Supplemental Const Specs.pdf

NOAH AND WILCOX EAST AML RECLAMATION PROJECT

BID NO. IA-113-363 SUPPLEMENTAL CONSTRUCTION SPECIFICATIONS

SUPPLEMENTAL CONSTRUCTION SPECIFICATIONS

EXPLANATION

A. The purpose of this Section of the Specifications is to provide supplemental information which is required to complete the Standard Construction Specifications and to set forth supplementary requirements, modifications and/or deletions which are required to make the whole of the Construction Specifications project specific.

B. References to Section, Paragraph and Sub-paragraph numbers used in these Supplemental Construction

Specifications are intended to coincide with reference numbers for corresponding Sections, Paragraphs and

Sub-paragraphs in the Standard Construction Specifications.

C. Where there is any variance between the Standard Construction Specifications and these Supplemental

Construction Specifications, the Supplemental Construction Specifications shall take precedence.

D. Where any section of the Standard Construction Specifications is modified or any Paragraph, Sub-paragraph or Clause thereof is changed or deleted by these Supplemental Construction Specifications, the unaltered provisions of that Section, Paragraph, Sub-paragraph or Clause in the Standard Construction Specifications shall remain in effect. Unless these Supplemental Construction Specifications make specific reference to the modification or deletion of a Paragraph, Sub-paragraph or Clause in the Standard Construction

Specifications, no changes are intended and paragraphs contained in these Supplemental Construction

Specifications are intended only to supplement, amplify, or clarify said Standard Construction Specifications.

E. The following set of standard specifications (updated June 2026), is used for this project:

02010 FIELD ENGINEERING

02100 MOBILIZATION, SITE CLEARING AND PREPARATION

02110 IMPOUNDMENTS

02120 SEDIMENT AND EROSION CONTROL

02200 EARTHWORK, ROUGH GRADING

02300 DRAINAGE SYSTEMS, GENERAL

02310 DRAINAGE SYSTEMS, DAMS AND STRUCTURES

02400 SUBGRADE PREPARATION

02500 FENCING

02700 PERMANENT SEEDING

F. Engineer: (per General Conditions 1-04)

Anthony J. Harbaugh, P.E., Shive-Hattery, Inc.

4125 Westown Parkway, West Des Moines, Iowa 50266.

Telephone: (515) 223-8104

Email: aharbaugh@shive-hattery.com

SECTION 02010 – FIELD ENGINEERING

1.3 QUALITY ASSURANCE

E. (New Paragraph) GPS machine control is highly recommended for this project but not expressly required.

F. (New Paragraph) Existing property corner posts noted in plans shall be surveyed by a licensed surveyor of the State of Iowa in accordance with the standards of practice prior to disturbance of said object. All survey information shall be provided to the engineer. Contractor shall hire a licensed land surveyor.

3.2 DIMENSIONS AND ELEVATIONS

B. (New Paragraph) Horizontal measurements are in U.S. Survey feet and are based upon the NAD 83 Iowa

State Plane Coordinate System, South Zone.

C. (New Paragraph) Elevation measurements are based upon the NAVD 1988 and are in U.S. Survey feet.

D. (New paragraph) Existing topography shown on this drawing was developed from Lidar information for

Marion County, Iowa, which is publicly available through the USGS at:

https://apps.nationalmap.gov/downloader/#/elevation

SECTION 02100 - MOBILIZATION, SITE CLEARING & PREPARATION

3.1 SITE ACCESS

B.

2. (added sub-paragraph) If existing entrance within the Right-Of-Way must be widened to facilitate access, approval from the Marion County Secondary Roads department must be obtained prior to performing the improvements.

3. (added sub-paragraph) Labor and other work required for the improvement of the entrance, except macadam stone, shall be considered incidental to Mobilization.

3.4 OFFICE AND LAY-DOWN AREA

B. Contractor’s Field Office

1. (Revise) Contractor’s office is not required for this project. The Contractor shall make certain that his representative on site has an operating cellular phone that can be used for communication with Engineer and Division. Provide adequate space for project progress meetings and provide sanitary facilities (toilet).

SECTION 02110 - IMPOUNDMENTS

3.8 TREATMENT AND DISCHARGE SUMMARY

B. (Revise) Contractor shall anticipate providing a minimum of two rounds of composite water samples for all water bodies at the site. Initial samples shall be taken and tested prior to any discharge and second samples shall be taken following any required treatment which is anticipated for all water bodies listed in the table on the Plans. Further rounds of composite samples may be necessary if satisfactory discharge parameters are not achieved after initial treatment and testing or if conditions change during discharge.

SECTION 02120 – SEDIMENT & EROSION CONTROL

2.1 (New Section) STONE FILTER

D. (New Paragraph) Material for stone filter shall meet the requirements of IDOT Section 4122.02-A for

Macadam Crushed Stone. Gradation shall be Gradation No. 13 of the Aggregate Gradation Table in Article

4109.02.

3.3 O. (New Section) RIPRAP DITCHES AND OTHER RIPRAP WORK

1. (New Paragraph) Riprap or erosion stone shall be placed over a 6” thick filter stone, where required, in areas shown on the Plans and in a manner which shall produce a reasonably well-graded mass of stone with the minimum practical percentage of voids. All riprap material shall be placed and distributed such that there shall be no objectionable accumulations of either the larger or smaller sizes of stone, and such that the entire mass of stone shall be in accordance with the lines, grades and thickness as shown on the Plans.

2. (New Paragraph) Contractor shall place the stone filter and riprap so as not to disturb the stone filter. Riprap or stone shall not be dropped more than two (2) feet when being placed on filter stone bedding. Contractor shall shape rock according to the detail and grading plans. Contractor shall mechanically tamp riprap with excavator bucket to lock stone together and reduce roughness of surface.

P. (New Section) BURIED GRADE CONTROL

1. (New Paragraph) Riprap shall be placed over a 6” thick filter stone 10-12” below the proposed grade in the terrace flowline in the locations as shown on the Plans. Voids in the riprap are to be choked with onsite soils during placement. Riprap and soils shall be placed in lifts to ensure all voids are filled throughout the entire depth. Riprap shall be covered with 10-12” of soil and have the appropriate subgrade amendments applied to the soil according to soil tests. Caution should be taken during subgrade and seedbed preparation to not disturb the riprap below the surface while providing a suitable finished surface for seeding. These areas should be permanently seeded, and no rock shall be visible above ground at the completion of seeding.

SECTION 02200 – EARTHWORK, ROUGH GRADING

1.4 JOB CONDITIONS

C. Earthwork Balance

1. (added language) The shrinkage factor is assumed to be 12% for the mass balance.

3.9 FILL PLACEMENT AND COMPACTION

H. (New Paragraph) Deep fill zones: zones requiring placement of fill deeper than fifteen feet (15’) shall require extra time to allow for settlement of the fill and underlying foundation soils. Once each increment of 15’ of fill is placed, at least thirty (30) days shall be allowed to elapse before performing additional fill operations in that zone. The waiting period may be reduced to no less than fifteen (15) days provided the

Contractor documents with detailed daily survey measurements that the settlement has ceased or that the majority of the settlement has occurred within the first 15-day waiting period. Establishment of benchmark locations for survey measurement shall be subject to Engineer’s approval.

3.13 MAINTENANCE

G. (New Paragraph) All maintenance, as described in this section, shall be considered incidental to the project and shall be completed at no additional cost to the Division.

SECTION 02220 – EARTHWORK, DAMS

NO CHANGES

SECTION 02300 – DRAINAGE SYSTEMS, GENERAL

2.5 TERRACE RISERS AND OPEN SIDED AREA INTAKES

A. Terrace Risers

1. (REVISE) Risers on both Marion County’s and Rachel Gullick’s property shall be made from corrugated metal pipe. 18 GA aluminized coating or approved equivalent shall follow ASTM

A742 and A929. Sizes shall be as shown on the Plans.

2. (REVISE) For the CMP risers on Marion County’s parcels, the top three (3) feet shall be perforated with at least forty (40), one (1)-inch diameter holes Providing a minimum of thirty

(30) open square inches per foot of riser. The below-grade section of the riser shall also be perforated. Tape over all prefabricated holes with tile tape except top twelve inches (12”) immediately below finished grade. If a non-perforated mid-section was procured, field drill sixteen (16) equally spaced, 5/16" dia. holes, in four (4) equally spaced rows with four (4) holes per row in the top twelve inches (12”) below finished grade. All remaining CMP exposed underground, other than the top 12” section of perforations, shall be wrapped with 8 mil Linear Low-Density Polyethylene black or opaque encasement. Minimum puncture and tear resistance suitable for backfill operations. Overlap seams a minimum of 12 inches and tape securely with tile tape.

For the CMP risers on Rachel Gullick’s property, the top four (4) feet shall be perforated with at least fifty three (53), one (1)-inch diameter holes Providing a minimum of thirty (30) open square inches per foot of riser. This should leave the entire above-grade portion of the riser perforated, but no perforations below grade. No factory-installed perforations allowed below grade. Wrap all non-perforated CMP above and below grade with 8 mil Linear Low-Density

Polyethylene black or opaque encasement. Minimum puncture and tear resistance suitable for backfill operations. Overlap seams a minimum of 12 inches and tape securely with tile tape.

Following subgrade and seedbed preparation operations, including terrace flowline trimming and maintenance, the bottom 12” of perforations on Rachel Gulick’s terrace risers shall be sealed to achieve 1’ of ponding in the terrace flowlines. Tape the bottom 12” of perforations and install a separate section of 18” Aluminized 18 GA CMP around the terrace risers. Place hand-compacted soil backfill in between the riser and the 18” CMP. See detail in plans.

Coordinate installation timing with Engineer and Division.

3. (REVISE) Below grade, the corrugated metal riser shall extend to the intake tee. If perforations are below grade, other than in specified area, then the openings shall be completely sealed with three (3) wraps of polyethylene tape or suitable tape.

4. (New Paragraph) Contractor shall install Yellow Standard Bar Guard by Agridrain, or approved equal, on top of intake.

6. (New Paragraph) Bar guards shall be fastened to riser using stainless steel zip ties or stainless steel self-tapping screws.

3.5 TERRACES

C. (New Paragraph) Terraces shall be maintained according to “Section 02200 – Earthwork, Rough

Grading-3.13 Maintenance”. Flowlines that have settled or accumulated sediment shall be corrected by the contractor and approved by the Engineer or Construction Observer, prior to application of lime or fertilizer as part of both the subgrade preparation and seeding operations.

3.6 TILING AND PIPE

A. Tiling

10. (New Paragraph) Tile installation over fills greater than 10’ must wait a minimum of 30 days after fill is placed to final grades to limit settlement post installation.

B. Pipes

11. (New Paragraph) Pipe installation over fills greater than 10’ must wait a minimum of 30 days after fill is placed to final grades to limit settlement post installation.

3.11 MEANDERED CHANNELS OR WATERWAYS (new subpart)

A. Perform initial construction of meandered channels or waterways during rough grading operations.

B. Construct meandered channels or waterways to the final alignment and grades shown on the plans immediately prior to subgrade preparation. Use care to develop each meander on the landscape.

a. Wing dikes shall be constructed at the upstream end of each rock riffle. The top of each dike shall be 12 to 24 inches higher than the adjacent rock keys and shall maintain a minimum top width of 6 feet.

C. A second final grading must be performed again following subgrade preparation and before seeding operations. Engineer reserves right to require a final staking of the meandered channel or waterway prior to final grading.

D. After achieving the second final grading, provide a light compaction of the soil to consolidate loose fill and to create a firm bottom in each meandered channel or waterway.

SECTION 02310 – DRAINAGE SYSTEMS, DAMS AND STRUCTURES

2.2 DRAINAGE CONDUITS

H. Polypropylene High-Performance Pipe (PPHP)

5. (New Paragraph) Provide a manufactured 2.5-degree bend at the location shown in the plans and install a concrete thrust block in accordance with the details shown.

I. C900 PVC Pipe

1. (New Paragraph) C900 PVC pipe designated as P33A and P33B in the plans shall be DR 18 or approved equal.

2. (New Paragraph) Provide a manufactured 2.5-degree bend at the location shown in the plans and install a concrete thrust block in accordance with the details shown. Joints at bend and next joint on either side of bend shall be mechanically restrained with polymer coated Megalug or approved equivalent. All bolts and rods shall be stainless steel.

2.3 ANTI-SEEP COLLARS AND FILTER DIAPHRAGMS

B. (New Paragraph) Anti-seep collars shall be Scheib Drainage HDPE collars, or approved equivalent.

Collars shall match the dimensions listed on the plans. Collars shall be installed according to the manufacturer’s recommendations. The cost of the anti-seep collar and any additional measures required in order to achieve a water-tight seal shall be considered incidental to the cost of the outlet pipe, as discussed in Section 02310-3.10C. Anti-seep collars shall not be installed unless the Engineer or

Construction Observer is present.

2.4 DROP INLETS AND OPEN SIDED AREA INTAKES

B. Drop Inlets

1. (New Paragraph) Riser structure designated as R33 in the plans shall be a modified SW-403, 48-inch × 48-inch reinforced concrete water control structure meeting Iowa DOT standards or approved equal. Furnish and install the structure, stoplogs, stoplog storage rack, concrete base, and all appurtenances. Stoplogs shall be PVC and stoplog railing shall be stainless steel. Submit shop drawings for review prior to fabrication. Provide two (2) stoplog lifting rods capable of removing the lowest stoplog from the ground surface and storing within the structure. Concrete structures shall conform to SUDAS 6010 and Iowa DOT 2403 unless otherwise noted.

Excavation, backfill, dewatering, water control, and all incidental items required for a complete installation shall be included in the contract unit price.

SECTION 02400 – SUBGRADE PREPARATION, WITHOUT COVER MATERIAL

3.6 LIME-MULCH APPLICATION

A. APPLICATION RATES

4. (New Paragraph) For bidding purposes, assume the application rate of “Agricultural Lime” for subgrade preparation is twenty-five (25) tons ECCE/acre.

3.8 (New Section) DEEP RIPPING

A. (New Paragraph) Portions of the site are planned for future tree plantings by others. De-compaction of the soils in these areas will improve sapling survival rates and growth potential. These zones are shown on Sheet 33 of the construction plans. These zones will require deep ripping to a minimum depth of 24” prior to subgrade lime and mulch application. Deep ripping shall be achieved by use of a ripper implement on a bulldozer or by other approved equipment. The shank(s) of the ripper shall penetrate a minimum of 24” into the soil measured from the soil surface. The maximum spacing of rips created by the shank is 24”. Ripping will only require one pass in one direction if full depth can be achieved. Multiple passes or cross ripping may be completed to loosen soil so that 24” deep shank penetration can be achieved. Contractor shall demonstrate to Engineer and Division the method and equipment which will be used to achieve a minimum depth of 24” for deep ripping. When an acceptable method is agreed to by the Engineer and Division, that method shall be used in the designated zones throughout the project.

4.1 B. MEASUREMENT AND PAYMENT

6. (New Paragraph) Deep Ripping: Contractor’s unit price for Deep Ripping shall constitute full payment for the de-compaction of soils in the areas as shown on the Plans to a minimum depth of

24” prior to subgrade treatment. The Deep Ripping area will be based upon the footprint as shown on Sheet 33 of the Construction Plans, rounded to the nearest one-tenth (1/10) of an acre. This work will be paid at plan quantity.

SECTION 02500 – FENCING

4.1 MEASUREMENT AND PAYMENT

A.

1. (New Paragraph) Field fence and gate shall be installed as shown and detailed in plans.

SECTION 02700 – PERMANENT SEEDING

2.4 SEED

D. (New Paragraph) The following seed mixes shall be used:

1. Standard AML Low-Diversity, High-Seed-Rate (LDHSR) Native Seed Mix (1,2)

Plant Type Common Name Scientific Name PLS lbs/ac

NON-NATIVE Timothy Phleum pretense 7.00

NON-NATIVE Orchard grass Dactylic glomerata 5.00

WARM-SEASON Big Bluestem Andropogon gerardii 3.00

WARM-SEASON Side Oats Grama Bouteloua curtipendula 3.00

WARM-SEASON Switchgrass Panicum virgatum 3.00

WARM-SEASON Indian Grass Sorghastrum nutans 3.00

WARM-SEASON Rough Dropseed Sporobolus compositus 3.00

COOL-SEASON Canada Wild Rye Elymus canadensis 3.00

COOL-SEASON Virginia Wild Rye Elymus virginicus 5.00

LEGUME Purple Prairie Clover Dalea purpurea 2.00

LEGUME Showy Tick Trefoil Desmodium canadense 1.00

SPRING FORB Golden Alexanders Zizia aurea 0.50

SUMMER FORB Common Yarrow Achillea millefolium 0.10

SUMMER FORB Purple Coneflower Echinacea purpurea 1.00

SUMMER FORB Oxeye Sunflower Heliopsis helianthoides 1.00

SUMMER FORB Wild Bergamot Monarda fistulosa 1.00

SUMMER FORB Wild Quinine Parthenium integrifolium 0.50

SUMMER FORB Yellow Coneflower Ratibida pinnata 1.00

SUMMER FORB Black Eyed Susan Rudbeckia hirta 0.50

SUMMER FORB Hoary Vervain Verbena stricta 0.50

FALL FORB Prairie Sage Artemisia ludoviciana 0.05

FALL FORB Saw Tooth Sunflower Helianthus grosseserratus 0.10

FALL FORB Stiff Goldenrod Solidago rigida 0.50

FALL FORB New England Aster

Symphyotrichum novae-angliae 0.10

Total Lb. PLS 44.85

4. Standard AML Wetland Fringe Seed Mix (1,2)

Common Name Scientific Name (Lb. PLS/ac)

Bebb’s sedge carex bebbii 0.03

Fox sedge carex vulpinoden 0.03

Blue joint grass calamagrostis canadensis 0.7

Cup plant silphium prefoliatum 0.7

Fowl mannagrass glyceria striata 0.7

Swamp Milkweed Asclepias incarnata 0.3

Yellow Marsh Marigold Caltha palustris L. 0.05

Prairie cordgrass spartina pectinata 4

Rice cut grass leersia oryzoides 0.04

American Sloughgrass Beckmannia syzigachne 5

Spike rush eleocharis palustris 0.05

Virginia wildrye elymus virginicus 10

Total Lb. PLS/acre 21.6

5. Standard Cover Crop Options (1)

Seed Rate

Season Common Name Scientific Name Lb. (PLS/ac)

Spring (2) Oats Avena sativa 32

Fall & Dormant (3) Winter Wheat Triticum aestivum 45

Modified Dormant (4,5) Winter Wheat Triticum aestivum 22

Cereal Rye Grain Secale cereale L. 22

3.4 LIMING AND FERTILIZING

E. (New Paragraph) For bidding purposes, assume the application rate of “Agricultural Lime” for seeding is five (5) tons ECCE/acre.

E. (New Paragraph) For bidding purposes, assume the application rate of Nitrogen is fifty (50) pounds per acre, Phosphorus is one hundred (100) pounds per acre, and Potassium is one hundred (160) pounds per acre.

3.5 SEEDING

D. SEED PLACEMENT

1. (REVISE) Seed all areas to be seeded with the appropriate seed mix as shown on the Plans and in the

Supplemental Specifications. Seed species shall be applied at the rates provided in the Supplemental

Specifications. Sow seed along the contour using a grassland or rangeland drill. The drill shall be equipped with double coulter furrow openers. The drill shall be subject to acceptance by Engineer. Drill seeding shall be accomplished with rows set no more than eight (8) inches apart. Set drill for half of the specified seeding rate, and drill entire area to be seeded two (2) times. Overlap each successive seeding pass at least one (1) row width and avoid drilling in previously created furrows to ensure complete coverage. Upon a show of green, non-acidic bare areas will be reseeded at no additional cost to Division.

END OF SUPPLEMENTAL SPECIFICATION