Oatmeal Rhubarb Crumble

Recipe is from Aunt Lola.

1 cup sifted flour
1/2 tsp salt
1 cup sugar or a little more
1 cup rolled oats, uncooked
1/2 cup melted butter or margarine
3 cups diced rhubarb
1/2 tsp cinnamon
1 TB water

Save 1 TB flour for rhubarb filling. Sift remaining flour, salt, and 1/2 cup sugar; stir in oats. Stir in melted butter or margarine until mixture is crumbly. Press half of the oat mixture evenly over bottom and sides of 9-inch pan. Combine rhubarb, 1/2 cup sugar, 1 TB flour, cinnamon, and water. Turn into crust. Sprinkle remaining oat mixture over fruit. Bake at 350 degrees until rhubarb is tender and crust is lightly browned, about 45 minutes. Makes one 9-inch pie.