.Stormwater Surface Filtration/Infiltration Facility Sizing Spreadsheet <br />24 Hour Storm, NRCS Type 1 A Rainfall Distribution <br />City of Eugene <br />Version 2.1 <br />Project Name: Qakleidh Meadows Cohousinq Date: 3/11/2013 <br />Project Address,. Oakleiah Lane Permit Number: <br />Eugene. OR 97402 Catchment ID: Rain Garden 15 <br />Designer: Michael A Cox <br />Company: SSW Ennineeers Inc; <br />Instructions: <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 topsoiUgrowing medium. <br />"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 'M inGlirat.n facility must be chosen as the facllty type to meet destination requirements <br />Site Data-Post <br />Total Square Footage Impervious Area= 1592 sgft <br />impervious Area Cl 98 <br />Total Square Footage of Drainage Area= 1592 sft <br />Weighted Average CI 98 <br />Total Square Footage Pervious Area= ~sgft <br />Pervious Area CN= 85 <br />Time of Concentration Post Development= min <br />iSite Data-Pre Development. ' (Data in this section Is only used If Flow Control is required) <br />I Pre-Development CN= 85 Time of Concentration Pre-Development= 1 d min <br />Data <br />Tested Soil Infiltration Rate= 2.5 in/hr (see Note 4) Destination Deslgn= in/hr <br />Design Soil Infiltration Rate= 2.5 in/hr Soil Infiltration Rate <br />Storms Used For Calculations <br />Requirement <br />Rainfall Dept h <br />Desi n Storm <br />(Pollution Reduction <br />1.4 <br />inches <br />Water Quality <br />IFlowcontrol <br />3.6 <br />inches <br />Flood Control <br />Destination <br />3.6 <br />inches <br />Flood Control <br />Facility Type= Filtration Rain Garden <br />Facility Surface Area= 147 sgft <br />Surface Width=1 <br />71ft <br />Facility Surface Perimeter= 56 ft <br />Surface Length=1 <br />211ft <br />Facility Bottom Area= 72 sgft <br />Facility Side Slopes=1 <br />31to 1 <br />Facility Bottom Perimeter= 44 ft <br />Max. Ponding Depth I <br />1 <br />in Stormwater Facility= I <br />6 <br />in <br />Basin Volume= 57.0 cf <br />1 Depth of Growing Medium (Soli)= 18 in <br />Ratio of Facility Area to Impervious Area= 0.092 <br />3/11/2013-10:57 AM 11 4 3 5 <br />