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Article 6: Development Standards 15 <br /> Section 6.14: Stormwater Management <br /> (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 Techniques <br /> (a) The benefits of infiltration techniques include: <br /> (i) Removal of both suspended and dissolved pollutants, <br /> (ii) They require less maintenance, <br /> (iii) They reduce flooding, <br /> (iv) They promote groundwater recharge, and <br /> (v) They help maintain stream flow during dry periods. <br /> (b) Where on-site infiltration methods 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 for infiltration of run-off shall also be located <br /> downslope from impervious surfaces and shall not include areas <br /> characterized by floodplains, highly erodible or impervious soils, steep <br /> slopes or previously disturbed areas. <br /> (d) Areas designated as suitable for septic tank nitrification fields may not be <br /> used for stormwater infiltration purposes. <br /> (B) Structural Stormwater Measures <br /> (1) In cases where non-structural methods may not adequately control the first ipA,h <br /> ef—stermwvater runoff from the first inch of rain due to the amount of impervious <br /> surface proposed to be developed, and other factors such as soil type, slope, <br /> presence of floodplains and erodible soils, and/or lack of vegetative cover <br /> °6 Imes, structural stormwater measures,which capture stormwater for slow <br /> release through an outlet, are required. <br /> (2) Where required, structural stormwater measures shall be constructed in <br /> accordance with this Section. <br /> (C) Impervious Surface and Detention Pond 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, structural stormwater measures are required when the proposed <br /> impervious surface ratio exceeds a specified percentage, which is below the <br /> absolute limit. <br /> 6.14.5 Applicability <br /> (A) The stormwater standards and regulations included herein are applicable to all new <br /> development within the Orange County planning jurisdiction, including private, public, <br /> state, and federal development not covered by a separate NPDES permit, as follows: <br /> (1) Falls Lake Watershed <br /> (a) Any activity that cumulatively disturbs greater than one-half acre of land <br /> in order to establish, expand or modify a single family or duplex <br /> residential development or a recreational facility. <br /> Orange County, North Carolina—Unified Development Ordinance Page 6-102 <br />