A 71-mile natural gas pipeline expansion would cut through one of the largest undeveloped estuaries along the Atlantic Coast.

A map obtained by conservation groups shows the pipeline cutting through property that would become part of the ACE Basin nature preserve that state agencies and private interests are working to protect, according to Columbia-based newspaper The State.

ACE stands for Ashepoo, Combahee, and Edisto and refers to three rivers that converse in the basin, which includes a system of marshes, wetlands, and forests.

The pipeline, known as the Elba Express Bridge project, would pass through part of the basin on its way to serve a proposed natural gas-fired power plant in Colleton County. Utility companies Santee Cooper and Dominion Energy are proposing to build the power plant.