Combine ground beef, salt and pepper and brown. Drain.
Add carrots, potatoes, onion and broth. Bring to a boil. Reduce heat; cover and simmer 15 to 20 minutes.
Stir in zucchini, tomatoes, mushrooms, thyme and Worcestershire sauce. Cook 5 to 10 minutes
Combine water and flour in a bowl. Gradually add to stew and stir. Stir until bubbly and thickened.