Preheat oven to 350 degrees F (175 degree C).
Place the sliced apples in a 9×13 inch pan. Mix the white sugar, 1 tablespoon flour and ground cinnamon together, and sprinkle over apples. Pour water evenly over all.
To make the topping, combine the flour, sugars, salt, oatmeal, and cold butter in the bowl of an electric mixer fitted with the paddle attachment. Mix on low speed until the mixture is crumbly and the butter is the size of peas. Scatter evenly over the apples.
Place the crisp on a sheet pan and bake for 1 hour until the top is brown and the apples are bubbly. Serve warm.
