C' <br />F_ <br />i <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: Oakleicih Meadows Cohousing Date: 311112013 <br />Project Address: Oakleigh Lane Permit Number: <br />Eugene. OR 97402 Catchment ID: Rain Garden 5 <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 />Design Requirements:.- <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 />Site Data-Post Development " <br />Total Square Footage Impervious Area= 927 sqft Total Square Footage Pervious Area= 0 sqft <br />Impervious Area CN= 98 Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 927 sft Time of Concentration Post Development= min <br />Weighted Average Cl 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= <br />2.5 <br />in/hr (See Note 4) Destination Design=. in/hr <br />D <br />i <br />S <br />il I <br />f <br />l <br />es <br />gn <br />o <br />n <br />i <br />tration Rate= <br />2.5 <br />in/hr Soil Infiltration Rate <br />Design Storms 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 Data_ . <br />Facility Type= <br />Filtration Rain Garden . Facility Surface Area= <br />100 <br />sqft <br />Surface Width= <br />5 <br />ft Facility Surface Perimeter= <br />50 <br />ft <br />Surface Length= <br />20 <br />ft Facility Bottom Area= <br />34 <br />sqft <br />Facility Side Slopes= <br />3 <br />to 1 Facility Bottom Perimeter- <br />38 <br />ft <br />Max. Ponding Depth <br />in Storrnwater Facility= <br />-6 <br />in Basin Volume= <br />35.8 <br />cf <br />Depth of Growing Medium (Soil)= <br />L--- 18 in Ratio of Facility Area to Impervious Area= <br />0:108 <br />3/1112013-10:55 AM <br />1 587 <br />