Pipeline crossings of sensitive, state or federally-regulated resources are occasionally unavoidable and can substantially increase project costs and negatively affect project timelines. During due-diligence surveys for invasive plants, field botanists identified an undocumented calcareous fen and associated state-listed wetland plants along the route of Enbridge’s LSr and Alberta Clipper pipelines in northwest Minnesota. Calcareous fens are rare peat-accumulating wetlands dominated by groundwater discharge, a high mineral content, and are protected by state law. Their hydrology and chemistry provide an environment for a suite of state-listed plants that are specifically adapted and unique to calcareous fens. By state statute, calcareous fens may not be filled, drained, or otherwise degraded by any activity unless the Commissioner of the Minnesota Department of Natural Resources (DNR) authorizes the activity under an approved Fen Management Plan. The proposed LSr and Alberta Clipper Pipeline route in the area was collocated with existing Enbridge pipelines installed before the fen was identified. State regulatory staff quickly officially recognized the Gully 30 Calcareous Fen which initiated a lengthy permitting process to authorize Enbridge to construct the LSr and Alberta Clipper Pipelines through the Gully 30 Calcareous Fen. Avoiding the fen would have involved an impracticable reroute along several miles of greenfield. The state (DNR) and federal (Army Corps of Engineers) process involved detailed characterization of the resource, development and approval of an alternatives analysis according to Section 404(b)(1) guidelines, and drafting and approval of a project-specific Fen Management Plan which stipulated specific construction mitigation procedures including winter construction and protective temporary drainage, and post construction monitoring requirements. This presentation introduces the calcareous fen resource and examines the permitting and iterative, comment-response construction-design process as an example of successful collaboration between state and federal agencies and Enbridge to construct a pipeline through a highly regulated, sensitive natural resource while maintaining schedule.

This content is only available via PDF.
You do not currently have access to this content.