Police were called to the Matahina Dam area about 6pm and, after an extensive search and rescue operation, Arnica's body was found in the river about 11pm.
Moses cried, and Savage remained unemotional, as Crown prosecutor Anna Pollett read out extracts of victim impact statements.
Moses' statement said: "Every morning when I wake up... I don't want to be here" and wondered when she would get peace.
She said she drank and smoked a lot to numb her pain, and two to three days a week she found it difficult to get out of bed.
Moses spoke lovingly of her daughter and the joy she brought to the family, Pollett said.
Arnica had been a "determined, generous and loving in life so far" and "adored" her father, Justice Davison said.
He said Savage had been diagnosed with as manic depression and bipolar disorder after the murder, but the jury did not believe he was insane.
However, Davison said Savage's mental disorder reduced his moral culpability "significantly".
He read out the summary of facts, stating that Moses had started a relationship with another man, who had been a close friend of Savage's and held hope of reconciliation.
She had said she was not going to return to live with Savage.
The night before Arnica's death, Tewi Savage's father said he was "f***** in the head" and disturbed.
Savage woke five times in the night, loudly singing songs and shouting: "They're coming to get me".
His parents, who lived next door, had to help him settle and fall asleep again.
Moses had also told Savage she was worried about his mental health.
On July 1, she told him she wanted to move to Australia, which angered Savage.
He went for a walk to cool off about 4pm and told Moses to "get the f*** out of his way".
Arnica said she wanted to go with him and Savage put her in her pram.
He took a book of religious writing with him.
His parents became concerned when he did not return by dark and they were joined by neighbours and others in the village to look for Savage and his daughter.
They found his clothing, her pram and blanket and eventually heard him calling out.
He was naked standing in thick blackberry bushes.
Savage said he had "f***** up" and went into the river and let Arnica go.
He also told police this and they found Arnica's body 2.5km downstream.
He had previous convictions for violent offending for which he had community-based sentences but none were against children.
Savage would spend his life in prison with a minimum non-parole period of 14 years.