Laserfiche WebLink
D. Sequential systems that combine several practices; <br />E. Permanent conservation easements, preferably with the easement <br />being held by a third party with no vested interest in ever seeing <br />the property developed; <br />F. Natural channel design for drainage -ways; <br />G. Bioengineering in drainage -ways; <br />H. Recreating floodplains; <br />I. Chemical and biological filters in storm sewer inlets; <br />I Sand filters; <br />K. Allowing roof water from buildings to run across lawn areas to <br />remove pollutants; <br />L. Onsite sewage disposals system replacement or conversion to sani- <br />tary sewers; <br />M. Low - impact development design; <br />N. Countryside development design meeting the criteria of the West- <br />ern Reserve Resource Conservation and Development Area; <br />O. Aquatic benches in retention basins and ponds. <br />(7) Technical Basis: The plan will contain a statement of the rationale uti- <br />lized to select the BMPs used to control pollution and to maintain and <br />protect water quality. <br />(f) Development Sites One Acre or Larger: A development site that disturbs <br />one or more acres of land shall identify: <br />(1) Storm Water Detention: The post - construction BMP(s) chosen must be <br />able to detain storm water runoff for protection of the stream channels, <br />stream erosion control, and improved water quality. <br />(2) Structural BMPs: Structural (designed) post - construction storm water <br />treatment practices shall be incorporated into the permanent drainage <br />system for the site. <br />(3) Properly Sized BMPs: The BMP(s) chosen must be sized to treat the <br />water quality volume (WQv) and ensure compliance with Ohio's water <br />quality standards in OAC Chapter 3745 -1. The WQv shall be equiva- <br />lent to the volume of runoff from a 0.75 -inch rainfall and shall be de- <br />termined according to the following equation: WQv = C * P * A / 12 <br />where: WQv = water quality volume in acre -feet C = runoff coefficient <br />appropriate for storms less than one inch (either using Table 1 or the <br />following formula: C= 0.8581 — 0.78i2 + 0.774i + 0.04 where i= fraction <br />of post - construction impervious area) P — 0.75 inch precipitation depth <br />A = area draining into the BMP in acres. <br />58 <br />