Tribal Partnership Program: Hydrogeologic Study and Groundwater Flow Model with Scenarios of the Shell Valley Aquifer, Turtle Mountain Reservation, ND

U.S. Corps of Engineers, St. Paul District
Published Sept. 27, 2021
Updated: April 9, 2024


The tribal population within the Turtle Mountain Indian Reservation relies on groundwater, mainly the Shell Valley Aquifer, as their source of water. In November 2019, the Turtle Mountain Band of Chippewa Indian (TMBCI) requested assistance to provide scientific information needed for managing tribal community groundwater resources and to better understand potential contaminate flow paths.


The Turtle Mountain Indian Reservation is located in north central North Dakota. The reservation is approximately 100 miles north and east of Minot, North Dakota.


Specific scientific information includes the hydrogeology of the Shell Valley Aquifer to understand better the sources and uses of groundwater, such as recharge from precipitation and losses to evapotranspiration and well withdrawals. The data will be incorporated into a newly constructed calibrated groundwater flow model for the Shell Valley aquifer (SVA). The groundwater flow model could be used to determine water levels during wet and dry conditions, to map groundwater flow direction, and to estimate aquifer properties such as hydraulic conductivities and storage coefficients useful for well-field planning and optimization. Additionally, the model could provide groundwater flow paths from (or to) point locations of potential contaminants.


A feasibility cost-share agreement between the Corps and the TMBCI was signed on July 12, 2021. The study includes a Technical Project Planning (TPP) Meeting and Work Plan Development, Groundwater Model Development, Monitoring Well Installation, Groundwater Sampling and Analysis, Groundwater Model Refinement, and final reporting. A draft report of the modeling information gathered was prepared and coordinated with the TMBCI Tribal Council in winter 2023-2024. Model results were presented to the Tribal Council and Water Board in February 2024. The report will be finalized in fall 2024.


The Tribal Partnership Program (TPP) is authorized by Section 203 of the Water Resources Development Act of 2000 (Public Law 110-114). The TPP provides authority for the U.S. Army Corps of Engineers to work with Indian nations to carry out water-related planning activities.


Modeling and Study                                       $890,000

Shared study costs                                          $890,000

Federal share costs                                            $801,000

Non-federal sponsor’s share                               $89,000