Z--IDIQ-RIVER REPAIRS AND UPPER BANK PAVING TASK ORDER 0006

Make repairs to the scour area located on the north bank (left) of McKellar Lake located beginning approximately 4,200 feet from the mouth of the lake by performing the following procedures. First, excavate and construct the root dikes and key trenches and the bankhead paving for the stone fill structure to be constructed (See Typical Plan Details Drawing). The azimuths of the root dikes and key trenches and the layout of the bankhead paving (50 feet by 100 feet) will be determined in the field and adjusted as directed by the Government Quality Assurance Representative. Next, construct the stone fill structure approximately 670 feet long using Graded Stone C across the opening of the overbank scour hole as depicted on the attached drawings. The stone fill should be constructed approximately 20-feet wide with side slopes of angle of repose of the stone (approximately 1V on 1.25H to 1V on 1.5H) to an elevation of approximately 204.00 ft. NAVD 88 (~+28 LWRP) beginning a distance of approximately 160 feet from ST 0+00 (XY=2489794.88, 12750420.83 - Horizontal Datum NAD1983 - UTM Zone 16N) along an azimuth of N 92 27'49" and should tie into the landward limit of the stone fill at a distance of approximately 830 feet from ST 0+00. (20,000 TN of Graded Stone C, Up to 350 CY Earthwork) Once construction of the stone fill structure to include the root dikes, key trenches, and bankhead paving is completed, the next phase of work should be to pave the existing bluff bank located riverward and landward of the stone fill limits with a 2-ft. thickness of Graded Stone C. The first area of paving (west side of stone fill) should begin at a distance of approximately 4,200 feet (XY=2489299.05, 12750356.37) from the mouth of the lake, should tie into the existing paved area along top bank of the lake which has previously been paved, and should continue lakeward (east) and tie into the stone fill structure that has already been constructed (total paving distance of approximately 660 feet). The paving should extend from the bluff top bank lakeward to an elevation of approximately +10 LWRP (Elevation 186.00 NAVD 88), or distance of approximately 100 feet, on minimum slopes of approximately 1V on 3H. Some minor grading of the bluff bank may be required to make the slopes suitable for paving. The second area of paving (east side of stone fill) should begin at the eastern limit of the constructed stone fill and proceed lakeward (east) for a distance of approximately 670 feet (XY=2491250.83, 12750512.56). This area of paving should extend from the bluff top bank lakeward to an elevation of approximately +10 LWRP (Elevation 186.00 NAVD 88), or distance of approximately 100 feet, on minimum slopes of approximately 1V on 3H. Some minor grading of the bluff bank may be required to make the slopes suitable for paving. (24,000 TN of Graded Stone C, Up to 1,150 CY Earthwork) NOTE: Special care should be taken to minimize damage to any existing trees located along the limits of work as well as the soybean crop located landward of top bank. The required order of work is as follows: 1. Construct the stone fill with root dikes, key trenches, and bankhead paving as specified above. 2. Pave the 2 areas riverward and lakeward of the stone fill as specified above. **Any deviation in this required order of work or a request to work concurrently on these items shall be coordinated through the Government Quality Assurance Representative with River Engineering and approved by the Administrative Contracting Officer prior to permission being granted.