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SPANGLER <br /> ENVIRONMENTAL <br /> Environmental Consulting I Litigation .Support I Environmental Services <br /> 6 May 2025 <br /> Ms. Laura Haywood <br /> Entitlements Program Manager <br /> Forestar—Carolinas East Division <br /> VIA E-mail: LauraHaywood@forestar.com <br /> RE: HWY 86 DD—Orange County,NC—Orange County Buffer Applicability Memo <br /> Ms. Haywood: <br /> Based on the email provided on 4 April 2025,"Below I've also included a snip of the Soil Survey in which <br /> all on-site streams were mapped,which means UDO Section 6.13.5(B)does apply for buffer purposes",via <br /> Orange County's Taylor Pershau, the project area is subject to UDO Section 6.13.5(B) Stream buffers for <br /> Soil Survey streams shall only be calculated using Method A as explained in Section 6.13.3.As a result,the <br /> buffer analysis described below, and depicted in the attached figures follows UDO Section 6.13.3(C) <br /> Method A—Stream Buffer Based on Slope and Groundcover. <br /> Stream Buffer Calculations: <br /> Using Google Earth elevation data, Spangler Environmental, LLC (SEL) spaced cross sections 200 feet <br /> from one another along the previously mapped streams and calculated the slope between the top of bank <br /> and out 250 feet perpendicular to the direction of flow for each one, as described in Method A. At cross- <br /> sections with a slope of less than 7.5% a 65-foot-wide buffer(50 foot wide (minimum) + 15 feet wide) is <br /> applied and cross sections with slopes greater than 7.5% have an 80-foot-wide buffer (50 foot wide <br /> (minimum) + 30 feet wide). This also applies to any other water features, including wetlands, with direct <br /> surface connection to the stream reach.Additionally,the north-eastern stream sections are within the FEMA <br /> 100-yr floodplain. These sections must have the slope/buffer width determined from the floodplain's <br /> outermost boundary, rather than the top of the stream bank. Please see the attached map "Cross-sections <br /> and Slope Map",for the slope and location of each cross section. <br /> Conclusions: <br /> Based on the Orange County UDO Section 6.13.3, SEL has completed the buffer/slope analysis, and the <br /> results are shown in the attached"Orange County Buffer Map."All the buffered streams and wetlands have <br /> had their buffer extended from 50-ft previously to now at least 65-ft and 80-ft in others,respectively.Orange <br /> County and SEL met onsite on 22 April 2025 to conduct the Surface Water Identification (SWID). The <br /> results are verified by Orange County and are shown in the maps and .dwg file provided. This conclusion <br /> only speaks to the stream features,the wetland feature's locations and extents have yet to be verified by the <br /> United States Army Corps of Engineers(USACE)Wilmington District and are subject to change,therefore <br /> their resultant buffers are as well. <br /> Please advise if you have any questions. <br /> www.spanglerenvironmental.comRaleigh I CharlotteCharleston • . <br /> 866-772-6453 <br />