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Mountain View W2rehouse <br /> Stormwater Site Plan <br /> The conveyance syslem was sized using the Manning's Equation with ilows calculaled <br /> using the Rational Method. The output and conveyance exhibit is provided in the <br /> Appendix oi lhis report. The characteristics of the site used for sizing the conveyance <br /> pipe are as follows: <br /> RoadwaylRoof/PavemenUParking = 1.37Acres (C value = 0.90) <br /> Landscapinq = 0.52 Acres C value = 0_� <br /> Total Area = 1.89 Acres <br /> The ralional method was used to calculate the peak runoff for the enlire site. The <br /> i <br /> developed 100-year slorrn event used lo size the corveyance system was determined <br /> � as foliows. <br /> I� Q = CIA (Cubic Feet per Second), where: <br /> C = Runof(Coe(ficient (Weighted) <br /> _ [(0.90)(1.37) + (0.25)(0.52)]/1.89 = 0.720 (ACTUAL) <br /> � _ [(0.90)(1.70) + (0.25)(0.19)]/1.89 = 0.835 (DESIGN) <br /> � (Although the site is approximatcly 72% impervious, a more <br /> conservative value of 90% was used for calculations, lhus a <br /> � Weighted Runoft Coe(ficient of 0.835 was applied) <br /> I = Peal: Rainfall Inlensity = 3.80 in/hr <br /> i <br /> • Per City o( cverett Slormwaler Management Manual Figure 1-5.1 <br /> • 100-year rainfall <br /> � . T� = Time of concenlration = 5 minutes (Minimum Allowable) <br /> • See Figure included in Appendix) <br /> P, = Area in Acres = 1.89 Acres <br /> Q;;,,;, = CIA = (Q835)(3.80)(1.89) = 6.00 cfs <br /> A similar calculation Iias been done for each individual calc�� basin. The following lables <br /> shn� i tf •� calculated floa�s and ihe resuiting hydraulic grade line elevations at each calch <br /> il � 1.. . TVIC k�LIJELINIC GHIILII' F���(;6I <br />