Combine water and broth; bring to a simmer in a large saucepan (do not boil). Keep warm over low heat.
Cook bacon in a Dutch oven over medium heat until crisp.
Remove bacon from pan, reserving 2 teaspoons drippings in pan. Crumble bacon; set aside.
Return pan to medium heat.
Add red onion; saut for 3 minutes.
Add barley; cook 2 minutes, stirring constantly.
Add wine and salt; cook 2 minutes or until liquid is nearly absorbed, stirring constantly.
Add broth mixture, 1/2 cup at a time, stirring until each portion of broth mixture is absorbed before adding the next (about 45 minutes total). Stir in bacon; cook for 2 minutes.
Remove from heat; stir in radicchio, cheese, and pepper.