L575 Levee Restoration Information

Background: The L575 Benton-Washington-McKissock-Buchanan-Atchison-Hamburg Levee System experienced significant damage during the 2019 Flood Event. This led to seven (7) breaches, along with substantial other damages, occurring throughout the Levee System.

Current Action: Complete the final repair contract to fully restore the L-575 levee system to its pre-flood condition. 

Restoration Activities:

 

Initial Breach Repair #1 – West of Thurman, IA

Initial Breach Repair #2 – West of Hamburg, IA

Interim Repairs Contract Final Repair Contract

Contractor

Western Contracting Corp. from Sioux City, IA

Newt Maritime Services from Dubuque, IA

Weston Solutions, Inc. of West Chester, PA

Aptim Federal Services, LLC of Alexandria, VA

Contract Amount

$7.5M

$12M

$19.5M

$58.3M

Contract Award

April 14, 2019

April 19, 2019

July 10, 2019

December 23, 2019

Construction Start

May 4, 2019

May 4, 2019

August 5, 2019

January 2020

Estimated
Completion

July 15, 2019 (Complete)

September 20, 2019 (Complete)

April 16, 2020

December 2020

 

Status Updates:

03 February 2021 - The contractor is approximately 75 percent complete with the current repair efforts included in the construction contract (this number fluctuates as additional repair areas are able to be added to the contract). As the required real estate is secured by the levee sponsors, the remaining levee repair areas can be added to the contract. Current repair efforts are focused on sheetpile installation along sections of the levee that were most damaged by the 2019 flooding. Other ongoing repair efforts include relief wells and toe drains along the levee system. 

08 September 2020 - The contractor is approximately 83 percent complete with the final levee repair project. Work is focused on relief well repairs/replacements and repairs along the Nishnabotna levee tie-back. 

16 July 2020 - The contractor is approximately 67 percent complete with the final levee repair project. Work is focused on relief well repairs/replacements and repairs along the Nishnabotna levee tie-back. 

10 June 2020 - The contractor is approximately 65 percent complete with the final levee repair project.

08 May 2020 - The contractor is approximately 60 percent complete with the final levee repair project. Seeding of the Upper Nishnabotna borrow area will be complete this week.

23 April 2020 - The contractor is completing drainage structure inspections and restoring side slopes along the levee and is approximately 50 percent complete with the final levee repair project.

10 April 2020 - The contractor is completing drainage structure inspections and restoring side slopes along the levee and is approximately 25 percent complete with the final levee repair project.

16 March 2020 - The contractor continues repair activities that focus on restoring the levee system to its pre-flood condition.

04 March 2020 - As of 29 February 2020, the entire L-575 levee system has been returned to full height which is a critical milestone in levee repairs. The team will continue with repair activities to restore the levee system to its pre-flood condition.

13 February 2020 - The contractor has closed all of the breaches on the L-575 levee system and is working towards returning all of the breach locations to their pre-flood heights over the next few weeks.

31 January 2020 - Initial closure of the final outlet breach is expected to be complete by early February 2020. The follow-on construction contract for final levee repairs was awarded on 23 December 2019 to Aptim Federal Services, LLC of Alexandria, VA in the amount of $58.3 million. The contractor is scheduled to have the levee system fully rehabilitated in calendar year 2021.

10 January 2020 - Closure of the final outlet breach is expected to be complete with the contractor demobilizing from the site by the end of January 2020. The follow-on construction contract for final levee repairs was awarded on 23 December 2019 to Aptim Federal Services, LLC of Alexandria, VA in the amount of $58.3 million. The contractor is scheduled to have the levee system fully rehabilitated by the end of the calendar year 2020.

18 December 2019 - The contractor has secured over 170,000 cubic yards of cohesive material and has begun closure efforts at the outlet breaches. Work on this contract is estimated to be complete late December 2019. The follow-on construction contract for final levee repairs is currently in the contract award process.

06 December 2019 - The contractor has completed stockpiling sand for Breach A and is currently mining cohesive material for stockpiling and placement at Breach B.  The follow-on construction contract for final levee repairs is under development.

22 November 2019 - The contractor has completed stockpiling sand for Breach A and is currently mining cohesive material for stockpiling and placement at Breach B. Work on this contract is estimated to be complete late December. The follow-on construction contract for final levee repairs is under development. A pre-proposal meeting for this contract was held on 19 November 2019.

08 November 2019 - The team continues to conduct resiliency and interim repairs throughout the L-575 levee system. This includes enhancing initial breach repairs, repairing areas that experienced significant erosion during the March 2019 flood event, and restoring the levee crest to provide construction access throughout the system.

24 October 2019 - The team continues to conduct resiliency and interim repairs throughout the L-575 levee system. This includes enhancing initial breach repairs, repairing areas that experienced significant erosion during the March 2019 flood event, and restoring the levee crest to provide construction access throughout the system.

13 October 2019 - The contractor continues work on the levee crest repairs at both the “A” and “B” inlet breach sites, increasing the resiliency of the repairs at these locations.

27 September 2019 – Breach “C,” the inlet breach southwest of Hamburg, IA, was closed on 25 September 2019. This initial closure stops the inflows and will allow for follow-on construction activities to increase the level of flood risk management to approximately the 4% annual chance exceedance (25-year) level for this section of the levee system until the system can be fully repaired.

Final inspection of the Breach "B" closure was held on 19 September 2019 with the Contractor planning to demobilize from the site in the next several days. The team continues to work through development of the interim repair designs as contract documentation is being finalized. Due to rising water levels on the Missouri River, the team is working with the Contractor to ensure the initial breach repair work at both locations is protected.   

13 September 2019 – The initial repair contract for Breach “B” is anticipated to be complete before the end of the month.  The team continues to work through development of the interim repair designs as contract documentation is being finalized.  Due to rising water levels projected by the National Weather Service on the Missouri River, the team is working with the contractor to ensure that the initial breach repair work at both locations is protected.

06 September 2019 – The Contractor is hydraulically placing sand at the Breach west of Hamburg, IA. With the additional dredging scope, all work on the Initial Breach B Contract is scheduled to be complete by mid-September. The Pre-Construction Meeting for the next phase of repairs was held on 18 Jul 2019 and the Contractor mobilized the project trailers on 25 Jul 2019. The team is working through real estate easement issues with construction activities scheduled to commence once the necessary real estate easements are obtained.

29 August 2019 – Hydraulic placement of sand in the scour area behind the south revetment, just behind the closed breach, is expected to be complete by mid-September. This will fortify the breach closure emplaced by filling the deep pit created from the flood event.

23 August 2019 – The Contractor is scheduled to begin hydraulically placing sand in the scour behind the south revetment this weekend with an expected two week duration. All work on the initial breach repairs should be substantially complete by early-September. USACE is working through real estate easement issues with resolution and construction commencement tentatively scheduled for the end of this week.

13 Aug 2019 – The initial breach was closed on 25 July 2019. Dredging de-mobilization is tentatively scheduled for 16 August 2019. The contractor is approximately 95% complete with the scope of work.

05 Aug 2019 – Work on the second stage (interim) repairs is anticipated to begin the week of 12 Aug 2019.

31 July 2019 – Initial Breach A is substantially complete and the final inspection was held on 15 July 2019. Initial Breach B was closed on 25 July 2019. The Contractor continues to place additional material to build the sand berm to the design width and height. All work on this contract is expected to be complete in late August 2019. A field office has been setup in order to begin the interim repairs.

22 July 2019 – Initial breach repair #1 is complete and the final inspection was held on 15 July 2019. The contractor for initial breach repair #2 has almost completed the sand berm, but has experienced difficulties with the increased flows realized from decreasing the breach opening. As such, the team pursued placement of roughly 800 tons of rip rap north of the breach to stem the flow down the levee toe and into the breach. The pre-construction meeting for the follow-on repairs occurred on 18 July 2019.

11 July 2019 – Hydraulic placement of sand continues to widen the sand berm pad at the first priority breach location.  Dredging operations also continue at the second priority breach location with the initial breach closure anticipated for mid-July.  A follow-on contract to raise and widen both initial breach repairs has been awarded. This work is set to begin on the first breach location in the upcoming few weeks.

20 June 2019 – For the breach west of Thurman, IA, the priority breach was initially closed on 20 June 2019.  This closure stops inflows through the breach and will allow for follow-on construction activities to further increase the level of flood risk management provided by the repaired levee section.

For the breach West of Hamburg, IA, the rock revetment is approximately 40% complete. Two additional tugs have been contracted to help haul shot rock from the quarry, which should help speed up the revetment schedule.  Once, the rock revetment has been repaired the contractor will be able to resume directing dredge material into the initial breach closure footprint.

10 June 2019 – For the breach west of Thurman, IA, the contractor resumed dredging operations on 03 June 2019 following the late high water event. Material placed prior to the recent (29 May 2019) high water event largely remained in place with minimal erosion observed.

For the breach West of Hamburg, IA, a contract modification was executed on 3 June 2019 to procure and place rock in a revetment alignment along the Missouri river to reduce flow velocity through the breach. The first rock placement in the revetment occurred on 3 June 2019. Both 18” dredges are also currently placing material to minimize material loss from the high water levels.

NOAA River Level Observations & Forecasts

NOAA Water Gauge Levels

L575 Levee Imagery

Video Gallery

Video by Michael Glasch
Aerial view near Levee L575 at 2011 setback, Apr. 15, 2019
U.S. Army Corps of Engineers, Omaha District
April 15, 2019 | 0:30
Aerial view near Levee L575 at 2011 setback, Apr. 15, 2019, following March 2019 runoff event. (Video by Mike Glasch)
More