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

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Presentation on theme: "Ross By-Pass Tunnel Cleanup Pre-Bid Project Overview May 2014 Ross Dam Skagit River Project Location This presentation is for general info. Consult the."— Presentation transcript:

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

2 Ross Dam Diablo Boat house City Light Admin Offices

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

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

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

7 Bypass Penstock Tunnel Hollow Jet Valves By-pass penstock Diablo Lake SumpPipe saddles Typical water Level (1205) Concrete Tunnel plug Tunnel Valve house Ross Dam

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

9 Tunnel & By-pass penstocks Inside Valve House

10 Scope of work 1.Install temporary weir (vendor) or permanent weir (SCL) 2.Install rock fall fence (vendor) 3.Remove and treat 1,000,000 gallons of water from tunnel to remove suspended lead (vendor) 4.Remove 10 – 30 cy sediment (vendor) 5.Verify & Dispose sediment – could be dangerous waste (SCL)

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

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 SCL Barge Spill way Ross Dam Temp rock fence

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 Settling tank #2 Back flush tank Settling tank #1 Source tank generator pump shack Sani can Electro coagulation Not to scale Sand filter Discharge to Diablo Lake Tunnel 80T Barge 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: –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 –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 FebMarAprMayJunJulAugSepOct Permits Procure- ment Submittal Tunnel Cleanup

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


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