35 20 23 DREDGING.pdf

FY21 Duluth-Superior Maintenance Dredging FY21MDDULSUPHARB

CERTIFIED FINAL - READY TO ADVERTISE

SECTION TABLE OF CONTENTS

DIVISION 35 - WATERWAY AND MARINE CONSTRUCTION

SECTION 35 20 23

DREDGING

04/06

PART 1 GENERAL

1.1 DEFINITION

1.2 SUBMITTALS

1.3 CHARACTER OF MATERIALS

1.4 PLACEMENT AREA CONDITIONS

1.5 DELIVERY OF PLANT AND ORDER OF WORK

1.6 ARTIFICIAL OBSTRUCTIONS

1.7 SHOAL REMOVAL

1.8 SOUNDINGS

1.9 VOLUME CALCULATIONS

1.10 CONTRACT COMPLIANCE

1.11 MONTHLY PARTIAL PAYMENTS

1.12 CONTINUITY OF WORK

1.13 ALLOWABLE PAY OVERDEPTH AND SIDESLOPES

1.13.1 Overdepth Dredging

1.13.2 Sideslopes

1.13.3 Shoals

1.13.4 Excessive Dredging

1.14 PERMITS

1.15 ENVIRONMENTAL PROTECTION REQUIREMENTS

PART 2 PRODUCTS

PART 3 EXECUTION

3.1 DREDGING

3.1.1 Method

3.1.2 Obstructions

3.1.3 Woody Debris

3.2 INSPECTION

3.3 CONDUCT OF DREDGING WORK

3.3.1 Restriction

3.3.2 Order of Work

3.3.3 Lights

3.3.4 Ranges, Gages, and Lines

3.3.5 Plant

3.3.6 Placement of Dredged Material

3.3.6.1 Method of Placement

3.3.6.2 Transfer Site

3.3.6.3 Vehicular Conveyance

3.3.6.4 Placement in Indicated Placement Areas

3.3.6.5 Misplaced Material

3.3.6.6 Government Furnished Placement Areas

3.3.6.6.1 Minnesota Point Placement Area

SECTION 35 20 23 Page 1

3.3.6.6.1.1 Location

3.3.6.6.1.2 Access

3.3.6.6.1.2.1 Allowable Pipeline Access

3.3.6.6.1.2.2 Allowable Equipment Access

3.3.6.6.1.3 Prohibited Areas

3.3.6.7 Submerged Pipeline

3.3.7 Condition of Scows, Hoppers, and Pipelines

3.3.8 Unloading of Scows

3.3.9 Navigation Warnings

3.3.10 Method of Communication

3.3.11 Salvaged Material

3.3.12 Safety of Structures

3.3.13 Plant Removal

3.4 CONTRACTOR QUALITY CONTROL

3.5 GOVERNMENT INSPECTION

3.5.1 Gauge Maintenance

3.5.2 Facilities

3.5.3 Transportation

3.5.4 Compliance

3.6 MEASUREMENT

3.6.1 Method of Measurement

3.6.2 Government Utilization of Multi-beam and Single Beam Sounders for Quantity and Clearance Surveys

3.7 FINAL EXAMINATION AND ACCEPTANCE

3.7.1 Examination

3.7.2 Acceptance

-- End of Section Table of Contents --

SECTION 35 20 23 Page 2

SECTION 35 20 23

DREDGING

04/06

PART 1 GENERAL

1.1 DEFINITION

Hard material is defined as material requiring the use of special equipment for economical removal, and includes boulders or fragments too large to be removed in one piece by the dredge.

1.2 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Sounding Equipment Description and Calibration Data Verification that the Contractor's sounding equipment has been calibrated to correspond with the Government's Hydrographic Surveying Manual EM 1110-2-1103, sounding equipment shall be submitted prior to commencing work. Also submit the description of the Contractor's sounding equipment and transducer frequency prior to commencing work.

Dredging, Conveyance and Placement Plan; G-AOF Prior to bringing equipment to the project site, submit plans of the proposed dredging, conveyance and placement operations.

Include the proposed method for transporting equipment over the knee-high concrete parapit wall located at the North end of the placement site near the Duluth Entry.

Dredging Placement Safety Plan; G-AOF Submit as required by the paragraph entitled "Placement in Indicated Placement Areas."

Notice Of Start Of Dredging Submit as required by the paragraph entitled "Dredging."

SD-02 Shop Drawings

Submerged Pipeline Indicate pipeline location and installation details.

Soundings Submit drawings of surveys during progress of work by soundings.

SD-06 Test Reports

Daily Report of Dredging Operations; G-AOF Report of Operations forms (ENG FORM 4267 or ENG FORM 27A), as

SECTION 35 20 23 Page 3 appropriate to the type of work being performed, are in QCS/RMS and shall be completed and furnished daily. Each report shall contain in the "REMARKS" space attesting that no overflow or discharge occurred from the dredging vessel(s) while dredging and while in transit from the dredging area to the unloading area. In the event an overflow or discharge occurs while dredging or while in transit, an oral notification shall not be made, and complete written report on the incident shall be made to the Contracting Officer in shortest possible time. When appropriate and approved, quality control compliance inspections may be reported under the "REMARKS" item on the form in RMS.

SD-11 Closeout Submittals

Material Placement Records Records indicating quantity and location of dredged material placement in the Government-furnished open-water and nearshore placement area(s).

1.3 CHARACTER OF MATERIALS

Area 1: Material dredged from the required dredging prism consists primarily of shoaled sand (medium to fine) with limited silt and organics.

Loose to dense Sand with silt is expected to be encountered in the overdepth dredging prisms as well as the required dredging prisms. Cobbles and boulders may also be encountered.

Area 7: Material dredged from the required dredging prism consists primarily of native sand (medium to fine), with a shallow, upper layer of silt and organics. Dense to medium dense clay may be encountered within the dredge and overdepth prism. Very heavy / thick vegetative matter (e.g.

thick mats of grassy / weedy material) may be encountered in the top layer as well. Loose to dense Sand with silt is expected to be encountered in the overdepth dredging prisms as well as the required dredging prisms. Cobbles and boulders may also be encountered as well as random and varying thickness dense clay layer seams may also be encountered in the dredge prism, not just the overdepth prism.

Area 15: Material dredged from the required dredging prism is primarily shoaled consisting of sand with varying amounts of silt and organic material. Native material consisting of dense sand with silt and gravel may be encountered in the overdepth prism.

In all areas, it is inherent in dredging operations in an old commercial/industrial harbor as Duluth-Superior Harbor to encounter an array of man-made debris such as cable, ratchets, tires, wrecks, scrap materials of various composition, processed rock, riprap, etc.

Woody debris of varying shapes and sizes was distributed throughout the harbor during the flood event of 2012. It is anticipated that wood debris will be encountered in dredge areas.

The records of previous dredging and sampling are available for inspection at the Office of the Engineering & Construction Office, U.S. Army Corps of Engineers, Detroit District, 477 Michigan Avenue, McNamara Building, Detroit, Michigan.

SECTION 35 20 23 Page 4

1.4 PLACEMENT AREA CONDITIONS

The limits of the placement area and conditions of use shall be in accordance with the drawings. Dredged materials placed outside of the limits of the placement area shall be removed at no additional cost to the Government and deposited within the area approved for placement of dredged materials. The Contractor is responsible for verifying proper placement of material into the designated placement area. Verification is to be supplied to the Government upon request.

1.5 DELIVERY OF PLANT AND ORDER OF WORK

Prior to bringing equipment to the project site, the contractor shall submit a Dredging, Conveyance and Placement Plan describing in detail how it plans to accomplish the work within the required period of performance.

1.6 ARTIFICIAL OBSTRUCTIONS

Except as indicated, the Government has no knowledge of cables, pipes, or other artificial obstructions or of any wrecks, wreckage, or other material that would necessitate the use of explosives or the employment of additional equipment for economical removal. However the Contractor is responsible for identifying any utilities or other channel crossings. Any existing channel crossings that are damaged due to the Contractor's operations shall be repaired at the Contractor's expense. If actual conditions differ from those stated or shown, or both, an adjustment in contract price or time for completion, or both, will be made in accordance with the clause 52.236-2 "Differing Site Conditions."

1.7 SHOAL REMOVAL

If, before the work is completed, shoaling occurs in any section previously accepted by the government, including shoaling in the finished channel, because of the natural lowering of the side slopes or other natural causes, redredging at the Contract unit price, within the limit of available funds, may be performed if agreed upon by both the Contractor and the Contracting Officer.

1.8 SOUNDINGS

The Solicitation represents the conditions existing at the time of survey.

Determination of quantities removed will be made from prior and after dredging soundings taken by the government and the calculations made there from to determine quantities by in-place measurement. After the government has made a determination of the quanitities to be paid, it will not reopen except on evidence of collusion, fraud, or obvious error.

1.9 VOLUME CALCULATIONS

In project areas surveyed using single-beam sonar, the volume of material removed will be calculated using the average end area (AEA) method. The HYPACK software Cross Sections and Volumes Program Philadelphia Pre-Dredge and Post-Dredge methods will be used for all single-beam volume computations.

In project areas surveyed using multi-beam sonar, the volume of material removed will be computed using a TIN (Triangulated Irregular Network) Model as outlined in the Hydrographic Surveying Manual EM-1110-2-1003, dated November 30, 2013. The average soundings from the edited multi-beam survey

SECTION 35 20 23 Page 5 data will be used to populate a one-foot by one-foot matrix at cell center, which will be used to perform the TIN Model volume computations. The HYPACK software TIN Model Program Philadelphia Pre-dredge and Philadelphia Post-dredge methods will be used for all multi-beam volume computations, with boxes checked for "Contour" and "Ignore Volume in Side Slope Overdepth."

Any corresponding plotted sounding sheets will be generated using a plot-scale-dependent matrix cell size utilizing the minimum depth from the one-foot by one-foot average dataset used to calculate volumes.

All plots of soundings on the solicitation documents and the USACE Great Lakes Navigation website are for graphical representation only and shall NOT be used for volume calculations. Volumes computed using soundings plots may mis-represent the volume of material to be dredged. Soundings representing the most up to date channel conditions may be found on the USACE Great Lakes Navigation website. All survey data used for volume computations shall be available to the Contractor upon request.

Surveys shall extend a minimum of 50’ or 1 cross section upstream and downstream of the defined project area where allowable. The extended survey outside the project area will be used to calculate infill material or shoaling occurring from areas outside of the contract area. Infill and/or Shoaling is specified in the Paragraph entitled “SHOAL REMOVAL”

1.10 CONTRACT COMPLIANCE

Contract acceptance is based on visual compliance to contract requirements and to ensure the contractor has met the required specified project depth with no shoals left behind based on the Government's after dredge surveys and in accordance with "paragraph 1.13.3 Shoals". The 1 foot x 1 foot average sounding will be binned to a 3 foot by 3 foot grid utilizing the minimum/shallowest depth generated in HYPACK. The 3 foot X 3 foot minimum/shallowest depth will be plotted in HYPACK and visually inspected for shoals, to ensure no shoals remain above the required project depth within the required dredge areas. Should any shoals remain on the Governments after dredge surveys within the contracted dredge areas, these shoals shall be removed by the contractor at no additional cost to the Government.

1.11 MONTHLY PARTIAL PAYMENTS

Monthly partial payments will be based on quantities determined by daily soundings taken by the Contractor or other means acceptable to the Contracting Officer. (See CLAUSE 52.236-16 entitled, "QUANTITY SURVEYS.") Sounding surveys for partial payment shall be conducted in the same manner specified in the Paragraph entitled, "PRIOR, AFTER AND CHECK SURVEYS," unless otherwise authorized or directed.

1.12 CONTINUITY OF WORK

Monthly partial payments will be made for work performed prior to final examination and acceptance. However, as final dredging is being performed for final examination and acceptance, no payment will be made for such final dredging work performed in any area until the depth required under the contract is secured in the whole of such area, unless prevented by ledge rock, original material, or other obstructions, which cannot be removed by the plant specified in the accepted bid, or the equivalent of such plant, without blasting or special apparatus. No payment will be made

SECTION 35 20 23 Page 6 for final excavation in any area not adjacent to and in prolongation of areas where full depth has been secured, except by decision of the Contracting Officer. If a nonadjacent area is excavated to full depth during the day to day operations carried on under the contract, payment for all work therein may be deferred until the required depth has been secured in the area intervening.

1.13 ALLOWABLE PAY OVERDEPTH AND SIDESLOPES

The total estimated dredging quantity shown on the Price Schedule of the Solicitation includes the required depth material plus the allowable overdepth material and allowable sideslope material. The allowable pay overdepth quantity is computed for the allowable overdepth prism immediately below the material required to be dredged. The allowable sideslope quantity is computed immediately above the payment limit line for sideslopes. A detail drawings are attached at the end of this Section to aid in defining these requirements. Estimated overdepth and sideslope quantities are provided below:

Dredge Area Overdepth Sideslope Required Area 1 3,000 CY 300 CY Required Area 7A 5,100 CY 3,500 CY Required Area 15 300 CY 100 CY

1.13.1 Overdepth Dredging

To cover inaccuracies of the dredging process, materials actually removed immediately below the required materials to be removed as determined from the prior to dredgeing soundings to a depth of not more than one (1) foot below the required pay prism line will be measured and paid for at the contract unit price. The maximum quantity of overdepth materials to be paid for will be equivalent to that quantity present within the one (1) foot overdepth prism immediately below the required materials to be removed as determined from the prior to dredging soundings. Any dredging below the allowed one (1) foot will be considered as excessive dredging.

1.13.2 Sideslopes

Materials actually removed, within limits shown on the drawings, to provide for final side slopes not flatter than one vertical (1V) on two horizontal (2H), perpendicular to the channel line or dredge limit line, whichever is applicable, but not in excess of the amount originally lying above the side slope payment limit line will be calculated and paid for. The provisions of this Subparagraph also apply to end slopes at the upstream and downstream dredging limits of the channel. However, if the Contractor elects to use the box cut method on the side slope this material will be paid for whether dredged in their original location or removed by dredging a space at the bottom of the slope to accommodate the side slope materials falling into the box cut.

1.13.3 Shoals

No shoaled material above the required pay prism line will be allowed for final acceptance.

1.13.4 Excessive Dredging

Any material removed below the overdepth allowance will be considered excessive dredging and will not be paid for. Materials taken from beyond

SECTION 35 20 23 Page 7 the limits specified in Subparagraphs "Allowable Pay Overdepth" and "Side Slopes", will be excluded from the computed total amount dredged as excessive channel dredging or excessive side slope dredging and for which payment will not be made. The final determination of the amounts of excessive dredging will be based wholly on the surveys made for final examination and acceptance. See Paragraph entitled "FINAL EXAMINATION AND

ACCEPTANCE."

1.14 PERMITS

The Contractor shall comply with conditions and requirements of the Corps of Engineers Permits and real estate instruments, and other State or Federal permitting requirements. Permits and real estate instruments for dredging and placement of material are attached as indicated. The Contractor is responsible for obtaining any additional permits as necessary to perform the work.

1.15 ENVIRONMENTAL PROTECTION REQUIREMENTS

Provide and maintain during the life of the contract, environmental protective measures. Also, provide environmental protective measures required to correct conditions, such as oil spills or debris, that occur during the dredging operations. Comply with Federal, State, and local regulations pertaining to water, air, and noise pollution.

PART 2 PRODUCTS

Not used.

PART 3 EXECUTION

3.1 DREDGING

Fourteen (14) calendar days prior to any dredging work being performed the contractor shall provide written Notice of Start of Dredging to the Contracting Officer so that the Government can schedule and perform prior soundings. The Contractor shall perform all dredging work to remove material to the required depths within the limits shown on the drawings as specified. Any materials in the allowable overdepth prism and allowable side slopes are not required to be removed. Rocks, cobbles (3 to 12 inches) and boulders (over 12 inch) may be encountered near breakwaters, revetments and pier heads and shall not be removed if they are part of the harbor structures nor shall toe stones be undermined. Indicated required dredging areas within required downstream and upstream dredging limits will be revised by the Government, after obtaining the before (prior to) dredging soundings. The Contractor may be required to suspend dredging at any time when for any reason the gauges or ranges cannot be seen or properly followed.

3.1.1 Method

Dredging under this contract is restricted to mechanical dredging.

3.1.2 Obstructions

Should original material, ledge rock, boulders, cobbles, rock fragments, wrecks, scrap materials, snags, stumps, piles, debris or other material be encountered which cannot be removed by the plant specified in the accepted bid, or equivalent plant, without blasting or special apparatus, the

SECTION 35 20 23 Page 8

Contractor shall remove therefrom all overlying material within the required dredging prism which in the judgment of the Contracting Officer can be removed by the use of the plant specified in the accepted bid or equivalent plant.

3.1.3 Woody Debris

Any woody debris encountered during dredging operations shall be disposed of offsite at an acceptable location approved by the COR. The Contractor shall bear all costs associated with this action.

3.2 INSPECTION

Inspect the work, keep records of work performed, and ensure that gages, targets, ranges, and other markers are in place and usable for the intended purpose. Furnish, at the request of the Contracting Officer, boats, boatmen, laborers, and materials necessary for inspecting, supervising, and surveying the work. When required, provide transportation for the Contracting Officer and inspectors to and from the placement area and between the dredging plant and adjacent points on shore.

3.3 CONDUCT OF DREDGING WORK

3.3.1 Restriction

Unless otherwise stated, the Contractor shall not dredge below a grade three (3) feet above pipes, cables, tunnels, and other submerged crossings shown on the drawings or indicated in these specifications (see clause 52.236-4 titled "Physical Data"). This restriction applies for a distance of twenty-five (25) feet upstream and twenty-five (25) feet downstream of each channel crossing. Any existing crossing that is damaged due to Contractor operations shall be repaired by the Contractor at its expense.

3.3.2 Order of Work

Dredge Area 1 shall be dredged and placed prior to all other dredge areas identified in the contract drawings. Dredge Area 7A shall be dredged and placed after all other dredge areas have been completed. Dredged material shall only be placed in areas that have already been cleaned (required full depth clean-up and optional surface clean-up, if awarded) and approved by the COR. The order of work may otherwise be completed at the Contractor's discretion. The Government reserves the right to change the order of work at any time.

3.3.3 Lights

If the contractor elects to utilize a transfer box for placement of Material at Minnesota Point, the Contractor shall not shine lights in the direction of the nearby residential and commercial properties, unless otherwise approved by the COR. Each night, between sunset and sunrise and during periods of restricted visibility, provide lights for floating plants, pipelines, ranges, and markers. Also, provide lights for buoys that could endanger or obstruct navigation. When night work is in progress, maintain lights from sunset to sunrise for the observation of dredging operations. Lighting shall conform to United States Coast Guard requirements for visibility and color.

SECTION 35 20 23 Page 9

3.3.4 Ranges, Gages, and Lines

Furnish, set, and maintain ranges, buoys, and markers needed to define the work and to facilitate inspection. Establish and maintain gages in locations observable from each part of the work so that the depth may be determined. Suspend dredging when the gages or ranges cannot be seen or followed. The Contracting Officer will furnish, upon request by the Contractor, survey lines, points, and elevations necessary for the setting of ranges, gages, and buoys.

3.3.5 Plant

Maintain the plant, scows, coamings, barges, pipelines, and associated equipment to meet the requirements of the work. Promptly repair leaks or breaks along pipelines. Remove dredged material placed due to leaks and breaks.

3.3.6 Placement of Dredged Material

All nautical vessels, pipelines and land based transport and conveyance systems shall be operated, loaded and unloaded in such manner as to prevent overflow, spills, leaks, waste, or other loss of dredged materials between point of pick-up and point of deposition within the placement area. Hauling vessels shall have sufficient sidewall height and integrity to prevent drainage over or through the sides and bottom during hauling.

3.3.6.1 Method of Placement

The method employed by the Contractor in conveying dredged materials to the placement area shall be as approved by the Contracting Officer at all times. Temporary dumping or placement of materials outside of the placement area for subsequent rehandling into the placement area is prohibited unless otherwise approved by the Contracting Officer.

3.3.6.2 Transfer Site

If use of a Contractor-furnished placement site entails use of a transfer site, or if a Government-furnished transfer site is specified for use, the Contractor shall take soundings across the full width and length of the transfer site mooring area prior to the start-up of and immediately after the completion of transfer operations under the contract. Soundings shall be taken on lines and at intervals acceptable to the Contracting Officer.

Prior and after surveys of the transfer site shall be submitted to the Government.

3.3.6.3 Vehicular Conveyance

Vehicular conveyance of dredged material is prohibited.

3.3.6.4 Placement in Indicated Placement Areas

Prior to placement of dredge material, the Contractor will submit a Dredging Placement Safety Plan, describing in detail the means and methods to be utilized to provide for the public safety at the placement area, all in accordance with the Accident Prevention Plan. Include all proposed safety signage and temporary chain-link fence panels, unless otherwise approved by the COR. Include location, design, and dimensions of all signs and temporary chain-link fence panels. Include how often the temporary chain-link panels will be inspected and maintained. During no work periods, SECTION 35 20 23 Page 10 weather days, or non-work days, provide a plan to maintain all signage and temporary chain-link fence panels. The dredged materials shall be deposited within the Government-furnished placement area shown on the drawings. The Government-furnished placement area has sufficient capacity to contain all materials to be dredged under the contract. Placement of the dredged materials within the placement area shall be as specified and shown except as otherwise directed by the Contracting Officer. Except as otherwise authorized by the Contracting Officer in writing, no placement shall be performed unless a representative of the Contractor for Quality Control is present at the time. The method employed by the Contractor in depositing dredged materials in the placement area shall be as approved by the Contracting Officer at all times.

3.3.6.5 Misplaced Material

Any material that is deposited elsewhere than in the places designated or approved by the Contracting Officer will not be paid for. The Contractor shall be required to remove at its own expense and deposit it in the place designated or as approved by the Contracting Officer.

3.3.6.6 Government Furnished Placement Areas

3.3.6.6.1 Minnesota Point Placement Area

3.3.6.6.1.1 Location

The initial placement location of material shall be coordinated with the COR. The Contractor will be required to start placement operations at any point within the limits identified in the contract drawings. The dredged material shall be placed, in accordance with section 01 57 24 paragraph titled "BEST MANAGEMENT PRACTICES," in an area bounded by the top of bank identified by the COR and the most landward 4.0 foot depth contour prior to placement. Drainage shall be maintained lakeward across the placed materials at all times. The materials shall be placed in such a manner which will not block or interfere with natural or constructed drainage into the lake. During placement, the contractor shall minimize erosion of existing shoreline sediments. If shore ice is present during placement operations, dredged materials shall be placed directly upon the ice within the required limits. Within these limits, the dredged materials shall be evenly distributed along the entire length of the placement area.

3.3.6.6.1.2 Access

Allowable access to the site shall be as directed and approved by the COR at all times. The Contractor shall restore the access area used during the performance of the contract to the original or better condition. Remove any gravel used to traverse grassed areas and restore the area to its original condition, including top soil and seeding as necessary.

3.3.6.6.1.2.1 Allowable Pipeline Access

If the contractor elects to utilize the allowable pipeline access route shown on the contract drawings, the contractor must coordinate the access with the COR. The contractor must walk the route with the COR. All pipeline shall be sufficiently secured to avoid movement during operations. Any locations where the pipeline crosses or interferes with a public walkway, the Contractor shall provide safe walkways over the pipeline. Public access to the Duluth Entry pier shall be maintained at all times, unless otherwise approved by the COR. Use of the allowable pipeline access route shall be as

SECTION 35 20 23 Page 11 approved by the COR at all times.

3.3.6.6.1.2.2 Allowable Equipment Access

The allowable equipment access for the placement area is provided via the Duluth Entry. All equipment offloading and access in support of operations within the optional clean-up and placement areas shall be coordinated through and approved by the COR at all times. The allowable equipment access area consists of a concrete walkway adjacent to the Duluth Entry SSP wall. The provided grassy staging area is separated from the concrete walkway by a knee-high concrete parapit wall. The Contractor is responsible for safely offloading all equipment and avoiding damage to the structures defined herein. If structures defined herein are damaged by the Contractor, the Contractor shall repair such damaged structures at no additional cost to the Government, as required by the COR. For equipment staging and fueling requirements, see specification section 01 35 13 paragraph titled "Work and Storage Areas."

3.3.6.6.1.3 Prohibited Areas

Conveyance of heavy equipment is prohibited beyond the placement area and allowable access route(s) approved by the COR.

3.3.6.7 Submerged Pipeline

If a leak occurs in the discharge pipeline, immediately discontinue using the line until leaks are repaired. Remove material placed due to leaks or breaks.

3.3.7 Condition of Scows, Hoppers, and Pipelines

All scows and hoppers used for transporting the dredged material shall be kept in good condition with coamings in repair. Doors of dump vessels shall be maintained in good repair and sealed in a proper manner to prevent the loss of dredged material. Decks of vessels shall be cleaned of dredged material before leaving the dredging area. Pipelines in hydraulic dredging systems shall be kept in good condition, free of leaks.

3.3.8 Unloading of Scows

When scow unloading is performed with the use of a clamshell or bucket, the placement area enclosure shall be returned to its original condition by removing all material deposited thereon to the satisfaction of the Contracting Officer.

3.3.9 Navigation Warnings

Furnish and maintain navigation warning signs along the pipeline.

3.3.10 Method of Communication

Provide a system of communication between the dredge crew and the crew at the placement area. A portable two-way radio is acceptable.

3.3.11 Salvaged Material

Anchors, chains, firearms, and other articles of value, which are brought to the surface during dredging operations, shall remain or become the

SECTION 35 20 23 Page 12 property of the Government and shall be deposited on shore at a convenient location near the site of the work, as directed.

3.3.12 Safety of Structures

The prosecution of work shall ensure the stability of piers, bulkheads, and other structures lying on or adjacent to the site of the work, insofar as structures may be jeopardized by dredging operations. Repair damage resulting from dredging operations, insofar as such damage may be caused by variation in locations or depth of dredging, or both, from that indicated or permitted under the contract.

3.3.13 Plant Removal

Upon completion of the work, promptly remove plant, including ranges, buoys, piles, and other markers or obstructions.

3.4 CONTRACTOR QUALITY CONTROL

The Contractor shall establish and maintain a quality control system for dredging and placement operations to assure compliance with the Contract requirements and provide a Daily Report of Dredging Operations by completing the appropriate form and completing all inspections of items under this system, including, but not limited to, the following:

a. Layout of work, and placement areas.

b. Proper dredging depths and placement heights.

c. Conveyance and placement operations.

d. Removal of misplaced material.

e. Safety requirements.

3.5 GOVERNMENT INSPECTION

3.5.1 Gauge Maintenance

The Contractor shall maintain its gauges, ranges, location marks and limit marks in proper order and position. The presence of a Government inspector shall not relieve the Contractor of its responsibility for the proper execution of the work in accordance with the specifications and drawings.

3.5.2 Facilities

The Contractor shall furnish, on the request of the Contracting Officer or any inspector, the use of such boats, boat operators, laborers and material forming a part of the ordinary and usual equipment and crew of the dredging plant as may be reasonably necessary in inspecting the work. However, the Contractor will not be required to furnish such facilities for the surveys prescribed in the Paragraph "FINAL EXAMINATION AND ACCEPTANCE."

3.5.3 Transportation

The Contractor shall furnish, on the request of the Contracting Officer or any inspector, suitable transportation from designated points on shore to and from the various pieces of off-shore plant and off-shore placement areas.

SECTION 35 20 23 Page 13

3.5.4 Compliance

Should the Contractor refuse, neglect, or delay compliance with these requirements, the specific facilities may be furnished and maintained by the Contracting Officer, and the cost thereof will be deducted from any amounts due or to become due the Contractor.

3.6 MEASUREMENT

The material removed will be measured by cubic yard in place, by means of soundings taken before and after dredging. Prior, after and check surveys will be made by sonic sounding methods. The Government will make prior and after surveys and may make check surveys. Measurements for final payment shall be based on Government surveys. Measurements for progress payment are based on the Contractor's check surveys. The Contractor shall make check surveys. Once the Government completes after surveys, any material determined to be left above project depth on the Government after surveys shall be removed by the Contractor at no additional cost to the Government.

As specified in paragraph titled "CONTRACT COMPLIANCE" hereinbefore, contract compliance is determined through the Government after surveys.

Additional soundings will be taken as the Contracting Officer may deem necessary. Only one (1) prior survey will be made for work required under each contract, by the Government. If additional prior surveys are required, due to the Contractor's operations, the cost of such surveys shall be paid by the Contractor. The cost of such surveys shall be the same as specified in the Paragraph entitled, "FINAL EXAMINATION AND ACCEPTANCE."

3.6.1 Method of Measurement

Hydrographic Surveys will be conducted to meet USACE Performance Standards as defined in the Hydrographic Surveying Manual EM 1110-2-1003 dated 30 November 2013. Surveys will be performed by multi-beam sweep type surveys and/or by single beam sounding equipment. The multi-beam sonar and the single beam sonar will be calibrated following procedures outlined in the aforementioned EM. The same equipment shall be used for priors and after surveys, using the same work platform.

3.6.2 Government Utilization of Multi-beam and Single Beam Sounders for Quantity and Clearance Surveys

The Government may elect to use either Multi-beam or Single beam sounding surveys. The same type of survey used for a prior survey shall be used for the after surveys and dredge material removed shall be based off Government Prior and After Surveys.

3.7 FINAL EXAMINATION AND ACCEPTANCE

3.7.1 Examination

As soon as practicable after the completion of the entire work or any section thereof (if the work is divided into sections) as in the opinion of the Contracting Officer will not be subject to damage by further operations under the contract, such work will be thoroughly examined at the cost and expense of the Government by sounding or by sweeping, or both, as determined by the Contracting Officer. Should any shoals, or other lack of contract depth be disclosed by this examination, the Contractor is required to remove same by dragging the bottom or by dredging at the contract rate for dredging, but if the bottom is soft and the shoal areas are small and

SECTION 35 20 23 Page 14 form no material obstruction to navigation, the removal of such shoals may be waived at the discretion of the Contracting Officer. The Contractor or its authorized representative will be notified when soundings and/or sweepings are to be made, and will be permitted to accompany the survey party. When the area is found to be in a satisfactory condition, it will be accepted finally. Should more than two (2) sounding or sweeping operations by the Government over an area be necessary by reason of work for the removal of shoals disclosed at a prior sounding or sweeping, the cost of such third and any subsequent sounding or sweeping operations will be charged against the Contractor at the rate of $3,500 per calendar day in which the Government plant is engaged in sounding or sweeping and/or is enroute to or from the site or held at or near the said site for such operations.

3.7.2 Acceptance

Final acceptance of the whole or part of the work and the deductions or corrections of deductions made thereon will not be reopened after having once been made, except on evidence of collusion, fraud, or obvious error,and the acceptance of a completed section shall not change the time of payment of the retained percentages of the whole or any part of the work.

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SECTION 35 20 23 Page 15

3.3.6.6.1.3 Prohibited Areas

3.3.6.7 Submerged Pipeline