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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
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Permitting Your Existing Dam


To build a new dam or alter an existing dam, either of which an impoundment capacity of 50 acre feet or more, you must apply to the DNRC Dam Safety Program for a hazard classification. The impoundment capacity is measured to the maximum normal operating pool which is usually the crest of the spillway.

Dams classified as high hazard and containing over 50 acre foot of water are required to obtain additional permits from the DNRC Dam Safety Program. “High Hazard” is not a reference to the dam’s condition, but rather the potential for loss of life downstream if the dam were to fail. If construction or repair is planned, a Construction Permit must be obtained. Prior to storing water, an Operation Permit must be obtained.

Dams classified as not high hazard are not required to obtain further permits. However regardless of permitting status, it is in a dam owner’s best interest, from a liability perspective, to conduct annual inspections and keep up on operation and maintenance. The Dam Safety Program is available to help any dam owner set up a program of inspections, operation and maintenance. Don’t forget to document! Should you ever end up in a court of law because your dam failed, documentation of your annual inspection could be worth its weight in gold!

Exempt from the Dam Safety Act are dams that are owned by the federal government, inspected by the Federal Energy Regulatory Commission, included in a mine operating permit issued by the Montana Department of Environmental Quality or associated with facilities certified under the Major Facility Siting Act. Non-federal dams on federal property with federal oversight are also exempt.

General Information – Dam Safety Permits

 

Downstream Hazard Classification

 

Construction Permits

 

Operation Permits

There are three components to getting an Operation Permit for a High Hazard dam:

1.    Five-Year Engineers Inspection

High Hazard Dams are required to have a formal comprehensive inspection at least once every five years.

2.     Operation and Maintenance Manual

 An Operation and Maintenance Manual is required to permit a High Hazard Dam

3.     Emergency Action Plan

 All High Hazard Dams must have an Emergency Action Plan.

Statement of Owner's Intent

Before DNRC can issue an Operation Permit, the High Hazard Dam Owner must agree to follow the Engineer's recommendations and state a timeline to meet the recommendations. Several forms are available to assist dam owners with this task:

Annual Operation Permit Requirements

Dam owners are required to complete an Annual Owner inspection.  This inspection is less formal than the five year inspection and can be done by the dam owner, their engineer or the dam tender.

The Emergency Action Plan must be updated annually.