Krishna to issue 358

[pbuttigieg]

Closes #1231

[pbuttigieg]

Content review:

• water table - as @KrishnaTO noted here, sources consider this more as the top layer of the zone of saturation, rather than the interface layer (xref here too). Following his proposal for redefinition and adding axioms.
• water table depth - as detected by @KrishnaTO and @marieALaporte, this is more the elevation of the water table, rather than its depth (in the sense of "depth of this pool", "depth of some snow") as intended by PATO:depth. Good catch! Added clarifying comment and adding synonyms.