Not to be confuse with a swallet …
This vortex is a result of water rushing through a culvert.
Swallets by the way are the opposite of springs.
They swallow surface water into the underlying aquifer below whereas springs send groundwater under pressure into surface waters above, forming what’s called a “boil” – so named because the surface rolls over on itself like water boiling in a pot.
Interestingly, just across the road from this vortex is what appears to be a “boil,” but not to be confused with a spring.
It’s just water gushing out of the culvert.
Not too far downstream, it quickly spreads out into sluggish sheet flow.