John was the academic leader for Waihi College in 2013 and his death had sent shockwaves through the school, Mr Cochrane said. "He's been at our school for seven years so we've got to know him very well and his family. It [the service] will be pretty moving."
Mr Cochrane said the Balchin family was well known to the school - several children were current and former students.
"We are coping as best we can. The kids and staff are quite emotional and upset by what's happened. We are all trying to deal with it, collectively, together."
Mr Cochrane will speak on behalf of the school at the service.
"There are lots and lots of fun stories. He was such a wonderful young man. He really enjoyed having fun but he did it in a very respectful and fun loving way. He had the ability to smile at himself.
"He was a little bit quirky but he was just so well liked by everyone he came into contact with really.
"It's just a real tragedy."
John is the fourth student from the college to have died in as many years. "We are hoping they will stop," Mr Cochrane said.
"In many ways it actually brings us together as a school. The students and staff are dealing with it together," Mr Cochrane said.
The school will be bolstered by support from the Waihi community on Monday, with people coming in to help prepare the service. Mr Cochrane said he was grateful.
Thames police Senior Sergeant Graham Shields said a specialist search and rescue dog had tracked John's last movements to the riverbed but it was still unclear how John came to be in the river.
A post-mortem examination was expected to offer light on the cause of death. The night had been particularly cold and it was possible John could have died from exposure rather than drowning.
"At this stage we aren't suspecting foul play or looking for anyone else," Mr Shields said.
John's funeral service will be held at Waihi College on Monday at 1pm.
