US Army Corps of Engineers
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Planning Assistance to States (PAS): Souris Basin Study

Published Sept. 25, 2017
Updated: Sept. 18, 2019
Description and Scope

Unprecedented flooding in the Souris River Basin in 2011 has focused attention on review of the water control operating plan during flood events. Interests in the basin, particularly in North Dakota, have asked that additional flood risk reduction measures be evaluated, above and beyond what is currently provided under the international agreement. The information gathered will help inform the state of North Dakota on their current flood risk and will be shared with international basin partners.

The study area includes the entire Souris River Basin to its confluence with the Assiniboine River and encompasses the key water control reservoirs: Rafferty, Grant Devine, Boundary and Lake Darling. The study is looking at the geographical limits of the basin in the provinces of Saskatchewan and Manitoba and the state of North Dakota.

Investigating and evaluating water supply and flood control options requires a thorough understanding of the water resources. Also needed is knowledge of the hydrological and hydraulic processes of the Souris River Basin under the current climate regime and climate change. Efforts are being made to ensure coordination and compatibility with ongoing undertakings of various agencies who are conducting investigations that complement this effort.


On September 8, 2017 a Project Partnership Agreement was executed between the U.S. Army Corps of Engineers and the non-federal sponsor, the North Dakota State Water Commission.

This project supports an interagency and international study board with members from the Corps, Hydrological and Meteorological Services of Canada‎, Environment Climate Change Canada, Water Security Agency Saskatchewan, Water Science and Management Conservation and Water Stewardship of Manitoba, ‎Boundary Waters Engineering Unit, National Hydrological Service, U.S. Geological Survey, U.S. Fish and Wildlife Service and the International Joint Commission.

The comprehensive work plan was finalized and sent to the International Joint Commission in October 2018. The study board is in the process of updating models and hydrographic curves and will finalize the study in fiscal year 2020.


The study was authorized by Section 22 of the Water Resources Development Act of 1974 (Public Law 93‒251), as amended. The study was conducted under the Corps’ Planning Assistance to States program, following the 50/50 cost share formula with the non-federal sponsor.


The total study cost is $705,000 ($352,500 federal/ $352,500 non-federal). The North Dakota State Water Commission is providing their cost share in $112,500 cash and $240,000 work-in-kind.