What characteristic of soil can indicate the presence of a water table?

The correct characteristic indicating the presence of a water table is the top 12 inches of soil. The uppermost layer of soil often reflects changes in moisture conditions due to the influences of the water table. This layer can exhibit signs such as saturation or specific coloration that are influenced by the proximity of the water table. For instance, if the water table is close to the surface, the soil in this layer may show mottling, gleying, or other indicators of anaerobic conditions, which are key signs of wetness influenced by the water table.

In contrast, medium texture of the soil does not specifically indicate the presence of a water table, as it simply refers to the size of soil particles and their distribution, which can vary widely regardless of the water conditions. The presence of loess material describes soil derived from a specific type of wind-blown silt but does not directly correlate with water table levels. Fine-textured A or B horizons, while they may relate to moisture retention, do not uniquely signal the location of a water table without further context such as saturation or color changes. Therefore, the top 12 inches of soil serves as the most immediate and informative indicator of water table presence.