Update the code to count for groundwater (SSM v.0.3.2)

A description of the changes is in issue 233

[x] Add a reference to related issues.
[x] @mentions of the person or team responsible for reviewing proposed changes.
[x] This pull request has a descriptive title.
[x] Code is written according to the guidelines.
[x] The checks by MISS_HIT style checker and linter, below the pull request, are successful (green).
[x] Documentation is available.
[x] Add changes to the changelog file under section Unreleased.
[x] Model runs successfully.
[x] Ask a meinatainer to re-generate exe file if matlab codes are changed. About how to create an exe file, see exe readme.

EcoExtreML / STEMMUS_SCOPE