|
|
File #:
|
22-437
Version:
1
|
|
|
|
Type:
|
Agreement
|
Status:
|
Agenda Ready
|
|
On agenda:
|
3/8/2022
|
Final action:
|
|
|
Title:
|
Director of Public Works requests the following actions:
1. Approval of the plans and specifications and authorization to advertise for sealed bids and opening of the bids at a time, date, and location to be published by the Director of Public Works pursuant to Section 20150.8 of the Public Contract Code for the following projects:
a. Dry Creek Road MPM 6.2, RDS 21-30
b. Dry Creek Road MPM 9.48, RDS 21-39
c. Dry Creek Road MPM 9.75, RDS 21-06
d. Diamond Mountain Road MPM 1.1, RDS 21-04
2. Approval of and authorization for the Chair to sign Amendment No. 3 to Agreement No. 210301B with ADKO Engineering (ADKO) increasing maximum compensation by $23,609 for a new maximum of $498,054 adding Dry Creek MPM 6.2 Storm Slide Repair to their scope.
|
TO: Board of Supervisors
FROM: Steven Lederer - Director of Public Works
REPORT BY: Dewey Phan, Assistant Engineer
SUBJECT: Approve Amendment #3 to Professional Services Agreement No. 210301B with ADKO Engineering for RDS 21-30 and approval of Plans and Specifications for the Storm Slide Repairs at Dry Creek Road MPM 6.2, 9.48, 9.75, and Diamond Mountain Road MPM 1.1.
RECOMMENDATION
title
Director of Public Works requests the following actions:
1. Approval of the plans and specifications and authorization to advertise for sealed bids and opening of the bids at a time, date, and location to be published by the Director of Public Works pursuant to Section 20150.8 of the Public Contract Code for the following projects:
a. Dry Creek Road MPM 6.2, RDS 21-30
b. Dry Creek Road MPM 9.48, RDS 21-39
c. Dry Creek Road MPM 9.75, RDS 21-06
d. Diamond Mountain Road MPM 1.1, RDS 21-04
2. Approval of and authorization for the Chair to sign Amendment No. 3 to Agreement No. 210301B with ADKO Engineering (ADKO) increasing maximum compensation by $23,609 for a new maximum of $498,054 adding Dry Creek MPM 6.2 Storm Slide Repair to their scope.
body
EXECUTIVE SUMMARY
In 2017 a series of storms caused significant damage at several locations, including the following project sites:
1. Dry Creek Road mile post marker (MPM) 9.75 - Sustained about 70 feet of embankment failure;
2. Diamond Mountain Road MPM 1.1 - Sustained about 50 feet of roadway and embankment failure.
Another site, most likely a result of the 2019 rains, was discovered at Dry Creek Rd. MPM 9.48, where 15 feet of roadway and embankment failure occurred. During later heavy rains, Dry Creek eroded the creek bank next to Dry Creek Road MPM 6.2, causing two significant slides and other damage. At this location, two separate retaining walls are being designed to repair the existing slide areas. Due to the potential susceptibility of a future slide in the area between the two existing slides, County staff recommends approval of the proposed Amendment #3 to Agreement No. 210301B with ADKO to design a longer and continuous wall which will encompass both existing slides and the area between them. This longer wall will be bid as an additive alternate to give the Board the option of awarding the longer wall.
For each site, designs for the projects are complete and the proposed repairs are to reconstruct the road and bank with a steel soldier pile and concrete lagging retaining wall. Staff recommends advertising the four repairs as one construction contract for economy of scale. Work is expected to be complete prior to the winter of 2022/23. Staff will return to the Board after bid opening with a proposed construction contract and a budget transfer request to fully fund the project using Measure T and SB1 funds.
FISCAL & STRATEGIC PLAN IMPACT
|
Is there a Fiscal Impact? |
Yes |
|
Is it currently budgeted? |
Yes |
|
Where is it budgeted? |
Fund 2040, Org 2040500. The Board appropriated the following funding for the design phase in the respective Projects: 22010 - Dry Creek Road MPM 6.2 = $196,085, S9106 - Dry Creek Road MPM 9.48 = $116,735, S7312 - Dry Creek Road MPM 9.75 = $171,657, S7127 - Diamond Mountain Road MPM 1.1 = $159,073, and Total = $643,550. The full cost of each project is estimated as follows: 22010 - Dry Creek Road MPM 6.2 = $1,141, S9106 - Dry Creek Road MPM 9.48 = $427,808, S7312 - Dry Creek Road MPM 9.75 = $980,541, S7127 - Diamond Mountain MPM 1.1 = $778,384, and Total = $3,337,808. The funding for 21059 (RDS 21-04), S7312 (RDS 21-06) and 22010 (RDS 21-30) is from Measure T fund and the funding for S9106 (RDS 21-39) is from SB1 Non-Operating Special Revenue Fund (SRF). When staff requests the Board award the construction contract, staff will request the budgets for Amendment #3 and the construction phase. |
|
Is it Mandatory or Discretionary? |
Discretionary |
|
Discretionary Justification: |
For Amendment #3, the County currently does not have the resources, capacity, or all expertise in-house to design a repair for this slide. For the slides at the four storm site locations, the proposed project will stabilize the roadway bank and reconstruct the roadway pavement sections. The requested approvals will allow for the solicitation for construction bids and move the project forward toward construction |
|
Is the general fund affected? |
No |
|
Future fiscal impact: |
Design began in Fiscal Year 2021-22 and construction could begin in Fiscal Year 2021-22. Construction will likely continue into Fiscal Year 2022-23. For the repairs next to Dry Creek bank, it is possible that 5 to 10 years of monitoring and additional budget will be required beyond FY 2022-23. |
|
Consequences if not approved: |
Future rain events could cause additional landslides. |
|
County Strategic Plan pillar addressed: |
Livable Economy for All |
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: Consideration and possible adoption of a Categorical Exemption Class 1: It has been determined that this type of project does not have a significant effect on the environment and is exempt from the California Environmental Quality Act. [See Class 1 (“Existing Facilities”) which may be found in the guidelines for the implementation of the California Environmental Quality Act at 14 CCR §15301; see also Napa County’s Local Procedures for Implementing the California Environmental Quality Act, Appendix B.]
BACKGROUND AND DISCUSSION
Winter storms that occurred between 2017 and 2021 caused damage to Dry Creek Road near mile post markers (MPM) 6.2, 9.48, 9.75 and Diamond Mountain Road near MPM 1.1. Dry Creek Road MPM 9.48 and MPM 9.75 sustained 15 feet and 70 feet embankment failure, respectively. At Dry Creek Road MPM 6.2, heavy rains over saturated a 70 foot long +/- portion of the road causing two slides and roadway distress. Diamond Mountain Road MPM 1.1 sustained 30 feet embankment failure. If the sites are not stabilized and repaired prior to the next significant rain event, it is possible that major and more disruptive failure will occur. County staff plans to advertise the four projects to bidders as one bid package for economies of scale.
Through a qualifications-based selection process, the County selected ADKO Engineering Inc. (ADKO), as the most qualified firm for the design of various storm repairs. On March 16, 2021, the Board approved an Agreement with ADKO for an amount of $182,857 for the design of the Dry Creek 9.75 slide repair. On December 14, 2021 the Board approved $197,540 in Amendment #1 for the design of the Dry Creek Road MPM 6.2 repair. On January 25, 2022 the Board approved $94,048 in Amendment #2 for the design of the Dry Creek Road MPM 9.48 repair. This Amendment #3 is for adding an additional $23,609 to the agreement for design of the potential continuous retaining wall for the Dry Creek Road MPM 6.2 site.
ADKO proposes to stabilize the road banks with steel soldier pile and concrete lagging walls and re-construct the roadways with full-depth asphalt repairs with minimal intrusion into Dry Creek. At Dry Creek MPM 6.2, the consultant designed two separate retaining walls totaling 149.5 linear feet, however, due to the potential susceptibility to a future slide between the walls, County staff recommends considering constructing a 60.5 linear foot long wall between the two separate walls to make a continuous 210 linear feet long wall. This portion will be bid as an additive alternate and recommended for award if the costs are favorable.
After advertisement and bid opening, staff will ask the Board to award the construction contract and approve a budget transfer to fund the entirety of the projects.
|