1q -:s - <br />Stormwater Surface Filtrationlinfiltration Facility Sizing Spreadsheet <br />24 Hour Storm, NRCS Type 1 A Rainfall Distribution <br />City of Eugene <br />Version 2.1 <br />Project Information <br />Project Name: Oakleigh Meadows Cohousinct Date: 3111/201 <br />3 <br />Project Address: Oakleigh Lane Permit Number: <br />Eugene, OR 97402 Catchment ID: Rain Garden 8 <br />Designer: Michael A Cox <br />Company: SSW Engineeers 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 topsoil/growing medium. <br />Choose "Yes" from the dropdown boxes below next to the design standards requirements for this facility. <br />I Pollution Reduction (PR) Yes <br />I Flow Control (FC) Yes <br />Destination (DT) No 'M infitmom facility must be chosen as the facility type to meet destination requirements <br />Data-Post <br />Total Square Footage Impervious Area= 2901 sgft <br />Impervious Area CN= 98 <br />Total Square Footage of Drainage Area= 2901 sft <br />Weighted Average Cl 98 <br />Total Square FootagePervious 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) I <br />I Pre-Development CN= 85 Time of Concentration Pre-Development= 10 min I <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 Calculations <br />Re uirement <br />Rainfall Depth <br />Design Storm <br />Pollution Reduction <br />1.4 <br />inches <br />Water Quali <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 <br />Facility Surface Area= 259 sgft <br />Surface Width=1 71ft <br />Facility Surface Perimeter= 88 ft <br />Surface Length=1 371 It <br />Facility Bottom Area= 136 sgft <br />Facility Side Slopes=1 31to 1 <br />Facility Bottom Perimeter= 76 ft <br />Max. Ponding Depth <br />1 <br />I <br />6 <br />in <br />in Stormwater Facility= <br />Basin Volume= 101.0 cf <br />Depth of Growing Medium (Soil)=l 18 in <br />Ratio of Facility Area to Impervious Area= 0.089 <br />3/11/2013-10:56 AM 11421 <br />