Keystone Dam Safety Modification Study Updates

Keystone Dam Safety Modification Study public comment period runs March 6 to April 5. 

KDSMS Documents

For Questions about the Draft Environmental Assessment Call


To submit comments about the Keystone Dam Modification Study email

Comments must be submitted by April 5, 2024

Informational Workshop Slides 

KDSMS Public Notice of 30 Day Comment Period 

Draft KDSMS Environmental Assessment

Habitat & Mitigation Analysis KDSMS

Clean Water Act Section 404(b)(1) Analysis KDSMS

Draft Biological Assessment KDSMS

Public Agency & Tribal Coordination KDSMS

Cultural Resources KDSMS 


KDSMS Workshop Slides - Feb. 12, 2019

KDSMS Public Notice - Feb 5, 2019

About the Keystone Dam Safety Modification Study


The purpose of the Keystone Dam Safety Modification Study is to identify plans to reduce risk of overtopping or failure in the event of an unprecedented flood. 

The accompanying Environmental Assessment has been prepared by the U.S. Army Corps of Engineers, Tulsa District to evaluate the Keystone Dam Safety Modification Study. 

This EA is an assessment of potential impacts that may result from the implementation of the final array of alternatives in comparison with the No Action Alternative.

The recommended proposals would not change the normal pool elevation or the flood pool elevation. Keystone Dam will operate according to the water manual. The top of the conservation pool would remain at 723 mean sea elevation and the top of the flood pool would remain at 754 mean sea elevation.

The recommendation to raise the elevation of the dam by approximately 11 feet would not change normal operation of Keystone Dam. The emergency storage gained from increasing the height of the dam would only be used in the event the gates are completely open and the lake continues to rise.

Keystone Dam Significant Events

  • Authorized by Flood Control Act of May 17, 1950
  • Construction began January 1957
  • Placed into Operation September 1964
  • Two hydropower units placed into operation May 1968
  • Record Release: 300,000 cubic feet per second on October 4, 1986
  • Keystone Dam Safety Modification Study Public Notice  February 5, 2019
  • Public Workshop For KDSMS February 12, 2019
  • Pool of Record: 757.2 (ft) on May 29, 2019
  • Release of Draft Environmental Assessment for KDSMS & Beginning of 30-day comment period March 6, 2024
  • Public Meetings for KDSMS Draft EA February 13-14, 2024

Keystone Lake Levels