The Saugus River Watershed Council is hosting its annual picnic and children’s festival from 6 p.m. to dusk Wednesday at the Saugus Iron Works National Historic Site, located next to the Saugus River at 244 Central St. The event, free and open to all, will include live acoustic music by Kirsten and Dave, along with a children’s art contest and a variety of games and hands-on environment-related activities. Participants are invited to bring a picnic dinner, blankets, and lawn chairs. Free drinks and desserts will be provided. The rain date is Thursday.