ITEM TITLE:
Approval of a Contract with Harris Sand & Gravel, Inc., for the 10 Mile Dike Maintenance project in the amount of $3,570,100.00.
SUBMITTED BY: Scott Benda, Senior Project manager
FISCAL NOTES:
Expenditure Required: $3,570,100.00
Unencumbered Balance: $4,794,046.63
Funding Source: 350-0750-55000.409
RECOMMENDATION:
Approve a Contract with Harris Sand & Gravel, Inc., for the 10 Mile Dike Maintenance project in the amount of $3,570,100.00.
SUMMARY STATEMENT:
The 10 Mile Dike Maintenance project was out to bid for forty seven days and three (3) bids were received. Harris Sand & Gravel, Inc., of Valdez submitted the low bid of $3,570,100.00. This project consists of both erosion repairs to groins 1, 2 and 4 and enhancements to widen the structures. Both the armored slopes and buried toe areas will reestablished and improved with the placement of new rip rap. The armored slopes will be reconstructed with a more gradual 3:1 slope. The 3:1 slopes have proven to be more resistant to riprap erosion damage than the steeper 2:1 slopes of the older designs. Existing riprap will be reused where feasible. In addition, the existing dikes will be widened so as to provide the necessary foundation for a planned dike raise project. This future project will be done in conjunction with the diversion channel work in the riverbed across from the subdivision.
Groins 1 & 2 were originally constructed in the mid 80’s and have experienced erosion damage to their riprap armoring and over steeping of their riverside slopes. Groin 4 was built in sections, with the first segment constructed in 1995 in response to a flooding event and later extensions added in response to high water events in ’15 and ’16.
Construction is scheduled to begin in July/August with the production of riprap material. Clearing and grubbing work can be done in the summer months but work is limited by the fish window that runs from March 31 through November 1. Depending upon the river conditions, work may be done where water is not actively flowing against the dike infrastructure or diverted away from it.
The engineer’s estimate for this project was $4,900,000.
This project was derived from the 35% design for the maintenance and dike raise project presented to the Flood Mitigation Task Force on October 21, 2020. The scope was accelerated over the gravel extraction and dike raise due to delays in permit issuance. This specific project was presented to the Flood Mitigation Task Force on December 16, 2020 and again on January 20, 2020 and approved by Council with the March 16, 2021 projects budget resolution.
All the work performed with the maintenance project will integrate with the second phase extraction project and dike raise if and when the Flood Mitigation Plan is approved by the Department on Natural Resources. DNR is evaluating the plan and most recent communications revolve around stockpile locations and the ability of the City to use the extracted gravel. DNR staff has once again turned over and a new point of contact has been assigned. Staff intends to redouble efforts with DNR to get the mitigation plan approved in preparation for the next phase now that the maintenance project construction is imminent.