Prepare the filling:  in a medium saucepan combine the berries, sugar, water, lemon juice and cinnamon.  Bring to a boil, reduce heat continue boiling for 8 minutes, stir occasionally.  Add cornstarch water mixture, return to a boil and boil an additional one minute, stirring constantly.   Remove from heat.

Preheat oven to 350 degrees. In a mixing bowl combine the flour. oats, brown sugar, cinnamon, baking soda and butter.  Stir until well combined.  Reserve 1 cup of mixture for the topping.  Press the remaining into a parchment lined 9 inch square baking dish.  Bake crust for 20 minutes.  Remove from oven, spread with blueberry filling and crumble remaining 1 cup of oat mixture over the top.  Bake an additional 25-25 minutes.  Cool, cut into bars.