Judge David Goodin described his behaviour as "devastating, cruel and spiteful", but said he would suspend the sentence because of the defendant's age and service in the Army.
Snellgrove was given an 18-month suspended sentence and a 20-week curfew, meaning he will have to remain inside his home between 7pm and 6am.
David Wilson, prosecuting, said during one week in February last year, Rivera had been subjected to harassment on an almost daily basis.
The court heard that after Rivera and his family moved into their home, Snellgrove had removed some trellis and part of a boundary fence that resulting in Mr Rivera installing CCTV cameras.
When police went to talk to Snellgrove, he referred to his army career and said he would "shoot people of their types".
In a statement read to the court, Rivera described Snellgrove as "a neighbour from hell" and accused him of "emotionally and mentally torturing" his family and making their lives a misery.
Frank O'Toole, for Snellgrove, accepted the veteran's behaviour had been obnoxious.
He said: "He now fully accepts what he did was wrong and should never have happened. He felt he couldn't talk to his neighbour and things got worse and worse as time went on."
He said Snellgrove had been injured while on service and now received an Army pension.
O'Toole said Snellgrove is planning to move to another area of Colchester to be near his daughter.
Snellgrove's campaign of harassment took place between February 1 and March 26 last year.
This story was originally published by Telegraph UK.
