- 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.
807.05 Hydromulching
- 676 - 807.05 -- Basis of Payment
1.P a y I t e m P a y U n i t Hydromulch “Type _______” Ton
2.Final Quanti ty Determination:
a.If the computed t ons of the hydromulch applied are within 5% (+/-) of the tons required as determin ed by the approved application rate, the final pay quantity will be the computed weight.
b.If the computed tons of t he hydromulch applied are less than 95% of the tons required as determin ed by the approved application rate, the Contractor shall apply additional hydromulch at locations as directed by the Engineer. The final pay quantity will be the computed weight after the additional application has been applied and will not exceed 105% of the tons required as determined by the approved application rate.
c.If the computed quantity of the hydromulch applied exceeds 105% of the tons required as determined by the approved application rate, the final pay quantity will not exce ed 105% of the tons required as determined by the approved application rate.
d.If upon visual inspection, the Engineer determines that the hydromulch application is “light” in some areas, even though the required tons as determined by the approved application rate was applied to the overall area of application, the Contra ctor shall apply additional hydromulch as directed by the Engineer. The final pay quantity will be the computed weight after the additional application has been applied and will not exceed 105% of the tons required as determined by the approved application rate. The quantity of hydromulch applied that is in excess of 105% of the tons required as determined by the approv ed application rate shall be at no additional cost to the Department.
3.Direct payment for water incorporated into the hydromulch will not be made. Water is subsidiary to the item.
4.Payment is full compensation for all work described in this Section. - 677 - SECTION 808 -- SLOPE PROTECTION
808.01 Description
1.This work shall consist of plac ing seed and a protective covering of mulch upon the completed shoulders, sideslopes, ditch bottoms, or backslopes as shown in the contract or as directed by the Engineer.
808.02 Material Requirements
1.The mulch being used for slope protection shall be as described in 806.02, except that straw will not be allowed.
2.The Material Requirements for Slope Protection seeding shall be as described in Subsection 801.02.
808.03 Construction Methods
1.The Contractor shall commence slope protection work within five calendar days after the finish grad ing operations have started.
2.The work on the project may be temporarily suspended for failure to initiate the finish grading and/ or slope protection operation.
3.Seeding: a. The initial seeding shall be dr illed at the rate specified in the contract.
b.The remainder of the seed sh all be broadcast over the mulch.
c.All seed may be broadcast if conditions preclude drilling, such as steep slopes or unsafe conditions.
4.Mulching: a. The Contractor shall pl ace mulch for the slope protection uniformly at 2 lbs/Sq Yd (1.1 Kg/m 2).
b.Mulch may be applied either by hand or mechanically.
c.A machine that chops a bale apart shall not be used. d. The Contractor shall place pi les of soil on the mulch to hold it in place. The soil piles shall be placed at intervals of not more than 40 inches (1 m) in any direction over the surface of the area mulched. The piles of soil shall be of sufficient size to hold the mulch in place. The sources from which the Contractor obtains the so il shall be approved by the Engineer and shall be left in a condition which is satisfactory to the Engineer.
e.In lieu of securing the mulch with piles of soil, the Contractor may use a mechanical device to anchor the mulch. The mechanical device shall either be a drum roller with cleats or a crawler tractor with cleated tracks.
1.The cleats on both the roller and the crawler tractor shall punch the mulch approximately 6 inches (150 mm) into the soil.
2.Either device shall have sufficient cleats to anchor all of the mulch.
3.Shoulders shall average ten cleat punches per square yard (12 cleat punches per m 2).
4.Areas other than shoulders shall average four cleat punches per square yard (five cleat punches per m2).
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 709–710 of 1,048.