting. Some of the scripts contained in this folder may be used within the ResSim watershed (such as OSI scripts) while others, with some modification, may be useful in the ResSim study watershed you are preparing. Review each script and its purpose carefully before deleting. If you decide that any of the scripts in the /scripts folder should be retained, then you should NOT delete the /scripts folder.

4. DO NOT Delete the Remaining folders.

The following folders contain files that are part of the definition of your ResSim watershed:
/maps
/reports
/rss
/shared
/study
/supplemental
Do not delete these folders.

5. File Cleanup

There are a few files that may still remain in the watershed that belong to the CWMS watershed and are not used by the ResSim watershed.

In the root folder of the watershed, the files you can delete without much question include:

*.wtrshd
*.log
*.projection
*.bak (although you might keep the stream.align.back file).

In the /shared folder, you can delete:

/extract
*.bak
*.dataStatus
*.validationEditor
caviProgramOrder.*

The /shared folder may also contain a variety of DSS files. Don't be too quick to delete these as they may be needed by the existing ResSim alternatives or may be useful as you develop new alternatives for your study.

6. Final Cleanup

At this point, you have thinned down the CWMS watershed into a ResSim only watershed. However, there may be additional cleanup you can perform. A document describing the steps for cleaning up a ResSim watershed can be found on the HEC-ResSim website at: https://www.hec.usace.army.mil/software/hec-ressim/documentation/Cleaning_up_an_HEC-ResSim_Watershed.pdf