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The work covered by this section consists of the construction, maintenance and removal of physical barriers placed around catch basins and/or drop inlets to reduce water velocity and trap sediment.
The quantity of temporary rock inlet sediment traps to be constructed will be affected by the actual conditions which occur during the construction of the project. The quantity of inlet sediment traps may be increased, decreased, or eliminated entirely at the direction of the Engineer. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work.
(A) Posts:
Either wood posts or steel posts may be used. Wood posts shall be a minimum of 6 feet long, at least 3 inches in diameter, and straight enough to provide a fence without noticeable misalignment. Steel posts shall be at least 5 feet in length, approximately 1 3/8 inches wide measured parallel to the fence, and have a minimum weight of 1.25 lb/ft of length. The post shall be equipped with an anchor plate having a minimum area of 14.0 square inches, and shall have a means of retaining wire and fabric in the desired position without displacement.
(B) Wire Staples:
Wire staples shall be a No. 9 staple and shall be at least 1 1/2 inches long.
(C) 1/4 inch hardware cloth:
The hardware cloth shall have 1/4 inch openings constructed from #24 gage wire (0.026 inch diameter) or larger, and have a minimum width of 24 inches as specified in ASTM A740.
(D) Other Materials:
Additional materials shall meet the requirements of Division 10 shown below:
Stone for erosion control, class ____ Article 1042-1
Sediment control stone Section 1005
(A) Type A:
Temporary rock inlet sediment trap type-A devices shall be constructed as shown on the plans. The rock inlet sediment trap type-A shall be constructed at the locations shown on the plans and at other locations directed by the Engineer.
The structural stone (Class B stone) shall be placed around the outside perimeter of the inlet structure with approximately 2:1 side slopes and shall be faced on the upstream side with sediment control stone approximately 12 inches thick.
The temporary rock inlet sediment trap type-A shall be constructed approximately 18 inches from the inlet structure and shall have a 2 foot minimum berm height. The temporary rock inlet sediment trap type-A shall be a minimum of 12 inches below the roadway shoulder or diversion point.
(B) Type B:
Temporary rock inlet sediment trap type-B devices shall be constructed as shown on the plans. The temporary rock inlet sediment trap type-B shall be constructed at the locations shown on the plans and at other locations directed by the Engineer.
The structural stone (Class A stone) shall be placed around the outside perimeter of the inlet structure with approximately 2:1 side slopes and shall be faced on the upstream side with sediment control stone approximately 12 inches thick.
The temporary rock inlet sediment trap type-B shall be constructed approximately 18 inches from the structure and shall have a 18 inch minimum berm height. The temporary rock inlet sediment trap type-B shall be a minimum of 12 inches below the roadway shoulder or diversion point.
(C) Type C:
Temporary rock inlet sediment trap type-C devices shall be constructed as shown on the plans. The temporary rock inlet sediment trap type-C shall be constructed at the locations shown on the plans and at other locations directed by the Engineer.
The 1/4 inch hardware cloth (wire mesh) shall be placed approximately 18 inches from the outside perimeter of the inlet structure intake. The trap shall be constructed using posts and shall be faced on the upstream side with sediment control stone. The hardware cloth shall have a minimum height of 24 inches and be installed a minimum of 12 inches below the shoulder or any diversion point. The sediment control stone berm shall be a minimum height of 12 inches and shall be on a 2:1 slope on sides.
1632-4 MAINTENANCE AND REMOVAL.
The Contractor shall maintain the temporary rock inlet sediment trap, and shall remove and dispose of silt accumulations at the inlet sediment traps when so directed by the Engineer in accordance with Section 1630.
Unless otherwise directed by the Engineer, temporary rock sediment traps shall be removed as the project nears completion, or at such time the Engineer deems the device to be no longer useful. The actual time of removal shall be as directed by the Engineer. Upon removal, the Contractor shall dress the area to give a pleasing appearance, and shall seed and mulch the area in accordance with Section 1660.
Temporary rock inlet sediment traps will not be measured for payment under this article.
The quantity of 1/4 inch hardware cloth to be paid for will be the actual number of linear feet of hardware cloth, measured in place from end post to end post of each separate installation which has been completed and accepted.
Payment for temporary rock inlet sediment traps will be as follows:
The quantity of structural stone measured as provided in Article 16104 will be made at the contract unit price per ton for "Stone for Erosion Control, Class ____" as provided in Article 16105.
The quantity of sediment control stone measured as provided in Article 16104 will be made at the contract unit price per ton for "Sediment Control Stone" as provided in Article 16105.
The quantity of hardware cloth, measured as provided above, will be paid for at the contract unit price per linear foot for 1/4 inch hardware cloth. Such prices and payments will be full compensation for all work, including but not limited to furnishing all fence posts, hardware cloth, hardware, and other materials; installing and maintaining the 1/4 inch hardware cloth.
The removal and disposal of silt accumulations will be paid for
as provided in Section 1630.