3.3.6  Time of Concentration.
   The time of concentration is defined as the longest time that will be required for a drop of water to flow from the upper limit of the drainage area to the point of concentration.
   The minimum times of concentration are shown below:
 
Parks and permanent open areas
20 minutes
Single-Family and Duplex residential
10 minutes
Multifamily, Business and Industrial
10 minutes
 
   In cases where it is evident that the actual time of concentration is more than that indicated above, the longer time of concentration should be used.