Iowa agriculture benefits from two important natural resources, the rich soils that blanket the landscape and sufficient precipitation, in most years, to produce large crop yields. While precipitation is essential to farmers, many of Iowa\u27s soils, especially in the northcentral part of the state, are poorly drained and at times contain excess water that can hinder field operations or ruin crops. In these areas, farm fields are often artificially drained by buried tile lines leading to ditches or to streams. Another, but less common, method is the agricultural drainage well, a shaft which funnels excess water directly underground. The upper parts of these wells are fed by tile lines; other wells also are designed to receive surface runoff. Ag-drainage wells are usually 5 to 10 inches in diameter and are cased from the land surface to the top of bedrock. They vary in depth from 30 to over 300 feet. There is currently no accurate count of these wells in Iowa, but most estimates suggest 600 to 700 with the greatest concentration in Humboldt, Pocahontas and Floyd counties
