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Beaver Lake Dam IRRM

Dam Safety Risk Management Process

graphic describing the beaver lake dam irrm

Updated Guide Curves

guide curve chart

IRRM Operational Changes

An IRRM is a series of temporary actions implemented by engineers designed to reduce the risk to downstream populations that may be associated with high water elevations at a USACE reservoir. Since 2017, a series of IRRMs have been implemented at Beaver Lake Dam. These IRRMs ranged from updated emergency action plans to water-proofing the operational equipment at the dam (gate controls) to faster, more effective evacuation of the water from the flood pool. Updating these flood pool evacuation operations was performed in a series of three steps, which are described below. 

1. Double flood risk management minimum release after floods.
  • Minimum releases from Beaver increased from 950 cfs to 1,900 cfs when Beaver Lake is in flood pool and conditions downstream allow.

  • Table Rock must be below elevation 917 feet

  • Combined Beaver, Table Rock, and Bull Shoals less than 50 percent flood storage

2. Deeper Drawdown After Surcharge (release to prevent gates from overtopping).

  • Drawdown of 1.0 to 1.5 feet from top of flood pool (from elevation 1,130.0 to 1290.0 or 1,128.5 feet depending on the time of year) after flood event

  • Provides extra 0.5 to 0.75-inch runoff storage​

3. Revised Guide Curves at Newport and Georgetown.


  • Regulate to 24 feet stage at Newport

  • Delay transition to springtime target stage by two weeks


  • When system storage is LOW, use current low target (blue)

  • When system storage is HIGH, use current high target (green dash), and

  • When system storage is VERY HIGH, use current late springtime (May) target (red dots).


  • When system storage is above 30 percent, regulate to higher summer target (red dots).

Newport and Georgetown IRRM Plans

graph of the changing water control under the IRRM

Additional Beaver Lake Dam IRRMs (Non-Operational)

  • Physical Improvements to Dam Equipment

    • Gate mechanical / electrical waterproofing 

    • Equipment wave run-up protection

    • Added sensors for remote operation

  • Preparedness Improvements

    • Emergency flood barriers for control house and powerhouse

    • Increased monitoring for potential seepage

    • Downstream warning system for Carroll County, Arkansas and Branson, Missouri

  • Communication​

    • Regular emergency exercises​ with stakeholders

Estimated Inundation Maps

Newport 21-24 Feet
small image of a map


Newport 34 Feet
map of newport estimated inundation at 34 feet

What is NEPA?

The National Environmental Policy Act is our basic national charter for protection of the environment. It is foremost a procedural law that helps ensure that federal decision makers take a hard look at the potential effects of a proposed action and allow the public and other stakeholders to comment on the federal agency’s effects analysis and consideration of reasonable alternatives. The NEPA analysis helps these decision makers understand the environmental consequences of the alternatives in comparative form before making a decision. This “hard look” is informed by the public and other stakeholders, starting with a project or study’s scoping phase.

graphic describing the national environmental policy act
* click the image to enlarge 

The environmental review process that accompanies Corps planning studies and its value to the public are not always easy to understand. Recognizing this, and to help the public and organizations effectively participate in federal agency environmental reviews, the Council on Environmental Quality wrote the informational A Citizen’s Guide to the NEPA