9212 HOLLY DR 2018-01-02 MF Import

c f C I C C C C C 11 I I L, I Page 4 of 29 Preliminary Conditions Summary The overall topography on the site slopes to the east corner of the site. See Figure 3a — Existing Hydrology and Figure3b — USGS Topographical Map. A depression on the north and west boundaries of the properties collects all runoff from the upstream western properties and all runoff from the northern section of lire property. See Figure 4 — Natural Drainage Pattern. Runoff is conveyed from the depression through 3 catch basins and 12" CPEP to the northeast property boundary. Outflow from the piping flows into a shallow stream flowing from the northwest along the property's northeast boundary. The stream flows along the sitc's property line and the neighboring properties to the northeast. The stream is shallow and evidence of property flooding can be seen. Most of the stream flow is through brush, garbage and debris from the neighboring properties. The stream also collects sheet flow from the northeast side of the property. Ninety feet southeast of the northern property corner, part of the stream enters a trash rack covered inlet into an uncovered broken -atch basin. The catch basin receives flow from a catch basin located on the property to the east and from the stream to the west. From the catch basin, drainage is conveyed underground along the NE property line to a catch basin at Holly Drive. The part of the stream not entering the catch basin pools along the NE property line. Storm water not collected on the north and northeast sides of the lot, sheet flows to the southeast property line. Water collecting at the southern most entrance to the existing mobile home community collects in a shallow ditch and catch basin that connects into the storm drainage system along Holly Drive. Water flowing towards the center entrance to the mobile home community collects at a depression 30 ft NE of the property line. Water collected at the depression is conveyed NE through underground concrete pipe to a catch basin at the northern most entrance to the mobile home community, 30ft off the SE property line. Flow then continues to the storm water system along Holly Drive.