Conn Creek Spillway Inspection And Repair

As of July 25, 2022, the project has been awarded. A timeline for construction has not been confirmed. The work generally consists of furnishing labor, equipment, materials and required services associated with removal and replacement of approximately 25 square feet of the concrete spillway floor slab to investigate and repair the underdrain system including, but not limited to, installation of drain pipe screen and drain rock. Concrete reinforcement shall be inspected, and may require replacement at the engineers discretion, in accordance with the design plans. There are significant site constraints--limited access, steep slopes and rocky ground. The City expects Bidders to propose means and methods to complete the work including concrete pouring and placement within the spillway. Spoils and demolition materials will have to be hauled and disposed off-site. Existing rebar and underdrain system will be investigated on-site for integrity or demolished. The Conn Creek Spillway is an uncontrolled spillway, where seasonal restrictions and inclement weather will determine accessibility for construction work. Generally, the spillway is inaccessible during the rain season from November - April. Additionally, no work will commence if the construction schedule and concrete curing times are within proximity to the rain season as determined by the Department of Safety of Dams (DSOD). Conn Dam Spillway is located on Lake Hennessy in Napa County approximately 15 miles Northeast of downtown Napa, along Highway 128 approximately 1.2 miles East of the junction of Silverado Trail. The facility is located at 1000 Sage Canyon Rd, St Helena, CA 94574 Latitude 3829'8.15" N, Longitude 12222'53.1" W SCOPE OF WORK Task 1. Demolition and Investigation 1. 2. 3. 4. Task 2. Drain Inspection and Underdrain Replacement 1. Extents of void and underdrain infill shall be determined by the engineer and verified by DSOD. CONN CREEK SPILLWAY REPAIR PHASE II 1 WTR2019-007 n tl Once concrete is removed notify the City engineer to inspect conditions of reinforcement, drain rock, and voided area. Measurement and Payment - The contract bid item no. 1 price for Demolition and Investigation includes full compensation for providing all labor, materials, tools, equipment and incidentals and for doing all the work involved in this section, complete in place, as shown on the plans, as specified in the Standard Specifications and these Special Provisions, as directed by the Engineer, and no additional compensation will be allowed therefor. Existing Drainpipe shall be inspected for rock and debris to be removed (flushed) as necessary. Install drain screen and #2 crushed rock in voided area underneath slab. If possible do not damage existing reinforcement. Reinforcement with more than 20% section loss shall be replaced. Refer to Demolition and Investigation Sequence on Sheet C-001 for inspection and replacement of reinforcement. If existing reinforcement cannot be saved, then new reinforcing will have to be placed per Section B on Sheet C-001 Removal and Disposal of concrete is estimated and paid based on the initial area outlined on Sheet C-001, approximately 25 SF. SWPPP provisions shall include BMP's as necessary including, but not limited to, concrete washouts and gravel bag berms along the downstream perimeter of work. Locate, mark, and sawcut drain inlet location to investigate extents of eroded drain rock area according to the plans provided in Attachment E. Inspection and determinations of extents will be made under the direction of the Department of Safety of Dams and the Design Engineer. Initial investigation was performed under the Spillway Re-evaluation program (Conn Creek Dam Spillway Assessment Phase II)- APPENDIX F is provided for reference. The contractor can review means and methods for installation and replacement. If the determination is made that work can be done in a timely and cost-effective method, reinforcement can be fully removed and replaced in the initial excavation area. Refer to Details 3 and 4 of Sheet C002 for evaluation. The City of Napa (City) is accepting proposals from civil construction firms offering services to inspect and construct necessary repairs to the Conn Dam/Lake Hennessey Spillway in compliance with any and all Department of Safety of Dams permit requirements which will consist of, but not necessarily be limited to the description below and approved design plans in Appendix E. Reference materials on Sheet C-002 and specifications on Sheet C-003. Contractor shall supply all necessary labor, materials, and equipment to furnish project complete in place Multiple Locations Are Available In This Project. *Information regarding subcontractor bidding has not been disclosed to the content management team at this time. Interested subcontractors should contact the general contractor directly for more information.

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 31 -	Earthwork, Site Clearing, Grading, Excavation and Fill, Subgrade Preparation, Excavation, Shoring, Tunneling and Mining, Tunnel Excavation.
Division 33 -	Utilities, Instrumentation and Control for Utilities, Water Utilities, Water Utility Distribution Piping, Water Utility Distribution Equipment, Disinfecting of Water Utility Distribution, Water Utility Storage Tanks.
Division 35 -	Waterway and Marine Construction, Dam Construction and Equipment.