BL036_24 Ad 2.pdf

March 28, 2024 Addendum No. 2

BL036-24

H-22 (Lake Wellbrook), H-25 (Dew Lake), and H-3 (Haynes Pond 3)

Dams Outlet Works Rehabilitation

The following addition/changes modify the Bid No. BL036-24 “H-22 (Lake Wellbrook), H-25 (Dew Lake), and H-3 (Haynes Pond 3) Dams Outlet Works Rehabilitation” Contract Documents, dated February 2024, as first advertised on February 21, 2024.

I. Questions:

Q1. When does the County anticipate issuing a notice to proceed for this project?

A1. The County anticipates issuing a notice to proceed as soon as possible after a bid is awarded and contracts are finalized. It is anticipated that a construction notice to proceed will be issued in the approximate timeframe of July to August 2024.

Q2. Is the contractor required to fill out their portion of the CSLFRF form and submit it with their bid?

A2. It is recommended that Bidders should submit the CSLFRF forms at the time of bid submittal, however if the forms are not submitted the bidder will be required to submit the forms upon request before the award will be made.

Q3. Will the contractor be required to furnish a temporary field office for the County’s use during construction of this project?

A3. The contractor is not required to furnish a temporary field office during construction. The contractor is still responsible for complying with any permit responsibilities related to keeping approved copies of the design plans and specifications available on site as referenced in the contract documents .

Q4. Please furnish the full pool surface area of each lake.

A4. Normal pool surface areas and storage volumes of each lake are provided from the original As Built Drawings and dam design reports and are listed below.

Lake Name Normal Pool Surface

Area (Acres) – As Built Approximate Normal Pool Storage Volume (Acre-ft)

Lake Wellbrook (H-22) 8.6 24

Haynes Pond 3 (H-3) 14.9 69

Dew Lake (H-25) 10.2 39

BL036-24

Q5. What permits will be obtained and paid for by the contractor?

A5. Per Technical Specification Section 01 41 00 and Supplementary Conditions, the contractor shall obtain any required permits except for the following, which shall be obtained by GCDWR:

• United States Army Corps of Engineers (USACE) Nationwide Permit 3 for Maintenance

• Gwinnett County Planning and Development – Floodplain Permitting Exemption

• US Fish and Wildlife Service (USFWS) coordination – Official Species List report

• National Resource Conservation Service (NRCS) coordination

• NPDES Permitting Exemption (where less than 1 acre is disturbed)

• Georgia Department of Natural Resources Stream Buffer Variance exemption

• Georgia Safe Dams Program Permitting exemption

Q6. Please confirm that the contractor will have to perform a hydrostatic pressure test for each section of bypass discharge piping with a minimum pressure of 1.5 times the maximum pressure of the system.

A6. As an alternative to completing hydrostatic pressure testing of the bypass discharge piping system the Contractor may elect to perform a visual inspections for leaks at the commencement of bypass pumping. The Contractor shall still perform monitoring, maintenance, and repairs of leaks in accordance with Section 31 23 19.

Q7. Please confirm that no more than two sites may be drawn down at the same time.

A7. Yes, that is correct. Please also note that at each site the maximum duration from completion of initial dewatering until start of lake refilling should be limited to 2 months.

Subject to approval from the engineer/DWR and assuming all other schedule requirements are met, a third site may begin initial drawdown/dewatering operations while work is nearing completion at the initial sites.

Q8. Will the control of water/dewatering plan have to be developed and stamped by a professional engineer?

A8. The control of water/dewatering plan does not require PE stamped approval. Inclusion of such may however be included at the discretion of the contractor. The control of water plan will be reviewed and approved by the engineer/DWR for compliance with all applicable requirements specified in the plans and specifications prior to implementation.

Q9. Will steel sheet piling be acceptable for use in constructing temporary cofferdams at all locations?

A9. Sheet piling that penetrates the dam embankment would not be allowed. Sheet piling may be considered acceptable elsewhere (ex: upstream of the dam embankment within the lake). DWR and the owner’s representative reserve the right to review and approve the plan, limits, and details prior to implementation.

Q10. Most of the Repair Notes on the structural drawings include the following statement:

“AFTER LAKE IS DRAWN DOWN, CLEAN THE ENTIRE EXPOSED INTERIOR AND

EXTERIOR CONCRETE SURFACE ON ALL SIDES OF THE OCS STRUCTURE WITH

PRESSURIZED WATER, OR OTHER ABRASIVE MEANS AS ACCEPTED BY THE

ENGINEER.” Does the term “entire exposed interior and exterior concrete surface” include the areas that might be covered due to silt build-up around the structure?

A10. Yes, intent is to clean entirety of structure. For reference, top of sediment and bottom of sediment elevations are provided on Sheet C-1 of each drawing set which are referred to as “TS” (top of sediment elevation) and “HB” (hard bottom elevation), respectively. The elevations provided as TS and HB in the plans are the result of survey completed in late 2020 and/or early 2021. All provided sediment elevations are approximate and can be expected to vary.

Q11. Most of the Repair Notes on the structural drawings include the following statement:

“INSTALL WATERPROOFING JOINT SEALANT INJECTION AT ALL HORIZONTAL

CONSTRUCTION JOINTS FOR FULL LENGTH OF JOINT ON ALL SIDES OF OCS.” Is there a specific unit pay item for execution of this work? If not, can one be added so the contractor can be compensated equitably for his work?

A11. Sealant should be included under Bid Item 12 (See M&P Line Item 12)

Q12. Bid Items 8a & 8b are for Selective Tree Removal (12-24” Diameter) and (Over 24” Diameter). Do these two items also include stump removal or will that activity be paid under Bid Items 9b and 9c?

A12. Stump Removal should be paid under Bid Items 9b and 9c.

Q13. In the line items the County has type3 Rip Rap, will the County be adding a line item for Type1 due to the magnitude of water flow?

A13. GDOT Type 1 riprap is provided as Bid Item 10.

Q14. Is the contractor required to restock the lakes upon completion of the projects?

A14. Fish restocking is not required as part of the scope of the projects.

Q15. Will the use of sheet piling or shoring be allowed around the structure?

A15. See answer to Q9.

Q16. Are these dams to be done consecutively or simultaneously?

A16. A maximum of two lakes may be drained in a given time. Upland work (ex: silt fence installation, seeding, construction exits) can done simultaneously at all 3 sites or consecutively. The Contractor will submit a Critical Path Construction Schedule on how they would complete the work given the required maximum project duration. See also response to Q7.

Q17. Will the use of the outlet control structures be permitted to drain the lakes?

A17. Based off the Structural Inspection Report completed by Stantec and dated December 6, 2019, the low-level gate at H-3 and H-25 sites are operable and can be incorporated into the water control plan. Recent inspection history indicates that the low level gate at H-22 is inoperable. However, means and methods to be outlined by the Contractor in the water control plan and submitted to the Engineer for acceptance prior to implementation. If an outlet control structure is utilized to drain a lake please note that drawdown and refill rates are still subject to requirements specified in Specification Section 31 23 19 1.5.A.1-3

Q18. Will a siphon pump system be required to drain and maintain the lake levels?

A18. A siphon pump system may be acceptable for use, but DWR and the owner’s representative reserve the right to review and accept the water control plan prior to implementation. The contractor will be responsible for means and methods dictating what is required to drain and maintain lake levels. See also response to Q17.

Q19. Will mechanical pumps be allowed to drain and maintain lake levels?

A19. A mechanical pump system may be acceptable for use, but DWR and the owner’s representative reserve the right to review and accept the water control plan prior to implementation. Use of mechanical pumps will be subject to all requirements listed in Section 31 23 19 including noise control requirements. Please note that in order to successfully drawdown a lake through mechanical pumping means pump capacity will be required to pass a minimum approximate baseflow listed in Section 31 23 19 4.1 as well as all additional storm inflow.

Q20. Pumps, siphons, etc. will have to be maintained 24/7, is the contractor permitted to be on site during off hours?

A20. Per Section 31 23 19, during bypassing pumping operations, the system will be required to be operated 24 hours per day, 7 days per week, including holidays. Refer to Section 01 00 000 3.24 for necessary approvals for night work, and working on Saturdays, Sundays, or trade recognized holidays.

Q21. Lining of the pipes will require extended hours. Will this be permitted?

A21. Refer to Section 01 00 00 3.24 for necessary approvals for night work, and working on

Saturdays, Sundays, or trade recognized holidays. Please note that a minimum of 72 hours’ notice prior to the scheduled date is required for such approvals. Requests for extended hours will be approved on an individual basis.

Q22. Please specify which modality of CIPP will be allowed. Steam cured, water cured, or UV cured.

A22. Water/Steam Cured CIPP or UV Cured CIPP are acceptable for use but DWR and the owner’s representative reserve the right to review and accept CIPP Installation Plan (Section 33 01 30.73)

Q23. Due to the variables of inversion techniques and the risk of environmental hazards is pull-in place permitted or preferred to minimize risk?

A23. Inversion techniques or pull-in place are acceptable.

Q24. Will infiltration of the host pipe through the dam be repaired or considered incidental to the project?

A24. If significant infiltration is observed in the host pipe based on review of the pre-installation CCTV, the Engineer will provide a plan to repair the pipe. This work, if needed, is not included in the base bid.

Q25. Please specify chemical grouts and epoxies permitted on this project.

A25. Presuming this is in reference to Section 33 01 30.73 3.2(A)(9) regarding the use of a resin/epoxy mixture for sealing void spaces between the host pipe and CIPP liner, the material shall be based on manufacturer’s recommendations and subject to Engineer acceptance. Use of alternatives such as a chemical grout would also be considered based on manufacturer’s recommendations and subject to Engineer acceptance.

If the question is related to use of epoxies for the CIPP liner itself, epoxies and resins shall adhere to the ASTM standards provided in Section 33 01 30.73.

Q26. Can the tree stumps be removed rather than ground down?

A26. Yes, tree stumps are to be removed (see M&P Line Item 9)

Q27. If stumps are ground is the contractor required to remove the debris?

A27. Debris from stumps and trees shall be assumed to be disposed of off-site.

Q28. When the fencing is removed is the contractor required to put back the new or existing fence?

A28. If the question is related to Bid Item A.2, then new fencing would be utilized.

Q29. Please specify which ASTM 2016 or ASTM 2019-20 standard will be utilized.

A29. TASTM F1216, ASTM F1743, and ASTM F2019 are considered acceptable. The applicable ASTM standard shall be based on the selected liner type (i.e., inversion and curing of a resin-impregnated tube, pull-in place installation of a cured-in-place thermosetting resin pipe, or pulled in place installation of glass reinforced plastic cured-in place pipe using the UV light curing method).

Q30. Please reference the Agreement Article 4.04. The items mentioned as “Special Damages” appear to be standard items that should be covered by liquidated damages.

Bonding companies do not like the open-ended verbiage stated in this article. Will the County place a monetary limit on these “Special Damages” or just allow liquidated damages to cover these items.

A30. Any potential damage will be to the total amount of the contract award.

All bidders shall acknowledge receipt of this addendum by inserting its number and date in the

Bid Form. Failure to do so may subject the bidder to disqualification. This addendum forms a part of the Contract Documents.

Sincerely, Brittany Bryant, CPPB

Purchasing Associate III