-~/3Z <br />Project Name: <br />Project Address: <br />Designer: <br />Company: <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 />OakleiQh Meadows Cohousing <br />Oakleigh Lane <br />Eugene. OR 97402 <br />Michael A Cox <br />SSW Engineeers Inc. <br />Date: 3/11/2013 <br />Permit Number: <br />Catchment ID: Rain Garden 4 <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 />Pollution Reduction (PR) Yes <br />Flow Control (FC) Yes <br />Destination (DT) NO 'An infiltration facility must be chosen as the facility type to meet destination requirements <br />ite Data-Post Devel <br />Total Square Footage Impervious Area= 1554 sqft Total Square Footage Pervious Area= 0 sgft <br />Impervious Area Cl 98 Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 1554 sft Time of Concentration Post Development=min <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 <br />Soil Data <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 />n Storms Used.For Calculations <br />Re uirement <br />Rainfall De th <br />Desi n 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 />Faci <br />Facility Type= <br />Filtration Rain Garden Facility Surface Area= <br />140 <br />sqft <br />Surface Width= <br />7 <br />ft Facility Surface Perimeter- <br />54 <br />ft <br />Surface Length= <br />20 <br />ft Facility Bottom Area= <br />68 <br />sqft <br />Facility Side Slopes= <br />3 <br />to 1 Facility Bottom Perimeter- <br />42 <br />ft <br />Max. Ponding Depth <br />in Stormwater Facility= <br />6 <br />in Basin Volume= <br />54.2 <br />cf <br />I <br />Depth of Growing Medium (Soil)= <br />18 <br />in Ratio of Facility Area to Impervious Area= <br />0.090 <br />3/11/2013-10:55 AM 11413 <br />