The Towers Outdoor Education Centre, based in Betws-y-Coed, could close permanently under plans put forward by Wolverhampton Council.
It comes as an investigation revealed £600,000 worth of repairs are needed – with a further £1.1 million required to refurbish it.
Mr Street, as part of Birmingham Young Volunteers (BYV) Adventure Camps, helped take underprivileged children in the city – nominated by Birmingham Social Services – to take part in outdoor activities in Wales.
The politician, who led the trips for more than 20 years, said the experiences were "valuable" to the youngsters – and was similar to what is offered at Towers.
Mr Street told the Express & Star: "For 20 years I actually ran a project that took kids from Birmingham to outdoor activity centres in Wales.
"We used to go camping and did all kinds of activities and the reason I did it is because I saw what a week of that gave those youngsters – a completely different set of experiences, teaching them independence and teamwork.
"It's so important. And for many of them, they were dealing with adults who could just accept them for being them."
The youngsters took part in raft building, gorge walking, carving, camping and swimming as part of the BYV camps.
"We did all those things with the youngsters and it was so valued," the former John Lewis managing director added.
"These are experiences you never ever forget.
"Some of the skills you learn that are the most valuable – the self confidence you develop, the independence, relying on colleagues as well.
"I know it's a difficult decision but I hope a way will be found to keep it going – I'm a huge believer in it."
A final decision will be made by Wolverhampton Council's cabinet next Wednesday with councillors being recommended to approve its closure – with the property later sold off at auction.