Tracks water sources on the farm — wells, surface tanks, ponds, streams, troughs, springs, hydrants — with their location, capacity, last-tested date, and which fields they serve.
The geom column is a GeoPoint. All source types are represented as a
single point: the well-head, the tank tap, the centroid of the pond, the
access point on the stream. We picked this in v1 because base_geoengine
19.0 doesn't ship a "any geometry" type — adding a polygon footprint for
ponds (surface-area, depth contours) or a linestring for streams would
need a follow-up farm_water_source_polygon extension model.
The field_ids many2many answers "which fields does this source serve?",
useful when planning rotational grazing or drought contingency.