C4b_Attachment B Scope of Work 12444626Q0074.pdf

POUNDS HOLLOW DAM REPAIR

Shawnee National Forest Hidden Springs Ranger District

Gallatin County, Illinois

PART 1 - GENERAL

1.1 SCOPE

A. This project is to repair the damage and surface failure on the Pounds Hollow dam. The contractor shall provide all labor, materials and equipment necessary to remove material from the surface failure areas, replace and compact the material to the existing grades and slopes of the surrounding dam and seed and mulch all disturbed areas.

1.2 ACCESS TO SITE

A. Contractor shall close the Forest Trail crossing the dam to public use and be signed on both sides of the dam.

1.3 CONTRACTORS OPERATIONS

A. Contractor shall provide barricades, fencing, etc. to prevent the public’s access to the construction site.

B. It is not anticipated that the contractor will need to lower the level of the dam to complete the repairs.

C. Contractor is responsible for removing all trash and debris from the job site daily.

PART 2 - MATERIALS

2.1 MATERIALS

A. See and Mulch

1. Contractor shall seed and mulch all disturbed areas.

2. Seed mixture shall be a standard commercially available lawn mix, free of noxious weeds.

3. Mulch shall be commercially available straw, certified free of seed, mold or other objectionable materials.

B. Earth fill

1. All fill materials shall be obtained from the required excavations and approved borrow areas.

The selection, blending, routing and disposition of materials in the various fills shall be subject to approval by the COR.

2. Fill materials shall contain no sod, brush, roots or other organic or perishable materials. Rock particles larger than the six (6) inches shall be removed prior to compaction of the fill.

C. Aggregate fill

1. All aggregates shall meet the requirements of Illinois Department of Transportation Highway

Specifications. Contractor shall provide certification from the quarry prior to delivery

PART 3 - EXECUTION

3.1 EXCAVATION AND EARTH FILL

A. The work shall consist of the excavation and earth fill required to repair the damage.

B. Contractor shall excavate the area of the damage to determine the limits of excavation. It is anticipated that the repair area is 100 feet in length, 15 feet in width and approximately 8 feet in depth. See Exhibit A for detail on the area to be excavated.

C. To the extent they are needed, all suitable materials from the excavation shall be used in the earth fill.

3.2 PLACEMENT

A. Earth fill in dams, levees and other structures designed to restrain the movement of water shall be placed to meet the following additional requirements:

1. Fill shall not be placed until the required excavation has been inspected and approved by the

Engineer.

2. Fill shall not be placed upon a frozen surface, nor shall snow, ice, or frozen material be incorporated in the fill.

3. Fill shall be placed in approximately horizontal layers. The thickness of each layer before compaction shall not exceed 12 inches.

4. The distribution of materials throughout each zone shall be essentially uniform, and the fill shall be free from lenses, pockets, streaks, or layers of material differing substantially in texture, moisture content, or gradation from the surrounding material.

5. If the surface of any layer becomes too hard and smooth for proper bond with the succeeding layer, it shall be scarified parallel to the axis of the fill to a depth of not less than two (2) inches before the next layer is placed.

6. Dam embankments shall be constructed in continuous layers from end to end of the repair.

3.3 CONTROL OF MOISTURE CONTENT

A. During placement and compaction of fill, the moisture content of the materials being placed shall be maintained within the specified range.

B. Water may be applied by sprinkling the materials after placement on the fill, if necessary.

C. Material that is too wet when deposited on the fill shall either be removed or be dried to the specified moisture content prior to compaction.

D. If the top surface of the preceding layer of compacted fill or a foundation or abutment surface in the zone of contact with the fill becomes too dry to permit suitable bond it shall either be removed or scarified and moistened by sprinkling to an acceptable moisture content prior to placement of the next layer of fill.

E. The minimum and maximum moisture content for placement of earth fill materials will be that the minimum moisture content shall be such that, when kneaded in the hand, the fill material will form a ball that does not readily separate. The maximum moisture content is when conditions are too wet to allow for efficient use of the hauling and compacting equipment.

3.4 COMPACTION

A. Earth fill shall be compacted according to the following requirements specified:

1. Each six (6) inch layer of fill shall be compacted by a minimum of 2 passes placement equipment per lift over the entire surface. Each pass shall consist of at least one passage of the roller wheel or drum over the entire surface of the layer.

3.5 DISPOSAL OF WASTE MATERIALS

A. All surplus or unsuitable excavated materials will be designated as waste and shall be disposed of by the contractor off Forest Service property.

B. When the quantities of suitable materials obtained from specified excavations are insufficient to construct the specified fills, additional materials shall be obtained from the borrow areas. The

Forest Service has no borrow sources available, contractor shall provide all borrow material from off Forest Service property.

3.6 SEEDING AND MULCHING

A. Seed and Mulch

1. Contractor shall grade the area to be seeded to match the surrounding ground.

2. Moisten seeding area before seeding.

3. Spread the seed mixture at the rate recommended by the manufacturer.

4. Apply mulch immediately after seeding at a rate of 3200 pounds per acre.