213Mulching

Mulching

Description

213.01This work consists of mulching the seeded areas, furnishing and placing wood chip

mulch in the planting beds and plant saucers, furnishing and applying hydromulch with tackifier on roadway ditches and slopes, furnishing and placing tackifier on mulch or soil on roadway ditches or slopes, and furnishing and installing metal landscape border for the separation of planting beds, per the Contract or as directed. Mulching may be accomplished by the crimping method using straw or hay, by the hydraulic method using wood cellulose fiber mulch, or by other approved methods with approved materials. When a specific mulching method is required, it will be designated in the Contract.

This work includes furnishing and applying spray-on mulch blanket or bonded fiber matrix on top of rock cuts and slopes after seeding or as temporary stabilization as shown on the plans or as directed by the Engineer.

Materials

213.02Materials shall conform to the following requirements

straw of oats, barley, wheat, rye, or triticale certified under the Colorado Department of Agriculture Weed Free Forage Certification Program and inspected as regulated by the Weed Free Forage Act, Title 35, Article 27.5, CRS. Each certified weed free mulch bale shall be identified by one of the following:

Forage Certification Program Number.

Mulch shall be inspected for and Regionally Certified as weed free based on the Regionally Designated Noxious Weed and Undesirable Plant List for Colorado, Wyoming, Montana, Nebraska, Utah, Idaho, Kansas, and South Dakota.

The Contractor shall not unload certified weed free mulch bales or remove their identifying twine, wire, or tags until the Engineer has inspected and accepted them.

The Contractor shall provide a transit certificate that has been filled out and signed by the grower and by the Department of Agriculture inspector.

The Contractor may obtain a current list of Colorado Weed Free Forage Crop Producers who have completed certification by contacting the Colorado Department of Agriculture, Division of Plant Industry.

Straw or hay mulch shall be a minimum of 10 inches in length. Straw or hay in a stage of decomposition (discolored, brittle, rotten, or moldy) or old, dry mulch that breaks in the crimping process will not be accepted.

The type and application rate of mulch material shall be as designated in the Contract.

213.02

fibers manufactured expressly from clean whole wood chips. The chips shall be processed in such a manner as to contain no growth or germination inhibiting factors. Fiber shall not be produced from recycled materials such as sawdust, paper, cardboard, or residue from pulp and paper plants. The wood cellulose fibers of the mulch must maintain uniform suspension in water under agitation. Upon application, the mulch material shall form a blotter like mat covering the ground. This mat shall have the characteristics of moisture absorption and percolation and shall cover and hold seed in contact with the soil. The Contractor shall obtain certifications from suppliers that laboratory and field testing of their product has been accomplished, and that it meets all of the foregoing requirements pertaining to wood cellulose fiber mulch.

The wood cellulose fiber mulch shall conform to the following requirements:

Table 213-1 Wood Cellulose Fiber Mulch Requirements Property Requirement Percent moisture content 10.0% ± 3.0% Percent Organic Matter* (Wood 99.3% ± 0.2% Cellulose Fiber) Percent Ash Content* 0.7% ± 0.2% pH 4.9 ± 0.5 Water Holding Capacity* 1200-1600 grams** Table 213-1 Notes: *Oven Dried Basis **Per 100 grams of fiber

The wood cellulose fiber mulch shall be packaged in units containing current labels, with the manufacturer’s name, the net weight, and certification that the material meets the foregoing requirements for wood cellulose fiber mulch.

powder produced either from the natural plant gum of Plantago Insularis (Desert Indianwheat) or pre-gelatinized 100 percent natural corn starch polymer. The powders shall possess the following properties:

Table 213-2 Properties Of Plantago Insularis (Desert Indianwheat)

Property Requirement pH 1% solution 6.5 - 8.0

213.02

Table 213-3 Properties of Pre-Gelatinized 100 Percent Natural Corn Starch Polymer

Property Requirement Organic Nitrogen as 5.5-7% protein Ash content 0-2% Fiber 4-5% pH 1% solution 6.5 – 8.0 Size 100% thru 850 microns (20 mesh) Settleable solids <2%

All fibers shall be colored green or yellow with a biodegradable dye.

The material used for mulch tackifier shall not contain any mineral filler, recycled cellulose fiber, clays, or other substances that may inhibit germination or growth of plants. Water shall conform to subsection 209.02.

having approximate dimensions; Width: 1/4 to 1/2 inch; Length: 3 to 4 inches. The Contractor shall submit a sample to the Engineer for approval at least 30 days before placing on the project.

steel conforming to ASTM A1011 or approved equal.

otherwise shown on the plans:

following:

213.02

Table 213-4 Properties of Mulch Blanket (Type 1)

Properties Requirement Test Method Organic Fibers 71% Min. ASTM D2974 Cross Linked Mulch 10% ± 2% Min. Tackifiers Reinforcing Fibers 2.5% Min. Biodegradability 100% ASTM D5338 Ground Cover at 90% Min. ASTM D6567 Application Rate Functional Longevity 12 Months Min. Cure Time < 8 hours Application Application Rate 3000 lb/acre

The organic fiber shall not contain lead paint, printing ink, varnish, petroleum products, seed germination inhibitors, or chlorine bleach. The organic fibers and reinforcing interlocking fibers cannot be produced from sawdust, cardboard, paper, or paper by-products.

in 50-pound bags containing both a soil and fiber stabilizing compound and thermally processed wood fiber. The wood fiber mulch shall be manufactured through a thermo-mechanical defibrating process containing a specific range of fiber lengths averaging 0.25 inches or longer.

213.02

Mulch Blanket (Type 2) shall meet the following requirements: Table 213-5 Properties of Mulch Blanket (Type 2) Property Requirement Test Method Fiber Retention On 28- ≥ 40% Tyler Ro-Tap Mesh Screen Method Moisture Content 12% ± 2% Total Air Dry Weight Basis Organic Matter 99.2% ± 0.2% Oven Dry Weight Basis Ash Content 0.8% ± 0.2% Oven Dry Weight Basis pH at 3% Consistency In 4.5-7.0 ± Water 0.5% Sterilized Weed-Free Yes Non-Toxic To Plant or Yes Animal Life Application Application rate 3,000 lb./acre

The soil and fiber stabilizing compound shall be composed of linear anionic copolymers of acrylamide pre-packed within the bag having a minimum content of 1.0 percent. The compound shall conform to the following:

Table 213-6 Soil and Fiber Stabilizing Compound Properties

Property Requirement Molecular Weight ≥ 12x106 Charge Density > 25% Non-Toxic To Plant or Yes Animal Life

minimum of 70 percent non-toxic thermally processed or refined long strand organic fibers and water soluble tackifier to provide erosion control and shall be designed to be functional for a minimum of 9 months. BFMs form an erosion-resistant blanket that promotes vegetation and prevents soil erosion. The BFM shall be 100 percent biodegradable. The binder in the BFM shall also be biodegradable. BFMs shall conform to the following requirements:

213.03

Table 213-7 Bonded Fiber Matrices Properties Property Requirement Test Method Ground Cover (%) 95 ASTM D6567 Biodegradability (%) 100 ASTM D5338 functional Longevity (months) 9 months minimum Cure Time (hours) 24-48 Cross-linked Tackifier 10% minimum Application Application Rate (lbs./Acre) 3000

The fibers shall not contain lead paint, printing ink, varnish, petroleum products, seed germination inhibitors, or chlorine bleach. Fiber shall not be produced from sawdust, cardboard, paper, or paper by-products.

Construction Requirements 213.03

control, hay or straw shall be uniformly applied, at a minimum rate of 2 tons hay or 2.5 tons straw per acre with no bare soil showing, at the rate designated in the Contract or as directed. It shall be crimped to a depth of 2 to 3 inches with a crimper or other approved equipment. The Engineer may order hand-crimping on areas where mechanical methods cannot be used. The seeded area shall be mulched and crimped, and tackifier applied at a rate in Subsection (c) within four hours after seeding. Areas not mulched and crimped within four hours after seeding or before precipitation or damaging winds on site shall be reseeded with the specified seed mix at the Contractor’s expense, before mulching and crimping. The seeded area shall be mulched and crimped within four hours after seeding. Areas not mulched and crimped within four hours after seeding or before precipitation or damaging winds on site shall be reseeded with the specified seed mix at the Contractor's expense, before mulching and crimping.

When tackifier is required in the Contract it shall be applied in the following order: (1) mulching, (2) mulch tackifier.

water to form a homogeneous slurry. The operator shall spray apply the slurry mixture uniformly over the designated seeded area.

Hydraulic mulching shall not be done in the presence of free surface water.

213.03

Mixing procedure for the hydraulic mulch and tackifier mixture shall be as follows:

Do not add fertilizer. Apply the hydromulch and tackifier mixture at the following rate:

Wood Cellulose Fiber Mulch Tackifier 2,000 lb/acre 100 lb/acre

not add fertilizer.

minutes. Mulch tackifier shall be sprayed over hay or straw using a nozzle that will disperse the spray into a mist that will uniformly cover the mulch.

Application Rate: Apply this as an overspray at the following rate or as approved by the Engineer.

Mulch Tackifier Powder Wood Cellulose Fiber Water 200 lb/acre 300 lb/acre 2,000 gal acre

and crimping to avoid nonuniform coverage. Areas not properly mulched, or areas damaged due to the Contractor's negligence, shall be repaired and remulched as described above, at the Contractor's expense. Mulch removed by circumstances beyond the Contractor's control shall be repaired and remulched as ordered. Payment for this ordered corrective work shall be at the contract prices.

The Engineer may order test sections be established for adjusting the mulching equipment to assure conformance with the specified application rate. The Engineer may order equipment readjustment at any time.

shall be uniformly applied to all planting beds as shown on the plans or as directed. Wood chip mulch shall be placed in all tree and shrub saucers in seeded areas. Wood chip mulch shall be capable of matting together to resist scattering by the wind.

213.03

the grades shown on the plans by an approved method that will not damage the border. Ends of metal landscape border shall overlap the next adjacent section a minimum of 6 inches. Metal landscape border shall be anchored with wire tie-downs at intervals of approximately 2 feet. Wire tie-downs shall be 9-gauge wire at least 14 inches long. Metal landscape border shall be inserted into the ground by driving against the wire tiedowns; ground may be moistened to ease entrance into the ground. Driving on edge of metal landscape border will not be permitted except when the edge is properly shielded. Metal landscape border may be bent for sharp angles and overlapped at closure of perimeter.

the Manufacturer’s mixing recommendations and installation instructions. No chemical additives with the exception of fertilizer, soil pH modifiers, extended-term dyes and bio nutrients will be permitted. The spray-on mulch blanket shall be mixed and applied as follows: The hydromulching vessel shall be filled with water to at least 1/3 capacity (high enough to cover agitators) before adding any material. Continue to fill vessel with water and slowly add the fibers while agitators are in motion. Run agitators at 3/4 speed. Continue to mix tank a minimum of 10 minutes before application.

Apply spray-on mulch blanket in a uniform application using a minimum 22-degree arc type nozzle. Apply hydro slurry in two directions (from top of slope down and from toe of the slope up, as well as, be applied at a minimum of two layers).

Co-polymer shall not be used use in channels, swales, or other areas where concentrated flows are anticipated and should not be used on saturated soils that have groundwater seeps.

Manufacturer’s mixing recommendations and installation instructions. No chemical additives with the exception of fertilizer, soil pH modifiers, extended-term dyes, and bio stimulant materials shall be permitted. BFMs shall be applied in a uniform application using a minimum 22-degree arc type nozzle. BFMs shall be applied in two directions (from top of slope down and from toe of the slope up, as well as, be applied at a minimum of two layers. Biodegradable BFMs shall not be applied immediately before, during, or immediately after rainfall if the soil is saturated.

BFMs shall not be used use in channels, swales, or other areas where concentrated flows are anticipated and shall not be used on saturated soils that have groundwater seeps.

Foot traffic, mechanical traffic or grazing shall not be permitted on treated areas until vegetated. Treated areas damaged due to circumstances beyond the Contractor’s control shall be repaired or re-applied as ordered. Payment for corrective work, when ordered, shall be at contract unit prices.

213.04

Method of Measurement

213.04The quantity of hay and straw mulch, wood chip mulch, wood fiber and, spray-on mulch

blanket, bonded fiber matrix, and tackifier will not be measured but shall be the quantity designated in the Contract, except that measurements will be made for revisions requested by the Engineer, or for discrepancies of plus or minus five percent of the total quantity designated in the Contract. Measurement for acres will be by slope distances.

The quantity of mulch tackifier to be measured will be the actual number of pounds of dry tackifier powder used.

Metal landscape border will be measured by the linear foot of completed and accepted metal border. Measured length of metal landscape border will not include required overlap splices.

Spray-on mulch blanket and bonded fiber matrix will be measured by the acre or by the actual pounds of product applied, as shown on the plans. The area will be calculated on the basis of actual or computed slope measurements. The Contractor shall verify, before application, weight of spray on mulch blanket and bonded fiber matrix bags for certification of materials and application rate.

Basis of Payment

213.05The accepted quantities will be paid for at the contract unit price for each of the pay

items listed below that appear in the bid schedule. Payment will be made under: Pay Item Pay Unit Mulching ( ) Acre Mulching (Hydraulic) Acre Mulching (Weed Free Hay) Acre Mulching (Weed Free Straw) Acre Mulching (Wood Chip) Cubic Foot Mulch Tackifier Pound Metal Landscape Border Linear Foot Spray-on Mulch Blanket Acre Spray-on Mulch Blanket Pound Bonded Fiber Matrix Acre Bonded Fiber Matrix Pound

Water, wood fiber, mixing and application for mulch tackifier will not be measured and paid for separately but shall be included in the work.

Adjusting or readjusting mulching equipment will not be paid for separately but shall be included in the work.

Payment for spray–on mulch blanket and bonded fiber matrix will be full compensation for all work and materials necessary to complete the item.

213.05

This Page Intentionally Left Blank

214.01