The statue of Rutherford - who left Canterbury College with three degrees in 1895 and earned a Nobel Prize in chemistry in 1908 - was recovered after a local police officer, Constable Jamie White, jumped into the flooding Wai-iti River after a man who was evading arrest.
A police spokesperson said the 35-year-old man was arrested and charged in relation to the theft, while the statue has been returned to the memorial site.
"Lord Ernest Rutherford is one of our most highly regarded New Zealanders and a great scientist of the 20th century.
"The memorial honours his legacy and is frequented by both locals and tourists alike, so to see the memorial damaged in such a senseless way was extremely upsetting for police and the Brightwater community."
Neither party were injured after jumping into the river and were able to get themselves back to shore safely.
"We'd like to thank the local community for their assistance in providing information to police, which ultimately helped us find the statue," the spokesperson said.
"It shows the great work that can happen when police and our communities work together."
