What condition indicates a high water table in soil?

A high water table in soil is commonly indicated by the reduction of iron due to anaerobic conditions. When the water table rises, it saturates the soil, leading to conditions where oxygen is limited or absent. This anaerobic environment causes certain chemical reactions, one of which involves the reduction of iron from its oxidized state (ferric iron) to a reduced state (ferrous iron). In the presence of saturated soil conditions, ferrous iron remains soluble, while oxidized iron can precipitate and create reddish or yellowish soil colors. Hence, the presence of reduced iron and characteristic mottling in the soil profile serves as a strong indicator of high moisture levels, affirming the existence of a high water table. This observation is often used in soil science and hydrology to assess soil saturation and drainage characteristics.