DelDOT Section 908: Soil Stabilization Practices

908.1Description.

This work consists of soil stabilization practices using perennial grasses, topsoil, topsoiling, and mulching.

908.2Materials.

A.Topsoil

1.Friable loam soil of uniform quality and free from heavy clay, frozen clods, lumps exceeding 2

inches in diameter and materials harmful to plant growth.

2.Void of Johnsongrass (Sorghum halepense), Canada Thistle (Cirsium arvense), Burcucumber

(Sicyos angulatus), Giant Ragweed (Ambrosia trifida), and Texas Amaranth (Amaranthus palmeri).

3.Determine and incorporate the type and amount of soil amendments, supplements, and process

needed to establish permanent vegetation.

B.Topsoiling

1.This material consists of the existing project soils designated for stripping, salvaging, and

temporarily stockpiling for later use in accordance with Section 202.

2.Void of Johnsongrass (Sorghum halepense), Canada Thistle (Cirsium arvense), Burcucumber

(Sicyos angulatus), Giant Ragweed (Ambrosia trifida), and Texas Amaranth (Amaranthus palmeri).

3.Determine and incorporate the type and amount of soil amendments, supplements, and process

needed to establish permanent vegetation.

C.Seeding

1.Use water meeting the requirements of Section 1021.

2.Grass and Agricultural Seeds.

a.Use seeds conforming to 3 Del. C. 1953, §1501.

i.For blended seed in bags, display a seed tag attached to the bag.

ii. For project mixed seed of special seed formulas or mixtures not specified in Tables 908.2-1 through 908.2-3 and Table 908.2-5, use seed previously inspected, tested, and approved by the Delaware Department of Agriculture for the designated purity, germination, weed seed limits, and pure live seed analysis. iii. Provide seed void of Johnsongrass (Sorghum halepense), Canada Thistle (Cirsium arvense), Burcucumber (Sicyos angulatus), Giant Ragweed (Ambrosia trifida), and Texas Amaranth (Amaranthus palmeri).

b.Use the following seeding tables:

i.Table 908.2-1 - Permanent Grass Seeding - Dry Ground (PGS-DG)

ii. Table 908.2-2 - Grass Seeding - Stormwater Facility (GS-SF)

iii. Table 908.2-3 - Permanent Grass Seeding - Subdivision Mix (PGS-SUB) iv. Table 908.2-4 - Temporary Grass Seeding (TGS)

v.Table 908.2-5 - Permanent Grass Seeding - Streambank (PGS-SB)

iv. Table 908.2-6 – Temporary Grass Seeding – Wetlands (TGS-W) Table 908.2-1 - Permanent Grass Seeding - Dry Ground (PGS-DG) Species %Weed1 % Purity % Germination Lbs./Ac. Seeding Dates Hard Fescue Mixture (Festuca longifolia and Festuca trachyphylla) 0.15 98 85 100 Creeping Red Fescue (Festuca rubra L) 0.15 98 85 85 Redtop (Agrostis alba) 0.75 95 90 40 Trifolium repens L. var. “White Clover”4 0.10 75 80 5 Total Perennial Seed Quantity2 (lbs/Ac.) 230 Winter Cereal Rye (Secale cereale) 0.75 98 85 20 1 Nov – 15 Feb Annual Ryegrass (Lolium multiflorum) 0.15 95 90 10 Feb – 30 Apr 1 Aug – 31 Oct Foxtail Millet (Setaria italica) 0.5 95 95 20 1 May – 31 July

Table 908.2-2 - Grass Seeding - Stormwater Facility (GS-SF) Species %Weed1 % Purity % Germination Lbs./ Ac. Seeding Dates Redtop (Agrostis alba) 0.15 95 90 30 Indian Grass (Sorghastrum nutans) 1.00 85 75 20 Deertongue (Dichanthelium clandestinum) 1.00 95 60 20 Switchgrass (Panicum virgatum) 1.00 95 70 40 Tickseed Sunflower (Bidens aristosa) 0.09 98 91 10 Black-Eyed Susan (Rudbeckia hirta) 0.00 99 97 10 Partridge Pea (Chamaecrista fasciculata) 0.22 99 93 10 Yellow Blossom Sweetclover (Melilotus officinalis) 0.10 99 92 10 Total Perennial Seed Quantity2 (lbs/Ac.) 150 Winter Cereal Rye (Secale cereale) 0.75 98 85 50 1 Nov – 15 Feb

Annual Oats (Avena sativa) 0.15 95 90 40 16 Feb – 30 Apr 1 Aug – 31 Oct Foxtail Millet (Setaria italica) 0.5 95 95 40 1 May – 31 July

Table 908.2-3 - Permanent Grass Seeding - Subdivision Mix (PGS-SUB) Species %Weed1 % Purity % Germination Lbs./Ac. Seeding Dates Turf-type Tall Fescue Cultivar3 (Festuca arundinacea var) 0.5 98 90 200 Perennial Ryegrass (Lolium perenne) 0.4 90 90 20 Kentucky Bluegrass (Poa pratensis) 0.4 90 80 30 Redtop (Agrostis alba) 0.75 95 90 40 Trifolium repens L. var. “White Clover”4 0.10 75 85 5 Annual Ryegrass (Lolium multiflorum) 0.15 95 90 20 Total Seed Quantity (lbs/Ac.) 315

Table 908.2-4 - Temporary Grass Seeding (TGS) Species %Weed1 % Purity % Germination Lbs./Ac. Seeding Dates Winter Cereal Rye (Secale cereal) 0.75 98 85 50 1 Nov – 15 Feb Annual Ryegrass (Lolium multiflorum) 0.15 95 90 40 16 Feb – 30 Apr 1 Aug – 31 Oct Foxtail Millet (Setaria italic) 0.5 95 95 40 1 May – 31 July

Table 908.2-5 - Permanent Grass Seeding - Streambank (PGS-SB)

Species %Weed1 % Purity % Germination Lbs./Ac. Seeding Dates Tall Fescue KY 31 (Festuca arundinacea) 0.5 98 90 180 Perennial Ryegrass (Lolium perenne) 0.4 90 90 20 Redtop (Agrostis alba) 0.75 95 90 20 Annual Ryegrass (Lolium multiflorum) 0.15 98 90 10 Total Seed Quantity (lbs/Ac.) 230

Table 908.2-6 – Temporary Grass Seeding – Wetlands (TGS-W) Species %Weed1 % Purity % Germination Lbs./Ac. Seeding Dates Redtop (Agrostis alba) 0.75 95 90 40 Deertongue (Dichanthelium clandestinum) 1 95 60 20 Switchgrass (Panicum virgatum) 1 95 70 40

1 Title 3 Delaware Code, Chapter 15, Seeds and its associated regulations identify several species of seed designated as Noxious Weeds by the Delaware Department of Agriculture. The Department will not allow these seeds in the allowable percentage of weed seeds. 2 Add the applicable quantity of seasonal nurse crop as listed according to the seeding date. 3 Base selection of Turf-type Tall Fescue Cultivars on performance within the Mid-Atlantic region as determined by the most current National Turfgrass Evaluation Program Progress Report. 4 Trifolium repens L. var. “White Clover” requires inoculation by Rhizobium leguminsarum biovar trifoli before seeding, unless purchased as pre-treated.

D.Erosion Control Blanket

1.Select from Rolled Erosion Control Products from the Approved Products List

(https://deldot.gov/Business/index.shtml#). The Department will not accept photodegradable products.

E.Turf Reinforcement Mat

1.Select from Rolled Erosion Control Products from the Approved Products List

(https://deldot.gov/Business/index.shtml#). The Department will not accept photodegradable products.

F.Erosion Control Mulch

1.Use hydraulic mulches when the manufacturer pre-packages all components. The Department

will not accept field mixing of hydraulic mulch additives or hydraulic mulch components. The Department will not accept paper or paper blend mulches.

2.Provide straw mulch consisting of unrotted small grain straw free of weeds.

G.Stabilized Construction Entrance

1.Seed Section 908

2.Stone, Delaware No. 3 Section 1004

3.Geotextile Section 1060

908.3Construction.

A.Handle temporary stockpiled materials as follows.

1.Store stockpiled material within the LOC and maintain a minimum of 50-feet away from

streams, open channels, drainage inlets, and wetlands.

2.When stockpiling material outside of the LOC, do so in accordance with the contract and provide

an approved Erosion & Sediment Control plan. Stabilize the work in the time specified in accordance with Section 908.3.B.

3.Install erosion and sediment control items in accordance with the contract and as directed by

the engineer around the base of the pile in advance of the actual stockpiling operation in the time specified in accordance with Section 908.3.B. Place erodible earth material in neat piles. The engineer will decide the pile height requirement within the operational right of way. Do not exceed a height of 20-feet for piles not within the operational right of way. Seed and mulch all erodible temporary stockpile surfaces in accordance with the temporary or final stabilization requirements of this section.

B.Temporary and Final Stabilization

1.Temporary Stabilization consists of operations required for complete temporary stabilization as

determined by the engineer.

2.Final Stabilization is complete vegetation growth consisting of perennial grasses reaching a

height of 3-inches and 70 percent uniform density over all seeded areas.

3.Stabilize all erodible earth material exposed by the work within the time frames specified below:

Table 908.3-1 Stabilization of Erodible Earth and Maximum Allowable Time to Stabilize Location Type of Stabilization Maximum Time to Stabilize Sediment Controls Temporary Stabilization 7 calendar days from completion of construction of BMP devices such as ditches, sediment traps, or dewatering basins.

Location Type of Stabilization Maximum Time to Stabilize Short term inactivity not meeting final grade and not to exceed 6 months Temporary Stabilization 14 calendar days from the end of ground disturbing work in the location. Areas meeting final grades or areas that will be inactive longer than 6 (6) months Final Stabilization 7 calendar days from the end of ground disturbing work in the location.

C.Slope Tracking

Track a cleated piece of equipment, such as a bulldozer, up and down the slopes so the cleats make horizontal indentations in the soil. Upon request from the contractor, the engineer may approve a different tracking pattern.

D.Points of Ingress and Egress

Construct, maintain, and remove stabilized pads of aggregate on a geotextile base at every exit from the construction site to prevent tracking dirt off-site.

E.Topsoil Construction

1.In areas where topsoil stripping is to occur, clear all brush, sticks, weeds, stones, bricks, ashes,

and other refuse that may hinder or prevent growth of future plant materials in areas that call for topsoil placement.

2.Do not place frozen topsoil or place topsoil on frozen grade. Remove clods and lumps larger

than 2 inches in diameter.

3.Determine and incorporate the type and amount of soil amendments, supplements, and process

needed to create the proper conditions for acceptance of permanent vegetation.

4.Loosen topsoil 3-inches deep within 72-hours before seeding.

5.Maintain topsoil until project acceptance.

F.Topsoiling

1.Place topsoil in accordance with Section 908.3.E.

2.Maintain topsoil in accordance with Section 908.3.E.

G.Seeding

1.The engineer will document the seed bag tags before seeding. Use seed mixes in accordance

with Section 908.2.C.2 or as indicated in the contract.

2.Keep seeded areas free from debris, and weeds in accordance with Section 105.13.

H.Erosion Control and Mulching Products

1.Submit product information and manufacturer’s recommendations for product placement to

the engineer no less than 2 working days before placement.

2.Place channel stabilization the same day of seeding operation. All other placement may occur

within 1-week or before the next rain event.

3.Maintain all erosion control products in accordance with the contract and the manufactures

recommendations.

4.Mulches

a.Spray hydraulic mulches in accordance with the manufacturer’s recommendations.

b.Straw Mulch

Spread straw mulch at a rate of 2-tons-per-acre. Immediately after placing the straw mulch, anchor mulch by crimping, tracking, liquid mulch binder, paper fiber, or netting. Apply liquid binder at the manufacturer’s application rate. Use 100 percent biodegradable netting secured so that the straw mulch does not move. Do not use plastic netting.

c.100 percent soil coverage at the conclusion of the operation.

5.Erosion Control Blanket

Place erosion control blankets in accordance with the manufacturer’s recommendation.

6.Turf Reinforcement Mat

Place turf reinforcement mat in accordance with the manufacturer’s recommendation.

I.Stabilized Construction Entrance

1.Construct stabilized construction entrances in accordance with the contract.

2.Obtain the engineer’s approval before adding to, deleting from, or changing the stabilized

construction entrance location.

3.When the contract requires pipe underneath the stabilized construction entrance, place the

pipe and grade to drain. Place the pipe before placing geotextile or stone. Excavate to the dimensions shown in the Standard Construction Details. Compact the subgrade, place geotextile on the compacted subgrade, and place the stone on top of the geotextile to the required depth.

4.Stabilize the entire width of each ingress and egress location. The engineer may direct the

Contractor to widen the entrance as required to prevent the entrance location from becoming a source of sediment.

5.Stabilized Construction Entrance Maintenance.

a.Ensure that all paved surfaces adjoining the project limits are free of dirt at the end of each

day.

b.After heavy use and after each rain, inspect the stabilized construction entrance to ensure

proper functioning. When the stone voids become filled with dirt, rake the surface to reestablish the voids.

J.Stabilized Construction Entrance, Top Dressing

Remove and replace the top 2-inches of stone with 2-inches of clean Delaware No. 3 stone when voids are filled, or as directed by the engineer.

K.Removing Stabilized Construction Entrance.

When the stabilized construction entrance is no longer needed for project access, or when directed by the engineer, remove all stabilized construction entrance materials. Restore to grade and stabilize the restored areas.

908.4Method of Measurement.

A.The Department will measure the quantity of soil stabilization work acceptably completed as

follows:

1.Topsoil by the square yard or ton.

2.Topsoiling by the square yard or ton.

3.Mulching by the square yard.

4.Seeding by the square yard.

5.The Department will measure Erosion Control Blankets (ECB) and Turf Reinforcement Matting

(TRM)by the square yard.

6.Stabilized construction entrance by the square yard.

7.Stone used for the topdressing by the ton.

8.Drainage pipe by the linear foot.

908.5Basis of Payment.

A.The Department will make no payment for the installation of erosion and sediment controls or

stabilization required by other agencies having jurisdiction on stockpiles located outside the areas designated in the contract.

B.The Department will pay the quantity of topsoil at the contract unit price per square yard or ton.

Price and payment constitute full compensation for:

1.Preparing the grade;

2.providing, hauling, and placing all materials;

3.maintaining topsoil;

4.loosening the topsoil; and

5.soil amendments and supplements.

C.The Department will pay the quantity of topsoiling at the contract unit price per square yard or

ton. Price and payment constitute full compensation for:

1.Preparing the grade;

2.hauling and placing all topsoil salvaged in accordance with Section 202;

3.maintaining topsoil;

4.loosening the topsoil; and

5.soil amendments and supplements.

D.The Department will pay the quantity and type of seeding at the contract unit price per square

yard. Price constitutes full compensation for preparing the ground and for providing and placing all materials.

E.The Department will pay for the seeding in accordance with the payment schedule described in

Table 908.5-1 as follows: Table 908.5-1. Payment Schedule

Seed Type Permanent Seed Permanent Seed Temporary Seed Completed Work at the time seed is acceptably placed production of a uniform stand of established perennial grass species having attained a height of 3 inches with a density of 70% of the seeded area for acceptance by the engineer. at the time seed is acceptably placed Percent of Total Item Price 100% 0% 100%

F.The Department will pay the quantity of erosion control and mulching product at the contract unit

price per square yard. Price and payment constitute full compensation for providing and placing all materials. Should the contractor elect to use multiple products from the approved product list, the unit price will apply to all products listed under the corresponding item description on the DelDOT approved product list.

G.The Department will pay the quantity of stabilized construction entrance at the contract unit price

per square yard. Price and payment constitute full compensation for:

1.Preparing, providing and placing all material except the stone and drainage pipe;

2.maintaining the stabilized construction entrance during the project, excluding placing additional

stone for topdressing;

3.for removing the stabilized construction entrance and topdressing; and

4.for restoring the site.

5.The Department will pay the quantity of stone in accordance with Section 302.

6.The Department will pay the quantity of drainage pipe in accordance with Section 601.

H.The Department will pay the quantity of stabilized construction entrance topdressing at the

contract unit price per ton of stone. Price and Payment constitutes full compensation for:

1.Remove and disposal of existing materials;

2.providing and placing all material; and

3.maintaining the topdressing of the stabilized construction entrance during the project

construction period.

I.The Department will consider costs associated with slope tracking as incidental to Section 202 and

slope tracking costs for preparing a seedbed as incidental to the topsoil Item.

J.The Department will consider soil amendments, supplements, and process as incidental to the

seeding item when purchased pre-treated. 908.5.1 Maintenance Bond.

A.Provide a maintenance bond for the appropriate seeding Items upon substantial completion of

the work. Provide a maintenance bond that meets the following requirements:

1.Equals 100 percent of the value of all permanent grass seeding Items paid to the contractor;

2.contains original ink signatures, not mechanical reproductions or facsimiles;

3.names the contractor as the principal;

4.with a term of 1 full year beyond the completion of permanent seeding work; and

5.written by a surety or insurance company in good standing and licensed by the Delaware

Department of Insurance to write surety bonds in the State of Delaware. ITEM DESCRIPTION UNIT 908001 TOPSOIL TON 908002 TOPSOIL SY 908003 TOPSOIL, 4” DEPTH SY 908004 TOPSOIL, 6” DEPTH SY 908005 TOPSOIL, 12” DEPTH SY 908006 TOPSOILING TON 908007 TOPSOILING SY 908008 TOPSOILING, 2” DEPTH SY 908009 TOPSOILING, 4” DEPTH SY 908010 TOPSOILING, 6” DEPTH SY 908011 TOPSOILING, 8” DEPTH SY 908012 TOPSOILING, 12” DEPTH SY 908013 TOPSOILING, 18” DEPTH SY 908014 PERMANENT GRASS SEEDING, DRY GROUND SY 908015 PERMANENT GRASS SEEDING, STORMWATER SY 908016 PERMANENT GRASS SEEDING, SUBDIVISION SY 908017 TEMPORARY GRASS SEEDING SY 908019 PERMANENT GRASS SEEDING, STREAMBANK SY 908020 EROSION CONTROL BLANKET MULCH SY 908021 TURF REINFORCEMENT MATTING, TYPE 1 SY 908022 TURF REINFORCEMENT MATTING, TYPE 2 SY 908023 STABILIZED CONSTRUCTION ENTRANCE SY 908024 STABILIZED CONSTRUCTION ENTRANCE, TOP DRESSING TON 908026 EROSION CONTROL MULCH SY

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Source: Delaware Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 606–0 of 786. View official source ↗

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907 WATER CONTROL PRACTICES

909 WATERWAY CONSTRUCTION PRACTICES

908SOIL STABILIZATION PRACTICES

Ask about Section 908

908.1Description.

908.2Materials.

908.3Construction.

908.4Method of Measurement.

908.5Basis of Payment.

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