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51 <br /> Envirotactics <br /> An Earth Systems Company <br /> 1.0 INTRODUCTION <br /> Envirotactics, LLC (Envirotactics), an Earth Systems company, in partnership with Spangler Environmental, <br /> LLC (Spangler), an Earth Systems company, has prepared this Groundwater Modeling Report in connection <br /> with our study of potential withdrawal impacts to adjacent single use wells from a proposed residential <br /> development's community well (Proposed Community Well).The Proposed Community Well was previously <br /> permitted and installed at the property having a street address of 3531 NC 54 W in Chapel Hill, North Carolina, <br /> and corresponding to Orange County PIN 9749422010 (Site). Figures 1, 2, 3 and 4 in Attachment 1, present <br /> the Site Location Map, the USGS Topographic Map, the Tax Map and the Land Use Map. Figure 5 in <br /> Attachment 1 depicts the two existing single use wells (i.e., Rigsbee and Griffin Wells) adjacent to the <br /> Proposed Community Well and included in our study. The Rigsbee Well is located approximately 600 feet <br /> west/northwest and the Griffin Well is located approximately 660 feet north/northeast relative to the <br /> Proposed Community Well. <br /> Envirotactics previously completed a desktop study to better understand the Site and locally adjacent area <br /> for consideration in planning the hydrogeologic study for the project. Attachment 2 contains the report <br /> associated with our desktop study. In addition to the understanding gained from our desktop study, our <br /> study considered data obtained from two (2), 24-hour pumping (drawdown) tests performed on the <br /> Proposed Community Well on September 11-12, 2024 and on July 16-17, 2025. Additionally, water level data <br /> from monitoring of ambient conditions (i.e., prior to drawdown of the Proposed Community Well) as well as <br /> direct observations documented during and following the July 2025 pumping test for all three wells were <br /> considered. <br /> The data from the two (2) pump tests were inputted into the commercially available aquifer test analysis <br /> software,AQTESOLV, developed by HydroSOLVE, Inc.,to estimate the transmissivity, hydraulic conductivity, <br /> and the storativity of the aquifer in which the Proposed Community Well is screened. The AQTESOLV- <br /> estimated hydraulic properties of the aquifer in which the Proposed Community Well is screened were then <br /> used in the Simple Groundwater Models available from the North Carolina Department of Environmental <br /> Quality (NC DEQ) Division of Water Resources, as applicable: <br /> • Distance Drawdown Analysis, <br /> • Reverse Distance Drawdown Analysis, <br /> • Time Drawdown Analysis, <br /> • Reverse Time Drawdown Analysis, and <br /> • Simple Finite Difference Model. <br /> The water level monitoring and pumping data as well as results of the groundwater modeling were then <br /> reviewed to gauge whether withdrawal, consistent with North Carolina regulations, from the Proposed <br /> Community Well to serve the proposed residential development would impact the adjacent single use wells. <br /> Envirotactics, LLC Page 1 of 20 Groundwater Modeling Report <br /> (732) 449-0077 Project No.6704 <br />