In large saucepan, combine water, celery, carrots, and onion.
Bring to a boil and simmer for 5 minutes
Add broccoli, and continue to simmer until the vegetables are tender/crisp
SAUCE:
Melt butter in kettle
Blend in flour, salt and pepper and garlic powder
Cook, stirring together until it thickens, about one minute
Add milk and stir until mixture thickens
Stir in cheese and ham cubes
Combine mixture with undrained vegetables
Stir and serve