Steven Smith was told by the judge that his "sordid past had finally caught up with him" after he was found guilty of multiple abuse offences dating back 30 years.
Leeds Crown Court was told that he systematically abused the girl, then when she tried to finally confront him and report the abuse when she got older, he went to her home and threatened her with the tool.
The 58-year-old from Castleford denied multiple charges dating back more than 30 years, but was found guilty of seven counts of indecent assault, and one count of indecency with a child.
A victim impact statement was read out to the court by prosecutor Julian Jones, who said the woman had been diagnosed with PTSD, had felt suicidal, still had to sleep with the light on and had struggled to lead a 'normal' life.
The court heard that she still wets the bed, even as an adult, because of the sickening ordeals Smith would put her through. She would purposely wet herself as a child to deter Smith from abusing her.
Smith, on remand in HMP Leeds following his trial, appeared via video link and shook his head continuously as the judge addressed him.
Recorder Geraldine Kelly told him: "You systematically and repeatedly sexually abused her over a 10-year period.
"She was entitled to be happy, care-free and innocent as a child, and you robbed her of her innocence.
"The harm you inflicted haunted her as a child, and now. She still wets the bed as an adult. She lives in fear of you.
"It must have taken a lot of courage to finally give her account to the police.
"In cross examination (in court) she was accused of lying. The scars from your actions were apparent.
"You were a bully. When she finally spoke out, your reaction was to bully her into silence, and threatened her with a shovel.
"She was so scared she capitulated and said she was lying. But your sordid past has finally caught up with you."
She jailed Smith for 17 years, including a two-year extended period of licence.
He will sign the sex offenders register for life.
Speaking after the case, Detective Constable Sophie Green, of Wakefield District Child Safeguarding Unit, said: “It took immense courage for the victim to come forward and report the terrible sexual abuse that she suffered as a child. She has shown great strength and bravery throughout this process and I hope that this conviction helps her get some closure on the awful events of her childhood.
“Smith, on the other hand, has demonstrated what a weak and cowardly individual he is. He refused to accept responsibility for his actions but was found guilty at trial and now been jailed for these offences.
“I hope that this case demonstrates that we can, and will, investigate non-recent sexual offences. These offences were reported over two decades after they occurred, but we were able to prosecute the man responsible.
“If anyone has been the victim of sexual offences, whether recently or in the past, I would urge them to please make contact.”