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Administration <br />(91s) 245-2575 <br />(e{e} 64/,-3002 (FAX) <br />www.ora n gecou ntyn c. gov <br />FROM: <br />DATE: <br />SUBJECT: <br />PLANNING & INSPECTIONS DEPARTMENT <br />Craig N. Benedict, AICP, Director <br />' '-\'-tr--i^. <br />ORANGE COUNTY <br />NORTH CAROLINA <br />131 W. Margaret Lane <br />Suite 201 <br />P. O. Box 8181 <br />Hillsborough, NC 27278 <br />MEMORANDUM <br />TO: Randy Horton, OWASA Water Dist. and Wastewater Collection Systems Manager <br />CC: Bonnie Hammersley, Orange County <br />Travis Myren, Orange County <br />Todd Taylor, OWASA <br />Allison Reinert, OWASA <br />Krista Paredes-Toledo, AECOM <br />Jesse Duclau, Moffat Pipe, lnc. <br />Craig N. Benedict, Orange County Planning & lnspections Director <br />October 26,2018 <br />Historic Rogers Road Sewer Expansion Project - Variance Request <br />Service Lateral Pipe Materials <br />Sewer <br />The Historic Rogers Road Sewer Project is a joint local government-approved and government- <br />funded initiative that includes over 18,000 linear foot of gravity sewer. The project is owned by <br />Orange County and managed by the Historic Rogers Road Work Group (HRRWG), which consists of <br />representatives from Orange County, Town of Carrboro, Town of Chapel Hill, and OWASA. <br />Orange County would like to request from OWASA a variance in the allowed pipe material for eleven <br />(11) sewer service laterals crossing Rogers Road and Purefoy Road (see attached map for locations). <br />Orange County would like to use a flexible pipe material such as Fusible PVC (FPVC) or HDPE for <br />these 11 crossings. All other sewer service laterals will use the standard ductile iron pipe. The <br />primary reason for the variance request is the inability to install 4-inch ductile iron pipe laterals within <br />the very limited right-of-way and easement widths available along these roads. Nominal4-inch ductile <br />iron pipe has an outside diameter (O.D) of 4.8 inches and a bell O.D. of 6.4 inches. This would <br />require an 8 inch auger, thus resulting in an overbore of 3.2 inches (i.e. 8 inches minus 3.2 inches). <br />NCDOT has formally notified the HRRWG that NCDOT would allow an overbore of up to 2.5 inches, <br />however, anything exceeding 2.5 inches will require a detailed engineering evaluation to determine if <br />the soils in the vicinity of the bores will remain stable and to certify that there will be no subsidence of <br />the road. The presence of rock also concerns the HRRWG, as an auger would be needed to install <br />the DIP service laterals - thus furthering the need to request the variance for a flexible pipe material. <br />The consulting engineer for this project, AECOM (formerly URS Corporation), has reviewed the <br />proposed scenario and recommends the use of an alternative pipe material. The use of a flexible pipe <br />materialsuch as FPVC or HDPE would facilitate a smaller installation footprint and avoid the potential <br />for significant project impacts associated with additional engineering evaluations and/or the need for <br />open cut construction. Moffat Pipe, lnc. (Moffat) proposes to install these 11 laterals through impact <br />moling, which would minimize the pits required on either side of the road and reduce the potential for <br />road subsidence. Tracer wire would be installed along the laterals to accommodate perpetual locating <br />efforts. Moffat would like to begin installing these laterals as soon as possible. The HRRWG would <br />greatly appreciate your consideration and written feedback on the matter at your earliest convenience. <br />We look forward to working with you on this aspect of the project. <br />Enclosure <br />DocuSign Envelope ID: 269B2631-52B5-4390-B0FC-CE96792761B9