In June 2021, the DWR completed an update of statewide Probable Maximum Precipitation (PMP) data through a two-year study conducted by Applied Weather Associates (AWA). Additionally, the DWR continues to develop updated dam design guidelines for North Dakota. While these guidelines are still in development, the selection and usage of PMP values in the design of dams will be governed by interim guidance.
Probable Maximum Precipitation Study and Interim Guidance
Regulatory Program: Dam Safety
The purpose of North Dakota’s Dam Safety Program is to minimize the risk to life and property associated with the potential failure of dams in the state. Functions of the Dam Safety Program include reviewing construction permit applications for dams, conducting dam inspections, maintaining an inventory of dams in North Dakota, determining the hazard classification of dams, and assisting with emergency preparedness activities.
The dam safety program reviews construction permit applications for dams, holding ponds, and lagoons, as required under NDCC 61-16.1-38. More information on construction permits can be found on the Construction Permits page.
A primary function of the Dam Safety Program is to conduct dam inspections and provide recommendations to dam owners regarding necessary maintenance and repairs. Dam Safety Program staff inspects non-federally owned high hazard and medium hazard dams on a rotational basis. Additional inspections are conducted following the spring runoff, on request from dam owners, or when there are concerns at a dam, such as during flood events.
Dam maintenance and repairs are the responsibility of the dam owner. Funding to assist with dam safety repairs may be available through the DWR cost-share program, or through other funding sources.
Emergency Action Plans
Emergency Action Plans (EAPs) are required for all high hazard and medium hazard dams under NDCC 61-03-25. An EAP is a formal document that identifies potential emergency situations that could occur at a dam and specifies the course of action to be taken when an emergency situation arises. The purpose of an EAP is to minimize loss of life and property damage.
Dam owners are responsible for developing, testing, and updating an EAP for their dam. The DWR has developed an EAP guidance document to provide additional guidance for developing, testing, and updating EAPs in order to comply with NDCC 61-03-25. A recommended EAP template, developed by the Natural Resources Conservation Service is also available. Additional general guidance on developing an EAP is available in the document “Federal Guidelines for Dam Safety - Emergency Action Planning for Dams” (link below). Funding to assist with developing an EAP may be available through the Cost-Share Program.
The Dam Safety Program maintains an inventory of dams in North Dakota. North Dakota’s inventory of dams can be found on the Maps/GIS data page.
Dams in North Dakota are classified as low hazard, medium hazard, or high hazard based on the potential for loss of life or property damage downstream if the dam were to fail. These classifications are defined in NDAC 89-08-01-01. The hazard classification is determined when an applicant applies for a construction permit for a dam. The hazard classification of a dam can also change over time due to changes in development downstream of the dam.
Low Head Dams
Low head dams are usually simple concrete or rock masonry structures that span the width of the river or stream, raising the water level behind them until it reaches a height sufficient to flow over the dam. These low head dams can create dangerous conditions that recreational river users may not be aware of or may underestimate. Under the right conditions, water flowing over the dam can cause a “roller effect” on the downstream side of the dam. Strong recirculating currents can trap and drown boaters, swimmers, or other water users. More information regarding safety at dams is available at the Association of State Dam Safety Officials.
Because low head dams are known to be dangerous, the DWR is providing free cautionary safety signs to the owners of these dams that may be in your area. DWR will provide multiple signs per dam, free of charge. However, installation efforts will be a local responsibility. For more information on these free dam safety signs, please call (701) 328-4953 or e-mail.
North Dakota Administrative Code - Link to Article 89-08 "Dams, Dikes, and Other Devices"
North Dakota Century Code - Link to Title 61 "Waters"
Guidance for Dam Owners and Designers
For more information on Dam Safety, please contact Karen Goff, Dam Safety Program Manager at (701) 328-4953 or e-mail.