Presentation is loading. Please wait.

Presentation is loading. Please wait.

Ross By-Pass Tunnel Cleanup Pre-Bid Project Overview May 2014

Similar presentations

Presentation on theme: "Ross By-Pass Tunnel Cleanup Pre-Bid Project Overview May 2014"— Presentation transcript:

1 Ross By-Pass Tunnel Cleanup Pre-Bid Project Overview May 2014
Ross Dam Pre-Bid Project Overview May 2014 Project Location This presentation is for general info. Consult the RFP for details. Skagit River

2 City Light Admin Offices
Diablo Boat house Ross Dam City Light Admin Offices

3 Getting to the work site
Diablo Boathouse Diablo dam Highway 20 To Ross dam Diablo Dam and boat house

4 Project Location: Ross Hollow Jet Valve House
Dam Valve house Hollow Jet Valves Opening to Tunnel Diablo Lake / Skagit River

5 Problem Past O&M work (sandblasting) left lead in the sediment in the tunnel. Can’t pump tunnel dry without discharging lead into Diablo Lake Goal Remove lead to allow future O&M work to pump tunnel dry when needed for inspections and repairs

6 Plan view By-pass intake structure Ross Lake Diablo Lake
Tunnel and two By-pass penstocks Hollow Jet Valves & Valve House

7 Bypass Penstock Tunnel
Diablo Lake Ross Dam Valve house Typical water Level (1205) 9 8 6 4 3 2 1 7 5 10 Concrete Tunnel plug Hollow Jet Valves By-pass penstock Tunnel Sump Pipe saddles

8 Cross Section of Pipe Supports
Penstocks Concrete wall Tunnel Doorway Not to scale

9 Inside Valve House Tunnel & By-pass penstocks

10 Scope of work Install temporary weir (vendor) or permanent weir (SCL)
Install rock fall fence (vendor) Remove and treat 1,000,000 gallons of water from tunnel to remove suspended lead (vendor) Remove 10 – 30 cy sediment (vendor) Verify & Dispose sediment – could be dangerous waste (SCL)

11 1. Opening to tunnel Lake level can fluctuate 4-5 feet daily.
~8-ft Higher lake level (elev 1205) ~5-ft Lower lake level (elev 1199) Lake level can fluctuate 4-5 feet daily. The lake may have waves.

12 1. Install weir Weir Isolate tunnel from fluctuating lake levels
Protect workers Keep debris out of tunnel Contractor can use SCL weir or build their own temporary weir Proposed SCL metal weir (install in June or October depending on Contractor’s preference)

13 2. Rock fall Protection (vendor)
Temporary fence

14 3A. Mobilize Valve House Spill way Temp rock fence SCL Barge Ross Dam

15 Vendor Submittals (pre-mobilization)
Health & Safety Plan Hazardous waste handling plan Work plan Contact info Water Tectonics Electro-coagulation operation manual Schedule Spill control plan Barge loading & operation plan * Temporary weir * Rock fall fence Equipment and materials * Need engineer stamp

16 Vendor Mobilization Load water treatment equipment on barge
Provide generator, pumps, worker shack, sani-can, ladders, lights, etc. * Some size restrictions: tunnels, barge load, barge access, etc.

17 3B. De-water Tunnel Pump out clean water & direct discharge to lake
Pump out dirty* water and treat prior to discharge Approximately 750,000 – 1,000,000 gallons Water is ~12 – 16-ft deep *Dirty = > 5 NTU turbidity

18 3C. Water Treatment on Barge
Discharge to Diablo Lake pump Tunnel shack Sand filter Back flush tank Settling tank #2 Settling tank #1 Source tank Electro coagulation Sani can generator 80T Barge Not to scale Water Tectonics is the MANDATORY SUB-CONTRACTOR Must use Electro-Coagulation Treatment System

19 4. Remove Sediment Workers enter all ten chambers
Remove sediment (dredge? Pressure wash? Sweep?) Dirty water and sediment pass through treatment Sediment collects in tanks

20 5A. Verification Clean water is discharged
Batch testing 1 – 3 times Weekly water discharge samples Sub-contractor operations Chambers are clean and lead free Visual inspection Water samples

21 5B. Waste disposal Vendor will: SCL will: Unload tanks from barge
Transfer sediment to waste containers Dispose of other debris (trash, sani-can, misc. debris) SCL will: Test for dangerous waste Haul lead-contaminated sediment and sand filter media to proper disposal site

22 Misc. Vendor tasks Collect samples & deliver to lab
Provide crew boat to shuttle staff Provide lodging for crews Reporting to SCL and Ecology Site cleanup (non-hazardous materials) Demobilization

23 Vendor Selection

24 Mandatory Pre-bid meeting
At SKAGIT – meet at Newhalem General Store RSVP Bring Hard Hat & Lock Out Tag Out locks Read and be ready to sign SCL LOTO policy If you don’t bring LOTO locks, you will be left behind at the General Store.

25 Vendor selection Requirements Pre-qualifications Worked off barge
Attend mandatory pre-bid Skagit site visit - Will use Water Tectonics as sub - Can obtain insurance in a timely manner Pre-qualifications Worked off barge Removed underwater sediment Handled contaminated material

26 Vendor selection (cont.)
50% price 50% approach – submit 4 page document Work plan Safety Environment Experience FYI: Prevailing wages apply

27 Tunnel Cleanup Schedule
Feb Mar Apr May Jun Jul Aug Sep Oct Permits Procure-ment Submittal Tunnel Cleanup

28 Payment Pay Activity 5% Submittals and Mobilization 10%
20% 25% 40% Activity Submittals and Mobilization Water Treatment System running 5 chambers clean All chambers clean Finish, cleanup, demob Stand by Incentive for finishing early: $1,000/day

Download ppt "Ross By-Pass Tunnel Cleanup Pre-Bid Project Overview May 2014"

Similar presentations

Ads by Google