Calcareous Fen Management Plan

Minnesota | Water

Overview

ISG navigated complex regulatory permitting processes with state and local agencies to develop a first-of-its-kind Calcareous Fen Management Plan (CFMP), demonstrating effective design solutions to protect fragile ecological communities while also meeting industry demands.


Opportunity

Calcareous fens were discovered on a proposed mining site. These rare and distinctive wetlands receive continuous groundwater discharge that is calcium enriched because of contact with bedrock or glacial deposits. A protection plan was needed to preserve this invaluable part of Minnesota's rich natural heritage while meeting the landowner’s operational goals.

Solution

Minnesota’s fourth Calcareous Fen Management Plan (CFMP), developed by ISG for a mining client, was approved by the Minnesota Department of Natural Resources (DNR) in cooperation with several state and local agencies. Calcareous fens require a stable groundwater level to maintain their ecological integrity. Therefore, a key component of the CFMP was to prevent water table fluctuations that occur with standard mining practices. ISG civil engineers took a fresh and original approach to this challenge by designing a 460 x 14 foot infiltration trench system that would hold the groundwater levels steady.

ISG Environmental Services staff also conducted testing at an alternate simulation site as part of a case study and pre-mining field test. Research data was collected for one year to measure the trench’s ability to maintain the groundwater level and chemistry necessary to support a calcareous fen. Upon successful completion of the study, the trench was constructed at the intended location along the Minnesota River in southern Minnesota and now provides adequate water supply for the calcareous fen.

The State’s approval of the CFMP included an ongoing monitoring program, and the project has successfully passed all consecutive annual reviews. ISG’s Environmental team continues to monitor this sensitive ecosystem annually, with reviews for several parameters, including water and peat levels, water chemistry, native plant species, and inspections for potential invasive species.


Market News

ISG Takes Root In Rogers, Arkansas, With A New Office + Acquisition of Unit Architecture

August 17, 2023 (Rogers, Arkansas) – In the midst of celebrating their 50th anniversary, ISG is proud to announce expansion into Rogers, Arkansas. This strategic move marks a chapter of growth as the firm seeks to make a positive difference in more communities across the nation.
Read More

ISG Reinforces Its Commitment to South Dakota With A New Office In Pierre

Pierre, South Dakota (August 15, 2023)—Within weeks of expanding its Sioux Falls footprint to The Bancorp Building at Cherapa Place, architecture, engineering, environmental, and planning firm ISG further strengthens its ability to support South Dakota communities by opening an office in Pierre. This new location will boost the firm’s ability to serve clients throughout central and western South Dakota.
Read More