solar field
If Ticks (or whatever gets binned in with them) must have their own shallows, then those shallows should be visually distinct on all maps, with ample area for each tier of shallows side-by-side to establish visual recognition relative to the waterline.
An example offender is High Noon. It doesn't provide clear visual distinction at-a-glance, and even if it did it does not provide enough area along any terrain drop to clearly indicate that transition from ground, to Tick-passable, to Tick-impassable. I say this having observed a 50+ OS player click Ticks onto the opponent's side of the map only for them to get stuck on the crossing, and given that players asking about whether or not ticks can cross a map is still a regular occurrence in team games.
Note that the topological consistency of a map's 'ground'/'submarine'-level geometry means that anywhere there is both a Tick-impassable shallow and dry ground, there must exist Tick-passable shallows. These should all be visually distinct.
Related:
rapid tusk
sinful totem