PREHEAT oven to 350°F. Line 13x9-inch baking pan with foil, with ends of foil extending over sides of pan. Mix graham crumbs, 1/2 cup of the pecans, the granulated sugar and butter; press firmly onto bottom of prepared pan. Bake 10 min.
BEAT cream cheese, brown sugar and flour in large bowl with electric mixer until well blended. Add sour cream and vanilla; mix well. Add eggs, one at a time, mixing on low speed after each addition just until blended. Place 36 of the caramels in microwaveable bowl. Add 1 Tbsp. of the water. Microwave on HIGH 1 min. or until caramels are completely melted when stirred. Add to cream cheese batter; stir until well blended. Pour over crust.
BAKE 40 min. or until center is almost set. Sprinkle with remaining 1/2 cup pecans. Cool completely. Refrigerate at least 4 hours.
PLACE remaining caramels in microwaveable bowl. Add remaining 1 Tbsp. water. Microwave on HIGH 1 min. or until caramels are completely melted when stirred. Drizzle over cheesecake; let stand until firm. Use foil handles to remove dessert from pan before cutting into bars to serve. Store leftovers in refrigerator.