Drain Tile

What is drain tile?
Drain tile is underground pipe of varying diameters, most often placed in crop fields that are very flat, so excess water will drain more efficiently to the nearest creek, ditch, or river. The benefit of an effective drainage system is increased agricultural productivity.

What is it made of?
In the late 1800s, tile was made of clay and placed in hand-dug, shallow trenches above the frost line. Because the tile was made of clay, most original tiles have broken and are difficult to find because drainage systems weren’t mapped. Today, drainage tile is made of corrugated plastic and is installed by machines that trench and lay the tile quickly (up to 30 feet per minute).

Why is water drainage necessary?
In this region of the United States, rain often pools in low lying areas because of the high annual rainfall (about 30 inches), the relatively flat landscape, and soil types high in clay. Actually, most of this area of Nicollet County was wetlands when settlers first arrived. Early farmers, in cooperation with their neighbors, dug drainage ditches and laid clay tiles to make the land suitable for agriculture.

How has the landscape changed with drainage?
Within the past 100 years, dramatic hydrologic changes have taken place in the Seven Mile Creek Watershed. Major documented changes include the installation of sub-surface drainage systems and the subsequent loss of wetlands to cropland:

  • In about 100 years (from the mid-1800s to 1938), 5,700 acres of wetland in the Seven Mile Creek Watershed were converted to cultivated cropland;
  • In the next 50 years (from 1938-1990), 5,300 more acres of wetland were converted to cultivated cropland.