1.Heat oil in a Dutch oven over medium heat. Add onion, celery and carrot and cook, stirring occasionally, until softened, about 5 minutes.
Add water, broth, barley, black beans, great northern beans, kidney beans, chili powder, cumin and oregano. Bring to a lively simmer over high heat. Reduce heat to maintain a simmer and cook, stirring occasionally, until the beans are tender, 1 3/4 to 2 1/2 hours (adding more water, 1/2 cup at a time, if necessary or desired). Season with salt.