Coat a Dutch oven with cooking spray; place over medium-high heat until hot.
Add turnips, carrot, onion, celery, and sweet red pepper; saute 1 5 minutes.
Stir in water and remaining ingredients.
Bring to a boil.
Cover, reduce heat, and simmer 2 hours.
Strain broth through a double layer of cheesecloth; reserve vegetables for other uses.
Cover and chill broth.
Store in refrigerator or freezer.
Use as a base for vegetable soups.