03 Construction Specification.pdf

STATE OF IOWA

DEPARTMENT OF AGRICULTURE AND LAND STEWARDSHIP

DIVISION OF SOIL CONSERVATION AND WATER QUALITY

Poc903130C NUTRIENT REDUCTION

WETLAND PROJECT

CONSTRUCTION CONTRACT

BID NO. 24-01

SECTION 30, TOWNSHIP 90 NORTH, RANGE 31 WEST

POCAHONTAS COUNTY, IOWA

PREPARED FOR: IOWA DEPARTMENT OF AGRICULTURE & LAND STEWARDSHIP

DIVISION OF SOIL CONSERVATION AND WATER QUALITY

WALLACE STATE OFFICE BUILDING

502 EAST 9TH STREET

DES MOINES, IOWA 50319

515-281-4246

PREPARED BY: DUCKS UNLIMITED

209 EUGENE ST

RADCLIFFE, IA 50230

832-704-3286

March 2023 i

TABLE OF CONTENTS

GENERAL REQUIREMENTS Page(s) DOCUMENT AA Notice-to-Bidders AA 1 DOCUMENT BB Instruction–to-Bidders BB 1-5 DOCUMENT CC Proposal and Schedule of Prices CC 1-5 DOCUMENT DD Construction Contract DD 1-2 DOCUMENT EE Proposal Guarantee (Bid Bond) EE 1 DOCUMENT FF General Conditions FF 1-27 DOCUMENT GG Special Conditions GG 1-3 DOCUMENT NN Performance Bond NN 1-3

CONSTRUCTION SPECIFICATIONS

CS-08 8-1 to 8-3

IA-01 1-1 to 1-3 IA-05 5-1 to 5-3 IA-06 6-1 to 6-4

IA-09 9-1 to 9-5 IA-21 21-1 to 21-4 IA-23 23-1 to 23-5 IA-26 26-1 to 26-2 IA-31 31-1 to 31-7 IA-46 46-1 to 46-4 IA-51 51-1 to 51-6 IA-61 61-1 to 61-4

IA-95

Site Preparation Pollution Control Seeding and Mulching for Protective Cover

Drain Tile Investigation and Removal Excavation Earthfill Topsoiling Concrete Tile Drains for Land Drainage Corrugated Metal Pipe Conduits Loose Rock Riprap Geotextile 95-1 to 95-5

PLANS

Cover Sheet 001 Specifications, Quantities, & Notes 002 Topography ^ Existing Conditions 051 Site Plan 101 Structure, Inlet, Berm, & Riprap Plan 201 Structure, Berm, & Wetland Profiles 202 Clay Core & 10-inch Tile Profiles & Riprap Toe 203 Water Control Structure Plan 204 Tile Plan 205 Water Control Structure Details 301 CMP WCS Details 302 Agri Drain WCS Details 303 Articulating Concrete Block Details 304 Seeding Plan 401 ii

APPENDIX I – ADDENDA & BID TAB *(ADDED AFTER BIDDING)

Addenda, if applicable * Pre-Bid Meeting Minutes * Pre-Bid Meeting Attendance List * Updated Plan Holders List * Bid Tab *

APPENDIX II – CONSTRUCTION ADMINISTRATION FORMS

DOCUMENT LL Notice-of-Award LL 1 DOCUMENT MM Notice-to-Proceed MM 1 DOCUMENT JJ Construction Progress Schedule JJ 1-2 DOCUMENT SS Application & Certificate for Payment SS 1-2 DOCUMENT HH Change Order Request HH 1-2 DOCUMENT II Construction Contract Amendment II 1-3 DOCUMENT QQ Iowa Sales & Use Tax Form QQ 1

APPENDIX I I –

CONSTRUCTION SPECIFICATIONS

Iowa IA-1-1 7/13

NATURAL RESOURCES CONSERVATION SERVICE

CONSTRUCTION SPECIFICATION

IA-1 SITE PREPARATION

1. SCOPE

Site preparation work shall consist of clearing, grubbing, stripping, refuse removal, bank sloping and structure removal on the site as necessary to rid the site of all undesirable materials on or near the surface and prepare the site for the structure. All woody growth within the construction area shall be cleared and all stumps and roots one inch in diameter or larger shall be grubbed from the site. In addition, all areas within 25 feet of the footprint of the structure shall be cleared and grubbed except as directed by the Engineer. The work shall also consist of the removal and disposal of structures (including fences) that must be removed to perform other items of work.

For wetland restoration, enhancement, or creation projects, the wetland area shall be disturbed as little as possible and existing naturally vegetated spillway areas shall not be disturbed.

2. FOUNDATION PREPARATION

The construction areas shall be stripped of all unsuitable materials such as organic matter, grasses, weeds, sod, debris, and stones larger than 6 inches in diameter.

In an earth embankment foundation area, all channel banks and sharp breaks shall be sloped to no steeper than 1.5 horizontal to 1 vertical.

The foundation area shall be thoroughly scarified before placement of fill material. The surface shall have moisture added or shall be compacted if necessary, so that the first layer of fill material can be compacted and bonded to the foundation.

3. STRIPPED MATERIAL DISPOSAL

Suitable soil material shall be stockpiled for use as topsoil. The other stripped materials shall be buried, removed from the site, or disposed of as directed by the owner or

NRCS.

Stockpiled materials around a construction site should not hinder subsequent construction operations.

4. DISPOSAL OF REFUSE MATERIALS

Waste materials from clearing and structure removal shall be burned or buried at locations approved by the owner. Buried materials shall be covered with a minimum of 2 feet of earthfill.

All refuse shall be disposed of in a manner which complies with all local and state regulations.

Iowa IA-1-2 7/13

5. SALVAGE

Items to be salvaged shall be as shown on the drawings. Structures and fencing materials that are designated to be salvaged shall be carefully removed and neatly placed in the specified storage areas.

6. SPECIAL SPECIFICATIONS

A. Measurement and Payment

Compensation for any work item described in the contract documents but not listed in the bid schedule will be included in the payment for the item of work to which it is made subsidiary. Such items and bid items to which they are made subsidiary are identified in Items of Work and Construction Details section of this specification.

For items of work which lump sum prices are established in the contract, the quantity of work will not be measured for payment. Payment for each item will be made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer or weight tickets. Payment will constitute full compensation of the work completed as defined by each work item.

B. Items of Work and Construction Details

1. Bid Item No. 2 – 6” Site Preparation Below Berm & Grade Stabilization Structure:

This item will consist of work to remove and dispose of existing material to remove vegetation on areas to be excavated or filled, which includes the berm and the grade stabilization structure. The total depth of vegetative stripping and topsoil stripping shall equal a nominal depth of 6" and estimated to be 800 cubic yards. The topsoil replacement quantity shall be paid separately. This material shall be stockpiled for replacement over the disturbed areas, which is included in a separate bid item (Bid Item No. 9).

This item will also include any tree and brush removal along with any fences. These shall be considered incidental to site stripping.

There is an existing culvert and debris within the drainage ditch/creek adjacent to the grade stabilization structure location, which shall be removed and hauled off site as part of this bid item.

This item will be paid out on a Cubic Yard Plan basis (no adjustments).

Iowa IA-1-3 7/13

2. Bid Item No. 3 – Grading/Scraping within Wetland:

This item will consist of work to remove and dispose of existing material within the wetland pool area as designated on the plans. Total depth of vegetative stripping and topsoil stripping varies from 0 inches to approximately 2 feet at the deepest location. The wetland grading area consists of grading “flat” from the existing 1207.0’ contour out to the existing 1209.0 contour to expand the wetland pool area (grading to elevation 1207.0’). The grading/scraping is estimated to be 7,500 cubic yards. The AutoCAD C3D surface can be provided for the wetland grading area. The topsoil replacement quantity shall be paid separately (see Bid Item No. 10).

This item will also include any tree and brush removal along with any fences. These shall be considered incidental to site stripping.

This item will be paid out as a Cubic Yard Plan quantity (no adjustments).

Iowa IA-5-1 2/11

CONSTRUCTION SPECIFICATION

IA-5 POLLUTION CONTROL

1. SCOPE

The work shall consist of installing measures or performing work to control erosion and minimize the production of sediment and other pollutants to water and air during construction operations.

2. MATERIALS

All materials furnished shall meet the requirements shown on the drawings or in the specifications.

3. EROSION AND SEDIMENT CONTROL MEASURES AND WORKS

The measures and works shall include, but are not limited to, the following:

Staging of Earthwork Activities: The excavation and moving of soil materials shall be scheduled so that areas unprotected from erosion will be minimized. These areas will be unprotected for the shortest time feasible.

Seeding: Structures and disturbed areas shall be seeded as soon as possible after construction is completed.

Temporary seedings may be used as an alternative to other stabilization measures as approved by NRCS.

Mulching: Construction areas that have been disturbed but have no construction activity scheduled for 21 days or more shall have erosion protection measures applied by the 14th day.

This erosion protection may be mulching or other approved temporary measures. Construction areas left open during a winter shutdown period shall be protected by mulching.

All seeding and mulching shall be completed in accordance with the seeding plan and Iowa Construction Specification IA-6, Seeding and Mulching for Protective Cover.

The following works may be temporary. If they are installed as a temporary measure, they shall be removed, and the area restored to its original state when they are no longer needed or when permanent measures are installed.

Diversions: Diversions may be required to divert clean runoff water away from work areas and to collect runoff from work areas for treatment and safe disposition.

Stream Crossings: Culverts or bridges may be required where construction equipment must cross streams.

Sediment Basins: Sediment basins may be required to settle and filter out sediment from eroding areas to protect properties and streams below the construction site.

Sediment Filters: Straw bale filters, geotextile sediment fences, or other equivalent methods may be used to trap sediment from areas of limited runoff. Sediment filters shall be properly anchored to prevent erosion under them.

Iowa IA-5-2 2/11

Waterways: Waterways may be required for the safe removal of runoff from fields, diversions, and other structures or measures.

4. CHEMICAL POLLUTION

The Contractor shall provide watertight tanks or barrels or construct a sump sealed with plastic sheets to be used to dispose of chemical pollutants, such as drained lubricating or transmission oils, greases, soaps, concrete mixer wash water, asphalt, etc., produced as a by-product of the construction work. At the completion of the construction work, sumps shall be removed, and the area restored without causing pollution.

Sanitary facilities such as chemical toilets or septic tanks shall not be placed adjacent to live streams, wells, or springs. They shall be located at a distance sufficient to prevent contamination of any water sources. At the completion of construction work, facilities shall be disposed of without causing pollution.

5. AIR POLLUTION

The burning of brush or trash or disposal of other materials shall adhere to local and state regulations.

Fire prevention measures shall be taken to prevent the start or the spreading of wildfires, which result from project work. Fire breaks or guards shall be constructed at locations shown on the drawings.

All public access or haul roads used by the contractor during construction of the project shall be sprinkled or otherwise treated to fully suppress dust. All dust control methods shall ensure safe operations at all times. If chemical dust suppressants are used, the material shall be a commercially available product specifically designed for dust suppression and the application shall follow manufacturer's requirements and recommendations. A copy of the product data sheet and manufacturer's recommended application procedures shall be provided to the Engineer five working days before use.

6. MAINTENANCE, REMOVAL, AND RESTORATION

All pollution control measures and works shall be adequately maintained in a functional condition as long as needed during the construction operation. All temporary measures shall be removed, and the site restored to as near original conditions as practical.

7. SPECIAL SPECIFICATIONS

Compensation for any work item described in the contract documents but not listed in the bid schedule will be included in the payment for the item of work to which it is made subsidiary. Such items and bid items to which they are made subsidiary are identified in Items of Work and Construction Details section of this specification.

For items of work which lump sum prices are established in the contract, the quantity of work will not be measured for payment. Payment for each item will be made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer or

Iowa IA-5-3 2/11 weight tickets. Payment will constitute full compensation of the work completed as defined by each work item.

1. Bid Item No. 26 – Silt Fencing:

This item shall include the supply, installation, and maintenance of silt fencing throughout the project, as specified within these plans and in compliance with Iowa Regulations. Erosion control measures shall be installed prior to the start of work and shall be maintained until final stabilization of the site. The contractor shall maintain, inspect, and provide all proper recording and reporting according to the permit regulations. 1,900 linear feet of silt fencing has been estimated for this project intended to be placed on the exterior side of the berm along the pre-existing spoil/berm of the larger drainage ditch (South Branch Lizard Creek). The silt fencing shall be installed in a manner to contain soil disturbance within the construction area and to prevent soil erosion into South Lizard Creek.

This item shall be paid on actual linear footage of silt fencing used; however, the contractor shall notify engineer prior to placing silt fencing more than the estimated plan quantity.

2. Bid Item No. 27 – Rock Check Dam:

This item will consist of providing a temporary rock check dam within the drainage ditch/creek just downstream of the grade stabilization structure location to prevent silt migration downstream of the construction area. The rock check dam shall consist of ¾”-1½” clean rock, or other material approved by the construction manager. The rock check dam shall be installed prior to performing excavation work within the creek and should be maintained throughout the project. Contractor shall remove the rock check dam upon project completion.

This item shall be based for on a lump sum basis.

3. Subsidiary Item, Pollution Control

This item shall consist of applying and performing all construction activities in a manner that will minimize water pollution, air pollution and soil erosion.

No separate payment will be made for Pollution Control. Compensation for this item will be other items as appropriate.

Iowa IA-6-1 02/11

IA-6 SEEDING AND MULCHING FOR PROTECTIVE COVER

The work shall consist of seeding, mulching, and fertilizing all disturbed areas and other areas as indicated on the drawings, or otherwise designated.

2. SEEDBED PREPARATION AND APPLICATION

The entire area to be seeded shall be reasonably smooth and all washes and gullies shall be filled to conform to the desired cross-section before actual seedbed preparation is begun. At this stage of the operation, the required fertilizer and lime shall be applied uniformly and incorporated into the top 3 inches of the soil with suitable tillage equipment. The seedbed preparation operation shall be suspended when the soil is too wet or too dry. The seedbed shall be loosened to a depth of at least three inches.

On side slopes steeper than 2-1/2 horizontal to 1 vertical, the 3-inch minimum depth of seedbed preparation is not required, but the soil shall be worked enough to ensure sufficient loose soil to provide adequate seed cover.

Unless otherwise specified, the seeding operation shall be performed immediately after preparation of the seedbed. The seed shall be drilled or broadcast by equipment that will insure uniform distribution of the seed.

3. MATERIALS

The seeding, fertilizing, and mulching requirements are as specified on Form IA-CPA-4.

Straw from cereal grains or hay will be used as mulching material. It shall be relatively free of weeds.

4. MULCH APPLICATION

The required mulching shall be performed as soon as possible after seeding unless otherwise specified. The mulch shall be applied uniformly over the area. The type and rate shall be as specified. When mulching is required, all areas seeded during any one day shall be mulched within 24 hours. The mulch may be spread by any means that results in a uniform cover.

The mulch shall be anchored. Anchoring of the mulch may be performed by a mulch anchoring tool or regular farm disk weighted and set nearly straight, by installation of mulch netting, or by other methods approved by Engineer.

5. SPECIAL SPECIFICATIONS

Compensation for any work item described in the contract documents but not listed in the bid schedule will be included in the payment for the item of work to which it is made

Iowa IA-6-2 02/11 subsidiary. Such items and bid items to which they are made subsidiary are identified in Items of Work and Construction Details section of this specification.

For items of work which lump sum prices are established in the contract, the quantity of work will not be measured for payment. Payment for each item will be made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer or weight tickets. Payment will constitute full compensation of the work completed as defined by each work item.

1. Weed Control (Not a bid item)

Weed control may be needed in portions of this site depending upon the start date of the contract, the initiation of grading, and the seeding dates.

Weed control will be added to the contract with a change order to be negotiated between Contractor and Division based on conditions observed and the type of weed control used and will be paid only once. If delays require additional weed control, this will be paid for at Contractor’s own expense.

Weed control may include placement of a cover crop such as oats or rye, spraying with appropriate chemicals, or disking. If thistles are present, only spraying is allowed for weed control and shall include appropriate chemicals designed to control thistles.

2. Bid Item No. 28 - Structure Seeding

This item will consist of seeding the dike except the upstream side slope below the weir elevation, auxiliary spillway, the tile outlet channel side slopes, and any other disturbed areas noted on the plans, or as determined by engineer.

All seed must be clean and weed free. Seeding rates are expressed in bulk pounds per acre. Seed quality shall not drop below 70% Pure Live Seed (PLS) where PLS = (percent germination plus percent dormant seed) times percent purity.

Seeding rates are as follows:

Smooth Brome grass 25 pounds/acre

Seed shall be applied with a drill and placed at ¼ to ½ inch deep.

Fertilizer shall be applied on the entire seeding area at the following rate:

Nitrogen (N) 30 pound/acre Phosphorus (P2O5) 30 pounds/acre Potassium (K2O) 40 pounds/acre

Iowa IA-6-3 02/11

Straw mulch shall be applied at a rate of 2 tons per acre on all areas receiving structure and channel seeding.

Seeding shall be completed during the following seeding periods:

Spring March 1 to May 15 Summer August 1 to September 15 Fall November 15 to Freeze-up

If construction is completed during any other time of the year, the seeding shall be performed at the next seeding period.

If seeding is completed during the spring seeding period, a companion crop of oats shall be seeded at a rate of 1-1/2 bushels per acre.

Measurement will be based on the areas successfully seeded to the nearest 0.1 acre.

3. Bid Item No. 29 - Buffer Seeding

This item will consist of seeding the areas designated on the plans as buffer seeding and include borrow areas, disturbed areas not seeded as part of structural seeding, and other areas within the easement. Buffer seeding is not required in area below normal pool elevation established by the weir elevation.

Some areas of the site may have existing CRP vegetation or steep slopes with existing vegetation. Local NRCS personnel will determine if these areas will be included as part of the buffer seeding areas for this project or will be left as is.

This may affect the bid quantity and Contractor will verify with Engineer the number of acres that will require buffer seeding.

All seed must be clean and weed free. Seeding rates are expressed in pounds of pure live seed per acre. All seed must be yellow-tagged Iowa ecotype unless approved otherwise by IDALS-DSCWQ.

Seeding mixture shall include a minimum of 5 native grasses and 10 native forbs. The mixture shall provide a minimum of 30 grass seeds per square foot and 10 forbs seeds per square foot. Number of seeds will be based on Iowa Conservation Practice 327 “Native Species for Wildlife”. Contractor’s proposed seed mix shall be submitted to Engineer and local NRCS office for approval at least 2 weeks before seed is to be applied.

Seeding shall be completed during the following seeding periods:

Spring April 1 to June 30 Fall November 15 to Freeze-up

The seed bed shall be properly prepared prior to seeding:

(a) Any weed control measures shall be completed prior to seeding.

If spraying is used, then a span of two weeks shall be allowed between spraying and seeding.

(b) If the land was in soybeans, no additional tillage is required. If the land was in corn or other vegetation, areas to be seeded shall be disked to thoroughly loosen and pulverize the soil to a

Iowa IA-6-4 02/11 depth of 3 inches. This may require multiple passes of equipment. If the land was used for pasture and has a smooth surface, the preparation in non-disturbed areas to be seeded shall include mowing any vegetation taller than 12 inches and applying an appropriate herbicide at the labeled rates to emergent growth 2 to 4 weeks after mowing. After the vegetation has died, the area shall be disked thoroughly loosen and pulverize the soil depth of 3 inches. If emergent growth occurs prior to seeding, the areas shall receive a second application of herbicide. Seeding shall not occur until the existing vegetation has died (about 1 week).

(c) If deeper disking is used at the site, a lighter disk or spring harrow shall be used to remove deep furrows.

(d) After disking operations and prior to seed application, the seedbed shall be firmed with a cultipacker or similar piece of equipment.

(e) No lime or fertilizer is to be applied.

Sow seed with contour using a grassland or rangeland drill set for the specified seeding rates. The drill shall be equipped with double coulter furrow openers.

The drill shall be subject to acceptance by Engineer. Overlap each successive seeding pass to ensure complete coverage.

Plant seed not more than 1/4 inch deep; some seed may be seen on the surface after seeding.

Broadcasting by centrifugal-type or hydroseeder broadcasters, or by hand shall be allowed in areas not accessible to drills or other equipment. Once broadcast, the seed must be covered with soil to a depth no greater than 1/4 inch by means of hand rakes or other approved methods.

Upon completion of the seeding operation, cultipack the seedbed to provide a positive seed-soil contact. If the drill seeder is equipped with an approved cultipacker or press wheels, separate operations shall not be necessary. The type of cultipacker/seeder to be used shall be subject to acceptance by Engineer.

No mulch shall be required.

Measurement will be based on the area successfully seeded and measured to the nearest 0.1 acre.

CS-8-1 3/22

Construction Specification 8—Mobilization and Demobilization

The work consists of the mobilization and demobilization of the contractor's forces and equipment necessary for performing the work required under the contract. It does not include mobilization and demobilization for specific items of work for which payment is provided elsewhere in the contract. Mobilization will not be considered as work in fulfilling the contract requirements for commencement of work.

2. EQUIPMENT AND MATERIAL

Mobilization shall include all activities and associated costs for transportation of contractor's personnel, equipment, and operating supplies to the site; establishment of offices, buildings, and other necessary general facilities for the contractor's operations at the site; premiums paid for performance and payment bonds including coinsurance and reinsurance agreements as applicable; and other items specified in section 4 of this specification.

Demobilization shall include all activities and costs for transportation of personnel, equipment, and supplies not required or included in the contract from the site; including the disassembly, removal, and site cleanup of offices, buildings, and other facilities assembled on the site specifically for this contract.

This work includes mobilization and demobilization required by the contract at the time of award. If additional mobilization and demobilization activities and costs are required during the performance of the contract as a result of changed, deleted, or added items of work for which the contractor is entitled to an adjustment in contract price, compensation for such costs will be included in the price adjustment for the item or items of work changed or added.

3. PAYMENT

Payment will be made as the work proceeds, after presentation of paid invoices or documentation of direct costs by the contractor showing specific mobilization and demobilization costs and supporting evidence of the charges.

of suppliers, subcontractors, and others. When the total of such payments is less than the lump sum contract price, the balance remaining will be included in the final contract payment. Payment of the lump sum contract price for mobilization and demobilization will constitute full compensation for completion of the work.

Payment will not be made under this item for the purchase costs of materials having a residual value, the purchase costs of materials to be incorporated in the project, or the purchase costs of operating supplies.

4. ITEMS OF WORK AND CONSTRUCTION DETAILS

CS-8-2 3/22

listed in the bid schedule will be included in the payment for the item of work to which it is made subsidiary. Such items and bid items to which they are made made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer

1. Bid Item No. 1 - Mobilization/Demobilization

This item shall consist of mobilizing and demobilizing personnel and equipment in preparation to perform the work within the scope of this contract.

Any work that is necessary to provide access to the site including, but not limited to, grading, temporary culverts, and clearing will be included in this item. When construction is completed access areas will be restored, as close as practical, to its original condition.

Any fence removed for access and /or to provide work area shall be replaced with same or like materials as approved by the engineer.

The Contractor shall exercise caution to minimize the amount of damage caused by the grading and clearing operations.

Portable toilets shall be provided at the construction site and used for the sanitary facilities.

This item shall not include transportation of personnel, equipment, and operating supplies within the work limits areas of this contract.

Payment will constitute full compensation for related subsidiary item, Pollution Control.

Payment will be made as the work proceeds and will be paid out on the percent of the project complete as the work progresses. Payment of the lump sum contract price for mobilization and demobilization will constitute full compensation for the completion of the work.

Payment will not be made under this item for the purchase costs of materials having a residual value, the cost of materials to be incorporated in the project, or the purchase costs of operating supplies.

CS-8-3 3/22

Contractor is to contact “Iowa One Call” for utility locations a minimum of two (2) days prior to any excavation/construction. The ticket number must be provided to Engineer.

2. Subsidiary Item – Pollution Control

Refer to IA-5, Pollution Control, Section 7.

3. Subsidiary Item – Temporary Crossing

A temporary crossing may be used to cross the creek during construction activities but must be coordinated with the property owner and the Engineer. The temporary crossing shall be considered incidental to the project, and the location of the temporary crossing shall be restored back to original conditions upon project completion. Drainage within the creek shall be maintained while the temporary crossing is in place.

Iowa IA-9-1 12/14

CONSTRUCTION SPECIFICATION

IA-9 SUBSURFACE DRAIN INVESTIGATION,

REMOVAL AND REPAIR

The work shall consist of investigation, location, repair, and/or removal of subsurface drains (tile) in wetland restoration area, enhancement, or creation project areas, or other situations where subsurface drains may be present.

2. INVESTIGATION AND LOCATION

An inspection trench at least 10 inches wide shall be dug at the location shown on the drawings or as directed by the engineer or his representative. The trench shall be at least 6 feet deep measured from the original ground line, unless otherwise shown on the plans. The Engineer or his representative shall examine the trench and excavated material to identify tile lines.

Size, material, operating condition, and direction of flow of each conduit shall be documented. Location and flow line elevation of each conduit shall be surveyed with horizontal and vertical control based on benchmarks shown on the plans.

The inspection trench shall be documented by surveying the natural ground and trench bottom location and elevations at the beginning, end, and every 50 feet for trenches longer than 50 feet.

Backfilling shall not be started without approval of the Engineer. See Section 5 for backfill specifications.

Trench shields, shoring and bracing, or other methods necessary to safeguard the workers and work, and to prevent damage to the existing improvements shall be furnished, placed, and subsequently removed by the contractor.

3. TILE REPAIR

Unless designated for removal, replace damaged conduit with new conduit having equal or greater capacity using material specified in Section 6 or 7. When replacing short sections of clay or concrete tile with single-wall corrugated polyethylene pipe, use the next larger nominal size.

Make connections with manufactured fittings and tight joints. Where joints have gaps that would allow soil to enter, cover the joint with a permanent type of material such as coal tar pitch treated roofing paper, fiber glass sheet or mat, or plastic sheet.

If the investigation trench has been excavated below the existing drain grade, backfill the trench with gravel or well-pulverized soil in layers not over four (4) inches thick and tamp by hand or manually directed power tamper to provide a firm foundation for the conduit at the existing grade.

Do not backfill with any soil containing broken tile fragments.

Using selected soil free of hard clods, rocks, or frozen soil, hand tamp the backfill material around the haunch of the pipe in layers not over four (4) inches thick to provide support. Hold the conduit

Iowa IA-9-2 12/14 in place mechanically while placing excavated material around and over the conduit to ensure proper alignment and grade is maintained. Complete the backfill operation according to Section 5.

4. TILE REMOVAL

Remove conduits as shown on the plans or directed by the Engineer or his representative, including envelope filter material or other flow enhancing material when present.

Cap or plug the open ends of the disconnected conduit to prevent soil entry when the conduit will continue to function downstream, or otherwise shown on the plans. For a minimum distance of two feet around each sealed conduit end, backfill in layers not over four (4) inches thick and tamp by hand or manually directed power tamper to a density equal to or greater than the surrounding undisturbed soil. Do not backfill with any soil containing broken tile fragments, large stones, frozen material, or large dry clods.

Where tile are located beneath an existing animal waste facility, remove the tile, or fill the entire length of tile with concrete or Portland cement grout as shown on the plans.

When tile removal is specified, the owner shall contact the Iowa Department of Natural Resources (IDNR) for permission to remove the drainage tile under the structure. The structure shall be emptied of waste or lowered to a point below the tile prior to its removal. The structure must be retested for percolation and the results submitted to IDNR and approval received prior to reusing the structure.

If shown on the plans or directed by the engineer, reroute upstream drain lines so the capacity of the upstream drainage system is maintained. Install conduit in accordance with Iowa Construction Specification IA-46, Tile Drains for Land Drainage.

5. BACKFILL

Compact soil around disturbed tile as specified in Section 3 (Tile Repair) and Section 4 (Tile Removal). Keep the backfill within 5 feet of the conduit free from large stones, frozen material, and large dry clods. Unless otherwise shown on the plans, backfill the remainder of the trench as follows:

For trenches located under or near structures, backfill in 12-inch layers and compact each layer to a density equal to or greater than the surrounding undisturbed soil.

For other locations, backfill the remainder of each trench with the excavated soil material which shall extend above the ground surface and be well rounded over the trench.

6. MATERIALS

Unless otherwise shown on the plans, conduit and fittings used for repair shall conform to the specifications listed in Table 1. Perforated pipe shall have a water inlet area of at least 1 square inch per foot, provided by perforations spaced uniformly along the long axis of the pipe. The perforations shall be circular or slots. Circular perforations shall not exceed 3/16 inch in diameter.

Slots shall not be more than 1/8 inch wide.

Iowa IA-9-3 12/14

Table 1. Acceptable pipe for subsurface drain repair

Kind of Pipe# Specification

Corrugated Polyethylene (PE) Pipe and Fittings, 3 to 6 inch ASTM F 405

Corrugated Polyethylene (PE) Pipe and Fittings, 3 to 24 inch ASTM F 667

Corrugated Profile Wall (Dual Wall) Polyethylene (PE) pipe, 2 to 60 inch ASTM F 2648$

Corrugated Profile Wall (Dual Wall) Polyethylene (PE) pipe, 12 to 60 inch ASTM F 2306$

Polyvinyl Chloride (PVC) Plastic Pipe, Schedules 40, 80 and 120 ASTM D 1785

PVC Pressure-Rated Pipe (SDR Series) ASTM D 2241

Clay drain tile ASTM C 4

Concrete drain tile ASTM C 412

#Pipe sizes are nominal, and rages are inclusive $Pipe conforming to AASHTO M252 (3 to 10 inch), or AASHTO M294 (12-60 inch) is acceptable.

which it is made subsidiary. Such items and bid items to which they are made made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer

1. Bid Item No. 21 – Drain Tile Investigation

This property contains pattern tile, which is designated on Drawing Sheet C051. A tile investigation had previously been conducted on this project, and

Iowa IA-9-4 12/14 a portion of known tile on the property were identified and measured at certain locations (see Sheet C205).

This bid item will consist of the excavation and all work necessary to locate and explore for all tile under the embankment, and to locate and determine the tie-in locations for the tile modifications shown on the plans.

Tile investigation shall be considered incidental to the removal of the 10” East main and the 10” South main tile lines, which will require complete trenching and removal of the pipe (exploring for additional tile in the process). Payment for tile investigation along the 10” tile lines should be included within the bid item for tile removal (Bid Item No. 20).

Tile investigation shall be considered incidental to the removal of 20 linear feet of 5” CPP at the 10 lateral tile lines that tie-in with the 10” East main tile (exploring for additional tile in the process). Payment for the tile investigation along the 5” CPP lateral tile lines should be included within the bid item for tile removal (Bid Item No. 20).

The drawings designate 390 linear foot of tile investigation (exploration) for the 5” CPP tiles East of the new 10” dual-wall pipe, which includes 30 feet of tile exploration to find each lateral tile. Additionally, 390 linear foot of tile investigation for the 5” CPP West of the new 10” dual-wall pipe is included in the estimated quantities to locate the 5” CPP at certain locations, so that those tiles can be tied-in to the 10” dual-wall pipe within the design slopes indicated in the drawings.

This item does not include the additional excavation required to excavate the embankment core trench. Excavation of the core trench is covered under Specification IA-21, Excavation (Bid Item No. 4).

Payment for Drainage Tile Investigation shall be made on a lump sum basis.

The extent of the tile investigation shall be as shown on the drawings. If extra work is required to locate additional tile not shown on the map, the Contractor can request additional compensation, but must be agreed to by the Division.

The investigation should reveal where the tile crosses the embankment footprint or where it is located if it does not cross the embankment footprint.

2. Bid Item No. 22 – Tile Removal

This bid item consists of tile removal only. The drawings indicate specific locations for tile removal, which should include a disconnect at each end of the designated “tile break,” as well as capping/plugging the open ends of the tile. The drawings also indicate specific locations for “tile removal,” which should include full removal of the existing tile for the distance specified. This item shall also include backfilling of the trenches. The open ends after removing tile should also be capped/plugged. Caps are part of a separate bid item (Bid Item No. 21).

Payment for tile removal is based on a linear foot basis and will be paid on a linear foot basis. Estimated quantities for tile removal are provided on Sheet C205 of the drawings for the various tile sizes.

Iowa IA-9-5 12/14

3. Bid Item No. 23 – Tile Caps

This bid item consists of providing and installing caps at the terminated ends of the tile, as shown on the drawings. Tile caps should be prefabricated caps made specific for the tile, or else, concrete plugs can be utilized, along with clay backfilling adjacent to the cap. 26 tile caps have been estimated for this bid item.

Iowa IA-21-1 7/13

IA-21 EXCAVATION

The work shall consist of the excavation required on the drawings and specifications and disposal of the excavated materials. The cutoff trench and any other required excavations shall be dug to the lines and grades as shown on the drawings or staked in the field. Structure or trench excavations will conform to all safety requirements of

OSHA.

2. USE OF EXCAVATED MATERIALS

Suitable materials from the specified excavations shall be used in the construction of required permanent earth fill. The suitability of materials for specific purposes shall be determined by the Engineer or his representative.

3. DISPOSAL OF WASTE MATERIAL

All surplus or waste material shall be disposed of in areas shown on the drawings or as approved by the Engineer or his representative. The waste material shall be smoothed and sloped to provide drainage.

4. STRUCTURE AND TRENCH EXCAVATION

Structure or trench excavations will conform with all safety requirements of OSHA.

5. BORROW EXCAVATION

When the quantities of suitable materials obtained from specified excavations are insufficient to construct the specified fills, additional materials shall be obtained from the designated borrow areas as shown on the drawings or as approved by the Engineer or his representative and the landowner.

Borrow areas shall be excavated and finally graded in a manner to eliminate steep or unstable side slopes or hazardous or unsightly conditions.

6. OVER-EXCAVATION

Excavation beyond the specified lines and grades shall be corrected by filling the resulting voids with compacted earthfill, except that if the earth is to become the subgrade for riprap, sand, or gravel bedding or drainfill, the voids shall be filled with material conforming to the specifications for the riprap, bedding or drainfill, as appropriate.

Iowa IA-21-2 7/13 which it is made subsidiary. Such items and bid items to which they are made made at the contract lump sum price and will constitute full compensation for completion of the work.

For items of work for which specific unit prices are established in the contract, the payment will be made based on the approved quantity measured by the engineer or weight tickets. Payment will constitute full compensation of the work completed as defined by each work item.

The volume of excavation as provided in the bid quantities has been determined from the topographic information shown on the Drawings using a computer program. Payment will be made based on the planned quantities provided unless additional excavation is directed by the Engineer. Excavation resulting from the contractor's improper construction operations, as determined by the Engineer, is not included for measurement and payment.

1. Bid Item No. 4 – Excavation – Core Trench for Grade Stabilization Structure and Berm

This item will consist of excavation and grading of material needed for the berm core trench, as detailed on the plans. There is known spoil material that exists along the proposed berm alignment that shall be excavated down to the pre-existing grade (prior to the spoil placement) before excavating down to the bottom of the core trench. This bid item also include excavation (315 CY) for the riprap toe stabilization shown on Sheet C203. Note that excavation required for the riprap toe will need to be accomplished using a long reach excavator.

Excavations required for tile exploration, new tile installation, riprap placement, are not included in this bid quantity and will not be measured for payment. The cost of excavation for these items are incidental and should be included as part of the associated bid item.

This item does not include the excavation for site stripping or topsoiling, which is part of Bid Item Nos. 2, 9, and 10.

This item includes the hauling of excavated material to be used as earthfill or spoil.

Iowa IA-21-3 7/13

The material excavated with suitable quality shall be used within the dike and/or “creek meander fill” as directed by engineer. It is assumed that only a portion of the non-topsoil excavated material at these locations shall be suitable for earthfill.

Suitable excess excavated material shall be disposed of along top of banks for tile outlet channels or in designated areas by Engineer or Engineer's Representative.

See IA-23 for compaction method.

Payment will be based on plan quantity unless unsuitable material is found in the bottom of the core trench.

Payment will constitute full compensation for the following related Subsidiary items: Pollution Control; Removal of Water; and Structure Excavation.

2. Bid Item No. 5 – Excavation – Grading Inlet Channels (to Wetland and to Draw-Down Structure)

This item will consist of excavation and grading of material needed for the two channels, as detailed on the plans.

This item does not include the excavation for site stripping or topsoil, which if part of Bid Item Nos. 2, 9, and 10.

This item includes the hauling of excavated material to be used as earthfill or spoil.

The material excavated with suitable quality shall be used within the dike and/or “creek meander fill” as directed by engineer. It is assumed that only a portion of the non-topsoil excavated material at these locations shall be suitable for earth fill.

Suitable excess excavated material shall be disposed of along top of banks for tile outlet channels or in designated areas by Engineer or Engineer's Representative.

See IA-23 for compaction method.

Payment will be based on plan quantity unless unsuitable material is found in the bottom of the core trench.

Subsidiary items: Pollution Control; Removal of Water; and Structure Excavation.

3. Subsidiary Item – Borrow Excavation

This item will consist of excavation of the borrow area for placement of cohesive material in the embankment core. The cost for excavation and transporting of borrow shall be included in Bid Item Nos. 6, 7, and 8 as part of Earthfill, IA-23.

Iowa IA-21-4 7/13

Borrow from any other area will not be allowed unless directed and approved by the Engineer.

The topsoil from the borrow area shall be removed to a minimum depth of 6" and stockpiled. When the borrow operations have been completed, grades shall be returned to that indicated on the plans and the topsoil shall be uniformly spread over the entire borrow area to a depth of 6" (if applicable).

No separate payment will be made for strip or respread of topsoil over borrow area. Compensation for this item will be included in the payment for borrow excavation.

4. Subsidiary Item - Structure Excavation

This item shall consist of the excavation necessary to install the steel sheet pile, riprap, corrugated metal pipe conduit, corrugated metal pipe tile outlets and water control structure in the locations and as shown on the drawings.

No separate payment will be made for Structure Excavation.

Compensation for this item will be included in payment for Corrugated Metal Pipe; CMP Drawdown Structure; Steel Sheet Pile; and Riprap.

Iowa IA-23-1 12/2015

IA-23 EARTHFILL

The work shall consist of the construction of earth fills required by the drawings and specifications. The completed work shall conform to the lines, grades, and elevations shown on the drawings or as staked in the field.

2. MATERIALS

All fill materials shall be obtained from required excavations and designated borrow areas. Fill materials shall contain no sod, brush, roots, or other bio-degradable materials.

Rocks larger than 6 inches in diameter shall be removed prior to compaction of the fill.

3. FOUNDATION PREPARATION

Foundations for earthfill shall be stripped a minimum of 6 inches to remove vegetation and other unsuitable materials. Foundation surfaces shall be scarified to a minimum depth of 2 inches.

Foundation and abutment surfaces shall not be sloped steeper than 1.5 horizontal to vertical unless otherwise shown on the drawings.

4. PLACEMENT

Fill shall not be placed until the required excavation and foundation preparation have been completed and the foundation has been inspected and approved by Engineer or his representative. Fill shall not be placed upon a frozen surface, nor shall snow, ice, or frozen material be incorporated in the fill.

Adjacent to structures or pipes, fill shall be placed in a manner which will prevent damage. The height of the fill adjacent to structures or pipes shall be increased at approximately the same rate on all sides.

The materials used throughout the earth fill shall be essentially uniform. Selective placement shall be as shown on the drawings or approved by NRCS.

If the surface of any layer becomes too hard and smooth for proper bond with the succeeding layer, it shall be scarified to a depth of not less than 2 inches before the next layer is placed.

The top surfaces of embankments shall be maintained approximately level during construction, except that a cross-slope of approximately 2% shall be maintained to ensure effective drainage.

When moving fill material from the borrow area(s) to the embankment by use of bulldozers only, the following steps shall be followed:

Iowa IA-23-2 12/2015

Immediately after the borrow material is pushed to the embankment, it shall be spread in horizontal lifts placed parallel to the centerline of the embankment.

Compactive effort will then be applied by operating equipment parallel to the centerline of the fill or embankment.

Lift thickness shall in strict compliance with Clause 6 below.

Sectional fills are not allowed unless they are shown on the construction drawings.

5. CONTROL OF MOISTURE CONTENT

The moisture content of the fill material shall be adequate for obtaining the required compaction. Material that is too wet shall be dried to meet this requirement, and material that is too dry shall have water added and mixed until the requirement is met.

The moisture content of the fill material shall be such that a ball formed with the hands does not crack or separate when struck sharply with a pencil and will easily ribbon out between the thumb and finger.

Earth foundations under and adjacent to concrete structures shall be prevented from drying and cracking before concrete and backfill are placed.

The application of water to the fill materials shall be accomplished at the borrow areas insofar as possible.

6. COMPACTION

Earth fill shall be compacted by one of the following methods as specified on the plans. If no method is specified, compaction will be in accordance with Method 1.

Method 1 - Earthfill shall be placed so that the wheels or tracks of the loaded, hauling equipment, traveling in a direction parallel to the centerline of fill, pass over the entire surface of the layer being placed. Low ground pressure vehicles shall not be used for this purpose.

Method 2 - Two (2) complete passes of a tamping-type roller will be made over each layer.