SW6230903_As-Built - Calculations_20230919

Track & Field Renovations
flMOORE COUNTY
SCHOOLS North Moore High School
IripENGAGE•INSPIRE•SUCCEED
Moore County Schools
1504 N.Moore Rd.
Robbins, NC
State Stormwater Permit
Supporting Documents
Narrativc
USCS Map
Dccd
Calculations
Final Submittal
August 22, 2023
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Runoff Volume Match Calculation

RUNOFF VOLUME MATCH DATE
1-Nov-22
PROJECT NAME PROJECT NO
North Moore HS Track Replacement 22-102 ry
LOCATION BY
Robbins, NC SM
Pre Development
Area of Interest 2,159,495 sf (entire 49.57-ac campus)
Impervious Area c=0.95 625,086 sf (exist. following 2019 project)
Pervious Area c= 0.35 1,534,409 sf (exist. following 2019 project)
Cc = 0.52
% Impervious = 28.9
Runoff Coeff. Rv (0.05 + 0.009 (% Imperv.)) = 0.31
Fraction of Rainfall Events that Produce Runoff, Pj = 0.9
Ave. Annual Rainfall Amount, P = 47.33 in (Carthage, NC)
Average Runoff Volume(ARV)
ARV - Pj x Rv x A x (P/12) = 2,380,292 cf
Post Development
Area of Interest 2,159,495 sf
Impervious Area c=0.95 639,681 sf (addition of 14,595-sf)
Pervious Area c= 0.35 1,519,814 sf
Cc = 0.53
% Impervious = 29.6
Runoff Coeff. Rv (0.05 + 0.009 (% Imperv.)) = 0.32
Fraction of Rainfall Events that Produce Runoff, Pj = 0.9
Ave. Annual Rainfall Amount, P = 47.33 in (Carthage, NC)
Average Runoff Volume(ARV)
ARV - Pj x Rv x A x (P/12) = 2,426,920 cf
% Increase: 2.0%

'DEQ Average Annual Precipitation and Nutrient Management Strategy Watershe•
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Precipitation Stations
• Average Annual Precip(inches) 47.33
Staron Name Carthage
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