ross by-pass tunnel cleanup
DESCRIPTION
Ross By-Pass Tunnel Cleanup. Ross Dam. Pre-Bid Project Overview May 2014. Project Location. This presentation is for general info. Consult the RFP for details. Skagit River. Diablo Boat house. Ross Dam. City Light Admin Offices. Getting to the work site. Diablo Boathouse. - PowerPoint PPT PresentationTRANSCRIPT
Ross By-Pass TunnelCleanup
Pre-Bid
Project Overview May 2014
Ross Dam
Skagit River
Project Location
This presentation is for general info. Consult the RFP for details.
Ross Dam
Diablo Boat house
City Light Admin Offices
Diablo dam
Diablo Boathouse
Diablo Dam and boat house
Highway 20
To Ross dam
Getting to the work site
Project Location:Ross Hollow Jet Valve House
Hollow Jet Valves
Valve house
Ross Dam
Diablo Lake / Skagit River
Opening to Tunnel
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
Plan view
Hollow Jet Valves &Valve House
By-pass intakestructure Ross Lake
Diablo Lake
Tunnel and twoBy-pass penstocks
Bypass Penstock Tunnel
Hollow Jet Valves
By-pass penstock
Diablo Lake
Sump Pipe saddles
Typical water Level (1205)
Concrete Tunnel plugTunnel
Valve house Ross Dam
123468 7 510 9
Cross Section of Pipe Supports
Penstocks
Doorway
Tunnel
Concretewall
Not to scale
Tunnel & By-pass penstocks
InsideValve House
Scope of work1. 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)
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)
1. Install weirWeir• 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)
2. Rock fall Protection (vendor)
Temporary fence
3A. Mobilize
Valve House
SCL Barge
Spill way
Spill way
Ross Dam
Temp rock fence
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
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.
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
3C. Water Treatment on Barge
Settling tank #2
Back flush tank
Settling tank #1
Source tank
ge
ne
rato
r
pumpshack
Sani can
Electro coagulation
Not to scale
Sand filter
Discharge to Diablo Lake
Tunnel
80T Barge
Water Tectonics is the MANDATORY SUB-CONTRACTORMust use Electro-Coagulation Treatment System
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
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
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
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
Vendor Selection
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.
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
Vendor selection (cont.)
• 50% price
• 50% approach – submit 4 page document– Work plan– Safety – Environment– Experience
FYI: Prevailing wages apply
Tunnel Cleanup Schedule
Feb Mar Apr May Jun Jul Aug Sep Oct
Permits
Procure-ment
Submittal
Tunnel Cleanup
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