- 673 - SECTION 806 -- MULCHING
806.01 Description
1.This work consists of provid ing, placing, and securing mulch on areas shown in the contract or identif ied by the Engineer as being seeded in accordance with Section 801.
806.02 Material Requirements
1.Mulch shall be either dry cured native prairie hay, native grass hay from seed growing operations, native grass hay from planted warm season grass stands, or straw. Brome hay, rushes, cattails, Reed Canary Grass, wide-bladed grass or invasive species are not allowed.
2.Hay or straw in a stage of decomposition so advanced as to "powder" in the mulch blower will be rejected.
3.The Contractor shall notify the Engineer as to where he/she proposes to obtain the hay.
4.Straw shall be from threshed oats, wheat, or rye. Rye straw shall not be used in any wheat growing area. The straw shall be baled before the seasonal growth of annual weeds.
5.Certification and Scale Tickets:
a.The mulch shall be certifie d as "Noxious Weed Free" by the "County Weed Control Authority" or other authorized agents.
b.Scale Tickets:
1.All mulch deliveries shall have scale tickets from a certified scale.
2.The Contractor shall give the Engineer a scale ticket for each load of mulch delivered to the site before the mulch is unloaded for use on the project. The scale tickets shall indicate the weight and be dated and signed by the scale operator.
3.The Engineer may, at any time, order the Contractor to reweigh the mulch as a check of the scale ticket.
c.The copy of the “Noxious Weed Free” certification and the scale ticket shall accompany each load of mulch.
1.Upon delivery to the site, a copy of the certification shall be placed in a weather-proof container a nd attached to the load of mulch it represents.
2.Prior to incorporation of the mulch, the Engineer will collect the copy of the ce rtification from the load.
806.03 Construction Methods
1.The Contractor shall apply th e mulch within 24 hours after planting the seed, unless otherwise directed by the Engineer. The mulch shall be applied uniformly over tilled areas with a mulch blowing machine.
2.Application Rates: a. Hay mulch shall be appli ed at the rate of 2 tons/acre (4.5 Mg/ha) when used in conjunction with the permanent seed mixture.
b.Straw mulch shall be applied at 2.25 tons/acre (5 Mg/ha) when used in conjunction with the permanent seed mixture.
806.03 Mulching
- 674 - c. Mulch may be applied as a tem porary cover, either alone or in conjunction with cover crop or a temporary seed mixture and shall be applied at a rate of 1.0 tons/acre (3.35 Mg/ha).
3.The mulch shall be applied loose enough to allow some sunlight to penetrate and air to slowly circulate, but thick enough to partially shade the ground, reduce water evaporation, and reduce wind and water erosion.
4.Securing:
a.Immediately after applying t he mulch, the Contractor shall secure it to the soil using a mulch crimper with approximately 6 inch (150 mm) cleats or other approved equipment with perpendicular, dull, disc blades.
b.All mulch shall be crimped the same day it is applied. c. The crimper shall be narrow enough or hinged to uniformly crimp the mulch into narrow and uneven areas. More than one crimping may be necessary if directed by the Engineer.
d.Proper installation will result in the mulch being a uniform cover with fibers being securely lodged within the soil.
806.04 Method of Measurement
1.The weight of the mulch is measured in tons (Megagrams).
2.The weight of the mulch requir ed is calculated by multiplying the measured area times the specified applic ation rate. The Engineer may direct in writing an application rate greater than the contract application rate.
3.Quantity Determination
a.When the total weight from the scale tickets is within 5% of the calculated weight, then the pay quant ity will be the calculated weight.
b.When the Engineer directs in wr iting the application of a weight greater than the calculated weight, t hen the Department will pay for the revised calculated weight of mulch.
c.When the weight tickets show that the weight applied is less than 95% of the calculated weight, t hen the Department pay quantity will be the weight determined by adding t he quantities on the scale tickets.
d.If the Contractor applies mo re mulch than directed by the Engineer, then the weight over 100% of the specified weight or the amount directed by the Engineer is provided at no additional cost to the Department.
806.05 Basis of Payment
1.P a y I t e m P a y U n i t Mulch Ton (Tn) [Megagram (Mg)] Temporary Mulch Ton (Tn) [Megagram (Mg)] 2. Payment is full compensation for all work described in this Section. - 675 - SECTION 807 -- HYDROMULCHING
807.01 Description
1.This work consists of furn ishing and placing hydromulch on areas shown in the contract or as directed by the Engineer.
807.02 Material Requirements
1.Hydromulches will be specified in the contract and selected from the Department’s Approved Products List.
a.Type HM1 is a hydromulch that may be applied dry or hydraulically. Upon wetting, the tacking agents are released to reduce sediment loss. The product is ty pically used in confined areas.
b.Type HM2 is hydraulically applied, wood mulch with tackifier, typically used on slopes 3.5:1 or flatter and urban areas.
c.Type HM3 is a hydraulically applied matrix containing organic fibers and tackifiers to provide eros ion control and facilitate vegetation establishment on 2.5:1 slopes or flatte r. The products are designed to be functional for a minimum of 6 months.
d.Type HM4 is a hydraulically applied, high performance matrix containing wood and other biodegradab le or synthetic fibers, polymers and water absorbents that requires no cu ring period. The product promotes vegetation establishment and may be ap plied to slopes 1.5:1 or flatter.
2.The hydromulch shall be delivered to the site in packaging that clearly identifies the manufacturer, product name and weight per bag.
3.The Contractor shall provide t he necessary water required for the hydromulching operation.
807.03 Construction Methods
1.The Contractor shall apply the hydromulch within 24 hours after planting the seed or as directed by the Engineer. The hydromulch shall be applied uniformly over tilled areas with a hydromulch machine.
2.Application Rates: a. Hydromulch shall be applie d at 1.5 tons per acre or as specified in the contract.
b.The required tons of hydromulch shall be determined by multiplying the amount applied per ac re by the acres of application.
c.The Engineer may direct the Contractor, in writing, to adjust the application rate resulting in an increase or decrease the required tons of hydromulch.
3.The Contractor shall refer to the manufacturer’s recommendations for appropriate matrix to water ratios.
4.To ensure complete and unifo rm coverage, the Contractor shall apply the hydromulch from opposing directions to prevent shadowing or as directed by the Engineer.
807.04 Method of Measurement
1.Hydromulch is measured by the ton.
2.The weight of hydromulch ap plied will be computed on the basis of the weight per bag multiplied by the number of bags used.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 707–708 of 1,048.