You should also incorporate information on the local and regional stress fields.  At least at deeper levels (that can allow upflow of hot water) there are strong correlations between shear extensional zones at fault irregularities and hot spring or fumarole locations.  Check groundbreaking (yes!) work by Curewitz and Karson (1997) and Jim Faulds et al (various).  This information may allow you to at least qualitatively zone fracture patterns for likely permeability.  Curewitz and Karson provide a "breakdown" radius that might help.

Use your data and expertise to set up field surveillance and monitoring, including wells, pieziometer said, location of seeps, springs, headwaters, fluctuation of water table, etc.    if you have opportunity to partner with geologist, surface/groundwater hydrologist, soil scientist for areas of interest, the effort may be improved.  If there are existing models that might be applied or adjusted to your area, you might test them, find out benefits and limits.  Having good geology map with faults, strikes, dips as well as topographic and soil maps helpful.  

You should seek fractured rock area where this water, usually follows faults or fractures in the rock. In other cases the water is located between rock hard and very healthy; and the layer of weathered rock, covered by a very impermeable soil on the surface. This happens in various parts of Costa Rica