South Dakota’s water infrastructure picture is shifting as multiple regional systems look to the Missouri River to meet long-term demand, with projects ranging from construction work to feasibility planning. A plan that began delivering water in 2012 through the Lewis & Clark system is now in the middle of additional development intended to raise how much treated Missouri River water local utilities can provide.
In one of the underway elements described by contractors, crews hired by the Lewis & Clark Regional Water System positioned concrete rings at a site along the west shore of the Missouri River to support a Ranney well drawing from an aquifer about 140 feet below the surface. The new well is part of a broader $150 million expansion effort for the system, which is designed to supply 44 million gallons of treated Missouri River water each day to 350,000 people across 20 communities in eastern South Dakota and parts of Iowa and Minnesota.
The Lewis & Clark system’s base build was authorized by Congress in 2000 and the initial deliveries began in 2012. Its base system is described as nearly completed at a cost of $711 million and built around the concept of drawing aquifer water through Missouri River bank wells, treating it, and then shipping it via a 54-inch underground pipeline that connects to smaller lines feeding individual communities.
Beyond the base system, the reporting describes two additional expansions. One expansion began in 2022 and is estimated to cost $150 million, with a target of increasing water flow to 60 million gallons per day by 2030 through upgrades that include expansion of the water treatment plant, a new storage facility, and construction of a new water collection well along the Missouri River near Vermillion. A second expansion is in a feasibility study stage and could increase flow to 165 million gallons per day to accommodate population and industrial growth across southeastern South Dakota, eastern Minnesota, and northwestern Iowa.
Farther north and west, the WEB Water system is also working through changes tied to growth. WEB, which launched in 1975 to tap the Missouri River and initially serve counties of Walworth, Edmunds and Brown, has taken Missouri River surface water from a point on Lake Oahe south of Mobridge, treated it, and delivered it through 688 miles of underground pipe since 1986. The system now provides up to 11 million gallons of water per day to 18 counties, with 15 in South Dakota and three in North Dakota.
WEB has spent $20 million on improvements since 2016, but those projects did not expand capacity for additional users. The system is now in the midst of an $82 million upgrade intended to accommodate expected growth by including 14 miles of a 49.5-inch parallel pipeline and expanding the treatment plant capacity from 11 million gallons per day to 17 million gallons per day.
Other efforts described by the reporting are at earlier stages. The Western Dakota Regional Water System, formed in September 2021, is pursuing a project built around a plan for a 72-inch pipeline roughly 161 miles from the Missouri River to the Black Hills region. Kristen Conzet, the system’s executive director, said the effort is gaining support and is pursuing a $13 million feasibility study required under the U.S. Bureau of Reclamation for a large project.
Conzet also said that 56 municipalities or water systems from Winner to Fort Pierre to Rapid City have signed on as partners that could receive water once the project is operational. She described the pipeline as needed for economic development, agriculture, tourism, tribal nations, and national security resiliency, and testified before Congress on April 16 in support of legislation authorizing a formal feasibility study.
U.S. Rep. Dusty Johnson of South Dakota told House members that water system expansion is needed to support regional growth, including at Ellsworth Air Force Base in Box Elder, which is expected to soon be home to the new B-21 bomber program. Johnson said, “Western South Dakota faces a clear and growing water challenge,” adding, “This is not just a local priority; it’s a national security imperative.”
The fourth project described is the Dakota Mainstem Regional Water System, which launched in 2023 and remains in planning. Kurt Pfiefle, director of the system, said the group examined current and future water needs and capacity, and concluded that they were not finished, using data to justify pursuing a pipeline plan.
So far, Pfiefle said 57 potential members have signed on to the Dakota Mainstem plan for a pipeline up to 96 inches in diameter that would carry treated water taken from Missouri River aquifers near Yankton. He said building the project could take more than 20 years and cost as much as $10 billion, and that Dakota Mainstem officials are preparing for their own feasibility authorization hearing before Congress.
References for readers: Housing starts and employment ratios are macroeconomic indicators and were not used to determine project scope in this story. However, FRED’s vintage-correct values for this article date list Housing Starts (Total, Privately-Owned) at 1,502.0 and the prime-age (25-54) employment-population ratio at 80.7.