1710 W MARINE VIEW DR 2024-01-03

2. PROJECT DESCRIPTION 2.1. EXISTING CONDITIONS The site is currently developed with a parking lot, providing access to West Marine Supply and The Inn at Port Gardner. The remainder of the site consists of landscaped areas and a gravel area where the Weyerhaeuser building use to be located. The site drains through an existing closed conveyance system to two outfalls north of the site. Runoff from the adjacent South Marina parking lot and a portion of 18th Street is also conveyed through this system. See Appendix C for the drainage map figure. Per previous soil testing in the site vicinity, the project contains sand, silty sand, and sandy silt that have a hydrologic classification of Type A and B. Please refer to soil borings attached to this report for more info. Due to the high groundwater level, infiltration was deemed infeasible for this site. 2.2. PROPOSED CONDITIONS The proposed project will include the addition of two multi -tenant commercial buildings including space for a food and beverage establishment with drive through access. The combined square footage of the buildings is 5,000 SF. Additional site improvements include parking, patio space, and landscaping. The proposed drainage from the site will be through a new conveyance system, see Section 6 of this report for details. 3. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN A construction stormwater pollution prevention plan (SWPPP) has been prepared for this project and is included in Appendix B. The SWPPP is prepared following the guidelines in the SWMMVWU Volume II. Execution of the SWPPP during construction will be the responsibility of the Contractor. 4. HYDROLOGY Currently, the 1.02-acre site is covered with mostly impervious surfaces (gravel and asphalt) and a small, 0.15 acre, portion of pervious landscaping areas. The total area within the project limits is 1.08 acres including the improvements to the curb ramps across the drive aisles and landscape frontage improvements. The drainage basin for the PGL site is 1.08 acres. The new buildings, parking lot, and landscaping areas, will result in a total impervious area of 0.83 acres and 0.25 acres of landscaping. The proposed PGL Basin is subdivided into smaller basins corresponding to new inlets, see Table 1 below for a summary of the proposed basins. The existing and proposed drainage basins are shown in Appendix C. Table 2, below, summarizes the off -site basin areas used in the analysis. The South Marina parking area is upstream of the PGL site, the Lombardi's parking lot is downstream. The areas at the North and East edges of the site, basin BO, are consisted roadway maintenance or underground utility improvements. This area is approximately 0.10 acres. The drainage patterns in these areas will not be modified and will drain to the existing conveyance system. The area around the covered dumpster enclosure drains to the sanitary sewer system through a separate drainage pipe.