Big Sandy Lake Dam Rehabilitation Project

U.S. Army Corps of Engineers, St. Paul District
Published Oct. 1, 2018
Updated: March 17, 2022

Sandy Lake Dam has undergone a series of modifications, repairs and periodic inspections over its 125-year history. From 2011 to 2016, a series of above and below water inspections identified several features that had deteriorated to a point that repair or replacement were necessary to maintain the long-term stability of the structure.


Sandy Lake Dam is located on the Sandy River in Aitkin County, Minnesota, 1.25 miles upstream of the junction between the Sandy River and Mississippi River.


Construction activities on the $5.3 million contract include replacing the deteriorating concrete wall in the lock chamber with removable steel panels, installation of a new mechanically-operated slide gate in the log sluice, replacement of the six existing slide gates, concrete repairs along the upstream face of the dam and various electrical updates to modernize operations and support mechanical operation of the six slide gates and log sluice gate. Phase 1 consists of repairs to the lock bulkhead wall and Phase 2 consists of repairs to the dam gates and log sluice.


The construction contract was awarded on Nov. 5, 2020, and construction began on Feb. 10, 2021. Cofferdams were constructed upstream and downstream of the lock chamber for Phase 1. The following Phase 1 activities have been completed to date: permeation grouting, concrete repairs, concrete apron extension. Construction is scheduled to be complete on Dec. 31, 2022.


The project authority is the Rivers and Harbors Act of 1880. Following the authorization for the reservoirs, Congress directed the Secretary of War to establish rules governing their regulation through the Rivers and Harbors Act of Aug. 11, 1888. The original authorized project provided supplemental flow during periods of low Mississippi River stages. Demands for storage releases for navigation were greatly reduced in the 1930s. Since then, Sandy Lake Dam has been operated for flood control, recreation, fish and wildlife conservation, water supply and water quality improvement.


FY 2021:

Construction Contract                                 $5,300,000

Engineering During Construction                 $204,000

USACE Services:                                               $350,000

FY 2022:

USACE Services:                                               $276,000