3~~ L <br />Story water Surface Filtrationllnfiltration Facility Sizing Spreadsheet <br />24 Hour Storm, NRCS Type 1A Rainfall Distribution <br />City of Eugene <br />Version 2.1 <br />:ct Name: Oakleigh Meadows Cohousing Date: 3/11/2013 <br />:ct Address: Oakleigh Lane Permit Number:- <br />Eugene, OR 97402 Catchment ID: Rain Garden 2 <br />gner: Michael A Cox <br />pany: SSW Engineeers Inc. <br />structions: <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 />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 />Pollution Reduction (PR) Yes <br />Flow Control (FC) Yes <br />Destination (DT) NO 'An infli tration facility must be chosen as the facility type to meet destination requirements <br />ite Data-Post <br />Total Square Footage Impervious Area= 1969 sgft Total Square Footage Pervious Area= 0 sgft <br />Impervious Area CN= 98 Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 1969 sft Time of Concentration Post Development=min <br />Weighted Average CN= 98 <br />Site Data-P.re 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 Note4) Destination Design= in/hr <br />Design Soil Infiltration Rate= 2.5 in/hr Soil Infiltration Rate <br />Used For Calculations <br />Requirement <br />Rainfall Depth <br />Design Storm <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 />Facility Type= <br />Filtration Rain Garden Facility Surface Area= <br />192 <br />sqft <br />Surface Width= <br />6 <br />ft Facility Surface Perimeter- <br />76 <br />ft <br />Surface Length= <br />32 <br />ft Facility Bottom Area= <br />87 <br />sqft <br />Facility Side Slopes= <br />3 <br />to 1 Facility Bottom Perimeter- <br />64 <br />ft <br />Max. Ponding Depth <br />in Stormwater Facility= <br />6 <br />in, Basin Volume= <br />72.0 <br />cf <br />Depth of Growing Medium (Soil)=l <br />18 <br />in Ratio of Facility Area to Impervious Area= <br />0.098 <br />3/11/2013-10:54 AM 1 581 <br />