Water levels were measured in 51 observation wells in the vicinity of the Elkhart Water Works Main Street well field during 5 days of normal pumping at the well field and little or no recharge to the ground water from precipitation. Water levels were measured once each day during December 18-22, 1989. Water-level altitudes were plotted and contoured on maps to determine the distribution of ground-water levels and directions of flow in the unconfined sand and gravel aquifer tapped by the well field.
Measured ground-water levels ranged from about 7.5 to 30 feet below land surface. Ground-water levels were highest north and northwest of the Main Street well field and lowest at the Main Street well field and near the St. Joseph River. Regional ground-water flow is toward the south or southeast. Ground-water levels near the river are higher than the river stage, indicating that ground water discharges to the river.
As a result of pumping, three cones of depression have formed in the water table in the mapped area. A small cone of depression northwest of the Main Street well field is caused by industrial pumping. Two cones of depression have formed at the Main Street well field-one in the eastern part of the well field and one in the western part of the well field.
Horizontal hydraulic gradients are variable in the study area but are largest in the eastern part of the Main Street well field and near the St. Joseph River. In general, water levels measured in seven sets of paired wells do not indicate a vertical hydraulic gradient; however, a downward gradient was measured in one set of paired wells near a pumped area at the Main Street well field.
