Stormwater Discharge CalculationsProject: Christian Brothers Auto - Carmel, IN
Project # 70050012 Prepared By: JRS
Subject: Stormwater Detention Basin Sizing Reviewed By:
Date:
Revised:
Determination of Post-Development Peak Discharge from Site
10-year and 100-year Storm Events
Rational Method
Design Information:
Site Information:
Total Area of Proposed Development =1.23 Acres
Impervious Area =0.73 Acre
Pervious Area = 0.50
Impervious "C" Factor =0.90
Pervious "C" Factor =0.30
Weighted "C" Factor for Post-Development Area of Site =0.59
Storm Information:
Time of Concentration = 8.00 Min
10-Year Storm Intensity (5-min) = 6.12 in/hr
100-year Storm Intensity (5-min) = 9.12 in/hr
Peak Discharge Rates:
10-Year Peak Discharge = 4.47 cfs
100-Year Peak Discharge = 6.67 cfs
* These rates represent the discharge from the Christian Brothers site. Restricted release to allowable rates will be accomplised
from the detention basin on the Aria Development.
May 30, 2019
P:\70050012\WIP DRAWINGS\Civil\Calcs\CBA Carmel - Master Storm.xlsm/STORM DISCHARGE
8/2/2019