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District seeks public comment on Draft Environmental Assessment for new water transmission main in McKenzie County, North Dakota

Omaha District
Published March 1, 2023

The U.S. Army Corps of Engineers, Omaha District is seeking public comment to evaluate the impacts of the proposed McKenzie County Water Resource District Phase II Transmission Main Project, located within and adjacent to the Missouri River and Lake Sakakawea in McKenzie and Williams Counties, North Dakota.

In compliance with USC Title 33, Chapter 9, Subchapter 1, Section 408, the McKenzie County Water Resource District has requested permission from the USACE for an alteration at the Garrison Dam Lake Sakakawea Reservoir federal project. USACE Omaha District has determined that the MCWRD Phase II Transmission Main project would entail an alteration to the federal project, and therefore requires permission under Section 408.

The requester’s proposed project involves the construction of approximately 4.25 miles of new 24-inch pipe from the existing Williston Regional Water Treatment Plant, south under the Missouri River and Lake Sakakawea, to the existing Lewis and Clark pump station where water enters the MCWRD rural distribution system. The alignment for the pipeline would be 150 feet off (horizontally to the west) from the centerline of the MCWRD’s existing 20-inch water main pipeline. The proposed action would include a mix of open cut excavation and horizontal directional drilling, or boring, to install the pipeline. Open cut trench segments would install the 24-inch pipeline approximately 9.5-feet deep below the surface, where the pipeline would be buried with a minimum of 7.5 feet of cover, same as the existing pipeline. The proposed bored segments of the pipeline would be at a deeper depth of 40 feet. 

The purpose of the proposed action is to provide MCWRD a supplemental water supply line for use when the existing line is not operational. Currently, the sole source of water to the MCWRD system is a 20-inch pipeline from the Western Area Water Supply Association Regional Water Treatment Plant. The segment of pipe that runs through the Missouri River floodplain would be difficult to repair and difficult to temporarily bypass. Without a supplemental source of water, a failure of the existing 20-inch pipeline could leave a majority of the MCWRD system without potable water for multiple months. The capacity of the existing 20-inch line is adequate to serve the current MCWRD customers in McKenzie County. The purpose of a supplemental water supply is not to serve additional customers, only to serve the existing MCWRD customers during an unanticipated failure or repairs of the existing line while out of service. A supplemental pipeline greatly reduces the risk that a pipeline failure of the existing line would leave the McKenzie County service area without water. The MCWRD management has assessed this risk and determined that it is sufficient to warrant installing a supplemental pipeline. The service area for the proposed waterline project is in the northwestern portion of McKenzie County, south of the City of Williston, North Dakota, which is the same as the existing pipeline’s service area.

The land owned by the federal government under the management of USACE within the MCWRD’s project area is known as the Lewis and Clark Wildlife Management Area associated with the USACE Garrison Dam Lake Sakakawea Federal Project, south of the City of Williston along U.S. Highway 85. Only project elements that would alter the federal project are within the review scope for the Section 408 permission request.

The public is encouraged to provide comments on the draft environmental assessment that can be viewed and downloaded at: https://usace.contentdm.oclc.org/digital/collection/p16021coll7/id/23357

Comments can be mailed to: U.S. Army Corps of Engineers, Omaha District; CENWO-PMA-C; ATTN: Adam Nebel (Reference 408-NWO-2023-0002); 1616 Capitol Avenue; Omaha, NE 68102-4901. Comments can also be emailed to: cenwo-planning@usace.army.mil.

All Comments must be postmarked or received no later than March 31, 2023.

Release no. 23-005