Final answer:
The first step in constructing a contour map of a water table is to determine the elevations at various locations and draw contour lines on a map to connect points of equal elevation.
Step-by-step explanation:
The first step in constructing a contour map of a water table is to determine the elevations at various locations. This is done by measuring the elevation of the ground surface at different points using a GPS receiver or other surveying equipment.
Once the elevation data is collected, contour lines can be drawn on a map to connect points of equal elevation. These contour lines can then be used to show the shape and depth of the water table.