In a 4- to 5-quart Dutch oven or pot bring water, split peas, barley, bouillon granules, and bay leaf to boiling; reduce heat. Simmer, covered, for 30 minutes. Stir in celery, carrots, and onion; return to boiling. Reduce heat. Simmer, covered, for 30 minutes more or until vegetables, peas, and barley are tender.
Stir in ham and 1/2 teaspoon pepper. Cook for 5 minutes more or until ham is heated through. Remove and discard bay leaf. Season to taste with salt and additional pepper. Makes 8 (1-1/2 cup) servings.