Future RFP: Special Notice Announcement for Environmental Remediation Dredging
The U.S. Army Corps of Engineers, New England District (CENAE) is issuing this Special Notice Announcement for Environmental Remediation Dredging of tidal flats in the Housatonic River adjacent to the Stratford Army Engine Plant, Stratford, Connecticut (https://www.nae.usace.army.mil/Missions/Projects-Topics/Army-Engine-Plant- Environmental-Restoration-Project/). The Army is remediating the Site under the Base Realignment and Closure (BRAC) Program, consistent with CERCLA, and CT DEEP is the regulatory agency. The February 2021 Decision Document selected sediment removal as the remedy. The purpose of this announcement is to solicit input from industry as to the construction means and methods as well as anticipated construction durations for the proposed work. CENAE plans to award this project using a best value design-bid- build approach. CENAE anticipates issuing the Request for Proposal (RFP) on or about January 2024, with award anticipated by July 2024.
The NAICS code for the work described below is 562910. (size standard of 750 employees).
The Solicitation is not available at this time. This special notice does not constitute a commitment by the Government.
CENAE conducted previous market research on this project in June 2020 and conducted an industry day in January 2021. The work originally consisted of remediating two areas: Outfall 008 and the tidal flats. Since then, Outfall 008 was pulled out as a separate project, solicited, and awarded separately. The work for Outfall 008 remediation was substantially complete in December 2022. The remediation of the tidal flat is the focus of this query. While the area and depths to be remediated have not changed, site logistics now prohibit Government provided access to the site by land.
CENAE is now tasked with updating the previously completed 100% design documents of the tidal flat remediation to reflect the new site logistics. The Former Stratford Army Engine Plant property has been sold by the US Government to a private developer. As such, the Government can no longer make the property available for project related activities, including staging, storage, laydown, processing, or stockpiling sediment. As a result, the execution of the Tidal Flat remediation project must be entirely water based. Furthermore, dredged sediment may no longer be stabilized and placed on site as originally envisioned, and all sediment must be disposed off-site.
Given the Government can no longer make the plant property available for project related activities and the change in disposal options, CENAE is issuing this Special Notice Announcement to elicit industry recommendations for means and methods of sediment removal, handling, transport, and disposal.
Dredging, dewatering, water treatment/discharge, backfilling, sediment sampling and transportation of material off-site must be performed by water-based operations and with minimal spillage or turbidity. Approximately 140,000 cubic yards (cy) of material need to be removed from the tidal flats. The selected contractor will need to meet dredge depth target elevations ranging from 1 to 4 ft below grade (bg). The dredge areas containing PCBs (approximately 14,000 cy) must be dredged prior to removing metals-only contaminated areas. Post dredging confirmation sampling is required. The contractor will not be required to dredge beyond 4 feet bgs.
The dredged material is silty/fine grained and needs to be solidified to meet DOT transportation requirements. All water that comes in contact with contaminated material must be treated prior to discharge. Dredged material is contaminated with metals and PCBs and must be disposed of off-site at RCRA D (solid waste, metals) and RCRA C/TSCA (PCBs) approved landfills, as appropriate. The tidal flats shall be backfilled to within one foot of original grade using a sandy material and approximately 2 acres of the tidal flat will be restored with salt marsh. Saltmarsh restoration and establishment period monitoring will be required for resource areas impacted by dredging operations under this contract.
Turbidity monitoring and control will be required for the duration of the project. If the construction exhibits turbidity levels below the Turbidity Criteria, the project meets the monitoring objectives of the plan. If turbidity levels exceed the Turbidity Criteria over the specified timeframe, the monitoring objectives of this project are not being met and inspections and corrective actions on the part of the contractor are necessary. Turbidity Criteria is described as: In-situ turbidity measured at the moored compliance monitoring buoy locations (outside at the work zone boundary) exceeding 30 NTUs above background station turbidity measurements, sustained over a 30-minute period, and represented as an average over the water column.
The work requires compliance under OSHA 29 CFR 1910.120 including a Health and Safety Program, Site Specific Health and Safety Plan, and Training (40 Hour HAZWOPER and 8 Hour Refresher Training) for all onsite workers.
To further depict the required work, figures extracted from the Design-Bid-Build Construction Documents prior to ownership change are included with this Special Notice. Items shown on these figures will be revised during the current design effort to reflect recently imposed changes and the industry feedback of this Special Notice.
Questions for Industry:
1) At a minimum considering the list of constraints below, what would the construction industry’s approach be for dredging approximately 140,000 cy of contaminated material from the tidal flats, backfilling 100,000 cy of clean sand, and restoring the tidal marsh via in-water operations only? Please provide a detailed response including challenges you foresee to construction (accessibility, production rate impacts, etc.) that industry would like USACE to note for design:
- The volume of material.
b. Not having any land access or land-based work areas during construction for dredging, sediment handling/processing/stabilization, water treatment, backfill, and saltmarsh restoration.
c. Material properties (grain size varies but generally is 60 to 80% silt, 10 to 30% sand,10 to 20% clay, with an organic content of 4 to 6%).
d. Very shallow water depths throughout the tidal flats, working around tides since tidal flat is exposed during low tide and susceptibility to coastal storm events.
e. Transporting dredged material via water to an offloading location for landfill transport.
f. Maintaining an acceptable turbidity level adjacent to and downstream of the project site as described under “project requirements”.
g. Minimizing suspension of contaminated sediments that could re- contaminate cleaned portions of the site.
h. Available dewatering technologies, equipment, and solidification agents capable of rendering sediment meeting disposal facility requirements and can be deployed on marine plant.
i. Available disposal facilities and their acceptance criteria.
j. Sequencing during dredging to remove PCB contaminated areas first, then metals contaminated areas.
k. Off-site disposal of the dredge material meeting two different regulatory categories (two disposal waste streams).
l. Executing a robust confirmation sampling program in conjunction with on going dredge equipment and activities.
m. Treating all water prior to discharge.
n. Protecting the existing breakwater and dike during construction.
2) Given that the Government can no longer make the plant property available for project related activities only and the contract documents allow for either mechanical or hydraulic dredging methodology to accomplish the work what type of equipment would you intend to utilize for this project?
a. If mechanical dredging and transport methods are selected, what equipment would you intend to mobilize to ensure a reasonable production rate? How would you operationally sequence the work to ensure that the PCB areas are removed first? How would you intend to maintain the turbidity barrier at the site during these operations? How would you intend to deal with the treatment of water from dredging operations? Where would you be transporting and disposing of dredged materials?
b. If hydraulic dredging and transport methods are chosen, what equipment would you intend to mobilize to ensure a reasonable production rate? How would you operationally sequence the work to ensure that the PCB areas are removed first? How would you meet varying dredge depths and limit over dredge volume? How would you intend to maintain the turbidity barrier at the site during these operations? How would you intend to deal with the treatment of water from dredging operations? Where would you be transporting and disposing of dredged materials?
c. Describe how you would backfill material to restore the tidal flats. Where would you source the material for backfilling and what equipment would you mobilize for this effort?
3) Would the contractor dredge, treat and dewater all the material within the work limits prior to transporting it to disposal sites? If material needs to be transported outside of the work limits while dredging operations are on-going, do contractors have the means for controlling turbidity limits rising outside of the work limits?
4) If the contract did not provide any upland area but did not prevent the contractor from working out their own agreements and obtaining uplands with any of the adjacent landowners, would you plan to bid the contract with only in water plants or would you pursue uplands to construct the project?
5) The period of performance of the original design was 18 months. Considering the all water-based approach can the new project be reasonably executed in the same window as before?
6) Considering the limitations and site constraints on this project as it currently stands, does industry have any recommendations/suggestions on how to simplify, reduce costs, or add value to the proposed construction elements?
Due Date: Responses are due by 3 March 2023. Responses should be addressed to the
U.S. Army Corps of Engineers, New England District, 696 Virginia Road, Concord, MA 01742-2751, ATTN: Heather Skorik, or via email to email@example.com. Interested firms shall provide the above documentation in one original form and one copy, if mailed.
To view the full Special Notice, click here.