901 W CASINO RD 2018-01-02 MF Import

The subject property consists of one drainage basin which currently discharges storm - water as sheet flow to the north as dictated by topography. The project site will be regraded to minimize pavement slope and to maintain adequate drainage patterns for a discharge into the existing storm drainage conveyance system located in West Casino Road. A storm drainage system will be provided for this project in accordance with City of Everett standards and guidelines. The system as designed will be relatively main- tenance free and provide the required biofiltration, via grass -lined Swale. In addition, an underground storage tank (1,000 gallon) shall be provided for on -site "wash -down" for possible gasoline spills. Stormwater will also pass through an oil/water separator vault prior to discharging into the existing city owned storm drainage system in West Casino Road. The proposed storm drainage systems shall be sized to adequately handle runoff produced by a 25-year storm. Please reference the drainage and pipe sizing calculations provided in this report. • _ : u � :: _ bY6'il The City of Everett has indicated the existing storm drainage system located in West Casino Road has been designed to adequately handle the runoff produced the contributing drainage basin in which the subject property lies without the provision of detention. Therefore, it has been indicated that a downstream drainage analysis will :iot be necessary.