LOCK FOUNDATION AND SITE PREPARATION FOR LOCK and DAM 25 NAVIGATION ECOSYSTEM SUSTAINABILITY PROGRAM (NESP)

Amendment 0006 The purpose of this amendment is to incorporate tax exemption language. All other terms and changes remain unchanged.

Amendment 0005 The purpose of this amendment is to remove FAR clause 52.236-16 and replace it with FAR 52.236-16 Alternate 1. This amendment also incorporates updated drawing sheets GI002 and CG203. All other terms and conditions remain unchanged.

Amendment 0004 This amendment is issued to provide replies to ProjNet Bidder Inquiries as of 8 Aprio, and make all resulting changes. See attachments for full details of Amendment 0004.

Amendment 0003 This amendment is issued to provide replies to ProjNet Bidder Inquiries, and make all resulting changes. ProjNet Bidder Inquiries is re-opened through 4:00pm CST, 3 April 2026. There are some attachments that must be requested in order to be provided via DoD SAFE. See attachments for full details of amendment 0003.

Amendment 0002 This amendment is hereby issued to make administrative updates to the above-referenced solicitation in accordance with the Government Responses to ProjNet Bidder Inquiries as of 4 March 2026:

Amendment 0001 This amendment is issued to make administrative updates to the solicitation.

Proposal will be submitted via EMAIL Angie Grimes at angie.l.grimes@usace.army.mil and Whitney Dee at whitney.r.dee@usace.army.mil The U. S. Army Corps of Engineers, St. Louis District, is seeking a firm to furnishing all equipment, labor, operators, supervision/site superintendent, quality control, supplies, materials, and incidentals necessary to satisfactorily perform and provide construction activities of lock foundation and site preparation work.

The lock foundation work establishes the lock wall and floor foundation. It consists of excavation and disposal of existing scour protection riprap that was part of previous scour hole emergency repair, dredging of sand fill, placement of sand fill in the proposed lock foundation, and placement of riprap berm.

Work also includes the construction of a separator wall that will separate the river side riprap berm from the dredged sand that will be placed as foundation material for the future river wall monoliths and lock floor. The separate wall will be a sheet pile wall braced with piles. This effort also includes a deflector on the downstream side of the dam to route water flowing through the tainter gated dam adjacent to the river walls around the sheet pile separator wall. For the site preparation work, additional dredge borrow will be placed upland for a future staging and laydown area and a sanitary outfall pipe will be installed.