Seminary Fen

The Seminary Fen Scientific and Natural (SNA) area is a 73 acre site located two miles east of Chaska, Minnesota east of Minnesota Highway 41 near Chanhassen. Named for an old seminary that was once located on the site, the Seminary Fen SNA contains one of the rarest types of wetland in the United States called a calcareous fen. A calcareous fen is wetland characterized by a substrate of non-acidic peat and an upwelling of cold oxygen-poor groundwater rich in calcium and magnesium bicarbonates. The fen is fed by upwelling groundwater from bedrock aquifers below the Minnesota River Valley. The cold clear water seeps upward and across the land to create an environment that is home to animals and rare plants that take advantage of this unique environmental niche. Fens have been protected since 1991 in Minnesota by the state’s Wetland Conservation Act. They cannot be drained, filled, altered or degraded. They are recognized as the environment for rare species of plants including the white lady-slipper. The site contains a trout stream, eight species of state-listed rare plants and important wildlife habitat.


In late 2003, the Minnesota Department of Natural Resources (DNR) requested MNTBAP assistance in assessment of the 160 acres property that constitutes the Seminary Fen in Chanhassen. The Minnesota Pollution Control Agency (MPCA) used 128(a) funding from Region V U.S. Environmental Protection Agency (EPA) to contract with Delta Environmental Consultants to perform a Phase I assessment of the 160 acres.

Development pressures existed in the site area with possible residential and commercial development. The DNR wished to assess the property to determine potential environmental issues as it desired to purchase the property to provide protection of Seminary Fen.

Recognized Environmental Conditions Identified in the Phase I Report

The Phase I revealed that in the 1900s the site was operated as a spa with mineral baths drawn from the mineral rich fen waters. Later, Assumption Seminary, associated with St. Catherine and St. Thomas colleges, was built on the site. The seminary burned down in about 2001. A number of Recognized Environmental Conditions were identified during the Phase I site assessment. A gasoline underground storage tank was historically located on the south side of the seminary garage. The seminary garage was used for auto body repair and restoration which typically involves the use of solvents, chemicals and petroleum products. There was the potential for dumping of household debris, demolition parts, gasoline containers, oil filters, and other materials. Septic systems were suspected at two houses at the seminary property and onsite solid waste management methods were unknown. The Phase I Environmental Report contained recommendations that a Phase II Environmental Investigation be performed to investigate the Recognized Environmental Conditions identified in the Phase I Assessment. The onsite buildings were torn down and the Phase I information used to facilitate DNR purchase of the property.

DNR Purchases the Site

In 2008, the DNR purchased 106 acres from a private land owner for 1.3 million dollars with state bonding funds provided by the Minnesota legislature. In the same year 73 acres of this land were designated as a scientific and natural area. The designation will allow public access to the fen area and will allow for some limited improvements to the site. DNR ownership of the Seminary Fen gives this sensitive area the protection it needs to ensure that the fen will be preserved for future generations to observe and study.


Environmental and economic benefits

The assessment of the Seminary Fen was necessary to investigate the condition of the fen as well as to develop a plan for the preservation of this valuable Minnesota resource.
Preservation of this fen as a SNA insures that the fen will be protected, but also preserves a place that can be studied to better understand this unique habitat.

Project Partners

  • Keary Cragan – EPA Region V Environmental Engineer
  • Region V EPA Brownfield’s provided 128(a) funding
  • MPCA VIC staff Gerald Stahnke – Project Manager and Catharine O’Dell – Project Hydrologist
  • Minnesota Department of Natural Resources