220 OLYMPIC BLVD VA OUTPATIENT CLINIC 2023-02-09

I • TDAs that have a total of 5,000 square feet or more of effective impervious surfaces, or • TDAs that convert 3/4 acres of more native vegetation, pasture,scrub/shrub, or unmaintained non-native vegetation to lawn or landscape, or convert 2.5 acres or more of native vegetation to pasture, and from which there is a surface discharge in a natural or manmade conveyance system from the TDA, or • TDAs that through a combination of effective hard surfaces and converted vegetation areas cause a 0.15 cubic feet per second (cfs) or greater increase in the 100-year flow frequency as estimate using an approved continuous simulation model and 15-minute time steps The 0.15 cfs increase should be a comparison of the post project runoff to the existing condition runoff. For the purpose of applying this threshold, the existing condition is either the pre- project land cover, or the land cover that existed at the site as of a date when the local jurisdiction first adopted Flow Control requirements into code or rules. Response: Flow control is required in accordance with the 2019 Manual for all new and 111 replaced surfaces, but not for the 2" grind and overlay areas that are exempt from flow control per the City of Everett. Flow control will be provided by means of a 20' x 110' x 8' detention vault for flow control. Please see the Flow Control section of this report for more information. Minimum Requirement#8: Wetlands ProtectionI Projects shall employ Stormwater Management BMPs in accordance with the following thresholds, standards, and requirements to reduce the impacts of stormwater runoff to wetlands. Response: As shown in Figure 3 below, existing wetlands are located approximately 600' to the south of the project site.The project is downstream of and does not discharge to these wetlands and no impacts to the existing wetlands are anticipated. I I I I I I I NAVIX Everett VA Clinic—Everett, WA 12