What is an aquifer?

An aquifer is a body of permeable rock or sand which stores or transmits groundwater. The void spaces in aquifers are filled with water and are interconnected, allowing water to flow through them. The water within an aquifer is constantly moving. Aquifer size can vary from a few square miles to thousands of square miles. The uppermost layer of water within an aquifer is referred to as the water table. Groundwater can be withdrawn from extracting wells for agricultural, municipal and industrial use by drilling beneath the water table. Aquifers are not only a highly useful source of water but also aid in sustaining adjacent rivers, lakes, and wetlands.

Geology of the Buffalo Aquifer:

The Buffalo Aquifer trends north to south about 5 miles east of Moorhead, Minnesota. The aquifer stretches 32 miles north-south and ranges between 1-8 miles in width. The aquifer is approximately 66 square miles in area and capable of containing as much as 270 billion gallons of water. Of that, approximately, 120 billion gallons could be withdrawn from the aquifer. Surface water sources influenced by the aquifer include the Red River of the North, the Buffalo River, and the South Branch Buffalo River. Clay is the primary soil type throughout the region with isolated pockets of silt and sand. The aquifer itself is comprised of a diamond shaped body of sand and gravel. The primary source of groundwater recharge is snowmelt and spring rain.

What are the risks of overusing aquifer water supplies?

When groundwater is extracted at a higher rate than it is being recharged, the aquifer can become depleted. Depletion can cause the water table to drop, which in turn will require deeper extraction wells. Simulations of ground-water development for some aqui­fers show correlations between increased ground-water withdrawals and declining lake levels and stream flows, lower water-table altitudes, and undesirable variations in ground-water quality.

Aquifer protection:

Wells can compromise groundwater quality by providing a path for contaminants to enter the aquifer. Groundwater can become contaminated by bacteria, nitrate, arsenic or other chemicals. The purpose of the wellhead protection program is to protect groundwater from contamination so that drinking water supplies are safe for human consumption.

What can you do?

• Be sure that the well is properly constructed with the appropriate casing and seals.
• Report chemical spills and contamination to the state of Minnesota’s 24-hour emergency number (Dept. of Public Safety Duty Officer). The number is 651-649-5451 or 800-422-0798.
• Properly seal any unused well.
• If performing maintenance, disinfect any equipment that is placed in the well.
• Maximize distances between possible contamination sources (fuel tanks, septic tanks, etc.) and the well. Additionally, the well should be upslope from these sources.
• Pesticides and fertilizer should be handled with care and not mixed near the well.