National Park Service releases Environmental Assessment for Effigy Mounds septic system

Existing system has failed and must be replaced; Public open house set for February 28 at Effigy Mounds Visitor Center

The National Park Service has released an Environmental Assessment for installing a new septic system in the park headquarters area at Effigy Mounds National Monument. The park’s current septic system, constructed in 1959, has failed and needs to be replaced, according to information shared by Effigy Mounds National Monument Superintendent Jim Nepstad. The Environmental Assessment assesses the impacts associated with either keeping things as they are, or installing a new system in the area between the facility's main parking lot and State Highway 76.

“Ground disturbance in a park like Effigy Mounds National Monument is something that must be done with the utmost care,” said Nepstad. “In preparation for an eventual replacement project, we have been consulting with our tribal and state historic preservation partners on this since the current system started having problems a couple of years ago. The current system has failed now, so we need to act.”

The new system will be designed to accommodate the park’s 70,000-80,000 annual visitors, and could be expanded, if needed. The proposed location for the new system is believed to have been heavily impacted back in 1959, when the majority of the park’s infrastructure was constructed. Most of this area appears to have been scraped below the cultural zone to create fill that was used to level off low spots in what became the parking lot. A series of soil profiles will be drilled this winter to confirm that this is the case, and the new system will be shifted accordingly if anything is found.

“The heaviest ground disturbance will take place in the location least likely to have any remaining archaeological context,” Nepstad continued. “Out of an abundance of caution, we will double-check ourselves before construction starts to ensure that assumption is correct. New lines will be installed with directional boring equipment to minimize trenching, but parts of the new system will require traditional excavation. Qualified archaeologists will carefully monitor all work, and tribal monitoring of the project is being encouraged.”

Copies of the septic system EA are available at https://parkplanning.nps.gov/efmosepticea, and comments may be electronically submitted there as well. The Environmental Assessment will be available for public comment through Monday, March 18.

A public open house is scheduled to be held Wednesday, February 28 from 2-5:30 p.m. at the Effigy Mounds National Monument Visitor Center located three miles north of Marquette on Highway 76. The open house will provide the public with an opportunity to speak with National Park Service subject matter experts about the project and the precautions being taken.