WINTHROP — Middle school students from Winthrop will join some 700 of their peers Friday at a forum on clean water ecosystems at the University of Southern Maine.

It’s the 12th annual Children’s Water Festival, sponsored by the Department of Environmental Protection and other state and federal and nongovernmental agencies. The idea is to educate young Mainers about the importance of clean water and threats to this natural resources.

There will be hands-on activities and exhibits.