Drainage systems shall have adequate capacity to convey the storm water 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 present state of development. An allowance, equivalent to the reduction in flow rate provided, shall be made for upstream detention when the upstream detention and release rate have previously been approved by the Board and evidence of its construction can be shown.
(Ord. 1995-10 § XIV D, passed 10-13-1995)