3003 W CASINO RD BLDG 40-YD 2019-11-27

Drainage Report—Revision 1 Boeing Everett-Rail Spur Parking Lot September 26,2013 9.3 ESC Requirement#3: Protection of Adjacent Properties Properties adjacent to the project site shall be protected from sediment deposition. BMPs relevant to ensuring that adjacent properties are protected from sediment include: • BMP E3.10: Filter Fence • BMP E3.15: Straw Bale Barrier 9.4 ESC Requirement#4: Timing and Stabilization of Sediment Trapping Measures Sediment barriers and other BMPs intended to trap sediment onsite shall be constructed as one of the first steps in grading. These BMPs shall be functional before land disturbing activities take place. Earthen structures shall be seeded and mulched according to the timing indicated in ESC Requirement#1. 9.5 ESC Requirement#5: Cut and Fill Slopes Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. In addition, slopes shall be stabilized in accordance with ESC Requirement#1. Specific BMPs used for stabilizing slopes include: • BMP E1.20: Clean Plastic Covering 9.6 ESC Requirement#6: Controlling Off-site Erosion Properties and waterways downstream from the development site shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. Specific BMPs used for controlling offsite erosion include: • BMP E3.10: Filter Fence • BMP E3.15: Straw Bale Barrier • BMP E3.30: Storm Drain Inlet Protection 9.7 ESC Requirement#7: Stabilization of Temporary Conveyance Channels and Outlets All temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected velocity of flow from a 2-year, 24-hour frequency storm for the developed condition. Stabilization adequate to prevent erosion of outlets, adjacent streambanks, slopes and downstream reaches shall be provided at the outlets of all conveyance systems. Specific BMPs used for stabilizing channels and outlets include: • BMP E2.70: Outlet Protection 9.8 ESC Requirement#8: Storm Drain Inlet Protection All storm drain inlets made operable during construction shall be protected to prevent unfiltered water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and prevent street wash water from entering storm drains until treatment can be provided. Sediment and street wash water shall not be allowed to enter storm drains without prior and adequate treatment. Inlets should be inspected weekly at a minimum and daily during storm events. Inlet protection devices should be cleaned or removed and replaced DCG, Inc. Page 9 of 11