Water for the Future Program September 24, 2015

1 Catskill Aqueduct Repair & RehabilitationWater for the Future ProgramSeptember 24, 2015 Jonathan Hoffman, PE; Pereira; Water for the Future Program Catskill Repair and Rehabilitation Overview and Goals Project Components By the Numbers Design Effort Logistics Questions3 Delaware Aqueduct 85 mile tunnel; 800 million gallons per day Leaking 15-35 mgd Water for the Future Program Bypass tunnel across the Hudson River connection planned for 2022 Catskill Aqueduct Repair and Rehabilitation Conservation / Demand Management Modified operations of reservoir systemWater For the Future ProgramRondout-West Branch Tunnel (RWBT)4 Goal.

2 Provide a rehabilitation Program for the Catskill AqueductRestore Transmission Capacity Extend Useful LifeEnsure Structural IntegrityCatskill Aqueduct Repair and RehabilitationASHOKANRESERVOIRSTEEL PIPE SIPHONPRESSURE TUNNELCUT AND COVERGRADE TUNNEL5 Max month averages routinely exceeded 600 mgdChlorine addition at Ashokan: Average Dose mg/L Cl2No chlorine addition from 1975 to presentRestore Transmission CapacityCurrent Capacity: ~590 MGDH istorical Capacity: above 640 MGDP rovide maximum available flow from Catskill system during RWBT outage6 Max month averages routinely exceeded 600 mgdChlorine addition at Ashokan: Average Dose mg/L Cl2No chlorine addition from 1975 to presentRestore Transmission CapacityCurrent Capacity: ~590 MGDH istorical Capacity.

3 Above 640 MGD7 Restore Transmission CapacityBiofilm Growth = Capacity Reduction WFF modeling includes the Catskill Aqueduct at 636 MGD Remove Biofilm, Chlorinate to MaintainOST MODELBIOFILM REMOVALBIOFILM8 Repair, replace, or seal aging mechanical equipment Culvert Drain Valves Siphon Drain Valves Large Diameter Blow-off Valves Install additional air ventsExtend Useful LifeLADDERSLUICE GATEC ontinue to provide Clean, Safe, Reliable Water long after the RWBT is Repair, replace, or seal aging mechanical equipment Culvert Drain Valves Siphon Drain Valves Large Diameter Blow-off Valves Install additional air ventsExtend Useful LifeLADDERSLUICE GATEAIR VENTS10 Ensure Structural Integrity Perform full internal inspection, except pressure tunnels Identify and correct structural deficiencies, crack/leak repair Perform internal laser scanning and stationingDuring the RWBT outage.

4 The Catskill Aqueduct will provide over 50% of NYC demand every day11 Ensure Structural Integrity Perform full internal inspection, except pressure tunnels Identify and correct structural deficiencies, crack/leak repair Perform internal laser scanning and stationing12 CAT-RR: By the Numbers Spread Out! 70 miles between #1 and #33 Average Spacing: Just over 2 miles Difficult Access: 36 x 36 hatch opening33 Culvert Drain Sluice Gates Low Points at 10 Siphon Pipes, 3 valves per siphon location Difficult Access: 36 x 36 hatch opening Valve location has about 24 of working space36 Siphon Drain Blow-Off Valves13 CAT-RR: By the Numbers Removal locations must be accessible Typically at Pressure Tunnel or Siphon starts59 Miles of Biofilm Removal Average Spacing.

5 1/2 mile apart Sizes range from 3-ft x 3-ft to 7-ft x 12-ft106 Possible Access Locations14 CAT-RR: By the Numbers 5 Counties Many permits and a lot of communication required20 Towns / Villages passed through Need backup to withstand extended some do not currently Upstate Community Taps15 Design Effort: Where to Start??Site Visits Initially drove about 50 miles of Aqueduct over 2 weeks Split: West of Hudson and East of Hudson Over 2 years, upwards of 100 site visit days, probably more!16 Design EffortInternal Inspections Performed multiple days of internal inspections Moving inspections Safe Work Plans Rescue Teams17 Moving Right Conditions MemoGeotechnical MemoInspection MemosHazardous Materials MemoFacility Planning Alternatives MemoBasis of Design Report30% Specifications.

6 DrawingsOperational Impacts MemoInspection Implementation MemoShutdown Procedures MemoUpstate Community Tap SequencingUnwatering MemoSteel Pipe Siphon Effort I think you need to be completewith the design by the 60% submittal. HUH?!?!?! Design is easy. Logisticsare what makes this project difficult. 19 Logistics Health and Safety Most work is Permit Required Confined Space Rescue Teams Remote locations + Bad Weather = Risk Control of Entrants Access and Egress Temperature effects on equipment20 Logistics Site Access Access over 14-ft wide berm Remote access roads Roads not design for heavy loads21 Logistics Shutdowns / Sequencing Defined shutdown windows October through April Planning on 10 week shutdown Maintain Upstate Community taps to full extent?

7 Prepare for Bailout22 Logistics Biofilm Removal Milesbetween large Access Points Handling dry biofilm versus wet biofilm How Clean is Clean ?23 Plan for the Logistics Problems Risks 85 Identified Risks 61 are RED Assess Mitigation Strategies and implement Planned on-site working meetings Starting discussions with Towns CM on-board already! All Hands on Deck24 Questions?Jonathan Hoffman, PE; Pereira.