Industry Questionnaire.docx

INDUSTRY DAY QUESTIONNAIRE

STILLING BASIN ACCESS AND MODIFICATIONS

November 2025

*This questionnaire is for general information and will not change the terms and conditions of any subsequent solicitation or contract. Response to this questionnaire does not automatically disqualify respondents from participating in a subsequent solicitation for proposals.

*This is part of our market research, to be used for preliminary planning purposes. THIS IS NOT A SOLICITATION FOR PROPOSALS AND NO CONTRACT WILL BE AWARDED FROM THIS PRESENTATION. No reimbursement will be made for any costs associated with providing information in response to this presentation or any follow up information requests.

*Information from contractors will be confidential and will not be shared outside of USACE.

*After the virtual meeting on 13 November 2025, the presentation slides will be uploaded on to SAM with the Industry Day Posting. Refer to the presentation slides for design concepts to aid in the completion of this questionnaire. Respondents are not required to respond to all questions below. Please provide responses to as many as possible.

One-on-One Contractor Interview Questions (Technical Approach) The following questions are intended to assist in the planning, design, and acquisition for the project. These questions are intended to gain insight on how industry may approach the construction of various features of work. This feedback will aid the Government in the design of access to the stilling basin.

To ensure efficient use of time in One-on-One Interviews, the Government will highlight specific discussion topics based on the response for each individual contractor. At Contractor discretion, adding “**” in front of specific responses will indicate areas of desired emphasis in the One-on-One Interview.

Splitter Wall Construction

1. The current concept assumes the splitter wall construction will occur in the wet via barges (tailwater depths will vary from 14 -18 feet based on hydropower discharge). Do you think it is possible to construct the splitter wall in the dry? If yes, how would you accomplish this?

2. Would you build both splitter walls at once or build the right splitter wall to gain access to the stilling basin and then build the second wall in YR 2 while working in the first bay? The ability to construct the splitter walls will likely be limited to the AUG – FEB time frame (due to the potential for spillway releases) with some restrictions on the number of shafts that can be open at one time. Is there a preference for which wall is built first and why?

3. Given the limited time window, is it reasonable to assume that a single splitter wall and its associated coffercells can be constructed in a single season between AUG – FEB?

a. Assume releases from the dam are limited to hydropower operation.

b. Assume that the derrick stone must be removed under the cellular cofferdam footprint prior to placement of the coffercells.

c. Assume drilled shafts must be backfilled within 24 hrs.

4. What number of drill rigs and number/size of barges would you anticipate will be needed in the stilling basin at one time to drill the shafts and construct the splitter wall within the AUG-FEB timeframe?

a. What is your preferred access into the stilling basin for the equipment and desired draft of the barges?

b. Existing baffle blocks will need to be removed for the construction of the splitter wall. Adjacent baffle blocks are expected to require modification to facilitate barge access. What width of lowering of the baffle blocks would you anticipate is required to facilitate construction access? Can the wall be constructed without lowering of the adjacent baffle blocks?

5. What is a reasonable duration for the baffle block removal and modification (lowering if needed)?

6. Discuss the method of construction of the drilled shafts and splitter walls and identify any concerns or efficiencies that may be gained from another strategy?

7. Can the verticality of the tangent drilled shafts ensure closure beneath the splitter to cutoff seepage when a bay is de-watered?

8. Assuming multiple drill rigs are on-site installing shafts, how much time is needed to emergency backfill open drill holes to grade and demobilize from the stilling basin if use of the full spillway is required? Is 48 hours adequate, if not, what is a reasonable time frame to rapidly demobilize?

Earthen Cofferdam

9. How would you build this cofferdam? Discuss any concerns with the installation, operation, and maintenance of the earthen cofferdam (and coffercells). What other types of cofferdam materials should be considered, like an impervious core of HDPE liner, flowable fill, or sheet piling?

10. Would you prefer to remove the Derrick Stone to improve water tightness or leave the Derrick Stone in-place and utilize de-watering (or other methods) to achieve water tightness?

Stilling Basin Access

11. Would you consider accessing the left bay from the left (north) side, keeping in mind the overhead high voltage power line in lieu of utilizing a multi-span bridge from the right side? This question is to determine if access on the left side is a reasonable approach or whether all access should be considered from the right (south) side. What modifications to the bank are required to create practical access from the left side?

12. What is heaviest vehicular construction load and maximum width that you would expect to operate on the temporary bridge? Assume that all equipment utilized in the middle and left bay will have to demobilize using the temporary bridge.

13. What methods of dewatering the stilling basin, after construction of the splitter walls and coffercells/cofferdam, would you likely integrate to manage surface and foundation seepage? How would you integrate the de-watering system with surface demolition and placement of the overlay slab.

Stilling Basin Modifications

14. Assuming anchor installation is in-progress and slab overlay construction has been halted due to the potential for a high pool event, how much time is needed to demobilize from the stilling basin if use of the full spillway is required? Is 48 hours adequate, if not, what is a reasonable time frame to rapidly demobilize?

Site Access

15. What is the minimum access road width needed for construction vehicles? For bidding purposes, what is the typical governing equipment size you assume for evaluating site circulation?

16. Would you use a conveyor belt system or pump for placement of concrete or other materials? What about a cable trolley system? The maximum size coarse aggregate is expected to be 1.5 to 3 inches. The NMA for the splitter walls may be ¾” to 1”.

17. Would you prefer to locate a concrete batch plant near the right abutment access road or near the stilling basin?

General Approach

18. Do you have any other innovative solutions that the design team should consider as it relates to the stilling basin access?

19. Do you have any sequencing restrictions to minimize dam safety/construction risk due to spillway flow during the installation of the stilling basin slab overlay and anchors.

One-on-One Contractor Interview Questions (Planning and Acquisition) The following questions are intended to assist in the planning and acquisition for the project. The Government is considering the use of Early Contractor Involvement or a traditional phased design-bid-build project. The Government is looking for both positive and negative feedback on the questions below. Please be concise in your responses.

1. The Government is considering the use of an Integrated Design and Construction (IDaC) contract with the intent of having early contractor involvement in the planning of the stilling basin access features of work. The Government will perform the design work with input from the Contractor.

a. What is your experience with Early Contractor Involvement (ECI) and Integrated Design and Construction (IDaC) acquisition strategies?

b. What opportunities and challenges have you experienced with these strategies? Provide input on benefits, opportunities, or risks of using IDAC in comparison to traditional delivery methods.

c. Conclude by providing your recommended delivery method for successfully completing the project.

2. Considering use of IDaC, What level design submission (% complete) best supports a competitive bid which will confidently support a maximum ceiling price and an initial target price?

3. What level design submission (95% or 100% complete) best supports a timely negotiation of the Bid-Option for construction to a Firm Fixed Price?

a. Based on the Contractor’s involvement during design, how long will it take to prepare a proposal for the Bid-Option?

b. Based on the Contractor’s involvement during design, how much time is necessary to finalize the proposal once the IFCs are issued?

4. What Pre-Construction Services should the Government consider to be necessary when developing a scope of services? Is there a rule of thumb or % that the Government should use when budgeting?

5. As part of IDaC, the Government will not allow for Fast-Tracking construction, however it may allow early work items such as long lead procurement items or site preparation if established as firm fixed price at time of selection. Does this impact your response on how best to structure the design package?

6. What selection criteria, in your experience, do you feel is least valuable for evaluating risk and success on a construction project of this size and type? What is most valuable?

7. If the Government does not choose to pursue IDaC, it may instead establish a prequalified source list of firms from which to solicit input on draft RFPs and eventually traditional design-bid-build packages. Please provide your input on this approach.

image1.jpeg image2.png