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Option BMP 12.30. <br /> Evaluation of the criteria to be met for roof basin area. <br /> Contributing Impervious Basin "X" is 2264 sq.ft.which is more than 2000 sq.ft. limit. <br /> Contributing Pervious area "Y" is 1246 which is less than 13000 sq.ft. limit <br /> Equivalent Impervious area; X+(Y/6.5) is 2264+192=2456 sq. ft.which is more than limit. <br /> Contributing Impervious Basin does not meet the criteria of this option. <br /> Option BMP 12.40. Raingardens <br /> The Contributing Impervious Basin area restrictions for BMP 12.30.are applied to Raingarden as well <br /> and therefore this option is determined infeasible. <br /> Option BMP 12.50. Downspout Dispertion System <br /> Restrictions to apply this system; <br /> There is no natural resource protection area adjacent to the lot into which run off can be dispersed. <br /> Some other design criteria such as distance from run off,trench dimensiosns etc.can not be fully <br /> implemented. <br /> Proposed Rooftop Stormwater System: <br /> East Building (2); <br /> Currently the site drains twards Wetmore Ave.to the West. Run off of the roof is split in 2 equal areas <br /> on South & North side each less than 700 sq.ft. Each area will discharge to the surface by providing <br /> splash blocks on each side and sheet flow across the drive way to the adjacent vegetation strip along the <br /> property lines.The run off will be directed through a drain pipe towards West and will discharge to tlhe <br /> surface once past building one, into front yard and vegetated fuffer area between property and <br /> Wetmore Ave. <br /> West Building (1); <br /> Similarly the roof area will be divided into 2 segmnets each with less than 700 sq.ft. Roof drains on each <br /> side will be connected to the same drain pipe collector of building 2,to discharge through front yard and <br /> buffer area as explained above. <br /> Driveway and other Pavements; <br /> Both sides of building 2 along divewasy a French Drain is provided (as shown on the plan)within <br /> Northern and Southern vegetation strips. Impervious surfaces are sloped towards these vegetated strips <br /> so that all the paved area run off as well as roof splash blocks of building 2 discharge into the gravel <br /> covered French Drain perforated pipe which will be connected to the solid pipe directed towards <br /> Wetmore Ave. as explained before. <br /> (Page5of8 <br /> CITY OF EVE E"TT ; 3200 Cedar Street ? Everett, WA 98201. ! 425-257-8810 ;everettwa.gov."__. .,,. <br />