To: Honorable Mayor and Members of City Council
From: Eric B. Whan, Acting Public Works Director
Prepared By: John Ferons, Senior Civil Engineer
TITLE:
Title
Emergency Storm Drain Repair of Minahen Street, Locust Street and Solano Avenue
LABEL
RECOMMENDED ACTION:
Recommendation
Adopt a resolution authorizing a budget appropriation in the amount of $80,000 for the Minahen Storm Drain Repair Project; determining that the emergency actions taken for the Project are terminated; and determining that the actions authorized by this Resolution are exempt from CEQA.
Body
DISCUSSION:
Pursuant to City of Napa Municipal Code 2.91.040, City Staff is providing this last staff report to City Council and recommending the emergency action be terminated by the City Council.
On August 10, 2018, based on a recommendation from the Deputy Public Works Director, as summarized in this report, the City Manager determined that the storm drain failures at Minahen Street, Locust Street, and Solano Avenue required immediate action to resolve an emergency, including entering into contracts for the purchase of pipe materials and performance of repairs.
The situation was declared an emergency by the City Manager pursuant to Napa Municipal Code Section 2.91.040 (Exceptions for Emergency Contract Procurements), and Public Works staff was authorized to procure the materials and begin the repairs before the next sink hole appeared. Public Works staff identified the necessary storm drain pipe and method to repair the failing system. G. D. Nielson Construction, Inc, a local contractor with the necessary equipment, personnel and experience needed to perform the repairs was hired via the emergency contract ordinance to perform the repairs.
The contractor has now completed the necessary storm drain pipe work, grouted the annular spaces, connected the existing storm drain inlets, and construction of the storm drain manholes. With these tasks completed, it ends the contracted scope of work for this project. City crews have mobilized to backfill any open excavations, compact aggregate base and asphalt pave the street surface in the storm drain repair locations. With the completion of the storm drain repairs, City crews will be scheduling the paving of the streets within the Minahen neighborhood at a future date.
A Time and Materials Contract with Nielson Construction for the pipe installation and grout repair at Minahen / Locust Streets was estimated at $290,000 and Solano Avenue estimated at $70,000. There is also an additional $200,000 contingency to cover any unforeseen circumstances.
During construction, unforeseen conditions occurred that required the use of the entire contingency and requires an additional appropriation:
1. Stronger Bulkhead Construction: To contain the grout within the annular spaces, bulkheads were constructed at each end of each reach. During the grouting process, it was determined that the density of the grout coupled with its viscosity was exceeding the typical methods used for bulkhead construction. As such, additional labor and materials were required to strengthen each bulkhead to withstand and contain the grout material until it cured.
2. Roots and Rocky Debris: As the need for the project demonstrated, the existing corrugated metal pipes were in a state of failure. In many locations the lower half of the pipe were missing due to corrosion and had been invaded by large root systems and rocky debris. To properly place the new pipe within the old pipe the roots needed to be cut and extricated along with the rocky debris.
3. Existing Pipe Alignment and Offsets: The existing pipe network was constructed in the early 1960’s and plans were on file at public works. However, there were three locations where the pipe was not constructed in the location as shown on the as-built drawings. These two locations required extensive, additional exploratory work to determine the pipe locations and subsequently required additional design, labor and materials to perform the repairs.
4. Existing Utility Conflicts: Existing utility locations are never exactly known until the open excavation occurs. In this case as the project progressed, several utilities were exposed and determined to conflict with proposed construction. Where possible, the project was revised to accommodate the utility. There was a gas-line conflict that required specific additional coordination with PG&E to relocate the gas line to accommodate the new storm drain line.
FINANCIAL IMPACTS:
Funding for the unforeseen conditions is proposed from:
SOURCES:
$ 80,000 General Fund Contingency Reserve (10000-25001)
(Appropriation)
$ 80,000 TOTAL
USES:
$ 80,000 Minahen Storm Drain Repair (30101-57601-SD08PW01GF-57601)
$ 80,000 TOTAL
CEQA:
City staff recommends that the City Council determine that the Recommended Action is exempt from CEQA pursuant to CEQA Guidelines Section 15302 which exempts the replacement and reconstruction of existing utility systems/facilities involving negligible or no expansion of capacity.
DOCUMENTS ATTACHED:
ATCH 1 - Resolution
NOTIFICATION:
None.