Test two-station methods

> CDI Proposal Tier 1: Add software unit and integration tests, to be run automatically each time the code is changed, to confirm that the new two-station capabilities are implemented as intended.

Compare two-station outputs to those in Bishop et al. and other tailwaters publications to validate the software output and better understand the value added

No files, tests, or entry points are named. First locate the two-station implementation and its existing test setup, then identify representative outputs from Bishop et al. and other tailwaters publications for comparison. Done means automated unit and integration tests run on code changes and validate the two-station outputs against the selected references.

Written by the indexing model from the issue text.