The liner for the Chippewa Calves manure lagoon was designed by Industrial and Environmental Concepts from Minneapolis, Minnesota. IEC decided to include provision for venting under the liner on this one million gallon lagoon due to the presence of methane in the soil. To that end, Multi-Flow lines were laid out at intervals across the bottom and up the side of the lagoon, terminating in a rock-filled trench at the top and around the perimeter of the pond. This relatively cheap insurance will prevent air bubbles and whale-backing. In some cases, this venting system can also double as a drainage system to remove ground water or to detect possible leaks.