Evaluation of potential recharge of the Castle Hayne Aquifer System by stream infiltration along Tranters Creek, Beaufort County, North Carolina / by John J. Johnson.
| Author/creator | Johnson, John J. author. |
| Other author | Spruill, Richard K., degree supervisor. |
| Other author | East Carolina University. Department of Geology. |
| Format | Theses and dissertations |
| Production | 1992. |
| Description | ix, 252 leaves : illustrations ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Variant title | Abstract title: Evaluation of potential recharge of the Castle Hayne Aquifer System in the vicinity of Tranters Creek, Beaufort County, North Carolina |
| Summary | The Castle Hayne Aquifer System is subdivided into three units on the basis of lithologic differences. The three units are, in ascending order: Beaufort unit of Late Cretaceous to Paleocene age and the Eocene Lower and Upper Castle Hayne units. Upper sands of the Cretaceous Pee Dee unit and thin unnamed beds of Oligocene age may be included where they are hydraulically connected to the Beaufort and Lower Castle Hayne units. Total withdrawals of approximately 65 million gallons per day from the Castle Hayne (primarily associated with pressure relief wells at Texas Gulf Mine near Aurora, NC) produced an elliptical cone of depression affecting more than 2,000 square miles. Head-difference analysis for the Castle Hayne and the overlying aquitard (primarily the Yorktown Fm) suggest areas of recharge of the Castle Hayne in highlands to the north and south of the western limits of the Pamlico Estuary. A pumping well and four deep observation wells were constructed (screen intervals approximately 50 to 80 feet below land surface) in the Castle Hayne Aquifer System near its western subcrop limits in order to evaluate the presence, magnitude, and possible location of recharge boundaries. Three shallow wells were installed to monitor the shallow aquifer. Upon completion of a constant-rate test, two additional wells (a shallow and deep) were installed to evaluate apparent anisotropic conditions in the aquifer. Results of the study reveal that a hydraulic connection exists between the shallow and deep aquifers and Tranters Creek. Drawdown data for the constant rate tests were analyzed with the nonequilibrium Theis and Jacob methods which yield an average value for transmissivity of 140 ft2/day and a storage coefficient of 2.5 x 10-4. Deviation of the drawdown data from the Theis curve during the later stages of pumping suggests recharge and that the aquifer is a leaky artesian aquifer (semiconfmed). The Hantush-Jacob equation yields a vertical hydraulic conductivity of the semipervious layer of 3.6 X 10-3 ft/day. Contours of equal drawdown were constructed from data obtained during the second aquifer test and indicate that a major direction of transmissivity (228 ft2/day) trends northwest-southeast and a minor direction of transmissivity (83 ft2/day) trends northeast-southwest. A linear relationship was observed between transmissivity and distance to the pumping well. Water quality data indicate that the Castle Hayne Aquifer System west of Washington is a viable source of potable water. The recognition of a vertical recharge boundary accentuates the importance of protecting these vital subcrop recharge areas from potential pollution. |
| General note | Submitted to the faculty of the Department of Geology. |
| General note | Advisor: Richard K. Spruill |
| Dissertation note | M.S. East Carolina University 1992 |
| Bibliography note | Includes bibliographical references (leaves 27-28). |
| 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 | ✔ Available |