Southwestern Three-Bean and Barley Soup

1 T. olive oil
1 large diced onion
1 stalk diced celery
1 diced large carrot
1 medium zucchini
9 cups water
4 cups vegetable broth
1/2 cup pearl barley
1/3 cup dried black beans
1/3 cup dried great northern beans
1/3 cup dried kidney beans
1 T. chili powder
1 t. ground cumin
1/2 t. dried oregano
3/4 t. salt

Heat oil in large pan, then add onion, celery and carrot and cook until softened.  Add water, broth, barley, beans, zucchini, chili powder, cumin and oregano.  Bring to a boil and then simmer until the beans are tender....about 2 - 2  1/2 hours.  Add more water, 1/2 cup at a time if necessary.  Salt to taste.