Laserfiche WebLink
Cit uild'n s ction Department <br />tember 21, 197 <br />page <br />Outlet Fib <br />Diameter = 6611 ' = 4.0% <br />Slope /31 <br />Approx. 10' in 2/ <br />_ .463( 5)8 (,04)2 = 1.2 CFS <br />Capacity 012 <br />( 2��b .74 < 1.2 CFS <br />poet Development Capacity .84 1.6)( ) <br />6" Dia. O.K. <br />Retention Detentions m3 <br />D.C. <br />24" Dia. Conc. Pipe Btwn 2 Catch Basins @ 84'-0" <br />V - (12.57)(3) = 38 CFT Catch Basin #4 <br />= 59 CFT Catch Basin #5 <br />V = (12.57)(4.66) = 251 CFT 24" Conc. pipe NO' Long <br />v Total (70) 348 CFT j 341 CFT <br />V Total <br />DETENTION/RETENTION SYSTEM #4 @ GYMNASIUM <br />pre Development Areas: <br />C ,6 <br />2,354 sq.ft. vacant Area Dirt & Grass 7 <br />1,819 Gravel � _ .95 <br />21 609 paving or Concrete <br />5,782 Effective C •9 <br />sq.ft. Total <br />post Development Areas: <br />25,762 sq.ft. Paving, cone. walks or roof C .95 <br />Design Storm: 1 in 10 years <br />pre Development frequency 1 in 25 j,ears <br />post Development frequency 1.3 in./nu. <br />Intensity Pre Development 1.6 in./hr. <br />Intensity Post Development 20 minutes <br />Duration <br />pre Developer Design Runoff: <br />.90(1.3)( 1) 25,782 = .90(931) = 836 CFT <br />T TZ <br />post Development Design Runoff: <br />.95()() 2 5,7 82 = .95(1,146) = 1,088.5 CFT <br />Runoff Differential = 256 CFT <br />