11102 EVERGREEN WAY 2018-01-01 MF Import

Vec�tat�d Bxaless Current City standards call for vegetated swales to be designed for the 2 year, 24 hour storm peak discharge, with higher flows diverted around the swale. If possible, the swales should be designed with a bypass system. The swale should then be designed per the following criteria for the 2 year, 24-hour storm: °n" = 0. 12 max velocity = 1.5 feet per second max. depth = 0.5 feet , ' If diveraion is not feasible, the following additional dasign criteria will apply for the 25 year, 24-hour storm: °n" = 0.035 max velocity = 4.0 feet per second max. depth = 1.o feet The entire contributing area must be used in calculating the croes-sectional area of the swale. Only the site�s paved area muat be used in determining the required length of swale. The following information regarding the vegetated swale must be submitted for review and approval: 1) dasign flow calculation 2) velocity and flow depth calculations 3) bypass sizing calculations 4) copy of site plan showing the contributing area 5) calculation of the length of swale required for each drainage area D��1N AEVSFW COMMENTB v�catated swalas: If the groundwater table in the area is hiqh, and/or the area ie generally shaded, the swale should be designed as a biofiltration swale. All runoff from paved areas must be routed through the design length of vegetated swale prior to discharge from the � site. Spot elevations in the bottom of the swale should be given at the head of the swale, at the swale outlet, and at approximately 50 foot intervals along the lenqth of the swale.