Stormwater Surface Filtration/Infiltration Facility Sizing Spreadsheet <br />24 Hour Storm, NRCS Type 1A Rainfall Distribution <br />(6~k~7~ <br />City of Eugene <br />Version 2.1 <br />Project Information <br />Project Name: Oakleiah Meadows_Cohousinci Date: 3/1112013 <br />Project Address: Oakleigh Lane Pennit Number: <br />Eu ene O 02 Catchment ID: Rain Garden 10 <br />Designer: Michael A Cox <br />Company:. SSW Engineeers Inc. <br />nstructions: <br />1. Complete this form for each drainage catchment in the project site that is to be sized per the Presumptive Approach. <br />2. Provide a distinctive Catchment ID for each facility coordinated with the site basin map to correlate the appropriate <br />calculations with the facility. <br />3. The maximum drainage catchment to be modeled per the Presumptive Approach is 1 acre (43,560 SF) <br />4.For infiltration facilities in Class A or B soils where no infiltration testing has been perfromed use an infiltration rate of 0.5 In/hr. <br />For all facilities use a maximum soil infiltration rate of 2.5 in/hr for topsoil/growing medium. <br />Choose "Yes" from the dropdown boxes below next to the design standards requirements for this facility. <br />Pollution Reduction (PR) Yes <br />Flow Control (FC) Yes <br />Destination (DT) NO *An infillrallon faclAy must be chosen as the facility type to meet destination requirernenla <br />Total Square Footage Impervious Area= 1567 sgft Total Square Footage Pervious Area=~sgft <br />Impervious Area CN= 98 Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 1567 sit - Time of Concentration Post Development= min <br />Weighted Average CN= 98 <br />Site Data-Pre: Development (Data in Ut)s.section 'is only used if Flow Control is required) <br />Pre-Development CN= 85 Time of Concentration Pre-Development= 10 min <br />oou uata- <br />Tested Soil Infiltration Rate= 2.5 in/hr (see Note 4) Destination Design= in/hr <br />Design Soil Infiltration Rate= 2.5 in/hr Soil. Infiltration Rate <br />Design Storms Used For-CalcOlations. <br />Requirement <br />Rainfall Depth <br />Design Storm <br />Pollution Reduction <br />1.41inches <br />Water Quality <br />Flow Control <br />3.61 inches <br />Flood Control <br />Destination <br />3.61 inches _ <br />Flood Control <br />r-acsn -Loma <br />Facility Type= Filtration Rain Garden <br />Facility Surface Area= 150sgft <br />Surface Width--I 61ft <br />Facility Surface Perimeter=1 621ft <br />Surface Length=I 251ft <br />Facility Bottom Area=1 661sgft <br />Facility Side Slopes= 31to 1 <br />Facility Bottom Perimeter=1 501ft <br />Max. Ponding Depth <br />1 <br />in Stormwater Facility= 6l In <br />Basin Volume= 56.2 <br />cf <br />Depth of Growing Medium (Soil)=l 18 in <br />Ratio ofFacility Areato Impervious Area= 0.096 <br />3/11/2013-10:56 AM 1 597 <br />