-7 L <br />Stormwater Surface Filtration/Infiltration Facility Sizing Spreadsheet <br />24 Hour Storm, NRCS Type 1A Rainfall Distribution <br />City of Eugene <br />Version 2.1 <br />Project Information <br />Project Name: Oaklelgh Meadows Cohousln_q Date: 311112013 <br />Project Address: Oaklekth Lane Permit Number: <br />Eugene. OR 97402 Catchment ID: Rain Garden 2 <br />Designer: Michael A Cox <br />Company: SSW Engineeers Inc. <br />nstructions: <br />Complete this form for each drainage catchment in the project site that is to be sized per the Presumptive Approach. <br />. Provide a distinctive Catchment ID for each facility coordinated with the site basin map to correlate the appropriate <br />calculations with the facility. <br />The maximum drainage catchment to be modeled per the Presumptive Approach is 1 acre (43,560 SF) <br />I.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 />"Yes" from the dropdown boxes below next to the design standards requirements for this facility. <br />I Pollution Reduction (PR) Yes <br />Flow Control (FC) Yes <br />Destination (DT) NO 'An infillrat'on facility must be chosen as the facility type to meal destination requirements <br />Data-Post <br />Total Square Footage Impervious Area= 1969 sqft <br />Impervious Area CN= 98 <br />Total Square Footage Pervious Area=~sgft <br />Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 1969 sft Time.of Concentration Post Development= min <br />I <br />Weighted Average CN= 98 <br />Site Data-Pre Development (Data In this section is only used if Flow Control is required) <br />Pre-Development CN= 85 Time of Concentration Pre-Development- 10 min I <br />Soil Data ~ <br />Tested Soil Infiltration Rate= 2,5 in/hr (See Note 4) Destination Design= in/hr I <br />Design Soil Infiltration Rate= 2.5 in/hr Soil Infiltration Rate <br />Storms Used For Calculations <br />Requirement <br />Rainf <br />II Depth <br />Design Stonn <br />Pollution Reduction <br />1.4 <br />inches <br />Water Quality <br />Flow Control <br />3.6 <br />inches <br />Flood Control <br />Destination <br />3.6 <br />inches <br />Flood Control <br />Data <br />Facility Type= Filtration Rain Garden Facility Surface Area= 192 sgft <br />Surface Width=J 61ft Facility Surface Perimeter=] 761ft <br />Surface Length=1 321 ft Facility Bottom Area=] 871sgft <br />Facility Side Slopes=[ 31to 1 Facility Bottom Perimeter=1 641 ft <br />Max. Ponding Depth <br />in Stormwater Facility= I 61in Basin Volume] 72.01cf <br />Depth of Growing Medium (Soil)=L 18 in Ratio of Facility Area to Impervious Area= 0.098 <br />1409 <br />3/11/2013-10:54 AM 1 <br />