9803 19TH AVE SE 2018-01-02 MF Import

9. DESIGN CRITERIA - The system has been designed to meet a combination of the City of Everett and the Washington State Department of Fish and Wildlife criteria A summary of the criteria by events and process are listed below: A) Stormwatcr treatment is provided by a wetpond meeting the City criteria of open and treatment volumes, 2 year storage volume and vegetation. B) Discharge from the treatment pond is control to 50% of the predeveloped 2 year storm during the 2 year developed design runoff. However the City has a 1" I minimum orifice size for outlet control. In this case the minimum opGce will be used because the drainage area and flows are too small to exceed the minimum orifice requirement. C) Runoff from the 10 year storm is controlled to the 10 year predeveloped runoff rate during the 10 year developed design storm. D) Runoff during the 100 year event is controlled to the 100 year predeveloped runoff rate. E) the detention volume above the 2 year storm event is increased by 50% for commercial property. A summary of design criteria regarding detention release rates, storage volumes and wet pond volumes are shown in Table 1, Burger King Design Criteria Summary Table 1 Burger King Design Criteria Summary Dean, Criteria 6 on Storm 2 Year Storm 1 eartorm 1 ear tonm Lennon 3,6301 6,6102 8� Volume, cf Wet Pond 3,6301 3,6301 3,6301 3,6301 Volume, cf Permanent 1815 Storage, cf Permanent 544 Treatment Storage, cf Pt Storage 2,980 4,673 Volume, cf veo . Ocs 4 cs cs Runoff Rate ntena a ease 0.063 0.063 Rate, cfs 13,630 of based upon 0.99" rainfall 2 detention volume for design storm plus additional 50% 3 1" minimum orifice size 96-016 3 Two Rivers Enoneaing