Police said Haily Schramm, 31, is charged with three counts of attempted second-degree murder.
She came to police attention when they called to the Sunset Library in response to a woman allegedly talking about suicide. The children were with her at the time.
Taken to a hospital for evaluation, she allegedly told staff there she had tried to drown the kids the night before.
The children were turned over to the state and a case built against Schramm, who was arrested Friday.