Section 2601.  Erosion Control

 

2601.01     Description.

Perform the following erosion control measures on areas within and adjacent to the right-of-way according to the contract documents and this specification:

·         Seeding and fertilizing,

·         Stabilizing crop seeding and fertilizing,

·         Overseeding and fertilizing,

·         Mulching,

·         Composting,

·         Sodding,

·         Special ditch control,

·         Turf reinforcement mat,

·         Slope protection,

·         Outlet or channel scour protection (transition mat), and

·         Mowing.

 

2601.02     Materials.

 

A.    Furnish materials meeting the requirements of Section 4169.

 

B.    Apply materials at no less than the minimum rate specified in the contract documents. Apply seed for native grass, wildflower, and wetland grass seeding on a PLS basis, as computed by the Engineer.

 

C.    Additional compensation will not be allowed for materials in excess of that specified, unless directed by the Engineer.

 

D.    If, after application of fertilizer, it is determined by test that the fertilizer fails to comply with minimum requirements, furnish and apply additional fertilizer to comply with minimum requirements as defined in Article 4169.03.

 

E.    Perform work in a manner that provides the Engineer the opportunity to verify the quantity of material furnished and the rate of application. Divide project area into small natural areas that are to be constructed as identifiable units. Furnish a tally of the quantities of each material as it is used on each area. This may include the quantities below:

·         Weights from approved scales of truck loads of bulk materials,

·         Other scaled weights,

·         Counts of containers, bags, or bales, or estimates of partially used packages of materials, as approved by the Engineer.

 

F.     Provide the Engineer with the opportunity to verify quality and quantities in a manner that will allow continuous operation with minimum delays.

 

G.    When handling inoculants and sticking agents, follow safety precautions as specified on the product label.

 

2601.03     Placement of Erosion Control.

 

A.    Equipment.

Use equipment meeting the requirements of Section 2001 and the following, except that other equipment which produces similar results will be considered for approval. Use methods and procedures consistent with equipment manufacturers' recommendations; however, do not operate ground driven equipment at speeds greater than 10 mph.

 

1.     Disk.

When preparing a seedbed on ground having heavy vegetation, use a disk having cutaway blades. Provide for the addition of weight to obtain proper cutting depth.

 

2.     Slope Harrow.

Use a rolling weight attached by heavy chain to a tractor. Use a chain of suitable length, with picks attached and a means of rotating the picks as the rolling weight is pulled in a direction parallel to the movement of the tractor.

 

3.     Field Tiller.

Use equipment designed for preparation of the seedbed to the degree specified.

 

4.     Rotary Tiller.

Use equipment with rotary type blades designed for preparation of seedbed to the degree specified.

 

5.     Spike Tooth Harrow.

Use equipment designed to:

·         Provide adjustment of the spike teeth to level the ground, or

·         Be used as specified by the Engineer.

 

6.     Compaction Equipment.

a.     Cultipacker.

1)    Use a pull type cultipacker with individual rollers or wheels. Cultipackers having sprocket type spacers between the wheels may be used. Ensure the cultipacker produces a corrugated surface on area being compacted.

2)    Use a cultipacker that operates separate from other operations. Attachment of cultipacker to the seeder or disk will not be permitted, except when the combined cultipacker seeder is manufactured to operate as a unit. Provide for the addition of weight.

b.     Compaction Rollers.

Apply Article 2001.05, A.

c.     Hand Tamping Equipment.

Use base plate type hand tamping equipment adapted to the performance of the work. Obtain the Engineer’s approval.

d.     Expanded Mesh Roller.

Use open grid type equipment or the cultipacker type equipment modified by covering with expanded metal mesh.

 

7.     Hydraulic Seeder and Mulcher.

a.     Use hydraulic seeding equipment with a pump rated at no less than 100 gallons per minute. Inoculant, seed, and fertilizer may be applied in a single operation, unless stated otherwise in the contract documents. Apply hydraulic mulch as a separate operation. Ensure the equipment has suitable working pressure and a nozzle adapted to the type of work.

b.     Ensure supply tanks have a means of mechanical agitation. Calibrate the tanks and provide a calibration stick or other approved device to indicate the volume used or remaining in the tank.

 

8.     Gravity Seeders.

a.     Ensure gravity seeders:

·         Provide agitation of the seed,

·         Have an adjustable gate opening, and

·         Uniformly distribute seed on the prepared seedbed.

b.     Use a seed hopper equipped with baffle plates spaced no more than 2 feet apart. Ensure baffle plates extend from the agitator shaft to within approximately 2 inches of the top of the seed hopper.

c.     Wind guards will be required to facilitate seeding when moderate wind conditions exist and when required by the Engineer. Place wind guards in front or in back (or both) of the seed outlet and extend to near the ground line.

d.     This seeder may be used for the application of fertilizer.

 

9.     Endgate Cyclone Seeders.

Ensure endgate cyclone seeders are:

·         Suitably mounted,

·         Provide movement by mechanical means, and

·         Drop through an adjustable flow regulator onto a rotating, power driven, horizontal disk or fan.

 

10.  Hand Cyclone Seeders.

Use a seeder that drops seed through an adjustable flow regulator onto a rotating, hand driven, horizontal disk or fan.

 

11.  Native Grass Seed Drill.

Use a drill that:

•       Is free of soil and seed when it arrives on the project,

•       Accurately meters and uniformly mixes various seed types throughout drilling operation,

•       Provides separate seed boxes to apply both small seeds and a large box with an aggressive picker wheel for continual mixing and applying fluffy bearded seed,

•       Has disc furrow openers and packer assembly wheels that compact soil directly over drill rows,

•       Contains a no till attachment manufactured by same manufacturer as the drill, and

•       Has dimensions to ensure it maintains uniform soil contact over seeded area without bridging. 

 

12.  Pneumatic Seeder.

Use a pneumatic (air blower) system with enough power and hose to reach 300 feet.

 

13.  Aerial Equipment.

When aerial application of seed and fertilizer is specified, use aerial equipment capable of providing a uniform distribution of seed and fertilizer on the specified area.

 

14.  Straw Mulching Machine.

Use a type that will uniformly apply mulch material over the desired area without excessive pulverization. Engineer may consider eExcessive pulverization as is the general absence of straw longer than 6 inches after distribution.

 

15.  Mulch Anchoring Equipment.

a.     Use mulch anchoring equipment designed to anchor straw or hay mulch into soil by means of dull blades or disks. Use blades or disks that:

·         Are flat,

·         Have a nominal minimum diameter of 20 inches, and

·         Are spaced at approximately 8 inch intervals.

b.     The blades may have cutaway edges. Pull mulch anchoring equipment using mechanical means. Use equipment that weighs approximately 1000 pounds. When directed by the Engineer, increase the weight (mass) of the equipment by the addition of ballast.

 

16.  Mechanical Trencher.

Use a machine designed for the specific purpose of constructing a trench for placement of check slots to depth specified.

 

17.  Mowers.

Use rotary, flail, disk, or sickle type mowers that do not bunch or windrow mowed material.

 

18.  Slit Seeder.

      Use a gas, diesel, or electric powered mechanical slit seeder that:

·         Is capable of cutting vertical grooves a maximum of 1/4  inch deep into the soil with a maximum horizontal blade spacing of 3 inches,

·         Deposits metered seed directly behind the vertical grooves, and

·         Contains packer wheels that press and firmly pack seed into the soil.

 

B.    Seeding and Fertilizing.

 

1.     On various portions of the right-of-way, except the traveled portion of the roadbed:

·         Prepare the seedbed,

·         Furnish, sow, and cover the seed, and

·         Compact the seedbed.

 

2.     Seed other areas as may be indicated in the contract documents or directed by the Engineer. The limits of areas to be seeded will be clearly marked before seedbed is prepared.

 

3.     Do not disturb areas having a satisfactory growth of desirable grasses or legumes.

 

4.     Sow seed only at times of the year when temperature, moisture, and climatic conditions will promote germination and plant growth. Normal seed application dates are according to Article 2601.03, C for each seed type. Perform seeding according to the following procedures:

a.     Seedbed Preparation.

1)    Ensure area to be seeded is relatively smooth. Fill washes and gullies to conform to desired cross section. When such fills exceed 6 inches, compact the material with a tractor wheel or other suitable field equipment. Coordinate preparation of ditches designated for special ditch control with the seedbed preparation.

2)    Thoroughly work areas accessible to field machinery to a depth of no less than 3 inches. Use mechanical rotary tillage equipment to prepare the seedbed on earth shoulders, urban or raised medians, rest areas, and islands. Hand prepare areas inaccessible to field machinery to a depth of not less than 2 inches. Ensure entire width of shoulder and areas around headwalls, wingwalls, flumes, and other structures are prepared in the manner specified.

3)    Where enough vegetative growth exists to sufficiently interfere with proper seedbed preparation, mow vegetative growth before seeding, at no additional cost to the Contracting Authority.

4)    Use crawler type or dual wheeled tractors to prepare seedbeds. Operate equipment in a manner to minimize displacement of soil and disturbance of the design cross section.

5)    Prior to rolling with cultipacker, harrow ridging in excess of 4 inches caused by operation of tillage equipment. Prior to permanent seeding, roll the area with no less than one pass of the cultipacker.

6)    Remove ruts that develop during the sequence of operations before subsequent operations are performed.

7)    After completing seedbed preparation, pick up and remove debris according to Article 1104.08, including 3 inch diameter or larger stones, logs, stumps, cable, or other objectionable material that may interfere with seeding operation.

b.     Application of Fertilizer.

1)    Spread fertilizer over the areas at the rate designated in Article 2601.03, C for each seed type, unless specified otherwise in the contract documents.

2)    Spread with a mechanical spreader which will secure a uniform application rate. Do not use truck mounted spreading equipment for bulk fertilizer. On areas accessible to field machinery, spread after the preliminary preparation of seedbed, but prior to sowing of seed. Disk in fertilizer and roll the area prior to application of permanent seed. If the roller cannot be operated satisfactorily, Engineer may permit substituting a harrow for the roller. Areas inaccessible to field machinery, spread fertilizer after preparation of seedbed and thoroughly rake into the soil.

3)    If using a hydraulic seeder, apply fertilizer in combination with seeding as specified in Article 2601.03, B, 4, d, 2. When the contract documents require two applications of fertilizer, perform second application during next permanent seeding period following initial seeding and fertilizer application.

c.     Preparation of Seed.

1)    Except when a hydraulic seeder is used, thoroughly mix all seed specified for the contract prior to placing seed in seed hopper. Seed mixing shall meet requirements of Materials I.M. 469.02. Permanent rural, permanent urban, urban stabilizing, Native Grass, Wetland Grass, and Wildflower seeding mixtures shall be mixed off-site by a seed conditioner approved by the Iowa Crop Improvement Association or other state’s Crop Improvement Association. 

2)    Inoculate legumes with a standard culture at the rate as specified by manufacturer of inoculant, according to Article 4169.04. Use a type of inoculant specified for each legume seed and approved by the Engineer.

3)    Do not allow inoculated seed to be exposed to direct sunlight for more than 30 minutes. Prior to use, reinoculate seed that is not sown within 8 hours after inoculation. Preinoculated seed with manufacturer's recommended protective coating may be used in lieu of seed with Contractor applied inoculant.

4)    When gravity or cyclone seeder is used for application of seed, inoculate legume seed according to manufacturer's recommended procedures before mixing with other grass seeds for sowing. If hydraulic seeder is used, inoculant, in quantities specified above, may be applied directly into supply tank with seed, water, and other material. Furnish and apply inoculant.

5)    Treat seed with a commercial sticking agent. Apply prior to application of inoculant, or as a mixture when the sticking agent is compatible with other materials, except with hydraulic equipment. A sticking agent optional if a liquid formulation of inoculant is used.

6)    Use mechanical mixing equipment to apply sticking agent and inoculant on seed quantities over 50 pounds per batch.

d.     Application of Seed.

1)    Sowing, Covering, and Compaction     

a)    On areas accessible to field machinery, seed may be sown with:

·         A gravity, cyclone, or hydraulic seeder,

·         A native grass seed drill, or

·         As specified in the contract documents.

b)    On areas inaccessible to field machinery, use of hand cyclone seeders may be used.

c)    Sowing of seed shall be performed as a split rate application (no less than two passes).

d)    Covering, compaction, rolling, dragging, or raking of seedbed will not be required provided the friable condition exists. For spring seeding (following fall seedbed preparation) after April 1, Contractor shall roll or harrow when, in the opinion of the Engineer, a friable condition does not exist. Cover stabilizing crop seeding and fertilizing with a light disking or other tillage equipment such as a rigid harrow, spring tooth harrow, or field cultivator.

e)    Follow sowing of grasses and legumes with at least one complete rolling with cultipacker. Roll shoulders immediately to prevent loss of seed due to air currents caused by passing traffic. For stabilizing crop seeding and fertilizing, follow tillage by rolling area with a cultipacker. If cultipacker cannot be operated satisfactorily, Engineer may permit harrow to be substituted for cultipacker. 

f)     Where compaction equipment will not operate satisfactorily, lightly drag or rake in seeded area by hand. Roll seedbed with a cultipacker before and after seeding. 

2)    Seeding and Fertilizing with Hydraulic Seeder. 

a)    A hydraulic seeder may be used when seedbed has been prepared according to Article 2601.03, B, 4, a. When a hydraulic seeder is used, apply seed or fertilizer, or both, at the rates specified in approximately 400 gallons of water slurry per acre.

b)    Apply mixture within 1 hour after fertilizer and seed are placed in hydraulic seeder. Use continuous agitation. Seed remaining in the fertilizer solution for more than 1 hour will be unacceptable. Additional seed at the specified rate will be required.

3)    Pneumatic Seeding.

Includes furnishing and applying compost to a depth of 1 inch on designated disturbed areas. Apply compost using a pneumatic (air blower) system with sufficient hose to reach 300 feet. Driving on soil to apply compost will not be allowed. Incorporate fertilizer into full depth of compost material. Prepare seedbed according to Article 2601.03, C, 4, a, 1. Apply seed within top 1/4 inch of compost material.

 

C.    Types of Seeding.

 

1.     Stabilizing Crop Seeding and Fertilizing (Rural).

a.     Preparation and Application.

1)    Prepare seedbed according to Article 2601.03, B, 4, a.

2)    Prepare seed according to Article 2601.03, B, 4, c.

3)    Apply seed according to Article 2601.03, B, 4, d.

4)    For stockpile stabilization seeding, seedbed preparation will not be required for areas not accessible to field equipment.

b.     Seed Mixture.

Unless otherwise specified in the contract documents, use rates and schedule shown in Table 2601.03-1.

 

 

c.     Fertilizing.

1)    Apply to seeded areas at the rate of 250 pounds per acre of 13-13-13 (or equivalent) unless specified otherwise in the contract documents.

2)    Apply provisions of Article 2601.03, B, 4, b.

d.     Application Dates.

Refer to Table 2601.03-1 for normal seed application dates.

 

2.     Stabilizing Crop Seeding and Fertilizing (Urban).

a.     Preparation and Application.

1)    Use a rotary tiller for preparation of seedbed according to Article 2601.03, B, 4, a. Prior to application of seed, ensure seedbed is firm, smooth, and free of material 1.5 inches in diameter or greater including clods, rocks, and other debris. Roll seedbed before and after application of seed. For rolling, use either open grid type equipment or cultipacker type equipment modified by covering with expanded metal mesh.

2)    Prepare seed according to Article 2601.03, B, 4, c.

3)    Apply seed according to Article 2601.03, B, 4, d.

4)    Prepare, roll, seed, and fertilize areas inaccessible to field equipment by hand or using hand operated equipment, including lawn type, hand cyclone, or gravity equipment.

b.     Seed Mixture.

        Unless specified otherwise in the contract documents, use seeding rates shown in Table 2601.03-2 for urban areas.   

 

 

c.     Fertilizing.

1)    Apply prior to preparing seedbed.

2)    Apply to seeded areas at the rate of 300 pounds per acre of 6-24-24 (or equivalent) unless specified otherwise in the contract documents.

3)    Apply provisions of Article 2601.03, B, 4, b.

d.     Application Dates.

Normal seed application dates are March 1 through May 31, and August 10 through September 30. Seed may be applied throughout the year unless ground conditions are unsuitable for seeding due to moisture or frost.

 

3.     Rural Seeding.

a.     Preparation and Application.

1)    Prepare seedbed according to Article 2601.03, B, 4, a c.

2)    Prepare seed according to Article 2601.03, B, 4, c. In areas without existing stabilized crop seeding residue, prepare seedbed according to Article 2601.03, B, 4, a, and apply seed according to Article 2601.03, B, 4, d.

3)    Apply seed according to Article 2601.03, B, 4, d. In areas with existing stabilized crop residue, apply seed with a native grass seed drill with a no till attachment through the small seed box. Seedbed preparation will not be required, except for areas with rills and gullies.

b.     Seed Mixture.

        Use seeding rates in Table 2601.03-3 for permanent seeding of rural areas, unless otherwise specified in the contract documents:

 

 

c.     Fertilizing.

1)    Spread over the areas at the rate designated. Unless otherwise specified in the contract documents, use a rate of 300 pounds per acre of 6-24-24 (or equivalent).

2)    Apply provisions of Article 2601.03, B, 4, b.

d.     Application Dates.

Normal permanent seed application dates are March 1 through May 31, and August 10 through  September 30.

 

4.     Urban Seeding.

a.     Preparation and Application.

1)    Use rotary tiller for preparation of seedbed according to Article 2601.03, B, 4, a. Prior to application of seed, ensure seedbed is firm, smooth, and free of material 1.5 inches in diameter or greater including clods, rocks, and other debris. Roll seedbed before and after application of seed. For rolling, use either open grid type equipment or cultipacker type equipment modified by covering with expanded metal mesh.

2)    In areas with existing urban crop stabilizing of 50% or greater density, full seedbed preparation and rolling will not be required. Apply seed using a slit seeder as defined in Article 2601.03, A, 18.

2 3) Prepare seed according to Article 2601.03, B, 4, c.

3 4) Apply seed according to Article 2601.03, B, 4, d.

4 5) Prepare, roll, seed, and fertilize areas inaccessible to field equipment by hand or using hand operated equipment, including lawn type, hand cyclone, or gravity equipment. Obtain Engineer’s approval for such equipment.

b.     Seed Mixture. 

Use seeding rates in Table 2601.03-4 for permanent seeding of urban areas, including areas previously maintained as a lawn.

 

c.     Fertilizing.

1)    Apply prior to preparing the seedbed.

2)    Spread over the areas at a rate of 300 pounds per acre of 6-24-24 (or equivalent).

3)    Apply the provisions of Article 2601.03, B, 4, b.

d.     Application Dates.

Normal permanent seed application dates are March 1 through May 31, and August 10 through September 30.

 

5.     Native Grass Seeding.

a.     Preparation and Application.

1)    In areas without existing stabilized crop seeding residue, prepare seedbed according to Article 2601.03, B, 4, a. Seed areas accessible to field equipment with native grass seed drill, gravity, or broadcast equipment. Cultipack as specified in Article 2601.03, B, 4, d. Broadcast seed other areas and follow with a light dragging or hand raking.

2)    In areas with existing stabilized crop residue, apply seed with a native grass seed drill with a no till attachment. Seedbed preparation and cultipacking will not be required. Seedbed preparation is required for areas with rills and gullies.

3)    Prepare seed according to Article 2601.03, B, 4, c. 

4)    Calibrate native grass seed drill to specified seeding rate for the project prior to operation at the project.

5)    Plant seed at a maximum 1/8 inch depth. Do not perform seeding when wet soil conditions would cause seed to be placed deeper than specified.

6)    Fill seed boxes loosely without packing seed to allow agitator wheels to run freely and seed flows freely through drill.

7)    Set no-till coulters to penetrate between 1/4 and 1/2 inch below soil surface. 

8)    Operate drill so the drive wheel maintains ground contact. Perform two passes with drill, with second pass being offset from first pass.

9)    Operate tractor between 3 and 5 mph to prevent drill from bouncing. 

10)  Remove seed remaining in drill at the end of each day. At the completion of seeding, remove remaining seed from drill by vacuum or other means. Hand broadcast remaining seed on project.

b.     Seed Mixture.

Use seeding rates in Table 2601.03-5 for areas designated for native grass seeding, unless specified otherwise in the contract documents.

 

c.     Fertilizing.

Not required unless specified otherwise in the contract documents.

d.     Application Dates. 

Normal seed application dates are April 1 through May 31 and November 1 until ground conditions are unsuitable for seeding due to moisture or frost.

 

6.     Wetland Seeding.

a.     Preparation and Application.

1)     In areas without existing stabilized crop seeding residue, prepare seedbed according to Article 2601.03, B, 4, a. Seed areas accessible to field equipment with a native grass seed drill, gravity, or broadcast equipment. Cultipack as specified in Article 2601.03, B, 4, d. Broadcast seed other areas and follow with a light dragging or hand raking.

2)     In areas with existing stabilized crop residue, apply seed with a native grass seed drill with a no till attachment. Seedbed preparation and cultipacking will not be required. Seedbed preparation is required for areas with rills and gullies.

3)      Prepare seed according to Article 2601.03, B, 4, c. 

b.     Seed Mixture.

Use the seeding rates in Table 2601.03-6 for areas designated for wetland grass seeding, unless specified otherwise in the contract documents.

 

 

c.     Fertilizing.

Not required unless specified otherwise in the contract documents.

d.     Application Dates. 

        Normal seed application dates are April 1 through June 30.

 

7.     Wildflower Seeding.

a.     Preparation and Application.

1)    Uniformly apply seed to areas with the seedbed prepared as in Article 2601.03, B, 4, a.

2)    Seed areas accessible to field equipment using a native grass seed drill at an approximate depth of 1/8 inch, or using gravity or broadcast equipment. Cultipack as specified in Article 2601.03, B, 4, d. Broadcast seed other areas and follow with a light dragging or hand raking.

3)    In areas with existing stabilized crop seeding residue, apply seed with a native grass seed drill with a no till attachment. Seedbed preparation and cultipacking will not be required.

b.     Seed Mixture. 

As specified in the contract documents.

c      Fertilizing.

Not required unless specified otherwise in the contract documents.

d.     Application Dates. 

        Normal seed application dates are April 15 through June 30. Normal seed application dates are April 1 through May 31 and November 1 until ground conditions are unsuitable for seeding due to moisture or frost.

 

8.     Special Seed.

        a.     Preparation and Application.

1)    Apply at the rate specified in the contract documents or as directed by the Engineer as a separate operation either immediately before or immediately after sowing the regular grass mixture.

2)    No additional work other than sowing of the seed will be required unless specified otherwise in the contract documents.

3)    On limited areas, this seed may be applied by hand cyclone seeders.

        b.     Seed Mixture.

        1)  As specified in the contract documents.

        2)  When not shown in the contract documents but directed by the Engineer, a special seed or seed mixture may be required in addition to the regular seed mixture.

c.     Fertilizing.

As specified in the contract documents.

d.     Application Dates.

As specified in the contract documents.

 

D.    Overseeding and Fertilizing.

 

1.     Seedbed preparation will not be required, provided overseeding is applied when ground is friable from frost action after February 1 and before April 1 or as directed by the Engineer.

 

2.     When, in the opinion of the Engineer, a friable soil condition does not exist, roll with a cultipacker or harrow.

 

3.     Areas with rills or gullies require seedbed preparation according to Article 2601.03, B, 4, a.

 

4.     Apply fertilizer according to Article 2601.03, B, 4, b.

 

5.     Prepare seed according to Article 2601.03, B, 4, c.

 

6.     Apply seed according to Article 2601.03, B, 4, d unless specified otherwise in the contract documents.

 

7.     Overseeding will not be allowed on more than 1 inch of snow cover.

 

E.    Mulching.

Mulch seeding areas unless otherwise designated otherwise in the contract documents.  For disturbed areas that are mulched only, scarify area to a 3 inch depth prior to mulching.

 

1.     Time of Mulching.

Apply to areas requiring mulch as soon as seed is sown and final rolling completed.

 

2.     Application of Mulch.

a.     Straw Mulch.

1)    Distribute evenly and uniformly and anchor it into the soil. Use an application rate for reasonably dry material of approximately 1.5 tons per acre of dry cereal straw, native grass straw, or other approved material, depending on the type of material furnished.

2)    In all accessible mulched areas, anchor mulch into the soil using mulch anchoring equipment with a minimum of two passes. Operate equipment along the contour.  Use crawler type or dual wheel tractors for mulching operation. Operate equipment in a manner to minimize displacement of soil and disturbance of the design cross section.

b.     Hydraulic Mulches.

1)    Apply at no less than 3000 pounds per acre using standard hydraulic mulching equipment, unless specified otherwise in the contract documents.

2)    If using with hydraulic seeding, apply as a separate operation.

 

F.     Composting.

Compost may be used as a top dress application or as an incorporated soil amendment.

 

1.     Top dress applications may be used for urban seeding or on soils that are highly erosive or sloped soils to prevent surface or rill erosion and to provide organic material and nutrients needed for vegetative establishment. Ensure areas top dressed with compost have little or no drainage onto them.

 

2.     In highly erosive soils or sloped embankments with drainage onto the area, incorporate compost by mixing it into the top soil a minimum of 2 inches to prevent the compost from washing off the slope.

 

G.    Sodding.

 

1.     Refer to the contract documents for areas to be sodded. Engineer may designate other areas for sodding.

 

2.     Prior to shaping the sodbed, Engineer will define upon the ground the limits of areas to be sodded, and indicate the center lines of waterways. Cover the designated areas with live sod meeting requirements of Article 4169.06.

 

3.     Closely place and properly fit sod against structures and adjacent sod according to the following provisions:

a.     Preparation of Sodbed.

1)    Shape and prepare surfaces to be sodded. Ensure areas are firm and even surfaces. Ensure they are free of material 1.5 inches in diameter or greater including clods, rocks, and other debris. Ensure ditch channels, slopes, and flumes to be sodded have a typical cross section as shown in the contract documents.

2)    Construct ditch channel to secure a relatively level, flat bottom ditch cross section with a minimum depth of 6 inches, measured from the finished sodbed ground line at the edge of the ditch. Scarifying prior to shaping may be necessary to assure the minimum depth. A minimum sod ditch overall width of 7.5 feet (sloping sides) will be required.

3)    Use a soil compaction roller complying with Article 2601.03, A, for compaction and reshaping of ditches. Limit layers of fill materials to no more than 8 inches in depth.

4)    After the surface of the layer has been smoothed and before material for the next layer is deposited upon it, compact the layer:

·         With no less than one pass of a soil compaction roller per inch of loose thickness of the layer, and

·         Until the roller is supported entirely on its tamping feet.

5)    The roller will be considered entirely supported on its tamping feet when the tamping feet penetrate no more than 3 inches into an 8 inch layer being compacted. A single section roller may be necessary for this operation in some locations.

6)    Extend the compacted area approximately 6 inches to 12 inches beyond the width of the ditch.

7)    After compaction, shape the ditch.

b.     Fertilizer for Sod.

1)    Two applications are required (initial and prior to final acceptance). After sodbed preparation and prior to placing sod, fertilize the area to be sodded and the adjacent disturbed area at a rate of 10 pounds per 1000 square feet. Use a commercial fertilizer specified for the project.

2)    Place the final application of fertilizer at a rate of 10 pounds per 1000 square feet within 5 calendar days of the end of the 30 calendar day watering period and prior to final acceptance of the project. Place the final application when the grass is dry and with a dry form of fertilizer.

3)    For both of the above applications, if the type of fertilizer is not specified, apply 13-13-13 (or equivalent). Spread with a mechanical spreader which will secure a uniform rate of application. Manipulation or mixing with the soil, other than that incidental to Article 2601.03, G, 3, d, will not be required.

c.     Placing Sod.

1)    Do not place sod between May 31 and September 1, or on frozen ground unless otherwise directed by the Engineer.

2)    Place in rows or strips. On slopes, place strips transverse to the flow of water over the area. On sides and bottoms of ditches and channels, place strips at right angles to center line of channel. Place tightly against each other so that no open joints are apparent.

3)    Stagger joints at the ends of sod strips at least 1 foot on adjacent rows or strips of sod. Cut sod to be placed in road ditch channels, intercepting ditches, or sod flumes where the total sodded width is less than 7.5 feet into strips having lengths equal to the width of the sodded area. At the top of slope or at the edge of a channel, lay sod so water from adjacent areas will have free flow onto the sodded area. In road ditch channels and flumes, begin sodding at the outlet or lower end and progress upward. On slopes, begin sodding at the bottom and progress upward. If necessary to protect sod already laid, furnish (without extra compensation) ladders or planks for workers to use.

4)    The Engineer may order sod flumes, slopes, and ditch channels to be staked to minimize erosion loss before establishment. Stake sod as shown in the contract documents and as required by the Engineer.

d.     Finishing Sod.

1)    Firm the soil along the edge of the sodded area. Properly shape and smooth the adjacent disturbed area to allow surface water to flow into the sod ditch. Excessive soil placed over the edge of the sod will not be permitted.

2)    Prepare and seed the seedbed for all rural disturbed areas adjacent to the sod. Rake the seed in. Seed the disturbed area with the following seed mixture at the rate of 2 pounds per 1000 square feet:

Fescue, Fawn                       80%

Ryegrass, Perennial           20%

3)    For urban projects adjacent to sod, use the seed mixture specified for the project. Mulch disturbed area with grass, hay, or straw at the rate of 70 pounds per 1000 square feet.

4)    After sodding and seeding, water the sod, sodbed, and disturbed areas according to Article 2601.03, G, 3, e.

5)    When sod ditches are constructed after October 1, overseed grasses the following spring, between March 1 and April 1, when weather and soil conditions are favorable.

6)    When initial watering of the sod does not secure adequate bond between the sod and soil, the Engineer may require rolling. If sod is allowed to be placed between May 31 and August 10, and it is not to be staked, roll the sod using equipment approved by the Engineer. Remove from the project sod rejected from sod ditches. Remove from the site any other material not otherwise incorporated into the work.

7)    In urban areas, islands, and rest areas, roll the sod prior to or following the initial watering using a hand operated, lawn type roller approved by the Engineer.

e.     Watering Sod.

1)    Provide watering equipment and an approved water supply before beginning any sodding operation. Six waterings will be required.  Allow no more than 1 hour to elapse between laying and initial watering of sod.  Perform the second, third, and fourth waterings at 4 calendar day intervals, and fifth and sixth waterings at weekly intervals. Perform waterings unless notified by the Engineer in writing at least 1 calendar day prior to the day the watering is to occur. A price adjustment will be assessed at a rate of $200.00 per day for each calendar day that the Contractor fails to complete the watering from the day watering is to commence.

2)    Ensure waterings are sufficient to thoroughly saturate sod, sodbed, and adjacent disturbed areas to a depth of approximately 4 inches.

3)    Each watering may require a maximum of 100 gallons of water per square. Apply water as a spray or dispersion to prevent damage to the sod. Complete each watering within a 4 hour period. More than one application for each watering may be necessary to provide adequate saturation without runoff.

f.      Urban, Island, and Safety Rest Area Sodding.

1)    Prepare areas to be sodded, except ditch channels, according to Article 2601.03, C, 4, a.

2)    During the total watering period, mow sod once to a 3 inch height approximately 3 weeks after placement.

 

H.    Special Ditch Control, Turf Reinforcement Mat, Slope Protection, and Outlet or Channel Scour Protection (Transition Mat).

Use material meeting the requirements of Article 4169.10. Engineer will designate areas for each type of work.

 

1.     Preparation of Area to be Treated with Special Ditch Control, Turf Reinforcement Mat, Slope Protection, and Outlet or Channel Scour Protection (Transition Mat).

a.     Shape ditch channel in the same manner as preparing a ditch for sod as provided in Article 2601.03, G, 3, a.

b.     Apply provisions of Article 2601.03, B, 4, a. 

c.     Remove material 1.5 inches in diameter or greater, including clods, rocks, and other debris, which may prevent contact of the specified material with the seedbed.

d.     Coordinate preparation and placement of the specified material with the seedbed preparation, seeding (including sticking agent and inoculant), fertilizing, and mulching of the adjacent area of right-of-way.

 

2.     Special Ditch Control.

a.     Seeding.

1)  Prepare seed according to the provisions of Article 2601.03 B, 4, c.  Sow seed prior to placement of special ditch control material according to Article 2601.03 B, 4, d.

2)    Seed ditches and depressed medians using the following seeding rates in Tables 2601.03-7 and 2601.03-8:

 

b.     Fertilizing.

1)    After the area is prepared and prior to laying the special ditch control material, fertilize at the rate specified. Apply provisions of Article 2601.03, B, 4, b. Spread with a mechanical spreader to secure a uniform rate of application. Manipulation or mixing with the soil other than that incidental to Article 2601.03, H, 7, will not be required.

2)    If the type of fertilizer is not specified for the project, apply 300 pounds per acre of 6-24-24 (or equivalent) to Medians and Ditches - Outside Shoulder Adjacent to Rural Seedings (Table 2601.03-8).

3)    No fertilizer will be required for Ditches - Outside Shoulder Adjacent to Native Grass Seedings. 

c.     Application.

1)    Space check slots on ditch channels so one check slot occurs within each 50 foot increment on slopes of more than 4%.

2)    Apply special ditch control (wood excelsior mat) without tension and in the direction of the flow of water. Where more than one strip is required, lap the lap joint no less than 3 inches. Bury anchor slot on top edge of special ditch control (wood excelsior mat) from 6 inches to 12 inches, as designated by Engineer.

3)    On junction slots, bury the upslope end of each strip of wood excelsior mat 6 inches. Firmly tamp the soil. Overlap the ends of the special ditch control (wood excelsior mat) at least 12 inches and staple, with the upgrade section on top.

4)    Staple terminal end at bottom of special ditch control (wood excelsior mat).

5)    Use staples meeting requirements of Article 4169.10, A. Space staples as shown in the contract documents.

 

3.     Turf Reinforcement Mat (TRM).

a.     Seeding.

1)     Prepare seed according to provisions of 2601.03 B, 4, c. Sow after TRM and soil fill have been placed and prior to laying the special ditch control (wood excelsior mat) according to Article 2601.03 B, 4, d.

2)     Apply in ditches and depressed medians using rates in Tables 2601.03-7 and 2601.03-8.

b.     Fertilizing.

1)    After TRM and soil fill have been placed and prior to laying special ditch control (wood excelsior mat), apply at the rate specified. Apply provisions of Article 2601.03, B, 4, b. Spread  with a mechanical spreader to secure a uniform rate of application. Manipulation or mixing with the soil other than that incidental to Article 2601.03, H, 7, will not be required.

2)    If the type of fertilizer is not specified for the project, apply 300 pounds per acre of 6-24-24 (or equivalent) to Medians and Ditches - Outside Shoulder Adjacent to Rural Seedings (Table 2601.03-8).

3)    No fertilizer will be required for Ditches - Outside Shoulder Adjacent to Native Grass Seedings (Table 2601.03-7). 

c.     Application.

Place type specified on channel or slope after shaping. Apply according to the contract documents. Furnish and apply a minimum of 1 inch of soil suitable for the establishment of vegetation on the TRM. Furnish and apply seed and fertilizer. Furnish and apply special ditch control (wood excelsior mat) one soil fill.

 

4.     Special Ditch Control over Sod.

When shown in the contract documents, place plastic netting or other approved material over sod and staple it in place. Space staples 3 feet apart in the row. Space rows no more than 2 feet apart. Place staples alternately to adjacent rows. No junction slots or check slots are required. Anchor slots and terminal ends will be required.

 

5.     Slope Protection.

a.     Seeding.               

1)  Prepare seed according to Article 2601.03, B, 4, c. Sow prior to placement of slope protection according to Article 2601.03, B, 4, d. 

2)  Use mixture specified. Seed slopes using seeding rates in Tables 2601.03-7 for slopes adjacent to native grass seedings and 2601.03-8 for slopes adjacent to rural seedings. 

b.     Fertilizing.

For slope protection, use fertilizer specified. Apply provisions of Article 2601.03, B, 4, b.

1)    After area is prepared and prior to laying slope protection, fertilize at the rate specified. Apply provisions of Article 2601.03, B, 4, b. Spread with a mechanical spreader to secure a uniform rate of application. Manipulation or mixing with the soil other than that incidental to Article 2601.03, H, 7, will not be required.

2)    If the type of fertilizer is not specified, apply 300 pounds per acre of 6-24-24 (or equivalent) to slopes adjacent to rural seedings.

3)    No fertilizer will be required for slopes adjacent to native grass seedings.

 

c.     Application on Backslopes.

1)     Where erosive gullies or rills have developed in backslope, fill with soil and compact prior to placement of mat.

2)     Apply slope protection without tension in a perpendicular direction on backslopes. Where more than one strip is required, lap the lap joint no less than 3 inches.

3)     Bury the slope protection in an anchor slot on the top edge of the backslope from 6 inches to 12 inches, as designated by the Engineer.

4)     On junction slots, bury the upslope end of each strip of slope protection 6 inches. Firmly tamp soil. Overlap ends of slope protection at least 12 inches and staple, with upgrade section on top.

5)     Staple terminal end at bottom of slope protection.

6)     Use staples meeting requirements of Article 4169.10, A. Space staples as shown in the contract documents.

d.     Application on Foreslopes.

1)     If erosive gullies or rills have developed adjacent to shoulder material, fill with suitable soil and compact prior to placement of slope protection. 

2)     Apply slope protection without tension parallel to the roadway on foreslopes. Where more than one strip is required, butt strips together and staple 3 inches from each edge.

3)     Install staples 3 inches from upside terminal and downside terminal.

4)     Use staples meeting the requirements of Article 4169.10, A. Space remaining staples as shown in the contract documents.

 

6.     Outlet or Channel Scour Protection (Transition Mat) (TM).

a.     Seeding

1)     Prepare seed according to the provisions of 2601.03 B, 4, c. Sow prior to placement of TRM and TM according to Article 2601.03 B, 4, d.

2)     Seed outlets or channels using rates in Tables 2601.03-7 and 2601.03-8. 

b.     Fertilizing

1)    Prior to laying the TRM and TM, apply fertilize to the area at the rate specified. Apply provisions of Article 2601.03, B, 4, b. Spread with a mechanical spreader to secure a uniform rate of application. Manipulation or mixing with the soil other than that incidental to Article 2601.03, H, 7, will not be required.

2)    If type of fertilizer is not specified, apply 300 pounds per acre of 6-24-24 (or equivalent) to Medians and Outlets/Channels - Outside Shoulder Adjacent to Rural Seedings (Table 2601.03-8).

3)    No fertilizer will be required for Outlets/Channels – Outside Shoulder Adjacent to Native Grass Seedings (Table 2601.03-7). 

c.     Application

1)     Place TM in channels or outlets at locations specified in the contract document.

2)     Prior to the placement of the TM, place TRM - Type 2 according to Article 2601.03, H, 3 to extend the entire length and width of the TM.  No special ditch control (wood excelsior mat) or soil fill is required under the TM. Seed is placed under the TRM.

3)     Place TM panels in such a manner as to produce a planar surface.

4)     Place each TM panel longitudinally with the flow. Overlap panels upstream over downstream, and/or upslope over downslope.

5)     Secure each TM panel to the soil with bullet anchors driven 30 inches into the ground. Anchors should be driven through both panels at the edges with overlapping panels. A minimum of eight anchors per panel is required.

 

7.     Finishing Adjacent to Special Ditch Control, Turf Reinforcement Mat, Slope Protection Areas, and Outlet or Channel Scour Protection (Transition Mat).

For adjacent areas disturbed, uniformly shape, fertilize, seed, and rake in the seed in the same manner required for disturbed areas adjacent to sod ditches, except use the seed specified in Article 2601.03, H. Complete this work during the normal permanent seeding period or by the date specified to complete seeding.

 

8.     Watering of Special Ditch Control, Turf Reinforcement Mat, Slope Protection, and Outlet or Channel Scour Protection (Transition Mat).

a.     Provide watering equipment and an approved water supply before starting special ditch control, TRM, slope protection, or TM work. Water the area no later than the day following placement of the materials. If Contractor fails to water by second day following placement a price adjustment will be assessed at a rate of $200.00 per calendar day until the watering has been completed.

b.     Apply three additional waterings at intervals of 5 to 8 calendar days. Perform waterings unless notified by Engineer in writing at least 1 calendar day prior to the day watering is to occur. If Contractor fails to complete watering before the 8th calendar day has elapsed, a price, adjustment will be assessed at a rate of $200.00 per calendar day, beginning on the 9th day, until the watering is completed.

c.     Ensure waterings are sufficient to thoroughly saturate seedbed to a depth of approximately 2 inches.

d.     Each watering may require a maximum of 50 gallons of water per square. Apply water as a spray or dispersion to prevent damage to the seedbed. Complete each watering within a 4 hour period.

e.     More than one application for each watering may be necessary to provide adequate saturation without runoff.

 

I.      Mowing.

 

1.     Mowing may be required prior to permanent seeding and any time during the growing season following permanent seeding. Engineer will notify Contractor in writing prior to each mowing. Notification may be issued as early as 15 calendar days following execution of the contract. Contractor will be given 5 mowing days, plus 1 additional day for each 50 acre increment, that has been requested to be mowed. A mowing day is a calendar day, exclusive of Saturdays, Sundays, or recognized legal holiday, on which weather or other conditions (not under the control of the Contractor) will permit mowing operations to proceed for no less than 3/4 of a normal work day in the performance of a controlling item of work. When multiple projects are combined into a single contract, mowing days will be administered independently for each project. Mowing days will be charged starting on the day following the Contractor’s notification. A price adjustment will be assessed at a rate of $200.00 per mowing day after the work was to be completed.

 

2.     Use suitable equipment for mowing. Bunching or windrowing mowed vegetation will not be permitted. When wet soil conditions result in rutting, suspend mowing. Repair rutting damage at the direction of the Engineer at no additional expense to the Contracting Authority. Hand equipment will be required for areas inaccessible to other equipment. Set the cutting height at approximately 6 inches. More than one pass may be required for each mowing.

 

J.     Completion of the Work.

 

1.     Complete all phases of this work, excluding the 30 calendar day maintenance of sodded areas, within the specified construction schedule.

 

2.     If a fertilized or seeded area is damaged by rain prior to the required mulching, refertilize or reseed, or both, that area at a rate not to exceed the specified rate as designated by the Engineer. Perform this work at no additional cost to the Contracting Authority.

 

3.     When any work included in the contract is washed out or damaged prior to final acceptance of the project, the Engineer may order replacement of the damaged portion at contract unit prices. The Engineer will advise the Contractor of the approximate quantity of replacement required. Perform these repairs during the normal seeding period for the seed type. Maintain the work in a manner satisfactory to the Engineer.  Should the repair work not be done with reasonable promptness, payment for repair will be limited to the work described at the time of notification. 

 

4.     The Contractor is responsible for replacement in addition to the quantity directed by the Engineer to complete the work in an acceptable condition should the Contractor fail to:

·         Make this replacement when directed by the Engineer, or

·         Perform necessary maintenance to the area.

 

2601.04     Method of Measurement.

Measurement for the various items of work involving erosion control, satisfactory completed, will be as follows:

 

A.    Engineer will compute in acres to the nearest 0.1 acre the surface areas of

·         Seeding and Fertilizing,

·         Stabilizing Crop Seeding and Fertilizing,

·         Native Grass Seeding,

·         Wetland Grass Seeding,

·         Wildflower Seeding,

·         Seeding Special Areas,

·         Overseeding and Fertilizing,

·         Mulching, and

·         Composting.

 

B.    Surface areas of Sodding: squares of 100 square feet calculated from measurements to the nearest foot.

 

C.    Debris picked up and removed according to Article 2601.03, B, 4, a: cubic yards by cross sectional measurement or in the hauling units, at the option of the Engineer.

 

D.    Special Ditch Control, Turf Reinforcement Mat, and Slope Protection: squares of 100 square feet calculated from measurements to the nearest foot. Measurement of actual ditch area covered will be used, but will not exceed an area based on the actual measured length and design width. Materials used for anchor slots, junction slots, check slots, terminal folds, and lap joints are incidental.  Sseed, and fertilizer for Special Ditch Control and TRM are incidental.

 

E.    Outlet or Channel Scour Protection (Transition Mat):  square feet calculated from measurements to the nearest foot.

 

F.     Watering: by counting loads from a transporting tank of known volume or by metering.

 

G.    Mobilization for watering: by count. Mobilization for the initial watering required at installation of the plant material will not be measured for count.

 

H.    Mowing described in Article 2601.03, I: acres to the nearest 0.1 acre of surface area.

 

2601.05     Basis of Payment.

 

A.    Payment for the various items of work involved in erosion control will be made as described below.

 

1.     When suitable soil for filling holes, gullies, or washes is not available adjacent to the area to be filled or when soil must be removed, payment for necessary loading and hauling directed by the Engineer will be as extra work according to Article 1109.03, B.

 

2.     Contract unit price per acre to the nearest 0.1 acres for the following. Payment is full compensation for preparing the area and furnishing and applying each material.

·         Seeding and Fertilizing,

·         Stabilizing Crop Seeding and Fertilizing,

·         Native Grass Seeding,

·         Wetland Grass Seeding,

·         Wildflower Seeding,

·         Seeding Special Areas,

·         Overseeding and Fertilizing, and

·         Composting.

 

3.     For sowing special seed as directed by the Engineer, but not provided for in the contract documents: delivered cost of the seed plus 10% of the contract unit price for Seeding and Fertilizing.

 

4.     Sodding:

a.     Contract unit price per square.

b.     Payment is full compensation for:

·         Preparing the sodbed,

·         Furnishing, placing, and finishing the sod,

·         Fertilizing, and

·         Repair of adjacent areas disturbed by the sodding operation.

c.     Payment will not be allowed for the Sod until the watering, as specified, has been completed. Replace or repair, at the discretion of the Engineer, Sod areas which are damaged by weather or other causes before the specified initial watering has been completed, at no additional cost to the Contracting Authority.

 

5.     Squares of staking of sod flumes, slopes, and ditch channels: 25% of the contract unit price for Sodding in addition to payment for Sodding.

 

6.     Mulch furnished and placed: predetermined contract unit price per acre (hectare) contract unit price per acre to the nearest 0.1 acre for mulching. Payment is full compensation for preparing the area and furnishing and applying mulch.

 

7.     Debris picked up according to Article 2102.03, C, for grading work:

a.     Payment for debris pickup of additional boulders resulting from Stabilized Crop Seeding and Fertilizing will be as described in Article 2102.05 for Class 12 boulders. If there is no Class 12 item, payment will be at 10 times the contract unit price for Class 10 excavation.

b.     Payment for the number of cubic yards of debris picked up and removed in conjunction with other work will be paid at 25% of the contract unit price for Stabilizing Crop Seeding or Seeding and Fertilizing, as applicable.

 

8.     Squares of Special Ditch Control or Special Ditch Control over Sod with material as specified:

a.     Contract unit price per square.

b.     Payment is full compensation for the special ditch control preparation and materials. This includes seedbed preparation, seed and fertilizer, special ditch control (wood excelsior mat), stapling and installation of materials.

 

9.     Squares of Turf Reinforcement Mat of the type specified:

a.     Contract unit price per square.

b.     Payment is full compensation for the Turf Reinforcement Mat, preparation and materials including shaping channels, ditches and slopes, soil fill, seed and fertilizing, and special ditch control (wood excelsior mat).

 

10.  Squares of Slope Protection with material as specified:

a.     Contract unit price per square.

b.     Payment is full compensation for the slope protection preparation and materials in addition to the amount paid for seed and fertilizer. This includes seedbed preparation, seed and fertilizer, slope protection, stapling, and installation of materials.

 

11.  Square feet of Outlet or Channel Scour Protection (Transition Mat) with material as specified:

a.     Contract unit price per square feet.

b.     Payment is full compensation for Outlet or Channel Scour Protection (Transition Mat), TRM, preparation and materials including shaping outlets/channels, ditches, soil fill (if required), seed, fertilizer and anchors.

 

12.  When a large area is to be watered, the contract documents will include an item for watering. For the quantity of water applied to sod, Article 2601.03, G, 3, e, and to special ditch control, TRM, slope protection, and TM, Article 2601.03, H, 8, payment will be the predetermined contract unit price per 1000 gallons. When an item for watering is not included, the cost of watering is included in the amount paid for the item to be watered.

 

13.  Mobilization for watering: pre-determined unit price for each mobilization for required watering. Payment will not be made for mobilization for watering for projects identified as erosion control or landscaping. Payment will not be made for mobilization for watering if labor and equipment is already onsite.

 

14.  Mowing as described in Article 2601.03, I: contract unit price per acre to the nearest 0.1 acres.

 

B.    Payment for these items is full compensation for furnishing all materials, equipment, tools, and labor necessary to complete the work according to the contract documents.

 

C.    Payment will not be allowed for any area seeded until fertilizer and mulch are placed.