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1 <br /> 1 <br /> PREFACE <br /> This project was started prior to 2009, stopped, and then resumed in 2013. The design <br /> and drainage components have been updated to be compliant with the 2012 City of <br /> Everett Storm Water regulations, resulting in larger storm water management facilities. <br /> Otherwise, the building design and above ground site characteristics remain essentially <br /> the same as the 2009 design. <br /> Principal changes are a much larger storm water detention vault, and a pipe conveyance <br /> for the storm outfall from the vault to an WSDOT catch basin. WSDOT also reversed <br /> their 2009 desire that we disperse into WSDOT right-of-way via a level spreader and use <br /> piped conveyance instead. <br /> SUMMARY <br /> All stormwater detention and water quality facilities are located onsite and are private. <br /> The outflow from the onsite facility is metered via a control structure, and is released via <br /> conveyance pipe to an existing WSDOT catchbasin located approximately 160ft <br /> downgrade of the subject property. This is the natural and historic water course for this <br /> property. <br /> The Anthem Self-Storage Facility Project proposes to build a storage building with a <br /> covered drive aisle on a 1.75-acre site. There will be approximately 1000 linear feet of <br /> looped driveway providing access to the storage units. The project site is located within <br /> the City of Everett, Washington, on SE Everett Mall Way just south west of the <br /> northbound on ramp to I-5. Access to the site will be provided from Everett Mall Way <br /> via a commercial driveway. A single detention vault is proposed to collect runoff from <br /> ' impervious surfaces, releasing via a control structure with release rates passing current <br /> City of Everett regulations as per WWHM2012 calculation methods (this product and <br /> software is also referred to as WWHM4 in some reports produced by this software). <br /> Water quality treatment will be provided by two Contech Catchbasin Stormfilters located <br /> upstream of the vault. As each of the Catchbasin Stormfilters have less than one acre of <br /> reach, the City does not require pre-treatment for sediment. Stormfilters have received <br /> 1 GULD by the DOE for water quality treatment as used in this design. Roofwater shall be <br /> connected directly to the storage system and bypass the filter and sediment devices. <br /> On May 29, 2007, HBA Design Group staff first visited the site and observed existing <br /> drainage patterns, topography, and ground cover. Subsequent site visits have observed <br /> no appreciable change in the undeveloped site. <br /> EXISTING CONDITIONS <br /> The proposed development site area is approximately 1.75 acres of second-growth forest <br /> with typical native understory. There is a 45-foot portion of the property that fronts <br /> 1 <br />