2405 MAPLE ST 2023-06-28 - Laserfiche WebLink

MAPLE ST .. .. ................................................................................ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.0311 5 year 0.0455 10 year 0.0569 25 year 0.0736 50 year 0.0879 100 year 0.1038 S. DEVELOPED CON[ ITIO ,`� The project entails demolishing the existing house and constructing a new single-family residence, detached garage (under separate permit) and driveway with supporting infrastructure and services. Runoff generated by the impervious areas on the site will be collected and conveyed to the public combined sewer system. The total lot area is 4,923 sf(0.11 acres) of which 2,460 sf(0.05 acres) will be impervious. The proposed area for house will be 1,232 sf. The residence will have a deck and patio that will be 158 sf collectively. The proposed detached garage will be 757 sf. The driveway from the garage to the alley will be 34 sf. New walkways from the garage and front yard to the proposed residence will be 279 sf. The total impervious surface area, including hard surfaces, will be 2,490 sf. All disturbed pervious areas (2,493 sf) will be compost amended and landscaped.Totals were evaluated using best available resources such as site plan, aerial maps and survey. Please see proposed site plan on the following pages. Per Volume V, Chapter 11 of the DOE 2019 Stormwater Management Manual for Western Washington, pervious areas utilizing BMP T5.13: Post-Construction Soil Quality and Depth are to be modeled as pasture.The table below provides a summary of proposed site conditions: DEVELOPED CONDITIONS (11 Impervious House 1,232 sf Detached garage 757 sf Driveway 34 sf Deck& Patio 158 sf Walkway 279 sf Total Impervious 2,460 sf Pervious Pasture 2,463 sf Total Pervious 2,463 sf TOTAL LOT AREA 4,923 sf JOB#19-336 Storm Drainage Report 5.2