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1 <br /> Drainage Report <br /> Boeing Everett-E-6 Parking Lot Expansion July 16,2013 <br /> ' Mill Gulch detention/water quality pond to the north of the Boeing plant. Onsite stormwater <br /> management through the use of BMPs was still analyzed for feasibility. Porous asphalt was <br /> considered for the top course; however soils were not conducive to infiltration. See Section 8.4 <br /> for additional flow control exemption information. <br /> 3.8 Minimum Requirement#8—Wetlands Protection <br /> As the project site is neither in, nor tributary to a wetland and does not directly or indirectly <br /> convey stormwater to a wetland, the project is not required to meet any applicable standards for <br /> this requirement. <br /> ' 3.9 Minimum Requirement#9—Operation and Maintenance <br /> An operation and maintenance manual consistent with Volume V of the Stormwater Manual has <br /> been provided in APPENDIX B. <br /> ' 4. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN <br /> The project is anticipated to add or replace more than 2,000 SF of impervious surface and <br /> therefore requires the development and implementation of a Construction Stormwater Pollution <br /> Prevention Plan(CSWPPP)prepared in accordance with the elements listed in section Volume 2, <br /> Chapter 2, Section 2.4 of the Stormwater Manual. A Temporary Erosion and Sediment Control <br /> Plan(TESC) is also required per the Stormwater Manual and is included as APPENDIX C. Both <br /> the SWPP and TESC Plan serve as guides as the contractor is required to design a working <br /> TESC plan for the site. Refer to TABLE 2 in this report for TESC measures. <br /> Each of the required elements of the CSWPPP are addressed in the following sections. <br /> 4.1 Element#1 —Mark Clearing Limits <br /> To reduce the area of soil exposed to construction, the limits of construction will be clearly <br /> marked before land-disturbing activities begin. The BMPs relevant to marking the clearing limits <br /> that will be applied for this project may include: <br /> • BMP C103: High Visibility Plastic Fence <br /> 4.2 Element#2—Establish Construction Access <br /> Construction vehicle access will be limited to one entry at the paved existing site access from the <br /> adjacent asphalt road to the west. If sediment is tracked offsite, roads/accesses shall be cleaned <br /> thoroughly at the end of each day, or more frequently during wet weather, if necessary to prevent <br /> sediment from entering drainage inlets. Sediment shall be removed from roads by shoveling or <br /> pickup sweeping and shall be transported to a controlled sediment disposal area. Street washing <br /> will be allowed only after sediment is removed in this manner. Street wash wastewater shall be <br /> controlled by pumping back on site to an approved infiltration facility. BMPs relevant to <br /> establishment of construction access for this project may include: <br /> • BMP C107: Construction Road/parking Area Stabilization <br /> 1 <br /> 20130715_Drainage Report Boeing Everett_Gate E-6 Parking Lot.doc Page 9 <br /> 1 <br />