The Pineland Sands area consists of 770 square miles of surficial glacial outwash, which is undergoing increasing ground-water development for irrigation. The aquifer material is commonly very fine sand to fine gravel, and grain size generally increases from south to north. Thickness, transmissivity, and theoretical well yields are highest in the northern part. In places, saturated thickness exceeds 100 feet, transmissivity exceeds 20,000 feet squared per day, and expected well yields exceed 2,000 gallons per minute.
Water in the aquifer is chemically suitable for irrigation. It is calcium bicarbonate water generally containing dissolvedsolids concentrations of 100-300 milligrams per liter.
An estimated long-term water budget for the aquifer involves inflow and outflow of 295 cubic feet per second. Over 80 percent of recharge to the aquifer is directly from snowmelt and spring rain; the remainder is from underflow across the northern boundary of the aquifer and locally from streams and lakes. Over 90 percent of discharge from the aquifer is flow to streams and lakes; the remainder is through evapotranspiration.
A mathematical model of the surficial aquifer was made to facilitate analysis of the hydrologic system. The model was calibrated through simulation of the natural ground-water flow system. Subsequent applications of the model to estimate effects of future ground-water development indicate that much of the system can safely support long-term, large-scale withdrawals.
Results of model analysis show that present development (withdrawals totaling 3.3 cubic feet per second) has no significant effect on the aquifer system. Simulations of hypothetical withdrawals of 60 to 120 cubic feet per second resulted in computed water-table declines as great as 12 feet in places. Most pumpage is derived from intercepted base flow to streams, thus reducing streamflow. Similarly, some lake levels can be expected to decline in response to nearby intensive development.
