PRELIMINARY STUDY OF GROUND WATER OCCURRENCE AND QUALITY ON LANGTREE PENINSULA, IREDELL COUNTY, NORTH CAROLINA

In the summer of 1999, the North Carolina Division of Water Quality, Groundwater Section conducted a limited study on a 2.6 square mile portion of Langtree Peninsula in Iredell County, North Carolina. During the study, data was compiled from existing water supply wells and available well records. The data indicate that the thickness of regolith in the area is variable, ranging from 0 to 137 feet, and that the median depth to ground water in the area is 29 feet. A comparison of well yield and total well depth indicates that well yield per foot decreases as well depth increases. Data collected during recent drilling in the area suggest that the decrease in yield is due to a decreased number of open fractures at depth. Based on the collected well data and published specific yield values for Piedmont regolith, the amount of groundwater in storage on Langtree Peninsula is estimated to be 5.4 billion gallons. An annual recharge of 440 million gallons to the peninsula is estimated based on the analysis of stream flow records from Norwood Creek in Troutman. This estimate is likely to be high due to differences in topography and land use that exist between the two areas. Annual water use on the peninsula is less than annual recharge and is estimated to be 51 million gallons. Groundwater withdrawals are not uniform across the peninsula. Groundwater withdrawal may exceed recharge in some areas. A limited number of samples collected and tested for pH, specific conductivity, nutrients, coliform bacteria, metals, pesticides and herbicides did not identify any significant problems with the present quality of groundwater in the area.