rfp-des-2026-19-addendum-5.pdf

Murphy Dam Outlet Works Improvements Project, Pittsburg, NH

ADDENDUM NO. 5

To: All Prospective Bidders Murphy Dam Outlet Works Improvements Project

Location: Pittsburg, NH

From: Charlie Krautmann – NHDES Dam Bureau

Re: Addendum No. 5

Date: June 11th, 2026

Please find the following ADDENDUM NO. 5 for the Murphy Dam Outlet Works Improvements Project which is to be included as part of the Contract Documents thereof.

As per Specification Section 00200, Article 13.09 the bid shall contain an acknowledgment of receipt of this Addendum No. 5, (and all addenda). The addendum number and date shall be entered in the space provided in Section 00301 – Bid Form, Article 3 – 3.01A

Please note bids are due Friday, June 19th, 2026 at 1300 (EST). Hard copy bids may be received as stipulated in the Contract Documents.

This Addendum has been issued to include clarifications to a few questions which include:

Item #1 – Clarification

Question – Demo of low level valves under bid item 16, but also mentioned on bid item 7.1.a.

Bid Item 11a also calls for demo of existing valves disposal. Please clarify.

Response – Bid Item 16 shall be the pay item for demolition, removal, and disposal of the existing DOW valves and associated control equipment. Bid Item 7 shall cover selective demolition not otherwise included in Bid Item 16 and necessary to prepare the work areas for new construction. Bid Item 11a shall cover furnishing and installing the new jet-flow gates and shall not be interpreted as the primary pay item for demolition and disposal of the existing DOW valves, except for incidental removals necessary for fit-up of the new work.

Item #2 – Clarification

Question – How many inches of new gravels for the south access road

Response – Provide a minimum of 6 inches of compacted gravel or crushed gravel surface material, placed over the proof-rolled and shaped access-road subgrade, unless otherwise directed by the Engineer.

Item #3 – Clarification

Question – Sequencing for valve demo?

Response – The existing DOW valves and associated control equipment shall not be demolished or removed until the new jet-flow gates, operators, controls, drain/air appurtenances, and related systems have been installed, tested, commissioned, and accepted for operational observation by the Owner/RPR. The Contractor shall submit a detailed sequence and schedule for review and approval. Existing outlet capability shall be maintained except during Owner-approved closure and water-control periods.

Item #4 – Clarification

Question – Is the concrete infills for where the existing valve actuators are removed, to be covered under any of the concrete items? If so, which one? Or are these to be covered in the demo item?

Response – The concrete encapsulation of the new liner extensions is to be covered under the bid item 01200-9c – Concrete Construction – Cast-in-place concrete for liner extension encapsulation.

Item #5 – Clarification

Question – Bid item 16 mentions demo of "low-level outlet valves". Please confirm this is referencing the 2 - 72" Dow Valves, and not the 30" Low-Level gate valve shown in sheet C-7.

Response – Bid Item 16 is intended to reference the existing two 84-inch DOW valves/operating components, not the new 72-inch jet-flow gates and not the 30-inch low-level gate valve. The 30-inch low-level gate valve and its associated operating equipment shown on C-7 is to be protected and not to be demolished.

Item #6 – Clarification

Question – Are the gravels for the staging area to be left in place?

Response – Yes

Item #7 – Clarification

Question – Contract agreement says the interest for delayed payments is 0, please adjust this to reflect 8-12%.

Response – NHDES will keep the interest rate for delayed payments at 0%, consistent with our standard contract language.

Accordingly, we request that the clause remain as written: “All moneys not paid when due as provided in Article 9 of the General Conditions shall bear interest at the rate of 0 percent per annum.”

Item #8 – Clarification

Question – Work hours, can we work more than 8-hours a day? Special conditions mentions only 8-hour periods.

Response – Yes. Workdays longer than eight (8) hours are permissible; however, extended hours must receive prior approval from both the Resident Project Representative (RPR) and the Agency, and must comply with all applicable local and State ordinances.

Item #9 – Clarification

Question – What is the material for the 6" drain to be extended next to the penstocks? Is there a flanged we can connect to? Please advise on the type of connection with existing pipe.

Response – Provide a 6-inch stainless-steel drain extension using ASTM A312 Type 304L or Type 316L stainless-steel pipe and fittings. Connect the new stainless-steel extension to the existing pipe (believed to be cast-iron) stub using a pressure-rated, restrained, bolted mechanical transition coupling coupling adapter suitable for joining the actual measured cast-iron outside diameter to the new 6-inch stainless-steel pipe outside diameter. The coupling shall be suitable for buried/encased wet service, with EPDM gaskets and stainless-steel or corrosion-protected hardware. Do not weld to the existing cast-iron pipe. Contractor to provide plan for the drain extension to the Owner and Engineer prior to proceeding with the work.

Item #10 – Clarification

Question – Are there any restrictions regarding operating the valves for testing as far as times a day? Time of the year? Etc.?

Response – No but to be coordinated and approved by Owner/RPR.

Item #11 – Clarification

Question – Is the intent that the penstock coatings are made in the field? Or at the shop? Is it only the interior of the penstock getting coated?

Response – Shop preparation, shop primer or shop coating may be used only where compatible with the final lining system and installation sequence. Field coating will be necessary along connection interfaces but the final coating system that meets the specifications could be applied in the field if desired by the Contractor. The required lining is for the interior water-contact surface. Exterior surfaces fully encased in concrete are not to be coated.

Item #12 – Clarification

Question – Are the jet flow valves to be field or shop coated?

Response – The jet-flow gates are primarily stainless steel and shall not receive paint on operating parts or mating/moving surfaces unless approved by the equipment manufacturer and unless coating does not void the warranty. Stainless-steel surfaces shall be passivated and protected from carbon-steel/iron contamination. The motor operator/final drive gear assembly shall receive a final shop-applied permanent coating system; primer or holding primer alone is not acceptable. The carbon-steel pipe spool shall be coated/field-lined as required for the final water-contact lining and per the coating requirements.

Item #13 – Clarification

Question – When the broom gate is closed and we are seeing seepage, is it reasonable to expect all seepage go through the low level outlet?

Response – During the mandatory site visit, prospective bidders were able to observe seepage conditions at the Dowel valves. While the low-level outlet may be used to manage some seepage, it should not be assumed that all seepage will be conveyed through that outlet alone.

The Contractor is responsible for providing any additional means and methods necessary to safely manage seepage during construction.

Item #14 – Clarification

Question – Bid Item 10 in the Measurement and Payment, looks like it only references the jib crane installation, but nothing about the penstock extension. Please provide M&P description for item 10.b.

Response – Bid Item 10b: Payment will be made at the Contract Lump Sum Price for furnishing and installing the downstream conduit liner extension complete. Work includes field verification, layout, shop drawings, calculations where required, fabrication, delivery, handling, surface preparation, field fit-up, bolting, flanges, butt straps or field splices if required, stiffeners, temporary supports, permanent supports, anchors, penetrations, weld/NDT inspection, soap testing, vacuum-box testing, field lining/coating repair, cleanup, and all labor, materials, equipment, tools, and incidentals necessary to complete the downstream conduit liner extension as shown on the Drawings and specified. Concrete encasement of the liner extension is paid separately under Bid Item 9c. Non-shrink grout is paid separately under Bid Item 9e. Jet-flow gates, operators, and gate-specific appurtenances are paid separately under Bid Items 11a and 11b.

Item #15 – Clarification

Question – Is the intent that the upstream connection of the penstock is via a flange that gets bolted to the existing valve?

Response – See Detail 1 on Sheet S2 depicting slip on ring flange with welded connections between the new and existing cast steel sections.

Item #16 – Clarification

Question – What is the size and specific material of the penstock SS drain lines and valves shown on sheet C-10?

Response – The existing 6-inch drain extension shown on C-10 shall be a 6-inch stainless-steel drain line, recommended ASTM A312 Type 304L or 316L. Separately, the JFG conduit drain piping/valve required by Section 35222 is 3-inch: provide a 3-inch full-port stainless-steel ball valve with ASME flanged or grooved-end connections, stainless-steel pipe ASTM A312 Type 304L or Type 316L, stainless flanges ASME B16.5, stainless grooved couplings/fittings Type 304 or 316, and stainless butt-weld fittings ASME B16.9. Threaded stainless-steel fittings are not permitted.

Item #17 – Clarification

Question – Please confirm there's no testing required for the penstock once installed, as there's no way to seal on the upstream site.

Response – A full-length field hydrostatic test of the existing penstock/installed liner extension is not specified, but testing and inspection are required. The Contractor shall perform the specified shop/source hydrostatic tests for the JFG, pipe spool, air-valve piping, and conduit-drain piping. Field splice/flange work shall be inspected and tested as shown on S-2, including PT/soap testing, RT where specified, and vacuum-box testing using AWWA C206 as a guide. Field dry and wet operating testing/commissioning of the JFGs and motor operators remains required following flowline encasement and JFG installation.

Item #18 – Clarification

Question – Please provide photos of existing dow valves, and photos or video footage of the penstock on the upstream side, as also of the broom gate.

Response –DropBox at the following link:

https://www.dropbox.com/scl/fo/sn9akvmvorv8le933bxd9/AF0dxZ-vt- YklMftj4Ym2kI?rlkey=22mrdf19n1egpok9oixxztkur&st=cd92n3mo&dl=0 https://www.dropbox.com/scl/fo/sn9akvmvorv8le933bxd9/AF0dxZ-vt-YklMftj4Ym2kI?rlkey=22mrdf19n1egpok9oixxztkur&st=cd92n3mo&dl=0 https://www.dropbox.com/scl/fo/sn9akvmvorv8le933bxd9/AF0dxZ-vt-YklMftj4Ym2kI?rlkey=22mrdf19n1egpok9oixxztkur&st=cd92n3mo&dl=0

Item #19 – Clarification

Question – Please confirm there are no Davis Bacon Wages or AIS Requirements.

Response – This project does not receive Federal funding; therefore, Davis-Bacon Act prevailing wage provisions do not apply, and there are no American Iron & Steel (AIS) requirements associated with this work.

Murphy Dam Outlet Works Improvements Project, Pittsburg, NH