8525 EVERGREEN WAY BURGER KING 2021-05-10

I Paul McKee From: Erik Emerson Sent: Friday, February 23, 2018 12:00 PM To: Paul McKee Subject: Burger King Restaurant, 8625 Evergreen Way Stormwater Review Comments Paul, Robin and I have reviewed the submitted documents for the Burger King project and have the following comments: 1. Provide the following in the Project Overview Section of the Stormwater Report: • The amount of new pollution-generating hard surfaces(PGHS), replaced PGHS, effective impervious surfaces, and converted vegetated areas needs to be provided. Note that the Drainage Report indicates that the existing parking lot would remain and be seal coated, but Sheet 5 (Paving Plan)shows the parking lot hatching as"new and/or replaced paving (4,707 square feet)". This discrepancy needs to be resolved in the Drainage Report and on the plans. • The Predeveloped Basin Map provided in the Drainage Report shows two basins: Basin A with flows discharging to the existing stormwater conveyance system beneath Evergreen Way and Basin B with flows discharging to the existing conveyance system beneath Holly Drive. Confirm whether Basins A and B are one or two Threshold Discharge Areas (TDAs). If the basins are two distinct TDAs,then the MR applicability must be documented separately for each TDA. If the basins are in fact one TDA, the Drainage Report should document that clearly. • A copy of Figure 2.4.2 from Volume I of the SWMM is provided in the Drainage Report, showing hand mark-ups of how the flow chart was navigated to determine MR applicability. The markups indicate that MR#1-9 apply because the project would add 5,000 square feet or more of new hard surface or convert%acres or more of vegetation to lawn or landscaped areas or convert 2.5 acres or more of native vegetation to pasture. However, Sheet 5 (Paving Plan)shows only 4,707 square feet of new or replaced hard surface area and less than the threshold amounts of converted vegetation areas. The MR applicability needs to be documented clearly in the Drainage Report and needs to agree with the areas shown in the plans. Per the above bullet, MR applicability should be evaluated for each TDA. • Difficult site parameters need to be discussed. If none exist, document that in the Project Overview section. • Document the date of the City's Design and Construction Standards and Specifications(e.g., January 2018)that was used as the basis of design. 2. The vicinity map should identify the route of stormwater off-site to the local natural receiving water. If there are no significant geographic features or sensitive/critical areas,state that in the narrative where the vicinity map is introduced. 3. Provide a site map in the drainage report.The site map should be at a minimum USGS 1:2400 topographic map as a base, should display, acreage and outlines of all drainage basins;existing stormwater drainage to and from the site; routes of existing, construction, and future flows at all discharge points; and the length of travel from the farthest upstream end of a proposed storm drainage system to any proposed flow control and treatment facility 4. Identify if the provided soils map has been field verified and documents the conclusions of such verification. 5. Identify the following information in the existing conditions summary: • The natural receiving waters that the stormwater runoff either directly or eventually(after flowing through the downstream conveyance system)discharges to. • Any area-specific requirements established in local plans, ordinances, or regulations or in Water clean-up Plans approved by Ecology. • A soils report prepared by a qualified professional is likely required but has not been provided. See the requirements for the soils report in Section 3.1.1,Volu• e I of the SWMM.