In a large skillet, cook the ground beef over medium-high heat until evenly brown. Drain off excess fat. In a large bowl, combine the cooked beef, refried beans, oregano, cumin and garlic powder.

Place four of the uncooked lasagna noodles in the bottom of a 9x13 inch baking dish. Spread half of the beef mixture over the noodles. Top with 4 more uncooked noodles and the remaining half of the beef mixture. Cover with remaining noodles. Combine the water and the salsa in a medium bowl, and pour over all.

Cover tightly with foil. Bake at 350 degrees F (175 degrees C) for 1 1/2 hours, or until noodles are tender.

In a medium bowl, combine the sour cream, green onions and olives. Spoon over casserole, and top with shredded cheese. Return to the oven, and bake for an additional 5 to 10 minutes, or until cheese is melted.