Patty Griffin, Shawn Colvin, the Indigo Girls and Little Feat are among the initial acts announced for this year’s Nashville Riverstages Festival set for April 30-May 2 in downtown Nashville. Several notable rock acts, including the Strokes and Foo Fighters, will also appear at the outdoor event. Other confirmed acts include Wyclef Jean, Styx, Fuel, deSol, Bone Pony, George Clinton, the Fountains of Wayne, Ween, Jonny Lang and Josh Rouse. Three-day tickets, available at Ticketmaster, are priced at $35 but will increase to $45 on April 1. Single day tickets are $25.