Drainage systems shall have adequate capacity to convey the stormwater runoff from all upstream tributary areas through the development under consideration for a storm of 100 year design return period calculated on the basis of the upstream land in its ultimate state of development. An allowance, equivalent to the reduction in flow rate provided, shall be made for upstream detention when such upstream detention and release rates have previously been approved by the town and evidence of its construction can be shown.
(Ord. 1999-05, passed 6-8-99)