UPDATE ON THE WATERFIX TUNNELS PROJECT. Breakthroughs in Tunneling September 2018

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1 UPDATE ON THE WATERFIX TUNNELS PROJECT Breakthroughs in Tunneling September 2018

2 PRESENTATION OVERVIEW Need for WaterFix Proposed Facilities Tunnel Design Challenges Engaging Innovation Current Status 9/28/2018

3 HUB OF CALIFORNIA WATER SUPPLIES Bay Delta Region Sacramento Sacramento San Francisco Stockton Los Angeles

4 Highly altered ecosystem Highly studied area Some regions are 100% dependent on Bay-Delta supplies Critical to California population and economy Unsustainable History of policy challenges SACRAMENTO/SAN JOAQUIN BAY-DELTA CRITICAL TO CALIFORNIA Bay Area 33% State Water Project Central Coast 37% Conservation, Local Groundwater and Recycling Metropolitan 30% Bay-Delta Central Valley 23 to 90% Los Angeles Aqueduct Colorado River Aqueduct 4

5 WATER SUPPLY PATHWAY (ISLAND SUBSIDENCE BETWEEN FT. DEEP) - 30 feet Sea Level

6 Fishery Declines Delta Smelt Seismic Risk Bay Area Faults KEY DELTA RISKS Levee Subsidence Sea Level Rise 6

7 CALIFORNIA WATERFIX IS IMPORTANT FOR CALIFORNIA

8 CALIFORNIA WATERFIX OVERALL PROGRAM Intakes Sacramento North Tunnels Intermediate Forebay Main Tunnels Byron Tract Forebay & PS Stockton South Tunnels Head Old River Gate

9 GEOLOGIC FRAMEWORK Holocene to Pleistocene Age Alluvial, fluvial and sedimentary basin deposits Alignment intersects overlapping layers of different strata Deposits basically unconsolidated (i.e. soft ground) High ground water at grade surface

10 GEOTECHNICAL PROFILE AT TUNNEL DEPTH Ave. Ground Surface

11 Outlet shaft RIVER INTAKES Sedimentation Basin 1 Sediment drying lagoons Sedimentation Basin 2

12 PROTECTING FISH Screen spacing 1.75mm Flow approach velocity = 0.2 ft/sec

13 RIVER INTAKE LOCATIONS

14 MAIN TUNNELS Twin bore main tunnels 30 miles long each 150 ft below grade 2-foot thick concrete liner Pressurized face tunnel boring machine ±45-ft excavated diameter 40-ft internal diameter

15 Single pass segmental concrete liner Single or dual gasket (tbd) Bolted radial joints Doweled circumferential CONCEPTUAL TUNNEL LINING LINING SYSTEM

16 70 LARGE DIAMETER TUNNEL BORING MACHINE PROJECTS TBM Diameter (ft) Port of Miami SMART Malaysia CA WaterFix Thimble Shoals Hong Kong TMCLK East Waterview Auckland NZ Madrid M30 Wuhan Metro China Sparvo Italy Seattle SR99 Hong Kong TMCLK West

17 REVIEW OF OTHER MEGA-TUNNEL PROJECTS The Eurasia Tunnel - Turkey Lee Tunnel - London Port of Miami Tunnel Florida East Side Access - New York Blue Plains Tunnel Project - District of Columbia Bay Tunnel - San Francisco Willamette River Combined Sewer Outfall Program - Portland Gotthard Base Tunnel - Swiss Alps SR-99 Alaskan Way Replacement Seattle = projects visited by program team

18 CALIFORNIA WATERFIX TUNNEL REACHES Intakes Intermediate Forebay Staten Island Shafts Bouldin Island Shafts Bacon Island Shafts BTF

19 PROPOSED BYRON TRACT FOREBAY OPTION Main Tunnels Clifton Court Forebay BTF Pumping Plant Byron Tract Forebay South Tunnels Connection Channel

20 CLIFTON COURT FOREBAY PUMP PLANTS Electrical Substation Pump Building Maintenance Building Gravity/surge discharge Pump Discharge Pump Unit 40-foot Main Tunnel

21 EVOLUTION OF THE MEGA PROJECT 9/28/2018

22 TUNNEL DESIGN APPROACH External Ground Water Pressure + Ground Loads Ring Compression from: External Ground Water Pressure Ground Loads of Overburden Result: Normal design condition for tunnel segmental liner Compression

23 ORIGINAL HYDRAULIC GRADE LINE 2 Drop 20 ft 29 ft Shaft IF 40 ft Diameter Main Tunnel 40 ft Diameter Main Tunnel CCF-N Intake Site, Typ. 20 ft 3 5 El +60 El +19 El +10 El. 0 Intermediate Forebay El +9 Total 9,000 cfs Sacramento River Clifton Court Forebay

24 River HGL (FT) VS. TUNNEL ALIGNMENT GW at 0' MPTO Net Tension (MPTO) IF Original concept Ground Water Elev (0.0) CCF

25 BAY DELTA DESIGN CONDITION Internal Hydrostatic Pressure Tension Ring Tension from: Internal Hydrostatic Pressure (HGL) greater than External Pressure Net internal water pressures from 20 to 60 feet hydrostatic head Results: Segment Tension Potential leakage out to surrounding ground

26 LEAKAGE CONSIDERATIONS Leakage can occur at: Segment Joint Segment Body Delta Geotechnical Conditions: Soil deposits may be too weak to provide significant confinement Unconsolidated deposits vulnerable to erosion/piping Hydraulic fracturing could lead to failure South Bay Outfall Tunnel Test

27 Consider effects of soil overburden: Refine analysis based on future geotechnical data Measure in situ stress regime Evaluate the depth of cover required ALTERNATIVES TO MINIMIZE LEAKAGE Consider alternate liner improvement: Plastic lining on intrados (PVC T-Lock, Agru Sure Grip) Thin steel lining on intrados or in segment body Use post-tensioned lining Explore capabilities of spray-on membranes Study the benefits of admixtures and fibers

28 ORIGINAL TUNNEL LINER

29 TENSION REINFORCEMENT FOR INTERNAL PRESSURE (1.375 to dia.) (#9 to #11 bars) T-Lock Membrane

30 EXAMPLE OF TENSION REINFORCEMENT San Diego South Bay Tunnel Outfall Project (1995) Diameter = 11 feet Segment = 9 inches Bolt = 1-inch diameter Tested internal head up to 40 feet

31 ORIGINAL TUNNEL LINING - SUMMARY Segment design is challenging: to account for internal water pressures associated with MPTO Testing program needed: to develop lining/joint design that can control leakage Special design measures needed: to mitigate risk associated with tension Cost and schedule impacts: High-tension tunnel design may be unique to tunnel contracting industry

32 IMPROVEMENTS TO THE ORIGINAL CONCEPT

33 HYDRAULIC GRADE LINE COMPARISONS El +60 Original El +10 Sacramento River El +19 Intermediate Forebay El. 0 El +9 Clifton Court Forebay Total 9,000 cfs Current El +10 Sacramento River El +0 Intermediate Forebay El. -16 El -9 El +9 Clifton Court Forebay Total 9,000 cfs

34 CURRENT CONCEPT GENERAL CONFIGURATION 2 Drop 28 ft Shaft 40 ft IF 40 ft Diameter Main Tunnel 40 ft Diameter Main Tunnel CCO CCF-N Intake Site, Typ. 28 ft 3 5 El +10 El +9 Sacramento River El +0 El -9 Clifton Court Forebay Intermediate Forebay El. -16 Pump Wet Well Total 9,000 cfs

35 River Net Tension (CCO) IF Current Approach HGL (FT) VS. TUNNEL ALIGNMENT Original Concept 9000 cfs, 1' river 9000 cfs, 10' river GW at 0' MPTO Ground Water Elev (0.0) CCF

36 Option Sacramento River COMBINED PUMPING PLANT OPTION HGL SUMMARY 9,000 CFS) Intake (ft) IF (ft) CCF (ft) (Pump Shaft) Original * Current Normal High Low *Pumping at river intakes HGL elevations for each option (source: AECOM study, June 2014)

37 CCO - TUNNEL DESIGN SUMMARY Main Tunnels: Compression-only liner design North Tunnels: Greatly reduced net tension Compression-only segmental liner: Conventional proven tunneling techniques Increased tunneling production rates Improved (shorter) construction schedule Reduced tunneling costs Minimizes risks of delay and cost variance Typical shear cone

38 ADDITIONAL BENEFITS OF THE REVISED CONFIGURATION Eliminates pump station construction in sensitive areas Combines three separate pumping facilities into one location Provides potential for gravity flow under certain conditions Minimizes potential for leakage from tunnel to surrounding soil 9/28/2018

39 RECENT EVENTS AND PLANS GOING FORWARD 9/28/2018

40 SIGNIFICANT ACCOMPLISHMENTS IN Completed EIR process with NOD issued by DWR Secured Biological Opinion from Fish and Wildlife along with Incidental Take Permit Formally established the Design and Construction Authority (DCA) 99% of State water Contractor Boards voted to participate in program. Advertised 4 initial procurement solicitations

41 ENTITY RELATIONSHIPS Provide Oversight of DCA Delta Conveyance Office (DCO) Provide Financing for WaterFix JEPA Agreement Finance Joint Powers Authority Delta Conveyance Design and Construction Joint Powers Authority (DCA) Design and Construct WaterFix

42 DELTA CONVEYANCE DESIGN AND CONSTRUCTION AUTHORITY FIRST MEETING MAY 17

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44 WATERFIX PROGRAM SCHEDULE Commence construction 1 9/28/ contingent on receipt of applicable permits

45 TUNNEL CONSTRUCTION SCHEDULE (AWARD THRU CONTRACT CLOSEOUT PRELIMINARY) Pre-tunneling Driving TBM Post tunneling Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Intake 2 to Intake 3 IF to Intake 5 North Tunnel ( IF to Intake 3) Main Tunnels from IF to Staten Island Main Tunnels from Bouldin to Staten Island Main Tunnels from Bouldin to Bacon Island Main Tunnels from CCF to Bacon Island 45

46 9/28/2018

47 QUESTIONS

48 SHAFT DESIGN/CONSTRUCTION Shaft Size and Depth Up to 150 feet deep, plus plug 180 feet diameter pump shafts feet diameter tunneling shafts Excavation/Support Methods for Soft Soils Slurry wall construction Secant pile constriction Break-in and Break-out Provisions Large diameter TBMs Pressurized conditions Groundwater Control Potential impacts on surrounding wells 56

49 LARGE AND DEEP SHAFTS Portland s Swan Island PS Shaft 135 ft dia. x 160 ft deep Slurry walls with tremie concrete slab Lee Tunnel, London, UK 125 ft dia. x 285 ft deep Slurry walls

50 DC WATER S BLUE PLAINS PS AND SCREENING SHAFTS Figure 8 arrangement 76 ft. & 132 ft. in diameter by 180 ft deep