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November 10, 2020 <br />Mr. Bruce Woody <br />Assistant Solid Waste Director <br />Orange County Solid Waste <br />1514 Eubanks Rd. <br />Chapel Hill, NC, 27516 <br />RE: GPR Study for Rebar Location <br />Orange County Regional Landfill <br />Chapel Hill, NC <br />DAA Project No.: R00592-204G <br />Dear Mr. Woody, <br />Draper Aden Associates (DAA) has completed the ground penetrating radar (GPR) study for the <br />Metal & White Goods Retaining Wall Repair located at the Orange County Regional Landfill facility <br />on Eubanks Road in Chapel Hill, North Carolina (Figure 1). The objective of this study was to locate <br />rebar within the east and west sides of the retaining wall. <br />GPR data were collected on November 3, 2020 in two grids, one located along the east side of the <br />retaining wall and the other located along the west side of the retaining wall (Figures 1 and 2). <br />The GPR grid on the east side of the retaining wall measured a maximum of approximately 21 feet <br />horizontally by six (6) feet vertically. The GPR grid on the west side of the retaining wall measured <br />a maximum of approximately 12 feet horizontally by seven (7) feet vertically. Individual grid <br />traverses were spaced one (1) foot apart in both orientations of each grid. The GPR instrument <br />used for this study operated at 1000 MHz, which provided subsurface imagery to a depth of <br />approximately three (3) feet. <br />The GPR data were visually reviewed real-time and interpreted for evidence of rebar. Strong <br />repeating reflectors indicative of rebar reinforcements were observed in the traverses from both <br />orientations, the locations of which were marked real-time using blue spray paint. Figure 3 depicts <br />the observed rebar locations as interpreted in the GPR data. <br />DocuSign Envelope ID: B2D44CC3-6321-4EF3-AFC6-547186A1261E