WFPK’s first Waterfront Wednesday kicks off the free monthly series with three solid acts. Shakey Graves — the moniker of Alejandro Rose-Garcia — is a ragged, stripped-down project that throws a fair share of distortion behind country and blues sensibilities. J.D McPherson draws on mid-20th century R&B and rockabilly to tag along with his powerhouse vocals. Nicki Bluhm and the Gramblers match breezy country-influences with a melancholy stream of songs. It’s a bill that you would probably have to pay $20 or more to see elsewhere.