Laserfiche WebLink
Two-year storm water peak flow during construction: 0.761 cfs <br />Ten-year storm water peak flow during construction: 3.53 cfs <br />All storm water flow calculations are provided in Appendix F. <br />2.3 Requirements Relative to Environmental Contaminants at the Site <br />The subject site and surrounding properties are part of the Everett Smelter Plume (ESP), <br />identified as part of a 1,000 square mile plume of surface soil impacted with elevated levels of <br />arsenic and lead. Testing completed at and adjacent to the subject site have confirmed levels <br />of arsenic at a maximum concentration of 1,273 milligrams per kilogram, or parts per million <br />(ppm), while lead has been identified at a maximum concentration of over 400 ppm. The <br />applicable state cleanup level for Arsenic is 40 ppm, while lead is 500 ppm. <br />As described above, work activities will include the removal and offsite disposal of arsenic- and <br />lead-impacted surface soil, followed by replacement with clean fill. Confirmation soil samples <br />will be collected following removal of impacted materials, which will be analyzed for total <br />arsenic and total lead at an accredited analytical laboratory. <br />Care will be utilized to prevent dust or fine soil particles from leaving the subject site via wind <br />or surface water. Soil wetting and/or use of plastic sheeting will be used to prevent migration <br />of dust. Catch basin inlet protection will be used to prevent fine soil particles from migrating to <br />the City of Everett Storm Sewer System. Wattles and silt fence will be utilized along the <br />northwestern edge of the subject site (i.e., adjacent to Alverson Boulevard). <br />Groundwater is not expected to be encountered during remediation activities. <br />TESC Plan and SWPPP 2 June 2015 <br />American Legion Memorial Park Page 6 <br />