1600 121ST ST SE 2016-01-01 MF Import

this volume is required to be permanent storaqe in the pond. The required detention volume must be provided as live stora7e in addition to the dead storage. The control structure must eneure that detention release rates do not exceed allowable release rates and that the detained volume ?n the pond reaches or exceeds the required wet pond volume for the 2 year storm. Orifice calculations must be submitted showing th�t the control structure is meeting both these requirements. The following information regarding the detention/wetpond must be submitted to the City for review and approval: 1) 2) 3) 4) 51 campleted City of Everett 'Jrai.nage Calculation Form wetpond sizinq calculations orifice sizing calculations stage-storaqe relationship of results of routing the 2 year the p�nd orifice eizina• the pond design storm through Non-publicly maintained restrictor devices may have a minimum orifice size af 1 inch. oil/Mater aeuaratore/arit removal vaulta: City standards call for the vault to have an inlet capacity determined by using the rational formula with a rainfall intensity of 0.5 inches per hour over the contributing area. Bypass piping is required for the vault per City standards. The vault inlet capacity should be reached at the point that the water elevation in the bypass pipe is at fts peak for the 10 year storm. The vault must be sized to provide a 15 minute detention time for the design flow. The entire contributing area must be used in calculating the size of the oil/water separator vault although only the paved surface is required to be routed through the separator. The oil/water separator for the designated wash area must be sized to give a 15 minute detention time for the anticipated hose flow to the area. The anticipated hose flow must be stated, and justification for the number used must be given.