Wikipedia
Tadlac Lake, also colloquially known as Crocodile Lake, is a freshwater volcanic maar lake.
The lake-filled maar is located along the southern shore of Laguna de Bay, the largest lake in the country
It is listed as one of the inactive volcanos in the Philippines
Tadlac lake is also notable for its history of annual lake overturns, locally called langal. This phenomenon, rare elsewhere but usually occurring in Tadlac lake during the cold months of December to February, is the result of trapped carbon dioxide erupting from the deep layers of the lake towards the surface, leading to fish kills due to low levels of dissolved oxygen.
During this period some indigenous fishes of the lake are often observed gasping for air near the lake surface.
This phenomenon was greatly heightened by the introduction of aquaculture to the lake in the mid-1980s, eventually leading to a massive and costly fishkill in 1999, which in turn led to the cessation of aquaculture activities on the lake.
Commonly confused or misnamed as Alligator lake.
Crocodiles however have been known to inhabit Laguna lake and surrounding bodies of water until the early to mid 1900s.
The lake is contained in a piece of land jutting out to Laguna de Bay that was known as Malilimbas Point,
Because of its origin, the lake has no outlet and is replenished only by rainfall.
It has an average depth of 27 meters (89 ft) so swimming is not recommended because of its depth and the sudden drop along its shoreline.
During the Spanish colonial period, the lake was known as Laguna de los Caimanes (Lake of Crocodiles or Crocodile Lake).
Today, crocodiles have been extirpated in and around Crocodile Lake and Laguna de Bay.
Suggested etymologies for the name tadlac include a kind of “wild ginger” and a grass closely related to sugarcane.
Questions
How did LB have hotsprings?
What is the relationship of the creeks around LB to the hotsprings?