1010 N BROADWAY EVCC 2018-01-01 MF Import

4.3.2 Offsite Conveyance System The conveyance system within the Fitness Center parking lot and up to the outlet in Tower Street was analyzed for capacity beginning with the 8-inch pipe at the property boarder(see Appendix A, Exhibit A-8). As described above, the Fitness Center conveyance was analyzed using the unit hydrograph (SBUH) method and Manning's Equation to check capacity. The analysis indicates that the system has capacity for the 25-year, 24-hour peak flow without overtopping. Additionally, the 100-year, 24-hour storm is contained within the storm system. The 2001 Reid Middleton report(Appendix B, Exhibit B-8), which summarizes the improvements to storm infrastructure in Broadway,Tower, and Waverly Streets on the Everett Community College campus, includes an assumed future expansion area. As this project results in an increase in that assumed area,the Reid Middleton calculations were reproduced using the increased area to ensure existing capacity is sufficient for the proposed work. This analysis is described in a memorandum in Appendix B, Exhibit B-9. The conveyance calculations are provided for reference. 5.0 ANALYSIS AND DESIGN OF REQUIRED SOURCE CONTROL BMPs This project does not fall under any of the specific business or manufacturing groups listed in the City of Everett Stormwater Management Manual. The pollutants of concern are oil and gas, and other fluid emissions from vehicles, and the use of pesticides and herbicides for landscape maintenance. This section will also address the construction practices dealing with pollutants other than sediments and spill control measures. 5.1 Proposed Source Control 1. Warning signs(e.g.,"Dump No Waste—Drains to Puget Sound")shall be stenciled or stamped on or adjacent to all storm drain inlets. Signs shall be repainted as needed. 2. Parking lots and drive aisles shall be swept periodically. Special care shall be taken not to flush water from the pavement surfaces into the storm drain system. 3. The use of pesticides shall follow the"Integrated Pest Management Plan,"provided in Appendix D. 5.2 Construction Source Control CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS Operation and maintenance activities, and storage and disposal practices at the construction site will be conducted to minimize the potential for contamination of stormwater runoff. Good housekeeping practices shall be maintained by the Contractor(s). Major equipment maintenance will be performed at a properly permitted location remote from the project site. The project site can be used for daily maintenance activities, such as periodic oil changes, to ensure proper operation of the equipment and to ensure that the equipment is environmentally safe. Heavy equipment that cannot leave the project site without being hauled on a trailer or truck can be worked on at theproject site, provided that the work is performed in a designated Contractor's staging area and that environmentally safe procedures are adhered to. Waste oil and contaminated debris will be removed from the site and disposed of in accordance with applicable regulations. Stormwater Site Plan Report 0C11:10 EverettCommunity College Index Hall Replacement&Surface Parking Lot"M" 7 209459.10/209459.11