The Table of Contents for this section is available.
The work covered by this section consists of the construction, maintenance, and removal of earth embankments used to trap sediment from water being pumped from bridge and culvert construction sites.
The quantity of stilling basins to be constructed will be affected by the actual conditions which occur during the construction of the project. The quantity of stilling basins 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.
Suitable excavated materials, as specified in Section 225, 230, and 240, shall be utilized in the construction of earth embankments for stilling basins, except where otherwise directed by the Engineer.
The pipe used for the overflow pipe may consist of any D.O.T approved pipe materials such as plastic, steel, or aluminum.
The following materials shall meet the requirements of Division 10:
Stone for Erosion Control Class ____ Article 1042-1
Sediment Control Stone Section 1005
The stilling basins shall be constructed at the locations shown on the plans and at other locations directed by the Engineer.
Earth dikes with a permeable stone drain shall be constructed in a rectangular form adjacent to the stream and culvert following the applicable requirements of Section 235. The earth dikes shall have a 4 foot maximum height. Additional depths may be attained by excavating below the natural ground.
The stilling basin shall be constructed with a Class B stone baffle and an 8 inch minimum diameter overflow pipe installed at the permeable stone drain.
1638-4 MAINTENANCE AND REMOVAL.
The Contractor shall maintain the stilling basins, and shall remove and dispose of silt accumulations at the stilling basins when so directed by the Engineer in accordance with Section 1630.
Unless otherwise directed by the Engineer, stilling basins 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.
The quantity of stilling basins to be paid for will be the actual number of cubic yards of basin capacity, measured in place and computed by the average-end-method. The measurements will be in internal measurements of the basin. The quantity of materials used to construct the basin that originates from another payment item (i.e. unclassified excavation, borrow excavation) will not be deducted from the volume of that original pay item.
The quantity of stilling basins, measured as provided above, will be paid for at the contract unit price per cubic yard for Stilling Basins. Such price and payment will be full compensation for excavation, constructing the earth embankments, permeable stone drain, furnishing and installing overflow pipe, cleaning out, maintaining, removing and disposing of the stilling basins and all components and reshaping the area.
Payment will be made under:
Stilling Basins Cubic Yard