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1 <br /> Basin 2 is a total of 42,931 SF (0.98acres). This basin involves two different soil types, <br /> Alderwood Gravelly Sandy Loam (34,027 SF {0.78acres}) Type C soil, on the east and Vashon <br /> Till (8,904 SF {0.20acres})Type B soil, on the west. <br /> DEVELOPED CONDITIONS <br /> The Serenity Meadows proposes to build 9 single-family homes including driveways on the 2.07 <br /> acre site. However, only 1.22 acres of the lot will be developed due to the wetland and associated <br /> buffer located on the west side of the property. Approximately 323 lineal feet of paved private <br /> roadway will be constructed to access from 7th Avenue SE. A wider access will be installed at <br /> the existing driveway access along the east property line, at the south corner. The proposed <br /> private road will consist of 2— 10 FT wide vehicular travel lanes with rolled curb and gutter (27 <br /> FT in width). A drainage system using catch basins with oil water separators flowing into <br /> adjacent rain gardens to provide for water quality and infiltration. <br /> DEVELOPED BASIN DESCRIPTIONS <br /> The proposed development is split into two separate drainage basins. <br /> The developed Basin 1 is a small basin of 6,812 SF (0.16acres) located on the east end of the <br /> developed site. This basin as with the existing basin flows east to the 7th Ave SE existing <br /> drainage system. The basin includes the front landscaped area 3,998 SF (0.10acres) on site and <br /> I 2,814 SF (0.06acres) of impervious area including the driveway to unit 1 and the private <br /> roadway from unit 1 to 7th Ave. SE. The driveway and sidewalk in Basin I area will use pervious <br /> pavement (See section "A" sheet C 6 and section "A" sheet C 4, of the construction plans for <br /> driveway and sidewalk details) . Pervious pavement includes 6inches of pervious pavement, 2 <br /> inches of 1.5 inch No. 8 sieve chocker course and 18 inches of 1.5 to 2 inch washed base rock. <br /> This creates pollution control and infiltration of both the sidewalk and driveway. Basin 1 is less <br /> than 5,000SF (0.06 acres 2.81SF), of impervious. No detention is required per the drainage <br /> manual. There are 2 catch basins with oil water separators in the private roadway to collect <br /> pollutants from the storm water to insure water quality. <br /> Basin 2 encompasses the central core of the project and flows west to the existing wetland on the <br /> west side of the site. The total area of Basin 2 is 46,485 SF (1.06acres). (See attached Developed <br /> Basin Maps in the Section II this report). For the purpose of calculations, Basin 2 was split into <br /> two separate sub-basins Basin 2A and Basin 2B. <br /> Basin 2A (North half) — This basin includes 0.58 acres of developed area and includes <br /> � p <br /> 0.24 acres of impervious and 0.34 acres of pervious area(landscape and/or natural). The <br /> basin has 4 rain gardens (flowing west) along the private road to collect drainage. The <br /> impervious area includes the north half of the asphalt private road (12' including curb), <br /> 3 <br /> I <br />