07.23_Responses_to_Bidder_Inquiries.pdf

Wormley Creek New Work and Maintenance Dredging FY 2017 Responses to Bidder Inquiries Solicitation W91236-17-B-0007

Bidder Inquiry ID: 6893041 There is no bid date and time listed in Item 13 and no Address Offer To in Item 8. Please clarify.

Thanks.

Response to Bidder Inquiry ID: 6893041 The bid opening information is listed within the FBO solicitation posting. The date and time listed on FBO is Apr 25, 2017 1:30 pm Eastern. The bid date and time and address will be added to the solicitation by amendment.

Bidder Inquiry ID: 6900670 Please provide the electronic survey data for the dredging area and disposal site.

Response to Bidder Inquiry ID: 6900670 Electronic survey data for the dredging area and disposal site will not be offered as part of the solicitation.

Bidder Inquiry ID: 6907430 Please provide geotechnical information available for the material to be dredged (boring logs, vibrocore logs, grab samples, sieve analysis, laboratory tests, etc.

Response to Bidder Inquiry ID: 6907430 Available geotechnical information (boring logs and boring locations, soil classifications, and grain size distribution curves) will be provided by amendment.

Bidder Inquiry ID: 6907434 Drawing Sheet/Detail: 7 of 21 The plans provided show floating docks in the Turning Basin. Will these be remove prior to the commencement of dredging? Who will be responsible for the removal of the docks? Who will be responsible for their replacement?

Response to Bidder Inquiry ID: 6907434 Please reference specifications section 35 20 23, paragraph 3.1.6 Removable Piers. “The Contractor shall coordinate with the USCG on the need to remove piers during construction. If removable piers, with USCG approval, are moved by the contractor, then the contractor will be responsible for the any damages sustained to the piers by the removal and reinstallation of the piers.”

To clarify, the floating docks are secured to the piling by "jet-dock" sections connected around the pile. If the floating docks are required to be removed, the Contractor will be required to disconnect, remove, and replace upon completion of dredging operations. The piles must remain in place as they support an electrical system. The Contractor may move the floating docks adjacent the work area to facilitate dredging operations. Images of the turning basin and floating dock system will be provided by amendment.

Bidder Inquiry ID: 6907436 Drawing Sheet/Detail: 6 of 21 The plans shows a pipeline route. Will the contractor be required to use that exact pipeline route?

Response to Bidder Inquiry ID: 6907436 As indicated on the drawings, sheet 6 of 21, the general pipeline route must be used as shown to not encroach upon vegetation, salt marsh areas, or wetlands.

Bidder Inquiry ID: 6907440 Permit No. NAO-2014-1391/VMRC#15-V0075 Page 3 Paragraph 6f states "Barges and scows used to transport dredge material may be filled only to a point where no overflow occurs. No overflow pipes are allowed." Also, Section 35 20 23 Page 19 Paragraph 31.7 OVERFLOW states "Barges and scows used to transport dredged material shall be filled only to a point where no overflow of dredged material occurs."

Please confirm that overflow will not be allowed by any of the following means:

a. Overflow over barge coamings

b. Overflow through skimmers with discharge through the hull below the waterline

c. Overflow through scuppers with discharge below the waterline

d. Decanting of the barge using pump(s) to lower the water level in the barge.

Response to Bidder Inquiry ID: 6907440 To clarify, overflow of water and clarified supernatant is allowed. Overflow of dredged material by any method will not be permitted. Decanting of the water and clarified supernatant within the barge or scow, using pump(s) to facilitate an economical load, will be permitted.

Bidder Inquiry ID: 6907442 During the barge loading process, or after barges are initially loaded, is decanting of free surface water by pumping allowed to increase the loading capacity of a barge?

Response to Bidder Inquiry ID: 6907442 Decanting of the water and clarified supernatant within the barge or scow, using pump(s) to facilitate an economical load, will be permitted.

Bidder Inquiry (email):

We understand this project requires beach placement of ~29,000 CY of sandy material and offshore placement of ~31,900 CY of silty material unsuitable for beach placement, and that both hydraulic and mechanical dredging are acceptable means of removal. Our question is: Would the Corps allow us to hydraulically load the material in the boat basin and inner channel going to the Wolf Trap Disposal Area into our 3000 CY split hull, bottom dump scow via hydraulic cutterhead dredge? We intend to use bow and stern anchors on the 3000 CY scow in a Corps approved deep water area in the river, in order to hold the barge steady and allow for sufficient clearance of its 16' loaded draft, this will also eliminate the risk of barge movement in any undesirable way while loading or standing by.

Response:

Yes, dredged material from the inner channel and boat basin may be removed by cutter-head dredge/ pipeline and hydraulically placed in a scow or barge for transport to the Wolftrap Alternate Dredged Material Placement Site. Regarding dredged material overflow and decanting of water within the barge or scow, clarifications will be posted to the solicitation by amendment.