Hydrogeologic study of the Castle Hayne aquifer system in northern Beaufort County, North Carolina : verification of well field design / by Debbie Warner.
| Author/creator | Gordon, Debbie W. author. |
| Other author | Spruill, Richard K., degree supervisor. |
| Other author | East Carolina University. Department of Geology. |
| Format | Theses and dissertations |
| Production | 1993. |
| Description | vi, 162 leaves : illustrations, maps ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The recognition in the late 1970s of elevated levels of trihalomethanes (THM) in the surface water supply prompted the City of Washington, North Carolina to evaluate water resource alternatives. After extensive evaluation and limited testing, the City of Washington opted for conversion from surface water to groundwater from the Castle Hayne Aquifer System (CHAS) to meet their future expanding drinking water needs. A well field consisting of 8 wells, spaced about 5,000 feet apart, and pumping at a rate of 700 gallons per minute (GPM) was proposed by Spruill and Hyder (1990). Eight 8-inch diameter test wells spaced about 5,000 feet apart were installed and tested. Transmissivities (T) ranging from 5,490 ft2/day to 25,400 ft2/day were obtained for the CHAS from the initial test phase. Eight 18-inch diameter production wells were installed at test well sites. The production wells were tested and calculated T values range from 6,890 ft2/day to 20,700 ft2/day. Storativity was found to be about 4 X 10-4. The Castle Hayne Aquifer is composed of an upper unit (94 to 106 feet thick) and a lower unit (48 to 70 feet thick) . The aquifer thickness as well as the T increase eastward across the well field. Specific Capacity (Q/s) for open borehole production wells ranges from approximately 29 GPM/ft to 98 GPM/ft. Q/s is typically 40% higher in larger (18-inch) diameter wells than in small (8-inch) diameter wells, even at even at substantially higher flow rates in the larger diameter wells. The Division of Environmental Management - Groundwater section required groundwater flow models showing the potential impacts of groundwater withdrawal of 4.2 million gallons per day on the groundwater system because the City of Washington is within North Carolina's Capacity Use Area No. 1. Two methods were used to model the system. Method I utilized distance/drawdown graphs and hand-plotted cones of depression to produce an analytical model. Method II utilized the QuickFlow computer model, a commercially available analytical groundwater flow model. Similar results were obtained with both models. The models indicate that the well field should supply potable water for the City of Washington and Northern Beaufort County of sufficient quantity with minimal affects on the potentiometric surface of the CHAS well into the next century. |
| General note | Submitted to the faculty of the Department of Geology. |
| General note | Advisor: Richard K. Spruill |
| Dissertation note | M.S. East Carolina University 1993 |
| Bibliography note | Includes bibliographical references (leaves 56-57). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |