rfp-des-2026-19-addendum-3.pdf

Murphy Dam Outlet Works Improvements Project, Pittsburg, NH

ADDENDUM NO. 3

To: All Prospective Bidders Murphy Dam Outlet Works Improvements Project

Location: Pittsburg, NH

From: Charlie Krautmann – NHDES Dam Bureau Scott Brough – GFT Josh Paquet - GFT

Re: Addendum No. 3

Date: May 27th, 2026

Please find the following ADDENDUM NO. 3 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. 3, (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 as part of the mandatory pre-bid site walk held on May 20th, 2026 and includes the following items:

Item #1 – Attachment A – Pre-bid Sitewalk Summary

A summary of the pre-bid sitewalk on May 20th, 2026.

Item #2 – Attachment B – Sign-in Sheet from Pre-bid Sitewalk

Attachment A

Summary of Pre-Bid Site Walk May 20th, 2026

SITE SHOWING MINUTES

Project: Murphy Dam Outlet Works Improvements Date: May 20, 2026

Owner: NHDES – Dam Bureau Project: D194012

Pre-Bid Site Showing was held for the referenced project on May 20, 2026, at 11:00 am on Lake Francis located in the Town of Pittsburgh, Coös County, New Hampshire. Attendees met at the parking lot adjacent to the Murphy Dam control building, located approximately 0.3 miles from NH Route 3 on Murphy Dam Road.

Attendees are listed below:

NHDES (Dam Bureau): Design & Construction Engineer / RPR (GFT):

Charlie Krautmann Scott Brough Kent Finemore Dan Mattaini Jake Ruiter Alan Williams Sam Comeau Jamie Bechok

Contractors, Sub-Contractors, & Vendors:

1. Rain for Rent 8. JP Sicard, Inc.

2. Coastal Diving 9. PC Construction

3. Royal Electric Company 10. Cianbro Corporation

4. SumCo Eco-Contracting 11. NE Infrastructure, Inc.

5. Prime Machine, Inc. 12. Wasser Coatings

6. Kingsbury Construction 13. T Ford Company

7. N.A. Manosh Corporation 14. Bancroft Contracting Corp.

MINUTES:

INTRODUCTIONS

NHDES and GFT staff briefed the group, introduced as stakeholders.

SAFETY MOMENT

NHDES discussed slips, trips, and falls, and confined space with emphasis on fall and confined space protection requirements considering safety concerns while accessing key areas of the work to be performed, including areas inside the Outlet Works Control Building (sub-basement), the Outlet Works Concrete Stilling Basin including the penstock terminus with two (2) dowel valves located immediately downstream of the OW control building, and the Broome Gate Control Building located directly upstream of the dam crest. The main spillway exit channel downstream bridge load restrictions were discussed for light duty vehicles only and main point of access for the public, including ATVs, snow machines, ballfield, fishing, and other general functions. Heavy loads for construction purposes need to utilize the Cedar Stream Road for access to the work while mobilizing equipment and deliveries.

Murphy Dam Outlet Improvements Project D194012 Page 1 of 4

GENERAL OVERVIEW & FUNCTIONALITY (not particularly stated, but for reference as add-on to minutes)

1.0 Dam Embankment

Murphy Dam (NATDAM No. NH00185, DES Dam No. D194012) is owned and operated by the State of New Hampshire and is regulated under the rules and regulations (Env-Wr-300) of the State of New Hampshire Department of Environmental Services (NHDES), Dam Bureau. The dam is classified as a high hazard potential structure.

Murphy Dam is located on the Connecticut River and creates the reservoir, Lake Francis along the municipal boundaries of Pittsburg and Clarksville in Coos County, New Hampshire. It is located approximately 5 miles from the Canadian border. The dam is part of a network of dams along the Connecticut River. There are three large lakes within the Murphy Dam watershed. Listed from upstream to downstream those lakes are Second Connecticut Lake, First Connecticut Lake, and Lake Francis.

Murphy Dam consists of a main zoned embankment dam, two saddle dikes, and Turner’s Dike; a spillway consisting of an earth-cut approach channel, concrete control structure with flashboards, stop logs, and stanchions, a ledge/concrete-lined spillway chute discharge channel, two dikes on either side of the discharge channel, a one-lane reinforced concrete bridge spanning the channel; and an intake tower which houses hoisting equipment and a Broome gate for the low-level discharge penstock, a 13-foot-diameter riveted steel penstock encased in concrete, a control building housing the flow control and monitoring mechanisms, and a concrete energy dissipation pool (stilling basin).

2.0 Existing Outlet Works and Stilling Basin

Discharge from the reservoir during normal inflows is controlled entirely by a low-level outlet conduit. The intake is completely submerged within the reservoir and consists of an excavated channel approach to an approximately 18-foot-high, 20-foot-wide, 47-foot-long concrete intake with a steel trash rack (NHDES, 2018).

Downstream of the intake, a 13-foot-diameter penstock conveys water from the intake through the dam to a control building and tailrace. The upper portion of the penstock is reinforced concrete, horseshoe-shaped which transitions to a circular shape, and extends from the intake to gatehouse (approximately 280 feet). A Broome gate and associated hoisting equipment are housed within the gatehouse and can be used to seal off flow through the low-level outlet for maintenance and inspection. Downstream of the gatehouse, the penstock is constructed with 7/16-inch riveted steel plate and is installed in an excavated rock trench completely encased in reinforced concrete with embankment fill placed above the concrete.

The low-level outlet conduit bifurcates just upstream of the control building into two 84-inch-diameter pipes.

A 30-inch-diameter pipe branches off the 13-foot-diameter penstock just upstream of the bifurcation and runs below the 84-inch-diameter pipes. The 30-inch pipe is controlled by a 30-inch Dow (butterfly) valve. The larger pipes are controlled by two 84-inch Dow valves. The valves are accessible in the valve pit, which is located in the lower portion of the control building. The Dow valves are used to control flow through the low-level conduit to meet the needs of minimum flow and downstream water users. Flow is measured using two venturi meters;

one located in the 13-foot-diameter pipe just upstream of the bifurcation and one on the 30-inch-diameter pipe.

The low-level outlet discharges into a concrete-lined stilling basin directly downstream of the control building.

The basin depth is controlled by three sets of bays of stoplogs separated by two 5-foot-wide piers; one bay in the center is 15 feet wide, while the other two on the side are 12 feet, 6 inches wide. Discharge from the stilling basin flows approximately 200 feet through an excavated channel and merges with the Connecticut River at about Elevation 1,300 feet.

3.0 Reservoir Operations

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Normal operation of Murphy Dam is based on a Water User Contract between the NHDES and downstream water users. Lake Francis is operated in conjunction with Great River Hydro’s operation of the First and Second Connecticut Lakes to maintain minimum flows and provide interim water storage for electric power generation at downstream Connecticut River hydroelectric facilities.

According to the STID, the flood operation procedures are implemented when the reservoir is equal to or above El. 1385 feet. When the reservoir reaches El. 1385 feet, the control valves are closed, thus storing all inflow.

When the reservoir reaches El. 1386 feet, the control valves are opened to discharge 100 cfs for every 0.1-foot rise. The discharge from the valves is limited to 200 cfs if the flow at the USGS Indian Stream Gage is projected to be above 4,250 cfs in 2 hours, the level at the USGS Dalton Gage is projected to be above El. 17.0 feet in 32 hours, or the level at the USGS North Stratford Gage is projected to be above El. 13.0 feet in 16 hours. NHDES will continue to pass flow through the control valves until the reservoir reaches El. 1388.67 (failure of first flashboards within Spillway Bay No. 5). Once the flashboards fail, the control valves are closed. If the reservoir elevation continues to rise, the control valves are reopened to discharge 100 cfs for every 0.1-foot rise When the reservoir reaches El. 1389.0 feet, the control valves are opened to a maximum allowed discharge of 2,000 cfs, the stanchions in Bays 2, 3, and 4 are tripped first, then the stanchions in Bay 1, as necessary to keep the reservoir below El. 1390.0 feet. If the reservoir elevation continues to rise the control valves are opened to their maximum discharge capacity of 3,900 cfs until the peak inflow has passed and the reservoir level recedes.

GENERAL DESCRIPTION OF THE WORK

Verbal questions from contractor attendees were allowed, however non-binding. Contractor attendees are responsible for providing written questions to DES and GFT accordingly.

DES offer all potential bidder to review on-site historic pictures, construction documents, and as-builts prior to discussing the scope of the project. Please refer to Contract Bid Specifications Section 00020 Notice to Contractor for project scope. It was noted that bids will be accepted at 29 Hazen Drive, PO Box 95, Concord, NH 03302-0095, until 1300hrs on June 19th, 2026, by hand or mail delivery. Bids may be submitted via mail or during business hours 8:00am to 4pm, Monday through Friday at the lobby desk at the above address.

In general, the discussion included the following project’s major tasks:

1. Replacement of existing 84-inch Dow valves with two 72-inch jet-flow gates and new hydraulic operator systems. Valve operations and improvements necessary to replace the dowel valves are seasonal based on water temperature constraints (Ref: Addendum 1 - Item #4).

2. Installation of concrete-encased steel penstock liner extensions and associated structural repairs.

3. Construction of a reinforced concrete operator platform with hydronic heating, jib crane, and new safety railings/fencing.

4. Electrical upgrades; including new control paneling, conduit, and ultrasonic flow-meter installations.

The proposed ultrasonic flow-meter is non-intrusive (no drilling through penstock wall for installation, required)

5. Access road improvements, erosion-control measures, and selective demolition of existing valves/equipment.

6. Addendum 1: Includes Item #3. Seeding and Restoration, Item #4. Proposed Schedule for Project Completion – Broome Gate Seasonal Constraints, Item #5 NHDES Shoreline Permit-By-Notification 2026-01072.

7. Addendum 2: Includes Item #1 - Addition of Bid Alternate No. 1 Replacement of the Existing Broome Gate Engine, Item #2 - Clarifications

8. DES may also request as part of amending the contract as an alternate add-on to replace the Broome Gate Control Building’s asphalt roof.

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SCHEDULE

• Reference Contract Bid Specifications Section 00840 Special Conditions – Schedule and Sequence o Special Note: Depending on lake elevation and recorded water temperatures (contractor’s responsibility to monitor, log, and report water temperature readings throughout construction to DES), closure of the Broome Gate to allow work in the dowel valve area may be permitted between October 1 and January 1, and between April 1 and June 1.

Authorization to close the Broome Gate during these periods is contingent upon upstream water temperatures (at forebay) being at or below 16 degrees Celsius at depths of 6 inches and at 2 feet below the actual surface elevation at the time of temperature measurements of the lake at the forebay sample sites.

• Reference Contract Bid Drawings Sheet No. G-3 (Drawing 3 of 5) Project Rehabilitation Schedule

• Reference Contract Bid Specifications Section 00020 Notice to Contractors and Specifications Section 00301 Bid Form (Article 6.01) – Time of Completion Dates: Substantial Completion (SC), no later than December 1, 2028; Final Completion (FC), no later than December 31, 2028

Any additions, deletions or corrections to these minutes should be forwarded to Charlie Krautmann at Charles.S.Krautmann@des.nh.gov within five (5) days of receipt. Otherwise, these minutes will be approved as written.

Charlie Krautmann cc: Attendees

Murphy Dam Outlet Improvements Project D194012 Page 4 of 4 mailto:Charles.S.Krautmann@des.nh.gov Charles.S.Krautmann Stamp

Attachment B

Sign-in Sheet from Pre-Bid Site Walk May 20th, 2026