212EROSION AND SEDIMENT CONTROL

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212.01Description

This work consists of constructing, installing, maintaining, and removing when required, best BMPs during the c ontract to prevent or minimize erosion, sedimentation, and pollution of waters of the U.S. as covered in

107.17, including wetlands. The Contractor will coordinate the construction of temporary BMPs with the

construction of permanent BMPs to ensure economical, effective, and continuous erosion and sediment control throughout the work. Control erosion and sediment using berms, dikes, dams, sediment basins, erosion blankets , netting, fiber wattles, compost socks, inlet protection, gravel, mulches, grasses, slope drains, and other approved erosion control devices or methods. Install erosion control BMPs before sediment control BMPs. Items not included in the contract , in the approved SWPPP, or in the PPP will be installed and maintained on a contingency basis and as approved. Provide a qualified WPCM as a construction stormwater manager throughout the work. See 107.17 for WPC M qualification requirements.

212.02Materials

Provide mater ials as specified in: Seeding ................................................................................................................................... 621.02 Aggregate for Untreated Base, Treated Base , and Road Mix (9.0% or less passing the #200) ........................................................................ 703.04 Metal Apron ............................................................................................................................. 708.21 Riprap ...................................................................................................................................... 711.04 Commercial Fertilizer ............................................................................................................... 711.07 Mulch ....................................................................................................................................... 711.10 Rolled Erosion Control Product (RECP) .................................................................................. 711.11 Turf Reinforced Mat (TRM) ...................................................................................................... 711.12 Fiber Wattle ............................................................................................................................. 711.20 Compost Sock ......................................................................................................................... 711.21 Inlet Protection ......................................................................................................................... 711.23 Geotextile ....................................................................................................................... 640 and 718 Provide other approved materials that meet commercial grade standards. 212

Submit for approval a plan and schedule as specified in 107.17 for installing temporary and permanent erosion and sediment control measures at the preconstruction conference o r before the start of the applicable construction. Incorporate ground disturbing activities, including haul roads, material sources, staging areas, and excess material sites. Do not start work until the plan including the erosion and sediment control schedule and methods of operations have been approved. Refer to the Department’s BMP manual and the standard drawings for appropriate selection and installation guidance. Stop earthwork operations when erosion or sediment control BMPs are determined by the Engineer to be inadequate. Resume only after demonstrating effectiveness of erosion and sediment contr ol BMPs. Provide temporary erosion control measures immediately when seaso nal limits prohibit permanent measures. Do not construct slopes more than 15 feet vertically, regardless of slope angle, before installing perimeter sediment control measures. For projects 5 acres or less or located in an arid, semi -arid areas during the seasonally dry period, sta rt installation of stabilization measures immediately in any areas of exposed soil where construction activities have stoppe d. Complete installation within 14 calendar days after start . For projects more than 5 acres start installation of stabilization measures immediately in any areas of exposed soil where construction activities have sto pped. Complete installation within 7 calendar days after start . Incorporate erosion and sediment control measure to prevent sediment transport from cut or embankment slopes Control measures may require the removal of sediments during maintenance operations. The Engineer may allow sediments removed to be used (e.g., topsoil ). Preserv e the function of control measures and prevent water pollution when disposing of sediments. Install all BMPs in accordance with the manufacturer’s written instructions, details, or as directed. Size and place BMPs to adequately handle the runoff water from a 2- year, 24- hour storm event.

Refer to the Department’s BMP Manual for guidance on temporary erosion and sediment control measures .

Seed slopes and other ground disturbed areas. It is not necessary for slopes to be completely constructed before seeding a finished portion of the slope. Seed as specified in 621.

minimum size of 1 inch to a maximum of 8 inches measured along the longest dimension.

and emergency spillway of the basin as approved.

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Prepare, maintain, revise, and amend the stormwater pollution prevention plan (SWPPP). Ensure project compliance with the erosion and sediment control and pollution prevention installation and maintenance requirements, water quality monitoring and discharge reporting requirements. Manage all pollution control measures at the project site, including field controls, inspections, records and CGP requirements specified in

and the CGP through the life of the contract

Coordinate erosion control maintenance operations before performing the work.

survey.

approval or hours recorded.

212.04Method of Measurement

The Engineer will measure acceptably completed work as follows:

the each.

item, including the materials used to construct outlet and overflow structures .

212.05Basis of Payment

The Department will pay for accepted quantity at contract unit prices as follows: Pay Item Pay Unit Slope Drain ............................................................................................. FT Sediment Trap ........................................................................................ Each 212

Diversion Ch annel .................................................................................. FT Diversion Ditch ....................................................................................... FT Dike ........................................................................................................ FT Berm ....................................................................................................... FT Open- Top Culvert ................................................................................... FT Waterbar ................................................................................................. Each Siltation Berm ......................................................................................... FT Stabilized Construction Entrance ............................................................ Each Soil Binder .............................................................................................. Acre Gabion .................................................................................................... CY Revet Mattress ....................................................................................... CY Stone Filter Berm Type____ ................................................................... CY Stone Filter Dam Type____ .................................................................... C Y Sediment Basin ...................................................................................... Each Inlet Protection ........................................................................................ Each Fiber Wattle ............................................................................................ FT Compost Sock ........................................................................................ FT Water and Pollution ................................................................................ CA Water Pollution Control Manager ............................................................ LS Erosion Control Maintenance ................................................................. HR The Department will not pay to install or repair temporary erosion and sediment control measures required due to the Contractor’s negligence, carelessness, or failure to install permanent measures as part of the work. Erosion and sediment control measures required for areas outside the project site (e.g., borrow pits, materials sources, haul roads, plant sites, and storage and disposal areas) is incidental to the work. The Department will pay for seeding, RECPs, TRMs, mulching, HECPs, and other seeding items under the appropriate contract pay items in 621. The following work is incidental and included in other contract pay items :

construct a stabilized discharge area.

channel, or diversion ditch.

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the Contractor’s normal operation within the slope limits.

The Department will pay for structure excavation and compacting backfill for gabion and revet mattress under 210. The Department will pay for geotextile for gabion and revet mattress under 640.

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213.01Description

Excavate suitable topsoil from stockpiles, sources outside the roadway, or from its natural position within the right of way that will be occupied by the roadway. Place and key in the topsoil on designated constructed cut and fill slopes and other designated areas after grading operations are complete.

213.02Materials

Obtain topsoil from approved sources from the soil profile A horizon layer that has a friable, loamy character and contains an organic matter amount normal to the region. Obtain topsoil from well -drained arable land that d oes not contain subsoil (from the soil profile B horizon layer), refuse, roots, heavy or stiff clay, stones larger than 1 inch, coarse sand, sticks, brush, litter, pesti cides, contaminated soil, noxious weeds, or other material detrimental to vegetative growth and establishment. Ensure the county weed authority has visually inspected approved sources for presence of noxious weeds before delivery or placement . Test sources if noxious weeds are located within or adjacent to the source site, and obtain approval from the county weed authority or authorized personnel from the Department or Idaho State Department of Agriculture that the source is acceptable to use on the project site. Incorporate vegetative matter into topsoil, except brush, trees, or noxious weeds. Other deleterious material (e.g., plastic, glass, metal, rocks) will not exceed 0.1 percent by weight or volume. Provide microorganism inoculants that contain a diverse mix of regional specific mycorrhizal species for specific condition, provide macronutrients and micro- nutrients that are tolerant of chemical imbalances in the soil, produce humic compounds and binding compounds, and improve soil structure. Soil Amendments .................................................................................................................... 711.18 Remove and di spose of vegetation at topsoil sources before taking materials from the source. Provide topsoil as specified below in Table 213.02- 1 and Table 213.02-2 . Table 213.02-1 – Topsoil Gradation Sieve Size Percent age by Weight Required to Pass a Square Mesh Sieve 1 in 98 - 100 No. 4 95 - 100 No. 8 80 - 100 No. 200 15 - 80