1815 13TH ST SEATTLE CHILDRENS NORTH CLINIC 2019-07-08

MAGNUSSON KLEMENCIC ASSOCIATES • ELEMENT#2: ESTABLISH CONSTRUCTION ACCESS The selected contractor shall update this section as required. • Construction vehicle access and exit shall be limited to one route. • Unpaved access points shall be stabilized with a pad of quarry spalls, crushed rock, or equivalent BMP prior to traffic leaving the construction site to minimize the tracking of sediment onto all roads and accesses. • Wheel wash or tire baths shall be located on site, if the stabilized constructions entrance is not effective in preventing sediment from being tracked onto roads/accesses. • If sediment is tracked off site, roads/accesses shall be cleaned thoroughly at the end of each day, or more frequently during wet weather, if necessary to prevent sediment from entering storm or combined sewer systems. Sediment shall be removed from roads by shoveling or pickup sweeping and shall be transported to a controlled sediment disposal area. Street washing will be allowed only after sediment is removed in this manner. • Street wash wastewater must be prevented from discharging into systems tributary to state surface waters. Options include discharge to the sanitary sewer, or discharge to an approved offsite treatment system. For discharges to the sanitary sewer, permits must be obtained from the City Industrial Pretreatment Program at (253) 798-3013. • Applicable BMPs: — BMP C105: Stabilized Construction Entrance — BMP C106: Wheel Wash — BMP C107: Construction Road/Parking Area Stabilization. ELEMENT#3: CONTROL FLOW RATES The selected contractor shall update this section as required. • Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. • Where necessary to comply with Minimum Requirement#7, stormwater detention facilities shall be constructed as one of the first steps in grading. Detention facilities shall be functional prior to construction of site improvements (e.g., impervious surfaces). • Applicable BMPs (if the detention facility is not constructed prior to installation of site improvements): — BMP C241: Temporary Sediment Pond ELEMENT#4: INSTALL SEDIMENT CONTROLS The selected contractor shall update this section as required. • Prior to leaving a construction site stormwater runoff from disturbed areas shall pass through a a sediment removal BMP. Runoff from fully stabilized areas (see Element #5) may be discharged without a sediment removal BMP, but must meet the flow control performance standard of Element #3. • BMPs intended to trap sediment on site shall be constructed as one of the first steps in grading. These BMPs shall be functional before other land disturbing activities take place. If installed early in the construction sequence the precast concrete detention vault may be utilized as a temporary sediment pond. Construction Stormwater Pollution Prevention Plan 6 Providence Regional Medical Center Everett, North Site, Everett, Washington