Melvin Morse, 60, is said to have held the face of his female companion's daughter under a tap several times.
Mr Morse has written several books on children's near-death experiences and has appeared on the Oprah Winfrey Show.
He has pleaded not guilty to child endangerment and assault charges against him.
The 12-person jury was chosen on Monday for the trial stemming from the alleged 2012 incidents.
The BBC's Kate Dailey, who is attending the court hearing in the town of Georgetown, says a clean-shaven Mr Morse shook his head vigorously as the prosecution claimed he had controlled every aspect of the girl's life.
It is alleged that the accused decided what the girl should wear, when she could use the bathroom and what she should eat, starving her sometimes and force-feeding her at other times.
Mr Morse was initially accused of grabbing the girl by the ankle and dragging her across a gravel driveway in July 2012.
When the victim was later interviewed, she reportedly told authorities Mr Morse had held her face under a tap at least four times since 2009.
Waterboarding is a term for the simulated drowning used by US interrogators on terrorist suspects. Critics say it is a form of torture.
Deputy Attorney General Melanie Withers said Mr Morse would hold the girl's face under the tap, usually at the kitchen sink, and run water in her nose and mouth, causing her to choke, vomit and fear for her life.
Defence lawyer Joe Hurley said it was not at issue that the girl ended up under a tap.
But he said that the alleged victim did not enjoy having her hair washed, and so hair washing, or the threat of it, was often used as punishment - a practice the family supposedly jokingly referred to as waterboarding.
Pauline Morse, the victim's mother, agreed in 2013 to plead guilty to misdemeanour child endangerment charges and to testify against Mr Morse.
But Mr Morse's lawyer argues the girl had "oppositional issues" and had lied about abuse by a half-sibling in the past.
The defence says it can show a pattern of deceitfulness from the girl and her mother.