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Thomson Residence March 5, 2021 <br />Stormwater Site Plan Report Section VIII, Page 3 <br />Operation and Maintenance Manual <br />This Operation and Maintenance Manual has been created for Thomson Residence, a single-family <br />residential development on a 0.21 ac lot located at 4320 Thomson Ave in Everett, WA. The proposed <br />stormwater management system consists of conveyance pipes, a detention tank with a flow control <br />structure, and catch basins. Included in this Operation and Maintenance Manual is an 11" x 17" grading <br />and drainage plan sheet showing the locations of the drainage improvements. Please note that this map <br />is generated during the design phase and may not reflect all changes made in permitting and construction. <br />CG Engineering may be contacted for an updated copy of this map once the as -built drawings are <br />completed for the site. The contractor will be responsible for the maintenance and operation of all <br />stormwater structures and BMPs requiring maintenance during construction and, after construction, <br />responsibility will pass to the building owner. A copy of the maintenance and operations manual shall be <br />retained on -site or within reasonable access to the site and shall be transferred with the property to any <br />new owner. A log of maintenance activities that indicate what actions were taken shall be kept and be <br />available for inspection by the City of Everett upon request. <br />Included in this manual are maintenance sheets taken from the 2014 Stormwater Management Manual <br />for Western Washington. Maintenance sheets are included for the following facilities/activities: <br />Catch Basins: Concrete structures with steel grates that collect stormwater runoff from the site and <br />act as junctions for storm conveyance pipes. <br />Catch Basin Inserts: Filter socks/traps to be placed in catch basins to prevent sediment -laden waters <br />from entering the public storm system. <br />Stormwater Detention Pipe w/ Flow Restrictor: A underground structure to detain stormwater so it <br />can be released at required rates. <br />Vegetation Management: Landscaping can include grading, soil transfer, vegetation removal, <br />pesticide and fertilizer applications, and watering. Stormwater contaminants include toxic organic <br />compounds, heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and pesticides. <br />Facilities shall be inspected for defects listed in the following facility sheets. Most maintenance tasks are <br />generally reactionary to a defect being found, rather than a matter of constant upkeep. It is generally <br />expected that few to none of these defects will be present upon the yearly inspection of each facility. The <br />facility sheets list the potential conditions warranting maintenance and the expected result following any <br />maintenance. Several engineer's notes for specific tasks are provided within the facility sheets. Unless <br />otherwise noted on the facility sheets the maintenance tasks should be performed on an "as needed" <br />basis: <br />(a) When the described defect is visible to whomever performs the yearly inspection, <br />(b) Should any defect become apparent between inspections. <br />250 4th Avenue South, Suite 200 <br />Edmonds, WA 98020 <br />ENGINEERING ph.425.778.8500 1 f.425,778.5536 <br />www.cgengineering.com <br />