Event for Students to Demonstrate the Sustainable Water Use/Management

I need to organize a couple of events for the students of the age group of 15-20 to give them the practical exposure or the clear idea of sustainable water use/management.

The event may also be of the type where ones who already have an idea about this can utilize/implement/participate with some innovative ideas in this domain.

Of course, the event should be attractive and interesting for youths.