In a small saucepan, combine the dates, water, brown sugar and orange zest. Cook and stir over medium heat until mixture comes to a boil, about 4 minutes. Cook and stir 3 minutes longer or until liquid is absorbed. Remove from the heat. Stir in orange and lemon juices. Cool to room temperature.
In a large bowl, combine the flour, baking powder, baking soda and salt. Cut in butter until crumbly. Add oats and brown sugar; mix well. Set aside half for the topping. Press remaining crumb mixture into a greased 13x9-in. baking pan.
Drop date mixture by small spoonfuls onto crust. Sprinkle with reserved crumb mixture; press down gently. Bake at 325° for 30-35 minutes or until golden brown. Cool on a wire rack. Cut into bars.