Water

Beware of water! Fighting underwater is much harder than fighting on dry land.
[description of penalties]
=====Rebreather:=====
=====For sale from Zephyr for 20 Resources. Upkeep of 2, Loadout required is 10.=====
Provides a constant 1.0 water adaptation, which is enough to overcome the river's penalties.
Furry Hide:
Available as a mutation from many fuzzy monsters. Once mastered you can upgrade it with 2.0 water adaptation, giving you a bonus in the river and less of a penalty in other, future areas.
Doesn't Breathe:
A 2-point merit that reduces water penalty magnitude by 50% before any of your adaptation.
So for example, someone who Doesn't Breathe with Furry Hide upgraded once in the river will reduce the penalty from -1.0 to -0.5, then up to a 1.5 bonus with the hide.