The mural of the Mystic River Watershed in the parking lot at the Mystic Lakes Dam is ready for its annual touch-up! If you're interested in grabbing a brush and helping the Mystic River Watershed Association touch-up the mural with the original artist, Yetti Frenkel, volunteers are invited to sign up for two-hour shifts from 10 a.m. to 4 p.m. via MyRWA's online form. All painting supplies will be provided; please bring water and sunscreen and wear clothes that you…