Combine shrimp, salt, 1/2 teaspoon garlic powder, and pepper in a mixing bowl; mix well. Set aside.
Cook bacon in a skillet until crisp. Drain, reserving drippings in skillet. Crumble bacon, and set aside. Add flour to hot bacon drippings; cook over medium heat, stirring constantly, 10 minutes or until roux is the color of a copper penny. Add onion, celery, and green pepper; simmer 5 minutes.
Add shrimp, remaining garlic powder, and water to cover, stirring well. Cook over medium heat, stirring frequently, until thickened. Add crumbled bacon; stir well. Serve over rice.