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(b) Impervious surface calculations for an individual development shall be <br />cumulative for original construction and any subsequent additions. One- <br />half of the width of any of any existing or proposed road adjacent to an <br />individual lot shall be included as impervious surface for that lot, except <br />in the case where an existing road was contained within a dedicated <br />public right-of-way at the time that the watershed regulations were first <br />applied to the watershed within which the development is located. <br />(4) Infiltration Systems <br />(a) The benefits of Infiltration Systems include, but are not limited to: <br />(i) Removal of both suspended and dissolved pollutants, <br />(ii) Relatively low maintenance requirements, <br />(iii) Flood reduction, <br />(iv) Promotion of groundwater recharge, and <br />(v) Maintenance of stream flow during dry periods. <br />(b) Where on-site Infiltration Systems are utilized, areas for such purposes <br />shall be designated on the plat and shall remain undisturbed both during <br />and after construction. <br />(c) Undisturbed areas designated for infiltration of stormwater runoff shall <br />also be located downslope from impervious surfaces and shall not <br />include areas characterized by floodplains, highly erodible or impervious <br />soils, steep slopes or previously disturbed areas. <br />(d) Areas designated as suitable for septic tank nitrification fields may not be <br />used for stormwater runoff infiltration purposes. <br />(B) Stormwater Control Measures (SCMs) <br />(1) In cases where non-structural methods may not adequately control the <br />stormwater runoff generated by the first inch of rain from all project surfaces due <br />to the amount of impervious surface proposed to be developed, or in cases <br />where Non-Structural Methods are not effective or appropriate due to factors <br />such as the presence of highly erodible soils, impervious soils, steep slopes, <br />and/or lack of vegetative cover, permanent Stormwater Control Measures <br />(SCMs), which capture stormwater runoff for slow release through a controlled <br />outlet, are required. <br />(2) Where required, SCMs shall be constructed in accordance with this Section. <br />(C) Impervious Surface and SCM Requirements <br />(1) For all protected watersheds, an absolute limit on the percentage of lot area <br />which can be covered with impervious surfaces has been established. See <br />Section(s) 4.2.5 and 4.2.6 of this Ordinance. <br />(2) In some cases, SCMs are required when the proposed impervious surface ratio <br />exceeds a specified percentage, which is below the absolute limit. <br />6.14.5 Applicability <br />(A) The stormwater management standards and regulations included herein are applicable to <br />all new development within the Orange County planning jurisdiction, including private, <br />public, state, and federal development not covered by a separate NPDES permit, as <br />follows: <br />(1) Falls Lake Watershed <br />124